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This research is a comparative study of untreated and treated date palm fiber (DPF) and kenaf (KF)-reinforced epoxy hybrid composite and explores the properties of DPF. The prepared hybrid composites were characterized in terms of tensile properties, impact properties, physical behavior, water absorption, and thickness swelling. The composites were prepared by hand layup technique. Treated 30% date palm and 70% kenaf (T-3DP7K) showed the highest tensile strength (26.45 MPa) and modulus (4.54 GPa) among untreated and treated hybrid composites. The scanning electron microscope revealed the behavior of fiber and polymers and also the cause of tensile test failure. The impact strength of T-1DP1K revealed highest impact resistant (5493 J/m) among untreated and treated hybrid composites. Remarkably, alkali-treated hybrid composites reduced the water absorption and thickness swelling compared to the untreated composites. In untreated composites, higher DPF content composites showed higher moisture content and dimensional instability. Overall, we concluded that among all hybrid composites, T-3DP7K showed better tensile properties, lowest water absorption, and lowest thickness swelling, and T-7DP3K showed better impact properties. [ABSTRACT FROM AUTHOR]

Natural fiber reinforced hybrid polymer composites have attracted many researchers’ attention compared to synthetic fiber composites due to their better mechanical properties. Besides being inexpensive, natural fibers are eco-friendly. In the literature, kenaf fiber has shown an enormous future for its suitability in technical applications. The present studies explore the mechanical properties of kenaf and kapok fiber reinforced hybrid polyester composites. The composites are prepared by simple hand lay-up technique. The test specimens were prepared according to ASTM standards and the tensile, bending, and impact strength was evaluated experimentally. The result shows that composite with equal contribution of kenaf and kapok fiber reinforcement has tensile and impact strength of 25.25 ± 4.29 MPa and 46.65 ± 0.01 KJ/m² respectively. As the kapok fiber content increases the bending strength and bending modulus of composites decrease. The results show that the tensile and impact strength of hybrid composites has improved considerably compared to neat kapok composites. Scanning electron microscopy (SEM) was carried out to examine the fractured surfaces of tested specimens. [ABSTRACT FROM AUTHOR]

The research's aim is to investigate the energy absorption, free-fall drop analysis, and failure analysis of Palm (P)/kenaf (K) fiber-reinforced MWCNT-phenolic composites. 3P:7K reinforced MWCNT–phenolic composites were made using manual mixing and hot pressing at 150°C with a pressure of 10 tonnes. Energy absorption was investigated using a drop weight impact tester. Free-fall drop test was performed to analyze the performance of the aircraft tray table prototype. Non-destructive testing was carried out to investigate the damage mechanism. The results demonstrate that as the impact energy increased from 1.50 J to 3.0 J, the crack length increased. There is a difference of 3% to 15% in the crack sizing between dye penetration and Digital Detector Array (DDA), indicating that DDA is more accurate. In the free-fall drop test, small cracks were detected in the dye penetration method on the prototype. The DDA approach, however, did not reveal any defects. The agglomerations were observed through DDA and Computed tomography. In this study, the hybrid CR/kenaf reinforced MWCNT modified phenolic composites exhibit superior performance that can act as an efficient and eco-friendly material for aircraft tray table application by preserving natural resources. [ABSTRACT FROM AUTHOR]

Natural fibers are very flexible materials; their properties vary with physical structure and chemical composition. Chemical treatment of fiber can chemically modify, clean the fiber surface, increase the surface roughness and stop the moisture absorption process. In the present study, kenaf bast fibers were treated with sodium hydroxide (NaOH), sodium carbonate (Na2CO3), ortho phosphoric acid (H3PO4), acetic acid (CH3COOH) and zinc chloride (ZnCl2) each with different concentrations. The morphological properties were investigated using scanning electron microscopy (SEM) which shows many impurities on untreated kenaf fiber surface. NaOH and ZnCl2 treated kenaf fiber surface is more rough than other chemical treatments. X-ray diffraction (XRD) was carried out to evaluate crystallinity index. NaOH treated kenaf fiber shows highest crystallinity index of 76.87%. Fourier transform infrared (FTIR) spectroscopy was performed to characterize chemical functional groups. In untreated kenaf fiber broad band at 3469 cm−1 confirms the presence of OH group. After chemical treatments this band disappears which confirms the removal of the OH groups. Thermo gravimetric analysis (TGA) carried out shows low fixed carbon content (64%) and maximum ash content (22%) for NaOH treated kenaf fiber. [ABSTRACT FROM AUTHOR]

