In this study, the influence of coupling agent concentration (0 and 3 wt%), wood fiber content (50, 60, 70, and 80 wt%), and size (40–60, 80–100, and 160–180 mesh) on the mechanical properties of wood/high-density-polyethylene (HDPE) composites (WPCs) was investigated. WPC samples were prepared with poplar wood-flour, HDPE, and polyethylene maleic anhydride copolymer (MAPE) as coupling agent. It was found that the tensile properties and the flexural properties of the composites were improved by the addition of 3 wt% MAPE, and the improved interfacial adhesion was well confirmed by SEM micrographs. It was also observed that the best mechanical properties of wood/HDPE composites can be reached with larger particle size in the range studied, while too-small particle size was adverse for the mechanical properties of wood/HDPE composites. Moreover, the tensile modulus, tensile strength, and flexural strength of WPCs decreased with the increase in fiber content from 50 to 80 wt%; the flexural modulus of WPCs increased with the increase in fiber content from 50 to 70 wt% and then decreased as the fiber content reached 80 wt%. The variances in property performance are helpful for the end-user to choose an appropriate coupling agent (MAPE) concentration, wood fiber content, and particle size based on performance needs and cost considerations. 相似文献
The effects of wood fibers on the rheological and mechanical properties of polystyrene/wood (PS/wood) composites were investigated. The composites with different ratios of PS and wood were prepared by means of internal mixer and, additionally, two different sizes of the wood particles were used, such as ~100 and ~600 µm. The rheological properties were studied using capillary rheometer, apparent shear rate, apparent shear stress, apparent viscosity, power law index, and flow activation energy at a constant shear stress were determined. The rheological results showed that the shear stress–shear rate variations obeyed a power law equation, and the composites exhibited shear thinning. The flow activation energy of the composites increased with the addition of wood particles. Mechanical results showed that stress at break of the composites was higher than that of pure PS, whereas the strain at break and impact strength of the composites were lower than that of PS. In addition, the mechanical properties of the present composites were improved when the small size of wood particles were incorporated. 相似文献
The mechanical properties of polystyrene reinforced with a mixture of hardwood aspen chemithermomechanical pulp (CTMP) and surface-treated glass fiber have been studied. The adhesion of cellulose fiber to glass fiber as well as to thermoplastics improved thanks to various surface treatments of CTMP, e.g. coating with polymer+isocyanate or with silane, and grafting with polystyrene. In general, compared with non-treated CTMP-filled composites, the mechanical properties improved when surface-treated wood fiber was used as a filler. Experimental results indicate better compatibility between treated wood fiber and surface-treated glass fiber as well as polystyrene and, consequently, the mechanical properties were enhanced. 相似文献
Glass fibers/drumstick fruit fibers (GF/DFF) reinforced with epoxy hybrid composites were fabricated using the rule of hybrid mixtures. Properties like impact strength, frictional coefficient, dielectric strength, and chemical resistance were studied. Treated and untreated DFF were reinforced along with GF to assess two different epoxy hybrid composites. The effect of alkali treatment on the above-mentioned properties was also studied. It is observed that the impact strength and frictional coefficient properties of the hybrid composites increased with increase in glass fiber content. Performance was elevated for alkali-treated DFF hybrid composites when compared with untreated DFF. Chemical resistance was significantly increased for all chemicals except carbon tetrachloride due to attack of chloride hydrocarbons on the cross-linking of the epoxy. Elimination of amorphous hemi-cellulose by alkali treatment improved the properties. Fiber-polymer interactions were studied by scanning electron microscopy on the cross-sections of fractured surfaces. 相似文献
—The mechanical properties of polystyrene filled with chemithermomechanical pulp and wood residues of softwood and hardwood species, which were precoated with phthalic anhydride and various polymers, e.g. polystyrene and PVC, have been investigated. The extent of improvement in the mechanical properties of the composite materials depends on the coating composition, the concentration of phthalic anhydride, the nature of the coated polymers, as well as the concentration of fiber, the nature of the wood species, and the nature of the pulps. Experimental results indicate that phthalic anhydride acts as a coupling agent, but when its performance was compared to that of poly[methylene (polyphenyl isocynate)], it seemed inferior to the latter. 相似文献
The influence of coupling agents on the melt rheological properties of natural fiber composites has been investigated in this work using capillary and rotational rheometers. Scanning electron microscopy was also employed to supplement the rheological data. It was found that molecular weight and molecular weight distribution of the polymer matrix and coupling agent characteristics influence the filler wetting and the melt flow properties of the filled composites. Generally, low molecular weight and narrow molecular weight distribution polyethylene matrix provides relatively larger increase of the viscosity of the composites. Coupling agents tend to increase the resistance to shearing, but wall slip effects may interfere with the measured values, especially at very high filler loadings. Entrance pressure loss in capillaries is also influenced by polymer matrix and coupling agent used.