Injectable composites mechanical properties improvement

Mucha and Krolikowski [39], studying the kinetics of isothermal crystallization of polypropylene, noticed that addition of a filler, e.g., wood flour, efficiently reduces the time of crystallization. This is desirable in the processing of composites as it reduces the injection-forming cycle and forms small spherulites improving the mechanical properties of composites. Transcrystalline structures are formed during polymer crystallization in the presence of lignocellulosic filler. 

The reinforcement of thermoplastics, notably polypropylene (PP) and polyamide (PA), with short glass fibers is a classical method to improve polymer mechanical properties. Fibers are dispersed more or less homogeneously in the polymer by melt compounding techniques such as twin screw extrusion to produce compounds ready for injection molding. Molded parts benefit from the better mechanical properties of the reinforcing fibers as the fibers bear a considerable part of the load applied to the composite structure. 

---