Effect of Processing on Ductility and Strength of Kevlar/Polyethylene Composites
Polymerization-filled composites (PFC) and melt-blended composites (MBC) were prepared to compare their mechanical properties. Improved ductility was obtained for PFC resulting from better fiber-polymer interfacial adhesion. On the other hand, ductility decreased upon increasing fiber content and strain rate, while normalized strengths were almost unchanged. This indicates that matrix and composites have similar responses to strain rate. Tensile strengths were compared with several modified models to include the effect of critical fiber aspect ratio. It was found that the numerical integration model with perfect interfacial bond in combination with Rosen's method for the critical fiber aspect ratio gave the best predictions among all the models tested. The results clearly show that the preparation technique has an effect on tensile strength of composites in relation with fiber distribution and interfacial adhesion.