Wood plastic composites based on recycled poly(ethylene terephthalate) and poly(butylene adipate-<i>co</i>-terephthalate)

Abstract

In this work, wood plastic composites (WPCs) were prepared from a selected recycled poly(ethylene terephthalate) (rPET)/poly(butylene adipate-co-terephthalate) (PBAT) blend ratio. The 70/30 (wt%/wt%) (rPET)/PBAT blend was incorporated with six loadings of wood flour (WF) (5–30 wt%) through melt mixing on a twin screw extruder, followed by injection molding. The mechanical properties of the WPCs, in terms of the impact, tensile and flexural strength, Young’s modulus and elongation at break were determined as a function of the WF content. The results showed that the impact strength and elongation at break of the WPCs were all lower than those of the neat blend. However, the WPCs at 5–15 wt% WF and all had higher impact strength and elongation at break than the neat rPET, respectively. In contrast, the tensile strength of all the WPCs was much lower than that of the neat rPET, and only at high WF content (20–30 wt%) exhibited higher tensile strength than the neat blend. In addition, the Young’s modulus and flexural strength of the WPCs were all higher than those of the neat blend. However, the WPCs at 5 and 10 wt% WF had lower Young’s modulus than the neat rPET, while all the WPCs had lower flexural strength than the neat rPET. Moreover, the WF acted as a nucleating agent, which consequently gave rise to the increased crystallization temperature, degree of crystallinity and melting temperature of the rPET component in WPCs, as revealed by the differential scanning calorimetry. However, thermogravimetric analysis showed a decrease in the thermal stability of the rPET/PBAT blend upon addition of WF. Meanwhile, all the WPCs exhibited an enhanced water uptake over the neat blend (up to 5.7-fold at 30 wt% WF).