Estudo da viabilidade do processamento pelo método ascendente de diferentes polipropilenos modificados

Abstract

In the manufacture of tubular films by ascendant method the melt polymer is submitted to strain and elongational flow in the end of matrix. In this process the material must present high values of melt strength to support high shear stress to avoid film rupture. The isotactic polypropylene (iPP) due to the structural characteristics has low melt strength that does not allow this kind of process since the film breaches during stretching. The change in the elongational viscosity of iPP by incorporation of long chain branching or crosslinking improves its performance in this type of process. The aim of this work was to study the viability to production of tubular films by ascendant for different modified polypropylenes.