Abstract
Natural cellulosic fibres, such as kenaf, have potential for use as replacement of man-made fibres in polymeric composites. The rapid depletion of synthetic resources, such as petroleum, and the growing consciousness of global environmental problems related to synthetic products push toward the acceptance of natural fibres as biocomposite components. Kenaf (Hibiscus cannabinus L.) is a multipurpose hibiscus species used to make engineered wood, clothing, packing material, rope and twine. Kenaf is essentially made up of cellulose (about 70%), predicting its excellent mechanical performance. Kenaf fibres are chemically treated before mixing with other polymer resins to enhance their fibre properties. Based on the previous literature, the effect of chemical treatment on the dynamic mechanical performance of kenaf cellulosic biocomposites remains unexplored. The present review focuses on the recent works on the influence of major chemical treatments used on kenaf fibre, such as alkaline, silane and acetylation on fabricated biocomposites. The present review also unveils other chemical treatments (e.g. zein and amino acid) and combined treatments on the fibre to improve the biocomposites’ dynamic mechanical behaviour.
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
Introduction
Environmental pollution and destruction have become global issues. As such, most governments in the world are working on green technology for sustainable development and optimising the ecosystem and commercial benefits (Razman et al. 2011; Golar et al. 2019; Ali et al. 2020). Coir, hemp, jute, flax, sugar palm, kenaf and sisal are natural fibres used as natural resources. The growing popularity and the market demand towards natural fibre in the current scenario are due to their advantages of low price, lightweight and versatile application (Jaafar et al. 2018; Ilyas et al. 2020b, d). Furthermore, the resources from a myriad of natural fibres are widely available, and the energy consumption is low (Sanyang et al. 2016; Zainuddin et al. 2019). Considering that global natural resources, such as fossil fuel, are decreasing in number, the global community is focusing on substituting natural fibres as reinforcing or filler material in composite fabrication (Omran et al. 2021; Ilyas et al. 2021). Natural fibre is gaining interest and utilised in various fields due to its low price, good biodegradability, wide availability and low density (Ilyas et al. 2020c). As such, natural fibre is becoming the new substituent for conventional fibre, including glass, carbon and aramid (Mansor et al. 2015; Mastura et al. 2017). Moreover, the dependency on non-renewable resources can be reduced in the composite fabrication, and the use of natural fibre in polymeric composites through the efficient reuse of plant by-product can overcome the high price of composite products (Johari et al. 2020a, b; Asyraf et al. 2020f).
Kenaf is a widely grown industrial and commodity crop in Malaysia. The crop is classified as a substitute for common plant fibres, such as sugar palm and pineapple leaf (PALF) fibres, because of short harvestable time and various traditional applications as a multipurpose crop, including livestock, food and other fibre advantages (Saba et al. 2015b). Kenaf grows to a height of 4 to 5 m at only around 5 to 6 months, indicating a rapid growth maturation (Rashdi et al. 2009), high abundance of resources and fast cultivation of the crop for industrial-scale production. Kenaf is regarded as a renewable material, and its fibre is sustainable and biodegradable (Joseph et al. 1996; John and Thomas 2008). In this case, kenaf rapidly consumes carbon dioxide at around 1.4 times its own weight and has a high rate of photosynthesis, which is triple than that of common plants (Serizawa et al. 2006). This cellulosic fibre also has low density (1.3 g cm−3). As such, kenaf is widely applied in various thermoplastic and thermoset composites to substitute current man-made fibres (Wambua et al. 2003; Bajuri et al. 2016). The kenaf fibre can reinforce any polymeric matrix via numerous methods, including pultrusion, hand lay-up, hot compression and filament winding (Eichhorn et al. 2001; Siqueira et al. 2010; Saba et al. 2015a). Therefore, in view of its versatility and advantages, the kenaf fibre may be an alternative to petroleum-based fibre and has attracted the interest of researchers, community and manufacturers.
Kenaf fibre composites are popular due to their manufacturability, cheap cost, sufficient energy requirements, abundance, renewability and safety (Davoodi et al. 2010) but have some drawbacks in terms of their physicomechanical and thermal performances. The main downside observed with the inclusion of kenaf fibre in polymeric resin is the lack of surface adhesion between two phases (Bajuri et al. 2016; Asyraf et al. 2020b), which results in the low properties of the final biocomposite laminate. According to Jaafar et al. (2018), the poor interfacial adhesion is due to the occurrence of impurities on the fibre surface morphology, thereby causing a rough topology, as shown in the red circle in Fig. 1. These impurities are made up of lignin, hemicellulose and pectin, which cause the poor compatibility of the fibre with the polymer matrix. Krishna and Kanny (2016) have mentioned that these impurities are made from hydroxyl groups that allow the kenaf fibre to have hydrophilic properties. Considering that most polymer resins, such as polyester (PE) and epoxy, are hydrophobic, the formation of good chemical bonding between kenaf fibres and their polymer is inhibited. Moreover, the inclusion of kenaf fibre in the matrix is frequently associated with agglomeration, which is attributed to insufficient dispersion because fibres tend to form covalent bonds (Liu et al. 2004a; Akil et al. 2011).
Fibre surface topology of untreated kenaf fibre observed using SEM (Jaafar et al. 2018). Creative Common CC BY license
These demerits, including the poor interfacial bonding and exhibition of the hydrophilic property of kenaf cellulosic fibre, can be avoided through various chemical treatments that alter the compatibility between the kenaf fibre and their matrix. These chemical treatments form fully cured and crosslinked kenaf cellulosic fibre that reinforces the polymeric matrix to attain improved mechanical strength (Jaafar et al. 2018) and thermal stability (Asim et al. 2018). A successful crosslinking between kenaf fibre and its matrix may occur when the hydroxyl group components, such as pectin, lignin and hemicellulose, are effectively washed from the fibre (Aziz and Ansell 2004). This phenomenon forms a strong chemical bonding between two phases’ interfaces and a good network and can increase the applications of kenaf fibre, such as marine and automobile sectors, because the process increases the resistance to creep, wear and tear (Asyraf et al. 2019a, 2020a, c, d, e). The enhancement in these properties can improve the service life of the material especially when exposed to extreme conditions, such as elevated temperature, high humidity and acidic environment (Asyraf et al. 2019b, 2020b).
Thus, from the literature, the kenaf fibre is useful for modern industrial applications, such as flooring (Saba et al. 2015b), household products (Mazani et al. 2019) and automobile interior components (Mansor et al. 2014) due to its versatility and numerous advantages. However, some issues have become critical problems that hinder reaching its full potential due to their interfacial adhesion and hydrophilic behaviour. Several research scientists have proposed to modify the fibre topology and component via chemical treatments to grasp their research purposes. Thus, this article provides a state-of-the-art review on the influence of chemical modifications on the dynamic mechanical performance of kenaf biocomposites in various applications. Additionally, this review can be used as a guide to gather information on fibre treatments (e.g. alkali, silane and acetylation treatments) to extend the quality of the dynamic mechanical properties of kenaf biocomposites.
Kenaf fibre and its biocomposites
In general, kenaf has originated from West Africa, but around 75% of kenaf is produced by India and China (Bajuri et al. 2017). As such, the kenaf plant is one of the vital bast fibre resources for these nations. More than 40% of the stalks acquired from kenaf have higher versatility than those from other plants and are useful in many applications (White and Higgins 1964). As such, kenaf is more economical compared with other plants.
The kenaf fibre can be obtained from its bark (Fig. 2) and is lightweight, biodegradable and has good mechanical performance (Tawakkal et al. 2012). However, Nishino et al. (2003) have specified that the shape, size and strength of fibres vary depending on their cultivation condition. The physicomechanical properties of kenaf fibre and other natural fibres are shown in Table 1. Figure 3 shows that kenaf fibres are used in their nonwoven mat form and as woven fabric in textiles, fibreboard, civil, automotive and electronic industries. Moreover, the fibre is frequently implemented as reinforcement in various thermoplastic and thermoset plastics, including epoxy, PE and vinyl ester. In addition, around 15 MJ of energy is required to produce 1 kg kenaf fibre, whereas 54 MJ is needed to produce 1 kg glass fibre in terms of energy consumption (Akil et al. 2011). This remarkable findings shows the low energy in the kenaf fibre production, which subsequently reduces production cost. Hence, the kenaf fibre shows some promising characteristics that can benefit the ecological system and manufacturing industries towards the use of green technology.
