Abstract. Polypropylene (PP) was blended with ethylene vinyl acetate copolymer (EVA) to form PP/EVA polymer blends. Wood powder (WP) was mixed into these blends at different weight fractions (50/50/0, 45/45/10, 40/40/20, 35/35/30 w/w PP/EVA/WP) to form PP/EVA/WP blend composites. The morphology, as well as thermal and mechanical properties, of these composites were investigated. The scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) results confirm the immiscibility of EVA and PP in the blends, and show that WP is primarily concentrated in the EVA phase. DSC results further show that the EVA crystallization behaviour is significantly influenced by the presence of WP. Dynamic mechanical analysis (DMA) results confirm immiscibility of PP and EVA, as well as an interaction between EVA and WP. Interaction between EVA and WP was further confirmed by Fourier-Transform infrared spectroscopy (FTIR). TGA results show that the blend composite degradation was also influenced by the presence of WP.

Abstract. In this study, polypropylene (PP)/linear low-density polyethylene (LLDPE) and maleic anhydride grafted polypropylene (MAPP)/LLDPE blend systems were comparatively investigated. The blends and composites contained equal amounts of the two polymers, and the compatibility and miscibility between the two polymers were investigated. Composites with 10, 20 and 30 wt% wood powder (WP), but still with equal amounts of the two polymers, were prepared and investigated. The morphologies, as well as mechanical and thermal properties, of the blends and the blend composites were investigated. The MAPP/LLDPE blend and composites showed better properties than the PP/LLDPE blend and composites as a result of the stronger interfacial interaction between MAPP, LLDPE and WP. The SEM and DSC results of the PP/LLDPE/WP blend composites showed that WP located itself more in the LLDPE phase. In the MAPP/LLDPE/WP composites the WP was in contact with both polymers, although it had a greater affinity for MAPP. The TGA results show that the MAPP/LLDPE blend and composites are more thermally stable than the PP/LLDPE blend and composites.

In this study, the main focus was on the effect of wood fiber (WF) content and particle size on the morphology and mechanical, thermal, and water-absorption properties of uncompatibilized and ethylene glycidyl methacrylate copolymer (EGMA) compatibilized ethylene vinyl acetate copolymer-WF composites. For uncompatibilized composites, the tensile strength decreased with increasing WF content, whereas for compatibilized composites, the tensile strength initially decreased, but it increased for composites containing more than 5% WF. Small-WF-particle-containing composites had higher tensile strengths than composites containing larger WF particles, both in the presence and absence of EGMA. WF particle size did not seem to have much influence on the degradation behavior of the composites, whereas water absorption by the composites seemed to be higher in composites with smaller particle sizes for both compatibilized and uncompatibilized composites.

The morphology and properties of blends of PP/HDPE and MAPP/HDPE blends, and their composites with wood powder, were investigated in this paper. The blends showed two-phase morphologies, and MAPP interacted better than PP with HDPE, while the WP interacted more strongly with MAPP. Although the different components in the blends were immiscible, they showed one crystallization peak. MAPP and HDPE showed separate crystallization peaks in the composites, and this separation of the crystallization became more resolved with