Processing-morphology-performance relationship of injected polypropylene blends and composites

VALERIA PETTARIN; CAREN ROSALES; MARIA ALEJANDRA COSTANTINO

Conferencia; International Conference on Polymers and Mould Innovations,; 2018

Many thermoplastic-composites are processed by an injection molding process. When dealing with semicrystalline polymers such as polyolefins, morphology is an important feature since it greatly affects thermal and mechanical performance of processed parts. The morphology of melt-crystallized polymers is known to be related to the fabrication technique. In composites and blends, morphology depends on factors such as the affinity and compatibility of the filler with the matrix, the matrix viscosity and the applied thermo-mechanical level, which depends on the processing conditions. The understanding of the fracture, microvoide formation and mechanics of composites and blends is crucial for engineers. In this work, the relationship be-tween processing and performance is reviewed for different injected polypropylene pieces: polypropyl-ene/clay nanocomposites, polypropylene/aluminum flakes microcomposites, and polypropylene/polyethylene blends. A complete characterization, including morphological and mechanical characterization is presented. Microstructure and morphology of materials were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarized optical microscopy (POM). Performance of pieces was evaluated by means of quasi-static fracture tests. The effects of the molding process and of the filler on the microstructure and fracture properties of the polymer composites are reported. Also, the effect of the occurrence of in-homogeneities, such as weld lines or flow lines is summarized.