Ripened kenaf plant (Karthikeyan and Kumar 2016). Creative Common CC BY license
Issues regarding kenaf cellulosic fibre biocomposite
The kenaf fibre consists of various plant components, which provide a rigid, strong and biodegradable fibre. However, several major defects are observed in terms of cellulosic fibre compatibility with polymeric resin to form a good composite laminate. This phenomenon is due to the influence of the high moisture uptake of kenaf fibre that creates a low-quality composite (Joseph et al. 1996, 2002). The high intake of water within the fibre is because of the hydrophilic behaviour induced from the chemical components of the plant fibre (Sreekala et al. 2000; Sreekala and Thomas 2003). In addition, wood fibres, such as kenaf, are composed of highly concentrated hydroxyl group components, which contribute to the properties of the hydrophilic fibre (Makarona et al. 2017; Yallappa et al. 2017; Deeraj et al. 2020). Therefore, a weak fibre–matrix bonding is due to the strong polar and hydrophilic properties of fibre and the polarity and hydrophobicity of polymer materials (John and Anandjiwala 2008; John et al. 2008; Zainuddin et al. 2017). Hence, the low fibre–matrix bonding causes a low ability of the stress transfer of fibre–matrix, which induces changes in the dimensions of the composite and propagates to the microcracks because of the low interlocking effect between two distinct phases of the composite (Paul et al. 2007, 2010; Farahani et al. 2012). The chemical modification of cellulosic fibre contributes to the improvement of the overall material properties, including mechanical, physical, chemical and electrical performances (Pottathara et al. 2016, 2018, 2019).
As a solution, chemical modifications, such as fibre treatments, are introduced to enhance the overall performances of the kenaf fibre as composite and bridge the gap of compatibility amongst hydrophilic fibre and hydrophobic resin features (Liu et al. 2019). Fibre treatments, such as acetylation, silane treatment and alkalisation, eliminate hemicellulose, wax, lignin and oil (Gopakumar et al. 2018; Saba et al. 2019) and reduce the fibre diameter (Bledzki and Gassan 1999), thereby assisting in the adhesion bonding strength between lignocellulosic fillers and resins.
Chemical treatments on the kenaf cellulosic fibre
The modification of kenaf fibres is commonly conducted using chemical reagents or substances. These substances allow the activation or the removal of certain components inside the kenaf fibre to bond the hydroxyl group and the resin inside the composite. Some types of chemical treatments have been stated in the previous literature. A common structure for untreated fibre conditions seems to be a pool of cementing material–hydroxyl group components. A common untreated cellulosic fibre is exposed to these cementing materials, including hemicellulose, lignin, wax and oils (Zhu et al. 2013), as shown in Fig. 4a. The chemically modified fibre has a clean and rough structure because the partial cement structure components are broken and washed away (Guduri et al. 2009), as displayed in Fig. 4b.
Alkalinisation
Alkalinisation or alkali treatment is a chemical treatment that utilises different concentrations of sodium hydroxide and removes the impurities on the fibre to increase the compatibility during reinforcement inside and thermoplastics (Alemdar and Sain 2008; Bachtiar et al. 2011). Generally, the process involves immersing the untreated fibre into the sodium hydroxide solution (Ray et al. 2001; Hassan et al. 2003; Ndazi et al. 2007). The advantage of this chemical treatment is the interruption of the hydrogen bonding in the chemical structure, thereby creating a rough fibre surface. Han et al. (2007) have proven this finding and shown a decline in the absorption peak intensity at the 1640 cm−1 band (red circle in Fig. 5), which is due to the removal of OH bending in the absorbed water molecules by alkali treatment. Mat Taib et al. (2016) have used X-ray photoelectron spectroscopy (XPS) and established shown an alkali-treated kenaf oxygen–carbon ratio of 0.59, which is higher than that of untreated kenaf fibre (0.37) and displays increased in the quantity of oxygen relative to carbon. This phenomenon occurs due to the increase in the proportion of carbon element, which may be attributed to the presence of carbohydrates on the fibre surface. Moreover, this observation has established that some polar groups are present on the surface of fibre after alkali treatment due to partial removal of the surface lignin. The removal of lignin and other materials (which make up the noncellulosic layer) from the fibre surface has exposed the underlying cellulose, which has high hydroxyl group content. Mohd Radzuan et al. (2020) reveal that the contact angle of the untreated kenaf/polypropylene (PP) composite (92°) is slightly higher than that of the treated composite (83.1°), as shown in Fig. 6. These attributes explain that the decreased wettability and hydrophilicity of the treated kenaf composite (Product T), which subsequently improves the overall mechanical property. Hence, the modification of the kenaf fibre via alkali treatment is a highly significant technique to enhance the fibre–matrix compatibility (Fig. 7).
FTIR spectra of alkali-treated kenaf fibres
Contact angles of a modified and b unmodified kenaf biocomposite
Raw and 5 wt % of alkali-treated kenaf fibre breakages from the polypropylene matrix (Han et al. 2007)
The sodium hydroxide solution aids in removing plant cellular components, such as hemicellulose, wax, lignin and oils, which inhibit the reinforcement of the polymeric resin by the fibre. Alkaline treatment fibrillates fibre bundles into small fibres, as shown in Fig. 8 (Liu et al. 2004b). The modification shortens the diameter of fibre and increases the aspect ratio and influences the crystalline properties to convert from cellulose I into cellulose II.
Formation of small fibres from alkali treatment
Equation (1) displays the alkali treatment reaction of cellulose-based fibres with sodium hydroxide solution (Rashdi et al. 2009):
Silane treatment
The silane treatment is a well-known fibre surface modification method used to boost the fibre–matrix compatibility in a composite. Silane, a coupling agent, is usually applied to stabilise the composite material. The chemical treatment is useful in reducing the amount of cellulose of hydroxyl groups, which subsequently escalate the fibre–matrix compatibility. When moisture is present, the hydrolysable alkoxyl group leads to the formation of chemical compounds, namely, silanols. The silanol reacts with the hydroxyl group in the fibre to covalently bond to the cell wall. Hence, hydrocarbon chains are confined from the swelling of the fibre, making an intertwined network from the diffusion of hydrocarbon chain with resin (Dhakal et al. 2007; Seki 2009). Cho et al. (2009) have supported the above statement and found that the Fourier Transform Infrared (FTIR) spectra (Fig. 9) in the upper band has established that the silane treatment forms the asymmetric stretching of either Si–O–C or Si–O–Si band on the kenaf surface in the peak around 1050 cm−1. Furthermore, the Si–C symmetric stretching bands can be found at 765 cm−1 (Herrera-Franco and Valadez-González 2005). Jacob et al. (2005) have shown the 29Si NMR through the presence of a signal at − 56.8 ppm chemical shift. This phenomenon can provide a justification that the fibre modification via the silane coupling agent establishes the connectivity of hydroxyl groups on natural fibre with silane reagent. This reputable finding admits that this coupling agent can increase the mechanical interlocking, which causes the condensation between silane and kenaf fibre surface.
FTIR spectra of pure and silane-treated kenaf fibres
The silane treatment, which causes the restructuring of the hydrocarbon chain, can affect the wettability of fibre. Hence, this treatment improves the chemical affinity of the matrix and is helpful in enhancing the tensile strength by reducing the effect of moisture to material properties, subsequently increasing adhesion (George et al. 2001; Huda et al. 2008). This argument is supported by Cho et al. (2009), who have reported the close interfacial contact of 0.5 wt. % silane-treated kenaf with its matrix (Fig. 10). Additionally, the pullout length of the treated fibre is comparatively shorter than that of the untreated fibre. Furthermore, Paul et al. (2008) and Pothan et al. (2000) have performed the solvatochromism analysis and discovered that the hydrogen bond-donating ability (α) of fibrils chemically treated with silane is lower than that of untreated fibrils, offering increased surface area due to the dissolution of hemicellulose and lignin and contributing to improved fibre–matrix interlocking. Overall, these findings from the previous literature indicate that the strongest fibre–matrix adhesion improves the stiffness and the strength of the biocomposite via the silane treatment.
