COMPATIBILISERS IN WOOD-POLYETHYLENE COMPOSITES AND THERE INFLUENCE ON THE MECHANICAL PROPERTIES AND WATER ABSORPTION
In this paper the improvement of the compatibilisation between wood particles and HDPE-matrix composites was investigated. A series of methods of compatibilisation and modification of the composite were performed and compared. The objective was to find the most suitable method for industrial up scaling, based on mechanical properties obtained. The tensile test of samples was performed, before and after water absorption investigation. Water absorption of composites was studied at two different temperatures: 25°C and 50°C. The water absorption kinetics was studied and it was found that water is absorbed in composites following the kinetics described by the Fick`s diffusion theory. After absorption, an important loss of properties was observed, due to the destruction of the wood structure due to the water absorbed.
Thermoplastics Reinforced with Wood Fillers: A Literature Review
Abstract Problems concerning the processing of thermoplastics reinforced with wood fillers are discussed. The high level of moisture absorption by the filler, its poor wettability, as well as the insufficient adhesion between untreated filler and the polymer matrix are reasons for the low tensile strength and high moisture sorption of composites. These shortcomings of composites can be prevented by the modification of the interface. The fiber-matrix compatibility and the composites properties can be improved by using some physical (e.g., steam explosion, corona, cold plasma) and chemical (cross-linking and acetylation of cellulose, grafting, use of coupling agents) methods. Modified wood-polymer interaction mechanisms are complex and specific for each definite system and processing conditions. Cellulose cross-linking and acetylation reduce hygroscopicity and swelling of wood and wood composites. Grafting of styrene to wood is effective for wood-polystyrene systems. The best coupling agent for wood-thermop...
Composite Molded Products Based on Recycled Thermoplastics and Waste Cellulosics. II. Kenaf Fiber-Recycled PE Composites
The mechanical properties and dimensional stability of kenaf fiber-filled recycled polyethylene (PE) composites have been evaluated at room temperature and after immersion in boiling water. The effects of levels of kenaf fiber and modified polyethylenes, as the coupling agents, on the performance of the composites have been discussed. Maleated PE offered best balance in mechanical properties and dimensional stability compared to those of chlorinated PE and chlorosulphonated PE. The variations in properties with change in concentrations of fiber and a coupling agent (i.e., chlorinated PE) have been statistically analyzed based on an empirical quadratic model. Good correlations of the experimental data for the physico-mechanical properties were obtained.