Among most of the natural fiber reinforced polymer composites, the specific wear rate of epoxy-kenaf fiber composite is the second least after sisal-polyester composite (El-Tayeb [10]). Conclusions The present investigation exposed the following conclusions: The preparation of hybrid polymer composites using an industrial/construction waste (marble dust) and natural fiber (kenaf) is possible using the polymer solution casting technique. Keywords: Polymer composites; waste marble dust; kenaf fiber; characterization; dry-sliding wear; ANN EN Polymer composites waste marble dust kenaf fiber characterization dry-sliding wear ANN 9235 9247 13 11/21/22 20221220 NES 221220 Introduction Polymers and their composites are growing as the emerging functional materials due to their excellent engineering properties like high corrosion resistance (Santos et al. [28]), lightweight (Phadtare et al. [22]), bio-degradability (Thakur, Thakur, and Gupta [33]), high strength (Ku et al. [16]), and improved wear resistance (Friedrich, Reinicke, and Zhang [12]). [Extracted from the article]

Effect of fiber treatment on the strain We can conclude from figures presented previously that all composite tensile properties are improved when increasing the fiber weight ratio and also after the chemical treatment of the fibers used for. Fiber weight ratio of composites HT

–The sustainable utilisation of Kenaf fibres (KF) as environmentally friendly reinforcement in mortar, concrete and polymer composites promotes the concept of a circular economy and sustainable construction. However, the hydrophilic nature of such biofibres adversely affects their structural applications as reinforcement in concrete, mortar and polymer. Therefore, the study examined the effect of alkali treatment (mercerization) on the surface sorption characteristics of KF. The effect of water sorption characteristics on the mechanical properties of surface-modified and untreated KF was also investigated in the study. Scanning electron microscopy was performed to examine the morphology and microstructure of the fibre surface along with the tensile fracture of the swollen/un-swollen fibres. The water absorption studies revealed that mercerization reduced the overall water uptake of KF by 16%, which enhanced the adhesion of the fibre surface. The findings provide the knowledge required by scientists and engineers for determining the water requirements for the design of bio-fibrous concrete composites. [ABSTRACT FROM AUTHOR]

Natural fiber capability as an acoustic panel is subjected to physical properties of the fiber. Chemical treatment was implemented in this study to improve kenaf fiber performances and utilized as a sound absorption material. This research aims to use sodium hydroxide (NaOH) treatment from 1% to 8% concentrations on kenaf fiber. Physical changes on the kenaf fiber strands due to NaOH treatment were observed using Scanning Electron Microscope (SEM). The subsequent effects on sound absorption were measured using Impedance Tube to determine the sound absorption coefficient (SAC) and noise reduction coefficient (NRC) values. Findings show that the diameter of kenaf fiber gradually decreased with the increment of the NaOH concentration. The eliminations of the hemicellulose and lignin layer of the strands causing the decreased of the strand diameter which was proven by FTIR analysis. Results from SAC shows that treated Kenaf fiber using 6%, 7%, and 8% of NaOH obtained higher SAC at high frequency range (>2500 Hz). Those samples obtained 0.67 coefficients for their NRC value. This research concludes the sound absorption capabilities of kenaf absorber was better using thinner strands and the 6% NaOH concentration was the optimum concentration to treat kenaf fiber for sound absorber. [ABSTRACT FROM AUTHOR]

Cement concrete is used in small structure to big multi-storied buildings. It is noteworthy to concentrate on concrete elements and mix ratio to achieve desirable strength with feasible cost of raw material. In this investigation, fibers reinforced concrete specimens (M50 grade) were prepared. The strength and durability were tested and compared with the properties of plain concrete (PC). The fibers such as coir, kenaf, and Polypropylene (PP) were used as reinforcement and the compressive, split tensile, flexural, and durability analysis were performed. The compressive test resulted that the natural fiber-based PC/Coir & PC/PP-Coir specimens displayed the maximum compressive strength of 64.5 and 66 MPa owing to the small density and slighter water up taking properties of coir and PP fiber. The split tensile test showed that the PC/kenaf specimen exhibited the higher split tensile strength of 7.3 MPa due to the presence of kenaf fiber with high young's modulus. Flexural test reported that the PC/PP-Coir/Kenaf specimen exhibited the higher flexural strength of 7.6 MPa because of reinforcing effect offered by coir, kenaf, and PP fibers. Durability study showed that the PC/PP and PC/PP-coir specimens displayed the minimum weight loss of 1.05 and 2.1% and the minimum loss in compressive strength of 3.4 and 4.6%, respectively, in alkaline medium. It was concluded from this study that the coir fiber could be a suitable candidate to improve the strength and durability of concrete. [ABSTRACT FROM AUTHOR]

