An Additive Model to Predict the Rheological and Mechanical Properties of Polypropylene Blends Made by Virgin and Reprocessed Components

In this work, an additive model for the prediction of the rheological and mechanical properties of monopolymer blends made by virgin and reprocessed components is proposed. A polypropylene sample has been reprocessed more times in an extruder and monopolymer blends have been prepared by simulating an industrial process. The scraps are exposed to regrinding and are melt reprocessed before mixing with the virgin polymer. The reprocessed polymer is, then, subjected to some thermomechanical degradation. Rheological and mechanical experimental data have been compared with the theoretical predictions. The results obtained showed that the values of this simple additive model are a very good fit for the experimental values of both rheological and mechanical properties.

Study on Rapid Manufacturing of CAFÉ Injection Mold

Rapid tooling developed from the rapid prototyping technology is a new method and technology of mold making, and this paper mainly studies the composite aluminum-filled epoxy (CAFÉ) mold，which is one of the rapid bridge toolings, applied to thermoforming of the plastic parts. The material formula of the CAFÉ mold with E51 as matrix is developed, and using the formula we have made the CAFÉ mold for the back shell of a cell phone charger, which is installed at the injection molding machine to do the test and finally successfully obtain the polypropylene sample. In addition, the process of making the CAFÉ mold is described in detail in the paper.