Polyvinyl butyral chemically modified with a silane agent in the molten state

Abstract

Recycled polyvinyl butyral (PVB) from the automotive industry was chemically modified by melt mixing with a vinyl trimethoxysilane (VTMS) silanation reagent, which tends to react with the hydroxyls present in the PVB structure to generate crosslinked bonds between the chains. This chemical modification resulted in the improvement of the solvent resistance to organic solvents without deeply impairing the mechanical properties of the polymer. The mixing of PVB with VTMS was carried out in an internal mixer equipped with roller type rotors and the mixture was subsequently compression molded. Soxhlet extraction confirmed a 70% increase in the modified polymer gel content. Depending on the mixing time, the dynamic crosslinking reactions occurring during this time did not prevent the compression molding of the polymer. Furthermore, static crosslinking was observed during compression molding, which resulted in the maximum crosslinking degree and solvent resistance. DMA analysis indicated different molecular structures produced by different mixing times and varying static and dynamic crosslink ratios. Infrared spectroscopy (FTIR) indicated that dibutyl sebacate was the main plasticizer of the recycled PVB. Thermogravimetric analysis suggested that the molecular structure of the modified polymer affected the decomposition of PVB. POLYM. ENG. SCI. 56:971–979, 2016. © 2016 Society of Plastics Engineers