Preparation and properties of novel resins based on cyanate ester and hyperbranched polysiloxane

Abstract

A novel kind of high performance cyanate ester (CE) resins was developed by copolymerizing 2, 2′-bis(4-cyanatophenyl) iso-propylidene with hyperbranched polysiloxane (HBPSi). HBPSi was synthesized through the hydrolysis of 3-(trimethoxysilyl)propyl methacrylate. The effect of the stoichiometry between CE and HBPSi on the structure and property of modified CE resins was investigated systematically. Results show that the incorporation of HBPSi can not only effectively promote the curing reaction of CE, but also increase the apparent free volume fraction of the cured network, and thus brings significant influence on the performances of the resultant resin. The impact strength of modified CE resin with 15 wt% of HBPSi is 19.6 KJ/m2, which is more than 2 times of that of pure CE resin. In addition, the toughened CE resin also exhibits better thermal stability, dielectric property and moisture resistance than original CE resin. The novel modified CE system successfully overcomes the key shortcomings of original CE resin, importantly, this work demonstrates that the new method proposed in this work for modifying CE resin by hyperbranched polymers maybe a right road to be used for developing high performance thermosetting resins.