Construction industries demand a material with high strength to endure severe environmental conditions like high temperature and humid and hence, it is noteworthy to assess the thermal and water transport properties of the material. In this investigation, the natural fibers based composites were fabricated using Indian almond and kenaf fibers by hand layup method. Entirely, two natural fiber composites viz. epoxy/Indian almond & epoxy/kenaf and two hybrid composites viz. kenaf/India almond/kenaf (K/I/K) & Indian almond/kenaf/Indian almond (I/K/I) were prepared. Thermogravimetric analysis (TGA) was carried out to analyze the thermal properties and water absorption study was carried out to analyze the transport properties. TGA study showed that the epoxy/kenaf composite exhibited a maximum onset temperature of 340.49°C owing to good bonding strength and the K/I/K composite displayed a maximum decomposition temperature of 380.21 ° with a minimum mass loss of 1.29 mg/min. Further, the epoxy/Indian almond composite showed a better flame retardancy property due to more char formation. Water absorption study resulted that the epoxy/Indian almond composite absorbed more water (35% at 50°C) compared to other composites due to spongy like structure and the presence of more voids on the surface of the fiber. Further, the epoxy/kenaf composite displayed more resistance to water penetration with maximum activation energy of diffusion of 2.63 kJ/mole. Transport properties such as diffusion coefficient, sorption coefficient and permeability coefficient were varied in line with temperature. The epoxy/kenaf composite showed least diffusion coefficient of 2.48 × 10−5 cm2/s, sorption coefficient of 1.05, and permeability coefficient of 2.61 × 10−5 cm2/s at 30°C among all other composites due to good bonding strength. [ABSTRACT FROM AUTHOR]

Surface treatment of natural fibers with the help of chemicals has been proved to be an effective method for improving the properties of its associated composites. The present research investigates the effect of nonacidic and cost-effective chemical treatment using sodium acetate on the properties of kenaf mats reinforced Polylactic acid (PLA) composites. In particular, geometrically different kenaf fiber mats (unidirectional, bidirectional, and randomly oriented) were chemically treated with varying concentrations (10%, 15%, and 20% w/v) of sodium acetate, for three different time periods (24, 48, and 72 h) at room temperature. Effect of chemical treatment on the surface of kenaf fibers was examined by scanning electron microscopy. Mechanical characterization of the developed composites was done on the basis of tensile, flexural, and impact tests to investigate the effect of treatment on interfacial adhesion. The composites in which fibers were treated with a 20% concentration of sodium acetate at 48 hr of treatment time exhibited the highest tensile, flexural, and viscoelastic properties. Apart from impact strength, the effect of chemical treatment on the properties of green composites was found to be significant. Eco-friendly treatment of natural fibers using sodium acetate may offer huge potential for commercialization of green composites in furthermore applications. [ABSTRACT FROM AUTHOR]

In this investigation, the dynamic mechanical properties of Indian almond – Kenaf fiber composite were investigated and the effect of stacking sequence was analyzed. Four types of composites viz. kenaf, Kenaf/Indian almond/Kenaf, Indian almond/Kenaf/Indian almond, and Indian almond were fabricated by hand layup technique. The experimental results revealed that the kenaf fiber composite showed the superior storage modulus and loss modulus values compared to all other composites due to the high stiffness of kenaf fiber and better bonding between the matrix and fiber. Among hybrid composites, Kenaf/Indian almond/Kenaf composite displayed a greater storage modulus and loss modulus than Indian almond/Kenaf/Indian almond composite due to the presence of two layers of high stiffness kenaf fiber. Further, the order of thermal stability of the composites was observed as: Kenaf > Kenaf/Indian almond/Kenaf > Indian almond/Kenaf/Indian almond > Indian almond. In addition, the Indian almond fiber composite and Indian almond/Kenaf/Indian almond composite exhibited good damping properties than other composites owing to the more mobility of polymer chain. Cole – cole plot showed that the structure of all the fabricated composites was heterogeneous in nature and kenaf fiber composite displayed the higher heterogeneity among all other materials. Moreover, the modeling of storage modulus and damping factor was performed and compared with the experimental results. The results showed good agreement with the theoretical and experimental values. [ABSTRACT FROM AUTHOR]

