Crystallization of Different Polypropylene Matrices in the Presence of Wood Fillers

摘要

The increasing global energy crisis and ecological risks in recent years have led to the interest in lignocellulosic fillers reinforced polymer composites. In this study, the nucleation ability of pine wood in polypropylene (PP) matrices was studied by differential scanning calorimetry. PPs with different melt flow index values (in range 3.2-25 g/10 min.) were used as the polymer matrix. Moreover, a new technique of wood treatment using gamma-irradiation was used. The experimental results clearly show that the nucleation activity of the wood particles is strongly dependent on the rheological parameter (e.g., MFI) of PP matrix. The composites containing PP matrix with lower MFI exhibited higher degree of crystal conversion, lower half-times of crystallization, and higher crystallization temperatures. Moreover, the applied gamma-irradiation of wood resulted in a negative effect on the crystallization rate of PP matrix and a distinct deterioration of the nucleation ability of wood surface. The interesting differences in nucleation activity of wood have been interpreted in the context of polymer chains length and relaxation times during crystallization. This article will spotlight the nucleating efficiency of filler, which is critical in polymer processing e.g., optimization of injection molding cycle time of composite materials. (C) 2014 Society of Plastics Engineers