MELT CHARACTERISTICS OF POLY-LACTIDE (PLA) NATURAL FIBRE-COMPOSITES

摘要

Melt processing characteristics and thermal properties of cellulosic fibre-polylactide (PLA) composites have been investigated. A twin screw mixer is used for composites compounding of PLA with five agro-wastes natural fibres obtained through two process paths. Distribution of torque, temperature and energy of the mixing process are generated directly from the twin screw mixer. Specific mechanical energy is calculated from the torque-time relationship while thermal properties (glass transition, melting and crystallization temperatures) are deduced from results of Differential scanning calorimetry test. Results show that ample time is required for Theological changes to take place in composites while changes in neat PLA commenced almost immediately. It is found that lower mechanical energy is consumed in compounding composites than neat PLA and this result in improved melt processing characteristics of composites compared to neat PLA. Analyses of thermal properties show that addition of fillers promotes lowering of inter molecular forces at the fibre-matrix interface giving rise to higher chain mobility. Thus, lower glass transition temperature with increase melting results.