SEM surface of kenaf/unsaturated polyester at a 0.0 wt. % and b 0.5 wt. % silane
The chemical reaction formula can be deduced from the silane reaction:
Acetylation
Apart from alkaline and silane treatments, acetylation is another famous treatment used by many researchers (Melo et al. 2012; Alsagayar et al. 2015). The process is a well-known chemical modification of esterification, which presents the plasticisation of cellulosic fibre. Chung et al. (2018) have supported this claim, and Fig. 11 displays that the peak (red circle) located at 1740 cm−1 is ascribed to the carbonyl stretching bond C=O within the ester bond. The chemical reaction takes place on the cell wall of the hydroxyl groups for lignocellulosic materials by using acetic compound at high temperatures (Dhakal et al. 2007). Chung et al. (2018) have confirmed both arguments by using FTIR analysis (Fig. 11) and found that two peaks at 1369 and 1222 cm−1 (blue circle) are attributed to the C–O and C–CH3 stretching bends, respectively, of acetyl group (Sun and Sun 2002), confirming the acetylation of kenaf. Zafeiropoulos et al. (2003) have found that the acetyl ester bonds are formed on the surface of acetylated flax fibres even though the coverage is heterogeneous based on the XPS and ToR–SIMS approaches. This finding shows a reduction in the amount of hydroxyl groups available for binding with water molecule. Thus, the sufficient acetylation remarkably reduces the amount of hydroxyl to improve the fibre–matrix compatibility. Overall, improvements can be attained using this chemical treatment by using acetic acid to break down the hydrogen bonding, which holds the whole chemical structure together. Subsequently, the surface roughness increases to activate the contact surface of the fibre–matrix (Wibowo et al. 2004; Ifuku et al. 2010) The acetylated kenaf fibre is cleaned from hydroxyl component impurities, which inhibit the interfacial adhesion of the fibre/matrix (Fig. 12).
FTIR spectra for untreated and acetylated kenaf cellulosic fibre with four consecutive times of immersion: 0.5, 1, 2 and 3 h (Chung et al. 2018). Creative Common CC BY license
Structural illustration of untreated and acetylated kenaf fibre in SEM micrographs (Chung et al. 2018). Creative Common CC BY license
The reaction order can be found in Eq. (3).
Other chemical treatments
Another chemical modification technique conducted by researchers to improve the interfacial surface of kenaf fibre is through the grafting technique via the polymethyl methacrylate (PMMA) and bleaching. The process aids in lowering the amount of the hydroxyl group in the kenaf fibre, which contributes to the improvement of the crosslinking with polymer resin and encourages the fibre to have a hydrophobic interface because the functional groups of PMMA alter the polar hydroxyl group to form covalent bonds. The functional groups of PMMA include isocyanates [–N=C=O], maleic anhydride (A–[CO]2–O–) and dichlorotriazine (–Cl–), forming chemical bonds to establish the stability of the composite (Bakar et al. 2015). According Bakar et al. (2015), a new sharp peak around 1724 cm−1 due to an ester group is observed (Fig. 13). This phenomenon can be because the kenaf fibre grafted by the methyl methacrylate by forming a covalent linkage subsequently enhances the compatibility between the kenaf and the PVC/EVA.
FTIR spectra of kenaf fibre reinforced in PVC/EVA matrix composites
The bleaching treatment requires the application of hydrogen peroxide as bleaching agent to eliminate the remaining lignin components from the fibre (Jonoobi et al. 2009). For instance, Sarkawi and Eichhorn (2010) have conducted a study on the bleached kenaf fibre composite by using Raman spectrometry to evaluate the micromechanics deformation behaviours of kenaf/epoxy composite and found that the Raman peak position (1095 cm−1) linearly decreases as the strain and stress increase and reverts to its original position after the fibre is deformed. This finding illustrates that the stress is transferred evenly from fibre to matrix due to improved interfacial adhesion from bleaching.
Thermal characterisation techniques
Material characterisation is one of the main parameters in understanding the properties of plant-based fibre in various conditions. Generally, material characterisation, including tensile, compression and flexural modes, is involved in mechanical testing with respect to an international standard, i.e. American Society for Testing and Materials (ASTM) standards.
The dynamic mechanical analysis (DMA) is a vital laboratory method especially for foods, pharmaceuticals, organic and inorganic chemicals, polymers and biocomposites. The DMA is crucial in examining weight loss, stiffness and strength, dimensional changes and heat flow in terms of temperature (Pothan et al. 2003). The analysis also portrays the behaviours of materials, such as crystallisation, molecular structure, decomposition, viscoelastic property, oxidation, stability, mobility, glass transition temperature (Tg), volatilisation, crosslinking, tensile properties and composition. In general, various thermal analysis approaches and methods, such as DMA, differential scanning calorimetry (DSC), differential thermal analysis, thermogravimetric analysis, thermomechanical analysis (TMA) and pyrolysis combustion flow calorimetry, are available. Thermal analysis methods are summarised in Table 2.
Dynamic mechanical analysis
The rise of modern DMA approaches carries a renaissance in the last few decades of thermal analytical techniques. The DMA is implemented for quality control applications and to compare material performance. Interestingly, the DMA is still one of the most essential tools for material engineering and characterisation fields because these tools effectively sense any possible dimensional change even at the nano level for any solid at specific loads (Gaisford et al. 2002). This test is usually conducted in various conditions depending on the purpose. The common standards applied to evaluate the dynamic mechanical behaviours of polymeric composites as a function of temperature are ASTM D4065, ASTM D4440 and ASTM D5279 (Dynamic Mechanical Analysis 2020). Typically, the DMA is conducted to assess differences in stiffness, damping and Tg of the polymeric composites during curing (Anuar and Zuraida 2011).
The DMA exhibits the outcomes on storage modulus (E′), which is related to the Young’s modulus of the composite. The storage modulus or E′ is exploited by material researchers to identify the stiffness of the composite. In general, the E′ describes the ability of a material/composite to store energy for the upcoming application (Majhi et al. 2010). A viscous response of a material/composite is referred to as loss modulus (E″) or dynamic loss modulus (Jawaid et al. 2013; Ilyas et al. 2020a). E″ establishes the output data on the tendency of material/composites to release the applied energy and is frequently linked with the term internal friction. E″ is sensitive to distinct types of relaxation processes, morphology, transitions, molecular motions and other heterogeneities of the material structure. The DMA aids material engineers and researchers to estimate the amount of polymer chains immobilised by the filler surface in accordance with that reported by Joy et al. (2017). Equations (4) and (5) exhibit the general equations used to attain E′ and E″.
The mechanical damping factor (tan δ) can be acquired from the ratio of E′ and E″ (Eq. 6). Figure 14 demonstrates the correlation amongst E′, E and tan δ in terms of trigonometry view. The resultant component from Fig. 14 is denoted as E* and called as shear modulus (complex modulus). In the analysis, high tan δ values usually indicate that the material/composite is a nonelastic strain component, whereas low tan δ values display high elasticity. A reduction in the tan δ of the composite is due to good fibre–matrix compatibility because the mobility of molecular chains between phase interfaces decreases. The molecular movement and the viscoelasticity influence mechanical damping factor, tan δ. Other minor defects, including dislocations, phase, grain boundaries and various interfaces, affect tan δ (Zhang et al. 2012). Figure 15 shows the example of dynamic mechanical properties (E′, E and tan δ) in a graph.
Relationship of storage and loss moduli and mechanical damping factor
Example of dynamic mechanical analysis results
Glass transition temperature
Typically, the Tg is an essential physical behaviour for composite materials especially thermoset polymer composites. The Tg can be used to indicate changes in mechanical behaviour or beginning of phase changes. The Tg identification is applied in DMA to compute the temperature region of the matrix from the glassy state (hard material) to the rubbery state (soft and pliable material) (Kosbar and Wenzel 2017), as shown in Fig. 16.
