CRYSTALLIZATION OF ISOTACTIC POLYPROPYLENE: PIGMENT, NUCLEATING AGENT AND RECYCLING EFFECTS

摘要

In order to produce thermoformed products of consistent quality, an understanding of the effect of material and process parameters on end part performance is necessary. In this investigation the effect of pigment, nucleating agent, and recycling regrind on the nucleation of homopolymer isotactic polypropylene have been studied. Differential Scanning Calorimetry was used to reveal the effect of these additives on the crystallinity, type of crystals, crystallization and melting temperatures at different cooling rates. It has been found that percentage cystallinities were increased as the concentration of the nucleating agent and first and fifth generation regrinds increase up to the saturation level. Although more hexagonal β crystals were formed by increasing the concentration of the pigment, the enthalpy of fusion was decreased.