Effects of Filler Type and Content on the Mechanical, Morphological, and Thermal Properties of Waste Casting Polyamide 6 (W-PA6G)-based Wood Plastic Composites

Cast polyamide 6 (PA6G), trade name Castamide, is a semi-crystalline polymer widely used in the engineering plastics industry. There is a need to recycle valuable waste (W)-PA6G generated during part manufacturing of this polymer (approximately 30%). This study attempts to utilize W-PA6G in the manufacture of wood-plastic composites as a polymeric matrix. The effect of lignocellulosic filler type (FT) and filler content (FC) on the mechanical, morphological, and thermal properties of W-PA6G-based composites were investigated. During manufacturing, N-butyl benzene sulfonamide (N-BBSA) and lithium chloride (LiCl) were utilized as a plasticizer and a melt temperature-lowering salt, respectively. The rice husk (RH) and Uludag fir wood flour (WF) filled W-PA6G-based composites were successfully manufactured using a combination of extrusion and injection molding. Compared to RH filled composites, WF filled composites provided better tensile and flexural properties (both strength and modulus) at 20% and 30% filler contents. Morphological study showed the nonhomogeneous distribution of fillers in the polymeric matrix. Lignocellulosic filler resulted in reduced melting temperature and crystallinity of W-PA6G-based composites. This reduction was more pronounced in RH filled composites.