An experimental investigation was conducted to identify the optimum fiber content and the effect of fiber alkaline treatment on kenaf fiber reinforced epoxy composites and reported in this article. The entire research work was carried out in two phases. In first phase, kenaf fiber reinforced epoxy composites with fiber weight fractions 20%, 30%, 40%, and 50% (on the total weight of composites) of raw untreated fibers were fabricated using hand layup followed by compression molding to identify the optimum fiber content. The prepared specimens were tested for tensile, flexural and impact properties as per corresponding ASTM standards. In the second phase the optimal fiber weight fraction was chosen to identify the effect of chemical treatment of kenaf fiber mats with NaOH and KOH solutions on mechanical properties. Based on the test results the optimum fiber content was identified as 40% with 45.98 MPa, 40.50 MPa, and 13.26 kJ/m2 as tensile, flexural and impact strength respectively; and 6% NaOH treatment recorded highest mechanical properties of composite such as 58.34 MPa in tensile, 55.34 MPa in flexural and 16.69 kJ/m2 in impact strengths respectively. Also 6% NaOH treatment shown 26.88%, 37.28%, and 25.87% improvement on tensile, flexural, and impact strengths respectively. [ABSTRACT FROM AUTHOR]

Owing to the increasing demand for high performance and lightweight materials, fiber metal laminates (FMLs) have become the alternative materials to replace metallic alloys. When the environmental friendliness of the materials is taken into consideration, plant fibers have shown an excellent potential to be employed as the reinforcements in FMLs. This work describes the mechanical behavior of kenaf and pineapple leaf fibers (PALF) reinforced metal laminates with various fiber contents, ranging from 10 wt% to 50 wt%. Fiber metal laminates were formed through the coalescence of metallic skin layers with the composite as the core. The mechanical tests were then conducted to study the tensile, flexural and Charpy impact properties of the structures. From the findings, it was concluded that both the kenaf and PALF based FMLs showed the optimum mechanical properties when the fiber content was fixed at 30 wt%. In addition, PALF based FMLs had shown higher mechanical properties over kenaf based FMLs. At a fiber content of 30 wt%, the tensile and flexural strength of PALF based FMLs were respectively 6.18% and 3.44% higher than kenaf based FMLs. In terms of impact properties, the impact strength of PALF based FMLs was 5.06% and 40.73% higher than kenaf based FMLs in the flatwise and edgewise orientations. [ABSTRACT FROM AUTHOR]

An eco-friendly and effective degumming method needed to be developed for producing kenaf bast fibers. This study devised a novel deep eutectic solvent (DES) method coupled with microwave and alkaline-ultrasonic treatment. The novel method could effectively remove the gummy matters, providing a smooth and clean fiber surface. The properties of the fibers were assessed including chemical compositions, surface structure, crystallinity index (66.68%) and thermal properties. The residual gum content (9.419%), fiber fineness (4.125tex), breaking tenacity (13.650 cn/tex) of the refined dry fibers produced by the novel treatment were comparable with the fibers produced by the traditional two-step alkali boiling method. Besides, the novel method could reduce the usage of chemical, water and time by 48.9%, by 66.7% and 66.8%, respectively. These results revealed that the novel combined DES pretreatment is a practical and feasible pretreatment method for kenaf bast degumming, demonstrating its facile, green energy-saving and fast properties in the degumming process. [ABSTRACT FROM AUTHOR]

In recent years, natural fibers have been used more frequently for their lower weight to strength ratio, low cost, and environmental-friendly attributes. In this work, sisal/kenaf fiber reinforced with epoxy matrix hybrid composite (HC) was manufactured and their mechanical properties were compared with the sisal fiber composite (SFC) and kenaf fiber composite (KFC). Water absorption was carried out to find the moisture absorption capacity of the manufactured HC. HC provides better properties when compared with SFC and KFC. Hybrid composite is suitable for light weight automobile applications. [ABSTRACT FROM AUTHOR]