Phase transition of polymeric materials
Overall, the Tg can indicate the state of a material. A low Tg denotes a glassy (brittle) state, whereas a high Tg denotes a rubbery (elastic) state. The glassy region is noticeably high in interlocking bonds, stiffness and region-restricted molecular movement. The rubbery region manifests the mobility of molecular chains when exposed to elevated temperature (Mahdi and Tan 2016). However, several polymers have applications above the specific Tg, and other polymers are useful below the Tg. For instance, rubber elastomers, such as polyisoprene and polyisobutylene, are applied and used due to their flexibility and softness in the rubbery state. Hard plastics (i.e. polystyrene and PMMA) are used in their glassy states (below their Tg, which is approximately at 100 °C above room temperature. A recent study has shown that Tg is notably different from the melting temperature (Tm). At Tm, the sample begins to melt, whereas at Tg, the sample becomes soft (Saba et al. 2016). The Tg can be examined using other thermal analysis methods, including DSC and TMA. Figure 17 illustrates the comparative identification of Tg from DMA, TMA and DSC.
Comparison of Tg obtained from DMA, TMA and DSC
Thermoset composites are present as either highly viscous liquid or ductile solid at temperatures above the Tg and as hard and brittle materials at temperatures below the Tg. Amongst various thermosets, the epoxy is the most crucial thermosets and highly crosslinked in the cured state. In this case, the epoxy polymer does not melt and demonstrates small softening at high temperature. Researchers have conducted analysis on epoxy and illustrated that the epoxy polymer can be implemented explicitly depending on the requirement applications either at below or above their Tg (Saba et al. 2016).
Previous literature on the effect of chemical treatments on the dynamic mechanical behaviour of biocomposites
Recently, several studies have reported the effect of kenaf fibre surface modifications on the dynamic mechanical properties of kenaf cellulosic fibre biocomposites. Some DMA experiments and results on modified kenaf fibre biocomposites are presented in Table 3.
Alkali treatment
Han et al. (2007) have utilised low concentrations of sodium hydroxide (2 wt. %, 5 wt. % and 10 wt. %) on kenaf fibre/PP composites and discovered that the E′ values of 25 wt.% and 5 wt.% alkali-treated biocomposites have improved by 15% and 25%, respectively, compared with those of the untreated biocomposite (4.8 GPa) at − 30 °C. The optimum value of tan δ height is located at the composite treated with 5 wt. % sodium hydroxide solution.
Aziz and Ansell (2004) have treated the kenaf bast fibre with 6% sodium hydroxide for 48 hand assessed the relationship of static and dynamic mechanical performances of the hybrid kenaf/hemp fibre-reinforced PE composites via alkalisation and fibre alignment. Results show that the alkalised and long fibre composites have high E′ and low tan δ values, which correspond to high flexural performance. A chemically modified and long fibre in the composite permits improved strength because the fibre orientation is well organised and has good fibre–matrix adhesion bonding. Subsequently, these factors aid in localised stress in a bending condition.
Fiore et al. (2015) have treated the kenaf fibre with 6% sodium hydroxide for 48 and 144 h. Best E′ and tan δ of kenaf/epoxy composites are achieved when the unidirectional kenaf fibre is treated at 48 h. Additionally, the trends in the dynamic mechanical behaviours of the composites are not influenced by the fibre stacking arrangement.
Silane treatment
Asim et al. (2018) have studied the effect of the silane treatment on kenaf and PALF fibres to improve the performances of hybrid kenaf/PALF in phenolic-reinforced composites. Both fibres are dipped into 2% silane solution for 3 h. A notable improvement is observed in the dynamic mechanical behaviours of hybrid phenolic composite at treated fibres at 7:3 of PALF and kenaf fibre, showing the highest E′ and E″. This finding is clearly due to the PALF that provides increased stiffness and enhanced interfacial adhesion of fibre–matrix after treating both fibres with silane.
Cho et al. (2009) have stressed that the chopped kenaf fibre is treated with three distinct silane treatments, i.e. 3-glycidoxypropyltrimethoxy silane (GPS), 3-aminopropyltriethoxy silane (APS) and 3-methacryloxypropyltrimethoxy silane at 0.5 wt. %, 1.0 wt. % and 3.0 wt. %, respectively. The composite laminate is made up of thermosetting (PP) and thermoplastic (unsaturated PE [UPE]). Cho et al. (2009) have exposed that the silane treatment by using 0.5 wt. % GPS for 2 h of immersion increases E’ value of the kenaf/PP and kenaf/UPE composites.
Lee et al. (2009) have studied the influence of GPS (1, 3 and 5 pph) on the dynamic mechanical performance of the long bast kenaf fibre–PLA composite by using the carding process. Lee et al. (2009) have indicated that 3 pph GPS-treated kenaf biocomposites with 1:1 kenaf to PLA ratio formulation are observed with optimal E′ results. The silane treatment by using GPS as a coupling agent can enhance the viscoelastic properties in the kenaf/PLA green composite.
According to Sis et al. (2013), the E′ of kenaf/PLA/PBAT/composites tremendously increases when the kenaf fibre is modified using 2 wt. % (3-aminopropyl)trimethoxysilane (APTMS). Thus, 2 wt. % APTMS is used to treat the fibre by washing out the hydroxyl components and improve the compatibility of hydrophilic fibre with hydrophobic resins. Subsequently, the tan δ values of treated kenaf/PLA/PBAT biocomposites decrease. This result is attributed to the limited molecular flexibility of the polymer chain because of the vicinity of the fibre surface caused by chemical bridging at their interfacial interaction (Ibrahim et al. 2010; Kumar et al. 2010).
Acetylation
Datta and Kopczyńska (2015) have implied that the greatest of E′ values kenaf fibre-based polyurethane composites are exhibited by samples with short kenaf fibre subjected to acetylation (1385 MPa) followed by those subjected to permanganate treatment (1046 MPa). Moreover, the Tg values of both treated kenaf composites are lower than those of pure kenaf composites because the treated composite has improved capability for irreversible viscoelastic dissipation of mechanical energy (Prisacariu 2011).
Chung et al. (2018) have studied the effect of time of immersion (0.5, 1, 2 and 3 h) into 28.5 vol. % acetic acid on the behaviours of kenaf/PLA biocomposites. Results display a detrimental improvement in the storage modulus (E′) at 2 and 3 h of immersion into acetic acid, which strengthens the kenaf/PLA composites. This observation is due to the improved bonding strength because the hydrophilic characteristics of the kenaf fibre are altered. The tan δ of biocomposite containing kenaf significantly improves for 2 h and longer because the low mobility of the polymer chain improves the interfacial adhesion.
Combined alkaline–silane treatment
Huda et al. (2008) have reported that alkali- and silane-treated kenaf fibre composites with 50 vol. % fibre offer a 161% increase in E′ compared with other kenaf/PLA composites due to the 3-APS pretreatment, which hydrolyses the OH group of the kenaf fibre by their ethoxy group to form silanol, thereby allowing the fibre to form stable covalent bonds to the cell wall (Dupraz et al. 1996). Subsequently, this treatment enhances the degree of crosslinking in the interfacial region of fibre–matrix and offers a suitable bonding result along with the creation of high-fibre surface area (Herrera-Franco et al. 1997; Singh et al. 1998). The application of sodium hydroxide solution also aids in the fibre compatibility with the matrix by removing the lignin, which contributes to the change in hydrogen bonding profiles to lower the tan δ of the individual composite.
Mokhothu et al. (2011) have investigated the behaviours of a biodegradable aliphatic–aromatic copolyester (CP) mixed with kenaf fibre. This study focuses on the influence of silane concentration (3%, 6% and 9%) in combined alkali–silane on the thermal and the dynamic mechanical behaviour of CP–kenaf composites. Results show all silane-treated composites show an almost similar E′ with their modulus value between the untreated kenaf and the single treatment of alkali. Outcomes depict that the silane–alkali-treated composites show two relaxation peaks, whereas the neat CP polymer and the kenaf composite subjected to single-alkali treatment have only one relaxation peak because the combination of alkali and silane treatments results in a semicrystalline composite.
