Influence of Repeated Injection Molding Processing on Some Mechanical and Thermal Properties of Wood Plastic Composites

Abstract

The influence of repeated cycles of injection molding on some mechanical and thermal properties of wood plastic composites (WPCs) was investigated. Pine wood flour (50 wt%) was mixed with HDPE (50 wt%) containing compatibilizing agent (MAPE, 3 wt%) in a co-rotating twinscrew extruder. The test specimens were produced by injection molding from the pellets dried to the moisture content (MC) of 1%. After the mechanical properties of the WPC test specimens were determined, the failed specimens were subsequently pelletized. These pellets were stored and dried for 4 to 6 h until the repeated injection was molded. These processes were repeated seven times. The results revealed that the flexural strength of WPCs increased by about 5.26% from the original granules to the third injection cycle, but further increments in the number of cycles decreased the flexural strength. The tensile strength and tensile modulus of the WPC specimens increased until the third cycle of injection molding while they tended to decrease after the third injection cycle.

Effect of Processing Technology, Nanomaterial and Coupling Agent Ratio on Some Physical, Mechanical, and Thermal Properties of Wood Polymer Nanocomposites

“…This might be attributed to the well-distributed ZnO nanoparticles in the WF and polymer matrix. This finding is consistent with earlier research [10,[14][15][16][17].…”

Quantifying effects of compositional variations on microstructural properties of polypropylene-wood fiber composites by melt rheology and tensile test data

“…Using of several additives and various formulation and/or processing attempts have been extensively studied so far to increase interfacial adhesion between components of WPCs. 3–15 Maleic anhydride grafted polyolefins (PE-g-MA, PP-g-MA, etc.) appear to be the most effective compatibilizers or coupling agents for WPCs.…”

A critical review on mechanical and morphological characteristics of injection molded biodegradable composites

“…Even though maximum tensile strength of the PLA/graphite composite was more in terms of specific tensile strength (σ/ρ), the foam fabricated PLA graphite composite was noticeably superior. Kaymakci and Ayrilmis [ 85 ] examined HDPE with pine wood flour (WF) containing partially biodegradable composite. Up to the third injection cycle, tensile strength of test specimens increased by 3.7 percent from the unreinforced material.…”

“…This is shown in Figure 19. Kaymakci and Ayrilmis [ 85 ] investigated the effect of repeated injection molding cycles on HDPE plus pinewood‐containing composite. Flexural strength of the composite increased by 5.26 percent while elastic modulus of the composite increased by only 2 percent.…”

“…The graphite was well dispersed through the polymer matrix providing an indication that blending of constituents of the composite was done correctly. Kaymakci and Ayrilmis [ 85 ] examined the interfaces between the blended matrix of a PLA50‐HDPE50 containing WF using SEM images. The addition of WF increased the overall complexity in terms of an improvement in mechanical properties especially the occurrence of low elongation at break.…”