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Red Balau saw dust was heat-treated at 180 °C and 200 °C for one hour and compounded with low-density polyethylene, LDPE, at 9, 20 and 37 wt%. The compounded materials were injection moulded into test specimens. Charpy impact assessment of the notched samples of the composites revealed that the peak load, P, and the critical stress intensity factor, Kc, increased with wood content and treatment temperature. While the energy to failure, W , and the critical strain energy release rate, Gc, decreased with wood content, the values were highest in composites made from wood flour treated at 180 °C and reduced in 200 °C treated wood composites. This behaviour revealed that heat treatment of wood flour at the 200 °C resulted in poorer impact properties of the composites. Dynamic mechanical analysis showed an increase in storage and loss modulus of composites made from untreated wood flour relative to the heat-treated ones. Tan delta values were also found to reduce in the heat-treated wood composites as a result of decreased damping. Heat treatment of wood flour at appropriate temperature enhanced both the mechanical and dynamic mechanical properties of the composites.

Mangrove wood fiber (MF) was treated at four different temperatures (120 °C, 140 °C, 160 °C and 180 °C) in order to improve its compatibility with polymer matrix. The chemo-structural, thermal and morphological characteristics of untreated and treated MF were analyzed. The chemical composition of the treated MF showed an increase in cellulose content from 46 to 56% at 120 °C, which decreased at further heating. The non-cellulosic constituents of the fiber were removed as indicated by the reduction in magnitude of absorbance peaks mainly at 3343 cm−1 and 1027 cm−1 in Fourier transform infrared spectroscopy. The X-ray diffraction depicted increased crystallinity with increased temperature due to the conversion of amorphous cellulose and some hemicelluloses to crystalline structures. Color spectroscopy showed higher values of lightness (L*) at 120 °C and 140 °C, with a corresponding increase in chroma coordinate a* and decrease in b* due to the chemical changes that occurred during the heat treatment. Surface morphology by field emission scanning electron microscopy revealed that heat treatment exposed the inner fibrillar feature of fiber, thereby increasing the roughness of the fiber surface. Thermogravimetry analysis further indicated that heat-treated MFs are more stable. Heat treatment improved the tensile strength and modulus of composites as fiber loading increased, while the flexural strength and modulus also showed the same trend. SEM images of tensile fractured surface indicated that the interfacial interaction between the matrix and untreated MF is weaker than the heat-treated specimens.

Glass fibre (GF), nanoclay (NC) and hybrid composites compatibilised with maleic anhydride polypropylene (MAPP) were prepared by extrusion and injection moulding. The fourier transform infra-red spectra revealed the characteristic absorption peaks of MAPP in the compatibilised GF and NC composites. A decrement in the peak intensity of X-ray diffraction patterns of NC composite was obtained as the MAPP content increased indicating a partial exfoliation of NC. The thermogravimetric analysis showed that the incorporation of MAPP into hybrid composites reduced the thermal stability of the material. The dynamic mechanical analysis showed an increase in the storage modulus in the hybrid composites with lower content of MAPP due to the enhancement in the interfacial adhesion between the GF, NC and PP matrix.

Glass fiber reinforced polypropylene composites were compounded with a twin-screw extruder and injection molded. Fiber length distribution study showed that more fiber degradation occurred during processing of the composites with higher fiber loading. Dynamic mechanical analysis carried out showed that magnitudes of storage and loss modulus of composites are improves with the presence of the glass fiber in the system. The incorporation of fibers into the composites has slightly shifted the glass transition temperature to lower values. On the other hand, the presence of the glass fiber reduces the magnitude of tan δ at α-transition dramatically due to the strengthening effect by the fibers. From impact test, it was found that increment in glass fiber loading leads to an increase in peak load, critical strain energy release rate and critical stress intensity factor indicating the improvement in the material toughness. However, there was no significant change observed in fracture energy. With respect to increasing in specimen geometry, despite an improvement in peak load and fracture energy of the impact specimen, the critical strain energy release rate and critical stress intensity factor values were decreased. On the other hand, increase in test temperature resulted in reduction of peak load and critical stress intensity factor due to increment in material ductility, whereby fracture energy and critical strain energy release rate improved.