Other chemical treatments
Grafting
Bakar et al. (2015) has concluded the highest E″ values of PVA/EVA polymer with the occurrence of grafted kenaf fibre at 30% loading. The Tg of PVC for the composite comprising grafted kenaf–PMMA composite has shifted to a higher temperature compared with that for the composite comprising ungrafted kenaf fibre. Moreover, the damping peak of grafted kenaf composites shows a slightly declined tan δ compared with that of the PVC/EVA blend and the ungrafted kenaf composites due to improved interfacial locking between kenaf and PVA/EVA upon grafting.
Amino acid treatment
Krishna and Kanny (2016) have modified the surface of kenaf/epoxy composites by using amino acid treatments, such as glutamic acid and lysine as reagent, for 24 h at room temperature. From their results, the E′ value in lysine treatment (2937 MPa) is found higher followed by that in glutamic acid treatment (2791 MPa) in comparison with neat resin at the temperature in the plastic region. Additionally, the presence of amino acid-treated kenaf fibres has dramatically reduced the tan δ value. These observations are noticeable due to the good effect or performance of the amino acid especially lysine on the fibre–matrix compatibility, enhancing the stress transfer and improving the fibre–matrix interfacial adhesion.
Zein treatment
John et al. (2010) have researched nonwoven kenaf/PP composites with fibre immersed in 2% zein solution for 2 h. In their study, the zein solution is obtained from corn gluten meal via the wet milling process. Results show that the dynamic mechanical behaviours especially E′ have increased in treated 30% kenaf composite. Moreover, the magnitude of the damping parameter in this experiment seems to have declined when the composite is chemically modified.
Conclusion
The kenaf fibre is one of the suitable or potential alternatives to conventional-based fibres in the development of composite material. The kenaf fibre has numerous advantages, e.g. energy saving and low cost of raw material and production in comparison with the current man-made fibre especially in their manufacturing. Kenaf is also a low-density fibre, which contributes in low-weight composite laminate. The surface modification of fibre is introduced in the fabrication of composite laminate to improve their material performance especially their dynamic mechanical properties. Common chemical modifications include alkalisation, acetylation and silane treatments. Several other treatments, such as grafting, immersion in zein solution, immersion in amino acid solution and combined treatments, have also been conducted on the kenaf fibre. Amongst the various chemical treatments, alkalisation appears to be the most efficient and cost-effective technique to improve the dynamic mechanical performance and the stiffness of the material.
The alkalisation (alkali treatment) on kenaf fibre aids in increasing the surface area of the fibre via the fibrillation effect as the process splits the single-fibre bundle into small ones. Hence, this treatment escalates the effective area for the mechanical interlocking between the two phases of composites, which are fibre and polymer, and subsequently leads to increased interfacial loading, which contributes to improve dynamic mechanical properties. Acetylation reacts with the cell wall hydroxyl groups in lignocellulosic materials via an acetic compound. In this case, the amorphous and the crystalline components react with acetic acid to form a covalent bonding by using hydrogen linkage to decrease the hydrophilicity of the kenaf fibre. Hence, acetylation improves the bonding of kenaf fibre with the polymer in the composite laminate, improving the storage of the composite. Acetylation reacts with the cell wall hydroxyl groups in lignocellulosic materials via an acetic compound. In this case, the amorphous and the crystalline components have reacted with the acetic acid reagent to form a covalent bonding by using hydrogen linkage to decrease the hydrophilicity of the kenaf fibre, thereby improving the kenaf fibre bonding with the polymer in the composite laminate and the storage modulus of the composite. Other treatments, such as grafting, zein and amino acid treatments, also seem to increase the fibre surface and the mechanical interlocking between the fibre and the matrix and the dynamic mechanical behaviours of kenaf fibre-reinforced polymer composite. For the combined treatment of alkali and silane, the reaction does not provide a significant improvement in terms of storage and loss moduli and damping parameter. Further studies are necessary to compare the combinations of treatment sequences as a function of the formed kenaf fibre and the effects of treatments on the physical, mechanical, dynamic mechanical, thermal and chemical properties of the kenaf composite.
References
Akil HM, Omar MF, Mazuki AAM, Safiee S, Ishak ZAM, Abu Bakar A (2011) Kenaf fiber reinforced composites: a review. Mater Des 32:4107–4121
Alemdar A, Sain M (2008) Isolation and characterization of nanofibers from agricultural residues—wheat straw and soy hulls. Bioresour Technol 99:1664–1671
Ali SSS, Razman MR, Awang A (2020) The nexus of population, GDP growth, electricity generation, electricity consumption and carbon emissions output in Malaysia. Int J Energy Econ Policy 10:84–89
Alsagayar ZS, Rahmat AR, Arsad A, binti Mustaph SNH, (2015) Tensile and flexural properties of montmorillonite nanoclay reinforced epoxy resin composites. Adv Mater Res 1112:373–376
Anuar H, Zuraida A (2011) Thermal properties of injection moulded polylactic acid—kenaf fibre biocomposite. Malays Polym J 6:51–57
Asim M, Paridah MT, Saba N, Jawaid M, Alothman OY, Nasir M, Almutairi Z (2018) Thermal, physical properties and flammability of silane treated kenaf/pineapple leaf fibres phenolic hybrid composites. Compos Struct 202:1330–1338
Asyraf MRM, Ishak MR, Razman MR, Chandrasekar M (2019a) Fundamentals of creep, testing methods and development of test rig for the full-scale crossarm: a review. J Teknol 81:155–164
Asyraf MRM, Ishak MR, Sapuan SM, Yidris N (2019b) Conceptual design of creep testing rig for full-scale cross arm using TRIZ-Morphological chart-analytic network process technique. J Mater Res Technol 8:5647–5658
Asyraf MRM, Ishak MR, Sapuan SM, Yidris N (2020a) Conceptual design of multi-operation outdoor flexural creep test rig using hybrid concurrent engineering approach. J Mater Res Technol 9:2357–2368
Asyraf MRM, Ishak MR, Sapuan SM, Yidris N, Ilyas RA (2020b) Woods and composites cantilever beam: a comprehensive review of experimental and numerical creep methodologies. J Mater Res Technol 9:6759–6776
Asyraf MRM, Ishak MR, Sapuan SM, Yidris N, Ilyas RA, Rafidah M, Razman MR (2020c) Evaluation of design and simulation of creep test rig for full-scale cross arm structure. Adv Civ Eng 2020:6980918
Asyraf MRM, Ishak MR, Sapuan SM, Yidris N, Rafidah M, Ilyas RA, Razman MR (2020d) Potential application of green composites for cross arm component in transmission tower: A brief review. Int J Polym Sci. https://doi.org/10.1155/2020/8878300
Asyraf MRM, Ishak MR, Sapuan SM, Yidris N, Shahroze RM, Johari AN, Rafidah M, Ilyas RA (2020E) Creep test rig for cantilever beam: fundamentals, prospects and present views. J Mech Eng Sci 14:6869–6887
