SILANE CROSS-LINKING OF PLASTICIZED POLY(VINYL CHLORIDE)

In this study the use of three different types of aminosilanes for cro sslinking plasticized PVC was investigated. The processing techniques used were milling, followed by press molding and extrusion. The proces sing conditions were carefully adjusted to minimize premature crosslin king. Crosslinking was carried out by immersing the samples in hot wat er for 4 h. Gel content was determined by Soxhlet extraction in tetrah ydrofuran. Tensile properties were measured at room temperature and at 100 degrees C or 130 degrees C. Bis(gamma-trimethoxysilylpropyl)amine was found to be the best of the three silanes investigated for crossl inking plasticized PVC, enabling adequate gel content to be obtained t o improve the properties at elevated temperature, while avoiding prema ture crosslinking. Compounds stabilized with either tin or Ba/Zn posse ssed adequate thermal stability at 190 degrees C. No changes were seen in the tensile properties at room temperature, but significant improv ements were obtained at 100 degrees/130 degrees C. Results obtained us ing thermomechanical analysis showed increased penetration resistance with increase in gel content. (C) 1998 John Wiley & Sons, Inc.