Polymer composites of polyamide 6,6 reinforced with short glass fiber were prepared by injection molding, conditioned under dry, 50 % relative humidity and wet. Investigations by DSC, DMA and tensile tests were conducted. FLD study showed that more fiber degradation occurred during processing of the composites with higher fiber loading. DSC analysis revealed that the incorporation of glass fiber and moisture into the PA 6,6 matrix resulted in a remarkable decrease in the degree of crystallinity. DMA results revealed the glass transition temperatures were sensitive to moisture absorption and their values moved to a lower temperature upon exposure to moisture. Incorporation of glass fiber into the polyamide 6,6 gave rise to a significant improvement in tensile modulus and tensile strength, while tensile strain was reduced. Exposure to different environments from dry to wet conditions resulted in a decrease in the strength and modulus, while tensile strains decreased.

Polypropylene/E-glass fiber/nanoclay were compounded with a twin-screw extruder and injection molded. Thermal, dynamic mechanical, and impact tests were carried out. Differential scanning calorimetry investigations showed that the incorporation of nanoclay into polypropylene/glass fiber composite shifted the melting temperature ( Tm) to higher values. The degree of crystallinity ( Xc) was strongly influenced by the presence of the glass fiber and nanoclay in the matrix. Dynamic mechanical analysis showed an increase in storage modulus ( E′); indicating higher stiffness of the hybrid composites when compared to the glass fiber composites and the virgin matrix. From the tan δ curves, a strong influence of glass fiber and nanoclay content on the magnitude of tan δmax value was observed. Impact test showed a reduction in the critical strain energy release rate, Gc for hybrid composites with higher nanoclay loading. The stress intensity factor, Kc values showed insignificant effect with the presence of nanoclay and GF.

Hybrid composites of PP/NC/GF were prepared by extrusion and injection molding. Molded specimens were analyzed by XRD, SEM, and TEM, together with characterization of thermal and mechanical properties. XRD results revealed that the interaction between NC particles and the PP matrix results in intercalation of the polymer chains, which increases the clay interlayer distance. TEM results revealed NC particle intercalation. TGA results showed that the incorporation of clay into the GF composite improves the thermal stability of the material. The initial thermal decomposition temperatures also shifted to higher values. Incorporation of GF into PP lowers the tensile strength of the binary composite, indicating poor fiber–matrix interfacial adhesion; however, introducing NC increased the strength of the ternary composites. Tensile modulus was enhanced with the incorporation of GF and further increased with an introduction of NC. Flexural strength and flexural modulus are both enhanced with an increase in fiber loading. The addition of clay nanoparticles further improved these properties.

Red Balau saw dust was heat-treated at 180°C and 200°C for 1 h. Treated and untreated wood flour were compounded with LDPE at 9%, 20%, and 37% by weight and molded in an injection molding machine. Thermal and mechanical properties of the resultant composites were investigated as a function of filler loadings and treatment temperature. Thermogravimetric analysis revealed an increase in degradation peak temperature ( Tp) of the heat-treated wood and composites. DSC revealed a decreasing trend in the degree of crystallinity ( Xc) of the matrix when heat-treated wood was used as filler. On the other hand, untreated wood showed an increase in Xc with increasing wood content. Tensile modulus increased with heat treatment and filler loading. Furthermore, flexural strength and modulus were found to increase with filler loading.

Glass fiber-reinforced PP composites compatibilized with maleic anhydride grafted polypropylene (MAPP) were compounded with a twin-screw extruder and injection molded. The composite specimens were subjected to DSC, DMA, tensile, and flexural property characterizations. DSC results showed that the presence of glass fiber loading and MAPP produced insignificant effect on the melting temperature of the composites. The melting enthalpy was decreased with glass fiber loadings, but no significant change was noted in the crystalline peak temperatures ([Formula: see text]). Incorporation of the compatibilizer led to a reduction in [Formula: see text]. Incorporation of glass fiber reduced the crystalline enthalpy of compatibilized and uncompatibilized systems. DMA results showed that composite properties were affected by the presence of the compatibilizer at low fiber loading (≤14% Vf). Tensile and flexural properties also showed sensible improvement of compatibilized against uncompatibilized composite systems.