Asyraf MRM, Rafidah M, Ishak MR, Sapuan SM, Yidris N, Ilyas RA, Razman MR (2020F) Integration of TRIZ, Morphological Chart and ANP method for development of FRP composite portable fire extinguisher. Polym Compos 41:2917–2932
Aziz SH, Ansell MP (2004) The effect of alkalization and fibre alignment on the mechanical and thermal properties of kenaf and hemp bast fibre composites: part 1—polyester resin matrix. Compos Sci Technol 64:1219–1230
Bachtiar D, Salit MS, Zainudin E, Abdan K, Dahlan KZHM (2011) Effects of alkaline treatment and a compatibilizing agent on tensile properties of sugar palm fibrereinforced high impact polystyrene composites. BioResources 6:4815–4823
Bajuri F, Mazlan N, Ishak MR, Imatomi J (2016) Flexural and compressive properties of hybrid kenaf/silica nanoparticles in epoxy composite. Procedia Chem 19:955–960
Bajuri F, Mazlan N, Ishak MR (2017) Effect of silica nanoparticles in kenaf reinforced epoxy: Flexural and compressive properties. Pertan J Sci Technol 25:1029–1038
Bakar NA, Chee CY, Abdullah LC, Ratnam CT, Ibrahim NA (2015) Thermal and dynamic mechanical properties of grafted kenaf filled poly(vinyl chloride)/ethylene vinyl acetate composites. Mater Des 65:204–211
Bledzki AK, Gassan J (1999) Composites reinforced with cellulose based fibres. Prog Polym Sci 24:221–274
Chandrasekar M, Ishak MR, Sapuan SM, Leman Z, Jawaid M (2017) A review on the characterisation of natural fibres and their composites after alkali treatment and water absorption. Plast Rubber Compos 46:119–136
Cho D, Lee HS, Han SO (2009) Effect of fiber surface modification on the interfacial and mechanical properties of kenaf fiber-reinforced thermoplastic and thermosetting polymer composites. Compos Interfaces 16:711–729
Chung TJ, Park JW, Lee HJ, Kwon HJ, Kim HJ, Lee YK, Yin Tze WT (2018) The improvement of mechanical properties, thermal stability, and water absorption resistance of an eco-friendly PLA/kenaf biocomposite using acetylation. Appl Sci 8:376
Datta J, Kopczyńska P (2015) Effect of kenaf fibre modification on morphology and mechanical properties of thermoplastic polyurethane materials. Ind Crops Prod 74:566–576
Davoodi MM, Sapuan SM, Ahmad D, Ali A, Khalina A, Jonoobi M (2010) Mechanical properties of hybrid kenaf/glass reinforced epoxy composite for passenger car bumper beam. Mater Des 31:4927–4932
Deeraj BDS, R. H, Jayan JS, Saritha A, Joseph K, (2020) Enhanced visco-elastic and rheological behavior of epoxy composites reinforced with polyimide nanofiber. Nano Struct Nano Objects 21:100421
Dhakal HN, Zhang ZY, Richardson MOW (2007) Effect of water absorption on the mechanical properties of hemp fibre reinforced unsaturated polyester composites. Compos Sci Technol 67:1674–1683
Dupraz AMP, De Wijn JR, Meer SATVD, De Groot K (1996) Characterization of silane-treated hydroxyapatite powders for use as filler in biodegradable composites. J Biomed Mater Res 30:231–238
Dynamic Mechanical Analysis (2020). https://www.intertek.com/polymers/testlopedia/dynamic-mechanical-analysis/. Accessed 13 July 2020
Eichhorn SJ, Baillie CA, Zafeiropoulos N, Mwaikambo LY, Ansell MP, Dufresne A, Entwistle KM, Herrera-Franco PJ, Escamilla GC, Groom L, Hughes M, Hill C, Rials TG, Wild PM (2001) Current international research into cellulosic fibres and composites. J Mater Sci 36:2107–2131
Farahani GN, Ahmad I, Mosadeghzad Z (2012) Effect of fiber content, fiber length and alkali treatment on properties of kenaf fiber/UPR composites based on recycled PET wastes. Polym Plast Technol Eng 51:634–639
Fiore V, Di Bella G, Valenza A (2015) The effect of alkaline treatment on mechanical properties of kenaf fibers and their epoxy composites. Compos Part B Eng 68:14–21
Gaisford S, Kett V, Haines P (2002) Principles of thermal analysis and calorimetry. Royal society of chemistry, Cambridge
George J, Sreekala MS, Thomas S (2001) A review on interface modification and characterization of natural fiber reinforced plastic composites. Polym Eng Sci 41:1471–1485
Golar M, Malik A, Muis H, Khairil M, Ali SSS, Razman MR, Awang A (2019) The adaptive-collaborative as a strategy comunications for conflict resolution on the national park. Ecol Environ Conserv 25:352–359
Gopakumar DA, Pai AR, Pottathara YB, Pasquini D, Carlos De Morais L, Luke M, Kalarikkal N, Grohens Y, Thomas S (2018) Cellulose nanofiber-based polyaniline flexible papers as sustainable microwave absorbers in the X-band. ACS Appl Mater Interfaces 10:20032–20043
Guduri BR, Semosa H, Meng YZ (2009) Green composites from woven flax fiber and bio-copolyester. In: 17th ICCM international conferences on composite materials. Edinburgh, UK, pp 27–31
Han YH, Han SO, Cho D, Il KH (2007) Kenaf/polypropylene biocomposites: effects of electron beam irradiation and alkali treatment on kenaf natural fibers. Compos Interfaces 14:559–578
Hassan MM, Islam MR, Shehrzade S, Khan MA (2003) Influence of mercerization along with Ultraviolet (UV) and gamma radiation on physical and mechanical properties of jute yarn by grafting with 3-(trimethoxysilyl) propylmethacrylate (silane) and acrylamide under UV radiation. Polym Plast Technol Eng 42:515–531
Herrera-Franco PJ, Valadez-González A (2005) A study of the mechanical properties of short natural-fiber reinforced composites. Compos Part B Eng 36:597–608
Herrera-Franco P, Valadez-Gonzalez A, Cervantes-Uc M (1997) Development and characterization of a HDPE-sand-natural fiber composite. Compos Part B Eng 28:331–343
Huda MS, Drzal LT, Mohanty AK, Misra M (2008) Effect of chemical modifications of the pineapple leaf fiber surfaces on the interfacial and mechanical properties of laminated biocomposites. Compos Interfaces 15:169–191
Ibrahim NA, Yunus MZW, W, Othman M, Abdan K, Hadithon KA, (2010) Poly(lactic acid) (PLA)-reinforced kenaf bast fiber composites: the effect of triacetin. J Reinf Plast Compos 29:1099–1111
Ifuku S, Morooka S, Morimoto M, Saimoto H (2010) Acetylation of chitin nanofibers and their transparent nanocomposite films. Biomacromolecules 11:1326–1330
Ilyas RA, Sapuan SM, Asyraf MRM, Atikah MSN, Ibrahim R, Dele-Afolabia TT (2020) Introduction to biofiller reinforced degradable polymer composites. In: Sapuan SM, Jumaidin R, Hanafi I (eds) Biofiller reinforced biodegradable polymer composites. CRC Press, Boca Raton, pp 1–23
Ilyas RA, Sapuan SM, Atiqah A, Ibrahim R, Abral H, Ishak MR, Zainudin ES, Nurazzi NM, Atikah MSN, Ansari MNM, Asyraf MRM, Supian ABM, Ya H (2020) Sugar palm (Arenga pinnata [Wurmb.] Merr) starch films containing sugar palm nanofibrillated cellulose as reinforcement: water barrier properties. Polym Compos 41:459–467
Ilyas RA, Sapuan SM, Norrrahim MNF, Yasim-Anuar TAT, Kadier A, Kalil MS, Atikah MSN, Ibrahim R, Asrofi M, Abral H, Nazrin A, Syafiq R, Aisyah HA, Asyraf MRM (2020) Nanocellulose/starch biopolymer nanocomposites: processing, manufacturing, and applications. In: Al-Oqla FM, Sapuan SM (eds) Advanced processing, properties, and applications of starch and other bio-based polymers, 1st edn. Elsevier, Amsterdam, pp 65–88
Ilyas RA, Sapuan MS, Norizan MN, Norrrahim MNF, Ibrahim R, Atikah MSN, Huzaifah MRM, Radzi AM, Izwan S, Azammi AMN, Jumaidin R, Ainun ZMA, Atiqah A, Asyraf MRM, Kian LK (2020) Macro to nanoscale natural fiber composites for automotive components: Research, development, and application. In: Sapuan MS, Ilyas RA (eds) Biocomposite and synthetic composites for automotive applications. Woodhead Publishing Series, Amsterdam