Hybrid laminates made using natural fibers have been finding applications in diverse fields such as automotive parts, building structures and sports goods. These laminates incorporate the benefits of the reinforcements used in constructions. The present work deals with the fabrication of hybrid laminate comprising of the natural fibers areca and kenaf in varying stacking sequences through the hand layup method. Epoxy resin (LY556) and hardener (HY951) are mixed in the ratio of 10:1 to prepare the matrix material. Six different hybrid laminates having five layers of areca and kenaf in different stacking sequences are produced. Two more laminates having either kenaf or areca in all the five layers and are produced to act as reference laminate. The prepared laminates are cut as per ASTM standards and subjected to tensile, compressive, flexural, impact and hardness tests in order to identify the properties of the fabricated laminates. The result shows that composite made with kenaf fiber as skin material and areca as core materials exhibit better tensile, flexural and hardness properties. Likewise, composites with outer layers of areca and core layers of kenaf fibers have high compressive and impact strength. The fractured surfaces after the mechanical tests are investigated through the Scanning Electron Microscope (SEM). [ABSTRACT FROM AUTHOR]

This study investigated the mechanical and wear properties of heat-treated pultruded kenaf fiber-reinforced polyester composites (PKFPCs) using pultrusion technique. A total of three heat treatment temperatures (120, 140, and 170°C) of PKFPC and untreated PKFPC were produced and their performance was compared. Different sliding conditions and different heat treatment temperatures on PKFPC were tested according to the Taguchi orthogonal array design of experiment. The worn surfaces and transfer films produced were examined using scanning electron microscopy. The results showed that PKFPC with a 140°C heat treatment exhibited better wear performance than untreated PKFPC and PKFPC with 120 and 170°C heat treatments. The flexural strength and modulus of PKFPC increased after heat treatment. The counterface roughness and heat treatment temperature are the most significant factors affecting the wear performance of PKFPC. The optimum sliding conditions to achieve lowest wear and friction in the tested operating environment were determined. [ABSTRACT FROM AUTHOR]

This work was undertaken to study the conductivity and dielectric behavior of a biopolymer electrolyte based on carboxymethyl cellulose that was synthesized from kenaf fiber. Biopolymer electrolytes comprised of various weight percentage ratios of the host polymer, ammonium acetate salt, and butyl-trimethyl ammonium bis(trifluoromethylsulfonyl)imide ionic liquid were prepared by the solution casting technique. The conductivity values were determined by impedance spectroscopy. The highest conductivity found was 2.18 × 10−3 S cm−1at ambient temperature for the film incorporated with 20 wt.% salt and 20 wt.% ionic liquid. In order to understand the conductivity behavior, a dielectric study was carried out. The results showed that the system obeys the Arrhenius rule and confirmed non-Debye behavior in the sample. [ABSTRACT FROM AUTHOR]

Composites of untreated and 6% sodium hydroxide (NaOH) treated kenaf fiber mat and unsaturated polyester resin matrix were manufactured via a resin transfer molding (RTM) technique. The treated fibers were characterized with SEM and XRD. Contact angle measurements of the fibers were performed using a tensiometer. Alkali treated fiber-unsaturated polyester composites showed superior flexural properties than the composites with untreated fibers. The water absorption pattern of these composites was found to follow Fickian behavior. The tendency of the composites to absorb water decreased when alkali treated fiber mats were used. [ABSTRACT FROM AUTHOR]

Kenaf-filled polylactic acid (PLA) biocomposites were prepared using dry blending, twin screw extrusion and compression molding. PLA was blended with raw and alkali treated kenaf, polyethylene glycol and ammonium polyphosphate (APP). Dynamic mechanical properties of biocomposites were investigated by dynamic mechanical analysis. Storage modulus of composites decreased, while magnitude of damping peaks increased with increase in APP content. TheTgof composites shifted to lower values with APP addition. Alkali treatment improved interfacial adhesion between PLA and kenaf. SEM analysis indicates good dispersion of APP in PLA matrix, however interfacial adhesion between PLA and matrix decreased with increasing APP content. [ABSTRACT FROM PUBLISHER]

This study was conducted to investigate the effect of nanoclay addition on thermal and dynamic mechanical properties of polypropylene (PP) biocomposites reinforced with bleached red algae fiber (BRAF), kenaf fiber (KF), and cotton pulp fiber (CPF). The nano-biocomposites were fabricated with 40 wt.% loading of all natural fibers and addition of nanoclay at 5 or 10 wt.% loading by the melting compounding and compression molding techniques. The nanoclay effects on the thermal and dynamic mechanical properties of the biocomposites were analyzed as a function of properties of natural fibers such as chemical composition, fiber length, and surface morphology. Although the thermal decomposition temperature of nano-biocomposites decreased with the addition of nanoclay, the dimensional stability of biocomposites greatly improved with increasing nanoclay loading. Also, the dynamic mechanical properties of nano-biocomposites for the PP reinforced with BRAF, KF, and CPF were enhanced with the addition of 5 wt% nanoclay compared to those of biocomposites without nanoclay. The highest enhancement in dimensional stability was obtained for the nano-biocomposites reinforced with BRAF natural fiber. These increases can be attributed to a uniform distribution of nanoclay and to a good interfacial adhesion between the reinforcement and PP matrix. The well dispersed nanoclay particles can have good interactions with both natural fibers and polymer matrix, with the incorporation of the reinforcing natural fibers restricting the mobility of the polymer molecules resulting in the raised storage modulus values. [ABSTRACT FROM AUTHOR]

