A study of Rheological Properties of Peroxide-degraded Polypropylene

Some results obtained during controlled degradation experiments of polypropylene have been presented. The experiments were carried out in a co-rotating twin-screw extruder using peroxide to promote chain scission. Peroxide concentration levels were in the range 0.02-0.6 %wt. It was found that the effect of peroxide concentration to be the most dominant variable. As a result the melt flow index of the resin increased dramatically and the flow curve of the resin shifted to lower viscosities as the concentration of the peroxide increased. The purpose of this study was to characterize the influence of peroxide degradation on rheological properties of polypropylene homopolymer. Results showed that rheological properties of PP change with peroxide degradation, significantly. With increasing of peroxide concentration complex viscosity and torque decrease. Degraded resins had more Newtonian behavior than original resin. Storage and loss modulus decrease with peroxide concentration. Dissipation factor and complex compliance increase with increasing DCP concentration.

Keywords:

Polypropylene , Controlled- rheology , rheological properties , peroxide degradation