Ilyas R, Sapuan S, Atikah M, Asyraf M, Rafiqah SA, Aisyah H, Nurazzi NM, Norrrahim M (2021) Effect of hydrolysis time on the morphological, physical, chemical, and thermal behavior of sugar palm nanocrystalline cellulose (Arenga pinnata (Wurmb.) Merr ). Text Res J 91:152–167
Jaafar CNA, Rizal MAM, Zainol I (2018) Effect of kenaf alkalization treatment on morphological and mechanical properties of epoxy/silica/kenaf composite. Int J Eng Technol 7:258–263
Jacob M, Joseph S, Pothan LA, Thomas S (2005) A study of advances in characterization of interfaces and fiber surfaces in lignocellulosic fiber-reinforced composites. Compos Interfaces 12:95–124
Jawaid M, Abdul Khalil HPS, Hassan A, Dungani R, Hadiyane A (2013) Effect of jute fibre loading on tensile and dynamic mechanical properties of oil palm epoxy composites. Compos Part B Eng 45:619–624
Johari AN, Ishak MR, Leman Z, Yusoff MZM, Asyraf MRM (2020) Influence of CaCO3 in pultruded glass fibre/unsaturated polyester composite on flexural creep behaviour using conventional and TTSP methods. Polimery 65:46–54
Johari AN, Ishak MR, Leman Z, Yusoff MZM, Asyraf MRM (2020) Creep behaviour monitoring of short-term duration for fiber-glass reinforced composite cross-arms with unsaturated polyester resin samples using conventional analysis. J Mech Eng Sci 14:7361–7368
John MJ, Anandjiwala RD (2008) Recent developments in chemical modification and characterization of natural fiber-reinforced composites. Polym Compos 29:187–207
John MJ, Thomas S (2008) Biofibres and biocomposites. Carbohydr Polym 71:343–364
John MJ, Francis B, Varughese KT, Thomas S (2008) Effect of chemical modification on properties of hybrid fiber biocomposites. Compos Part A Appl Sci Manuf 39:352–363
John MJ, Bellmann C, Anandjiwala RD (2010) Kenaf-polypropylene composites: effect of amphiphilic coupling agent on surface properties of fibres and composites. Carbohydr Polym 82:549–554
Jonoobi M, Harun J, Shakeri A, Misra M, Oksmand K (2009) Chemical composition, crystallinity, and thermal degradation of bleached and unbleached kenaf bast (Hibiscus cannabinus) pulp and nanofibers. BioResources 4:626–639
Joseph K, Thomas S, Pavithran C (1996) Effect of chemical treatment on the tensile properties of short sisal fibre-reinforced polyethylene composites. Polymer (Guildf) 37:5139–5149
Joseph PV, Joseph K, Thomas S (2002) Short sisal fiber reinforced polypropylene composites: the role of interface modification on ultimate properties. Compos Interfaces 9:171–205
Joy J, Jose C, Yu X, Mathew L, Thomas S, Pilla S (2017) The influence of nanocellulosic fiber, extracted from Helicteres isora, on thermal, wetting and viscoelastic properties of poly(butylene succinate) composites. Cellulose 24:4313–4323
Karthikeyan N, Kumar SV (2016) Fabrication and analysing the mechanical properties of Kenaf fibre mat reinforced composites. J Chem Pharm Sci 9:3147–3150
Kosbar LL, Wenzel TJ (2017) Inclusion of synthetic polymers within the curriculum of the ACS certified undergraduate degree. J Chem Educ 94:1599–1602
Krishna KV, Kanny K (2016) The effect of treatment on kenaf fiber using green approach and their reinforced epoxy composites. Compos Part B Eng 104:111–117
Kumar M, Mohanty S, Nayak SK, Rahail Parvaiz M (2010) Effect of glycidyl methacrylate (GMA) on the thermal, mechanical and morphological property of biodegradable PLA/PBAT blend and its nanocomposites. Bioresour Technol 101:8406–8415
Lee BH, Kim HS, Lee S, Kim HJ, Dorgan JR (2009) Bio-composites of kenaf fibers in polylactide: role of improved interfacial adhesion in the carding process. Compos Sci Technol 69:2573–2579
Liu W, Mohanty AK, Drzal LT, Askel P, Misra M (2004) Effects of alkali treatment on the structure, morphology and thermal properties of native grass fibers as reinforcements for polymer matrix composites. J Mater Sci 39:1051–1054
Liu W, Mohanty AK, Askeland P, Drzal LT, Misra M (2004) Influence of fiber surface treatment on properties of Indian grass fiber reinforced soy protein based biocomposites. Polymer (Guildf) 45:7589–7596
Liu Y, Lv X, Bao J, Xie J, Tang X, Che J, Ma Y, Tong J (2019) Characterization of silane treated and untreated natural cellulosic fibre from corn stalk waste as potential reinforcement in polymer composites. Carbohydr Polym 218:179–187
Mahdi EM, Tan JC (2016) Dynamic molecular interactions between polyurethane and ZIF-8 in a polymer-MOF nanocomposite: microstructural, thermo-mechanical and viscoelastic effects. Polymer (Guildf) 97:31–43
Majhi SK, Nayak SK, Mohanty S, Unnikrishnan L (2010) Mechanical and fracture behavior of banana fiber reinforced polylactic acid biocomposites. Int J Plast Technol 14:57–75
Makarona E, Koutzagioti C, Salmas C, Ntalos G, Skoulikidou MC, Tsamis C (2017) Enhancing wood resistance to humidity with nanostructured ZnO coatings. Nano Struct Nano Objects 10:57–68
Mansor MR, Sapuan SM, Zainudin ES, Nuraini AA (2014) Conceptual design of kenaf fiber polymer composite automotive parking brake lever using integrated TRIZ-Morphological Chart–Analytic Hierarchy Process method. Mater Des 54:473–482
Mansor MR, Sapuan SM, Hambali A (2015) Conceptual design of kenaf polymer composites automotive spoiler using TRIZ and morphology chart methods. Appl Mech Mater 761:63–67
Mastura MT, Sapuan SM, Mansor MR, Nuraini AA (2017) Conceptual design of a natural fibre-reinforced composite automotive anti-roll bar using a hybrid approach. Int J Adv Manuf Technol 91:2031–2048
Mat Taib R, Ariawan D, Mohd Ishak ZA (2016) Surface characterization of alkali treated kenaf fibers by XPS and AFM. Key Eng Mater 694:29–33
Mazani N, Sapuan SM, Sanyang ML, Atiqah A, Ilyas RA (2019) Design and fabrication of a shoe shelf from kenaf fiber reinforced unsaturated polyester composites. In: Ariffin H, Sapuan SM, Hassan MA (eds) Lignocellulose for future bioeconomy, 1st edn. Elsevier, Amsterdam, pp 315–332
Melo JDD, Carvalho LFM, Medeiros AM, Souto CRO, Paskocimas CA (2012) A biodegradable composite material based on polyhydroxybutyrate (PHB) and carnauba fibers. Compos Part B Eng 43:2827–2835
Mohd Radzuan NA, Tholibon D, Sulong AB, Muhamad N, Haron CHC (2020) New processing technique for biodegradable kenaf composites: a simple alternative to commercial automotive parts. Compos Part B Eng 184:107644
Mokhothu TH, Guduri BR, Luyt AS (2011) Kenaf fiber-reinforced copolyester biocomposites. Polym Compos 32:2001–2009
Ndazi BS, Nyahumwa C, Tesha J (2007) Chemical and thermal stability of rice husks against alkali treatment. BioResources 3:1267–1277
Nishino T, Hirao K, Kotera M, Nakamae K, Inagaki H (2003) Kenaf reinforced biodegradable composite. Compos Sci Technol 63:1281–1286
Omran AAB, Mohammed AABA, Sapuan SM, Ilyas RA, Asyraf MRM, Koloor SSR, Petrů M (2021) Micro- and nanocellulose in polymer composite materials: a review. Polymers (Basel) 13:231
Paul SA, Reussmann T, Mennig G, Lampke T, Pothen LA, Mathew GDG, Joseph K, Thomas S (2007) The role of interface modification on the mechanical properties of injection-moulded composites from commingled polypropylene/banana granules. Compos Interfaces 14:849–867
Paul SA, Piasta D, Spange S, Pothan LA, Thomas S, Bellmann C (2008) Solvatochromic and electrokinetic studies of banana fibrils prepared from steam-exploded banana fiber. Biomacromolecules 9:1802–1810
