Preparation and characteristics of silicone grafted poly(ethersulfone)s

Abstract

The need for engineering plastics with better, specialized properties is increasing in the world market. In particular, poly(ethersulfone) (PES) have achieved an excellent position in the global market among other thermoplastic polymers by virtue of their superior properties, such as thermal stability, high heat-distortion temperature, chemical inertness, electrical performance, and flame retardancy. The characteristic feature of PES is highly stable diarylsulfone groups with sulfur in its highest state of oxidation as a highly electronegative sulfone. These polymers are applied in the electronics, aircraft, automobile, medical, and aerospace industries as coatings, adhesives, and composites. Silicone-containing polymers have attracted powerful interest for many years, and have been widely used to provide enhanced material performance. These polymers have many attractive attributes such as flexibility, low surface tension, excellent electrical properties, good weatherproofing ability, non-flammability, and high gas permeability, as well as stability toward heat and chemicals. In general, the introduction of stable functional groups as substituent has been of interest to materials science researchers, as they can be used to impart special functionality to polymers as well as to improve processability. In recent research by our group, an efficient method to fabricate allyl-terminated polymers based on bisphenol A polycarbonate and vinyl-terminated polysulfone were studied. These novel classes of polymers are of considerable interest for a number of applications, including those involving high-temperature use and membranes. These results and our curiosity about the polymer containing siloxane groups prompted us to investigate the structure-related properties of silicone polymers. In this paper, we synthesized and characterized a series of grafted silicone PES. Siloxane was grafted into PES, which have propenyl functionality in their main chain, through hydrosilylation reaction. Propenyl-PES, a highly reactive precursor to hydrosilylation, was synthesized in a different manner and fashion to that of previous reports. To vary the content of grafting silicone in the polymer main chain, the degree of propenyl functionality in the propenyl-PES was varied. We focus specially on the influence of the chemical structure and contents of silicone content to thermal properties, contact angle, and surface morphology. It was anticipated that its incorporation into a polymer chain would result in a polymer with enhanced water repellant and hydrolytic stability.