Conducting kenaf/polyaniline (KF/PANI) biofibers were successfully prepared via in situ oxidative polymerization. It was demonstrated, for the first time, the possibility of imparting new electronic properties on KF by coating with acid-doped PANI. The morphological analysis revealed three different PANI morphologies on the KF, depending on the type of acid doping. Enhanced interaction was achieved between the fiber-PANI surfaces, mainly from the π − π interactions. The newly developed conducting biofibers achieved enhancement in DC conductivity up to fivefold compared to the unmodified KF. Mechanical test on the conducting biofibers revealed no significant loss in the tensile properties. [ABSTRACT FROM AUTHOR]

In this research, investigation on the interfacial shear strength of poly(lactic acid)-kenaf fiber biocomposite was investigated using microbond tests. Tensile properties and fracture behaviors of single kenaf fiber are tested via in situ monitoring with acoustic emission (AE). During tensile loading, acoustic signal recorded higher amplitude of above 20 dB up to the maximum force, which corresponds to breakage of single kenaf fiber. Based on microbond tests and AE evaluation, a correlation has been established on failure of kenaf fiber, which is due to debonding of filament and internal structure, cracking of fiber and breakage of fiber. [ABSTRACT FROM AUTHOR]

The kenaf fiber/soy protein resin interface was characterized. The soy protein isolate (SPI) was modified using a polycarboxylic acid, Phytagel® (PH), to make an interpenetrating network-like (IPN-like structure) structure of the resin. The effects of different PH contents on the interfacial properties were characterized using single fiber composite (SFC) tests and optical microscopy. Kenaf fiber strength was characterized using tensile tests. Kenaf fibers were extracted from nonwoven mats. The length of each kenaf fiber was extended by gluing it to long polyethylene filaments on both sides. After drying the glue, dog-bone shaped SFC specimens were prepared using pure and modified SPI resins. The dried SFC specimens were taken out from the mold and hot-pressed (cured) at 120°C. The interfacial shear strength (IFSS) was calculated using the shear-lag analysis. Single fiber tensile tests at different gauge lengths were performed. The average stresses were computed by fitting the data to Weibull distribution. These values were used in the calculation of the IFSS. After the SFC tests, the specimens were observed under the optical microscope to characterize the fiber fracture modes and the region around the fiber fracture. The SFC tests showed that the IFSS is a function of the PH content which controls the resin shrinkage. It was also seen that the interfacial failure mode is also a function of the PH content. These finding were confirmed by the microbead tests in which E-glass fibers were used with the modified SPI resins. [ABSTRACT FROM AUTHOR]

The interest in lignocellulosic fiber composites has been growing in recent years because of their high specific properties. In this work, a new technique was used to prepare specimen to observe the transcrystalline zones in kenaf fiber-polypropylene composites. A maleated polypropylene (MAPP) coupling agent was used to improve the stress-transfer efficiency in the composites. Transcrystallinity was observed for both the uncoupled and coupled composites, although the rate of growth was higher for the coupled composites. Dynamic mechanical spectroscopy was used to observe the relaxations of the composites. The peak temperature of the β-relaxation, associated with the glass-rubber transition of the amorphous molecules, of the coupled composites was higher than that of the uncoupled composites. Restricted molecular mobility due to covalent interactions between the MAPP and the lignocellulosic surface may account for the shift to higher temperatures. It appears that during compounding the extractives sheared from the fiber surface is an important factor in determining the β-relaxation of these composites. The intensities of the α-transition, related to molecular mobility associated with the presence of crystals, is proportional to the fiber volume fraction. Thus it is possible that the molecules responsible for the α-transition are predominantly in the transcrystalline zone. These 'rigid' amorphous molecules in the transcrystalline zone do play a role in composite behavior and need to be considered when tailoring interphases. [ABSTRACT FROM AUTHOR]