Paul SA, Joseph K, Mathew GDG, Pothen LA, Thomas S (2010) Influence of polarity parameters on the mechanical properties of composites from polypropylene fiber and short banana fiber. Compos Part A Appl Sci Manuf 41:1380–1387
Pothan LA, Zimmermann Y, Thomas S, Spange S (2000) Determination of polarity parameters of chemically modified cellulose fibers by means of the solvatochromic technique. J Polym Sci Part B Polym Phys 38:2546–2553
Pothan LA, Oommen Z, Thomas S (2003) Dynamic mechanical analysis of banana fiber reinforced polyester composites. Compos Sci Technol 63:283–293
Pottathara YB, Bobnar V, Gorgieva S, Grohens Y, Finšgar M, Thomas S, Kokol V (2016) Mechanically strong, flexible and thermally stable graphene oxide/nanocellulosic films with enhanced dielectric properties. RSC Adv 6:49138–49149
Pottathara YB, Bobnar V, Finšgar M, Grohens Y, Thomas S, Kokol V (2018) Cellulose nanofibrils-reduced graphene oxide xerogels and cryogels for dielectric and electrochemical storage applications. Polymer (Guildf) 147:260–270
Pottathara YB, Thomas S, Kalarikkal N, Griesser T, Grohens Y, Bobnar V, Finšgar M, Kokol V, Kargl R (2019) UV-Induced reduction of graphene oxide in cellulose nanofibril composites. New J Chem 43:681–688
Prisacariu C (2011) Polyurethane elastomers: from morphology to mechanical aspects. Springer, Wien
Rashdi AAA, Sapuan SM, Ahmad MMHM, Khalina A (2009) Water absorption and tensile properties of soil buried kenaf fibre reinforced unsaturated polyester composites (KFRUPC). J Food Agric Environ 7:908–911
Ray D, Sarkar BK, Rana AK, Bose NR (2001) Effect of alkali treated jute fibres on composite properties. Bull Mater Sci 24:129–135
Razman MR, Hadi AH, Jahi JM, Idrus S, Mohamed AF, Harman Shah AH (2011) Transformation for better living environment in urban region: application of the principle of transboundary liability and the montreal protocol experiences. Akademika 81:93–102
Rouison D, Sain M, Couturier M (2004) Resin transfer molding of natural fiber reinforced composites: cure simulation. Compos Sci Technol 64:629–644
Saba N, Paridah MT, Jawaid M, Abdan K, Ibrahim NA (2015) Manufacturing and processing of kenaf Fibre-reinforced epoxy composites via different methods. In: Sapuan SM, Jawaid M, Yusof N, Hoque ME (eds) Manufacturing of natural fibre reinforced polymer composites. Springer, New York, pp 101–124
Saba N, Paridah MT, Jawaid M, Abdan K, Ibrahim NA (2015b) Potential utilization of kenaf biomass in different applications. In: Agricultural biomass based potential materials. Springer, pp 1–34
Saba N, Jawaid M, Alothman OY, Paridah MT (2016) A review on dynamic mechanical properties of natural fibre reinforced polymer composites. Constr Build Mater 106:149–159
Saba N, Alothman OY, Almutairi Z, Jawaid M (2019) Magnesium hydroxide reinforced kenaf fibers/epoxy hybrid composites: mechanical and thermomechanical properties. Constr Build Mater 201:138–148
Sanyang ML, Sapuan SM, Jawaid M, Ishak MR, Sahari J (2016) Recent developments in sugar palm (Arenga pinnata) based biocomposites and their potential industrial applications: a review. Renew Sustain Energy Rev 54:533–549
Sarkawi SS, Eichhorn SJ (2010) A study on deformation micromechanics of kenaf fibre and kenaf/epoxy composite using raman spectroscopy. J Rubber Res 13:59–72
Seki Y (2009) Innovative multifunctional siloxane treatment of jute fiber surface and its effect on the mechanical properties of jute/thermoset composites. Mater Sci Eng A 508:247–252
Serizawa S, Inoue K, Iji M (2006) Kenaf-fiber-reinforced poly(lactic acid) used for electronic products. J Appl Polym Sci 100:618–624
Singh B, Verma A, Gupta M (1998) Studies on adsorptive interaction between natural fiber and coupling agents. J Appl Polym Sci 70:1847–1858
Siqueira G, Bras J, Dufresne A (2010) Cellulosic Bionanocomposites: A Review of Preparation, Properties and Applications. Polymers (Basel) 2:728–765
Sis ALM, Ibrahim NA, Yunus WMZW (2013) Effect of (3-aminopropyl)trimethoxysilane on mechanical properties of PLA/PBAT blend reinforced kenaf fiber. Iran Polym J (Engl Ed)) 22:101–108
Sreekala MS, Thomas S (2003) Effect of fibre surface modification on water-sorption characteristics of oil palm fibres. Compos Sci Technol 63:861–869
Sreekala MS, Kumaran MG, Joseph S, Jacob M, Thomas S (2000) Oil palm fibre reinforced phenol formaldehyde composites: influence of fibre surface modifications on the mechanical performance. Appl Compos Mater 7:295–329
Sun XF, Sun RC (2002) Comparative study of acetylation of rice straw fiber with or without catalysts. Wood Fiber Sci 34:306–317
Tawakkal ISMA, Talib RA, Abdan K, Ling CN (2012) Mechanical and physical properties of Kenaf-Derived Cellulose (KDC)-filled polylactic acid (PLA) composites. BioResources 7:1643–1655
Wambua P, Ivens J, Verpoest I (2003) Natural fibres: Can they replace glass in fibre reinforced plastics? Compos Sci Technol 63:1259–1264
White GA, Higgins JJ (1964) Growing kenaf for paper. In: Second international kenaf conference proceedings, Palm Beach, Florida, pp 27–40
Wibowo AC, Mohanty AK, Misra M, Drzal LT (2004) Chopped industrial hemp fiber reinforced cellulosic plastic biocomposites: thermomechanical and morphological properties. Ind Eng Chem Res 43:4883–4888
Yallappa S, Deepthi DR, Yashaswini S, Hamsanandini R, Chandraprasad M, Ashok Kumar S, Hegde G (2017) Natural biowaste of Groundnut shell derived nano carbons: synthesis, characterization and itsin vitro antibacterial activity. Nano Struct Nano Objects 12:84–90
Zafeiropoulos NE, Vickers PE, Baillie CA, Watts JF (2003) An experimental investigation of modified and unmodified flax fibres with XPS, ToF-SIMS and ATR-FTIR. J Mater Sci 38:3903–3914
Zainuddin N, Ahmad I, Kargarzadeh H, Ramli S (2017) Hydrophobic kenaf nanocrystalline cellulose for the binding of curcumin. Carbohydr Polym 163:261–269
Zainuddin S, Mascunra Amir A, Kibi YR, Khairil M, Zarina Syed Zakaria S, Rizal Razman M (2019) Social engineering model of natural resources management of Palu City. J Eng Appl Sci 14:275–279
Zhang Z, Wang P, Wu J (2012) Dynamic mechanical properties of EVA polymer-modified cement paste at early age. Phys Procedia 25:305–310
Zhu J, Zhu H, Njuguna J, Abhyankar H (2013) Recent development of flax fibres and their reinforced composites based on different polymeric matrices. Materials (Basel) 6:5171–5198
Acknowledgments
Authors are very appreciate and thankful to Program Pelajar Cemerlang (PPC2019), Jabatan Perkhidmatan Awam (JPA) and Kursi Rahmah Nawawi for providing scholarship award and financial aids to the principal author to carry out this research project. The authors also would like to thank to Universiti Kebangsaan Malaysia for the financial support through research grant, Dana Pecutan Penerbitan-LESTARI UKM (PP/LESTARI/2020) and XX-2018-008.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare that they have no conflict of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Asyraf, M.R.M., Rafidah, M., Azrina, A. et al. Dynamic mechanical behaviour of kenaf cellulosic fibre biocomposites: a comprehensive review on chemical treatments. Cellulose 28, 2675–2695 (2021). https://doi.org/10.1007/s10570-021-03710-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10570-021-03710-3