EXTRUSION OF POLYPROPYLENES WITH ORGANIC PEROXIDES

摘要

A process to form a polypropylene composition comprising combining at a temperature within a range from 190°C to 320°C a polypropylene resin and within the range from 0.01 wt% to 3 wt% of at least one organic peroxide, by weight of the polypropylene composition and within a range from 100 to 4000 ppm each of phosphorous- and hindered phenol antioxidants; the polypropylene resin comprising at least 50 mol% propylene, and having a molecular weight distribution (Mw/Mn) greater than 6, a branching index (g') of at least 0.97, and a melt strength greater than 10 cN determined using an extensional rheometer at 190°C. The resulting polypropylene composition comprises at least 50 mol% propylene and has a peak extensional viscosity of greater than 500 kPa•s at a strain rate of 0.01 sec-1 (190°C) and a melt strength of at least 40 determined using an extensional rheometer at 190°.