Silane crosslinking of plasticized poly(vinyl chloride)

In this study the use of three different types of aminosilanes for crosslinking plasticized PVC was investigated. The processing techniques used were milling, followed by press molding and extrusion. The processing conditions were carefully adjusted to minimize premature crosslinking. Crosslinking was carried out by immersing the samples in hot water for 4 h. Gel content was determined by Soxhlet extraction in tetrahydrofuran. 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 crosslinking plasticized PVC, enabling adequate gel content to be obtained to improve the properties at elevated temperature, while avoiding premature crosslinking. Compounds stabilized with either tin or Ba/Zn possessed adequate thermal stability at 190 degrees C. No changes were seen in the tensile properties at room temperature, but significant improvements were obtained at 100 degrees/130 degrees C. Results obtained using thermomechanical analysis showed increased penetration resistance with increase in gel content. (C) 1998 John Wiley & Sons, Inc.