The effect of filler type on the mechanical, thermal and rheological properties of cellulose-filled thermoplastic composites
Published: 2010
Han, Y.
Gardner, D. J.
Nader, J.
Publication Name: Proceedings of the International Convention of the Society of Wood Science and Technology and United Nations Economic Commission for Europe -- Timber Committee
Abstract:
Over the past several decades, interest in the development of new composite materials derived from cellulose-based fillers and thermoplastic polymer matrices has received considerable attention. The mechanical and rheological properties of the composites are found to be a function of the particle size, filler loading, dispersion and the interfacial interaction between the fillers and polymer matrix. The role of cellulose-based filler type and size effect has not been studied in great detail. In this study, the effects of adding microcrystalline cellulose with variable particle sizes (15, 50 and 90 µm), alpha cellulose (60 µm), silicified microcrystalline cellulose (50 µm) and wood flour (70 µm) on the mechanical, thermal and rheological properties of polystyrene composites were investigated. High impact polystyrene (HIPS) composites with varying concentrations from, 5 to 20 wt. percent of cellulose-based fillers were prepared by thermal compounding followed by injection molding. It was observed that the larger sized fillers produced higher flexural modulus values than the smaller sized fillers. Also, the tensile strength increased with particle size. Particle size did not seem to have much influence on the thermal degradation behavior of the composites. Results show that MCC has increased thermal stability when compared to SMCC. SMCC also shows better mechanical properties than untreated MCC. Significant differences were found in size and shape of the AC and MCC filler materials. Alpha cellulose had the lowest circularity, aspect ratio and solidity values. The increased viscosity was more pronounced when smaller sized fillers were used. Because of the lower thermal mixing viscosities, future experiments may prove larger fillers sizes to have better dispersion with better matrix interactions than composites made from small sized fillers.