Compósitos polipropileno/mica: efeito da granulometria e do tratamento de acoplagem na carga.

Abstract

The influence of mica content and granulometry on mechanical, thermal and thermo-mechanical properties of compression molded polypropylene composites was investigated. Filler at 10-40% weight contents were added to polypropylene on an internal mixer coupled to a Haake-Buchler's Rheocord System 90 Torque Rheometer. Experimental results showed filler granulometry to affect the composite's properties and that best results were obtained for the mica sieved through an ABNT n° 200 (d = 75 jura) sieve. It is believed that this filler size promotes better filler-matrix interaction, better filler dispersion and a greater number of tie molecules in the matrix cristalline structure. Mica surface treatment with an UCARSIL system PCI A PC IB considerably increased the composite's properties up to 20% filler content. By contrast mica surface treatment with an A-174 silane coupling agent was ineffective to promote better properties in this system.