Liquid oxygen compatibility and toughness of epoxy resin modified by a novel hyperbranched polysiloxane

Abstract

Liquid oxygen compatibility and toughness of epoxy resin are improved by adding a novel hyperbranched polysiloxane (HBPSi) containing a large number of silicon-oxygen bonds. At first, HBPSi is successfully synthesized via dipropylene glycol and triethoxy vinyl silane, and the catalyst is barium hydroxide. A series of characterization results can prove that HBPSi have been successfully synthesized. Then, the HBPSi is used to modify epoxy resin. Char yield is increased 10.39% by only 5 wt% loading with HBPSi in epoxy resin. Thermogravimetric analysis (TGA) result show that epoxy resin modified by HBPSi shows higher thermal properties. And the liquid oxygen sensitivity coefficient (IRS) of the modified resin is also reduced from 7% to 0%, and the liquid oxygen compatibility of the resin is improved. The elongation at break is increased 84.8% by only 3 wt% loading with HBPSi in epoxy resin, and when the amount of HBPSi added reaches 10 wt%, the IRS of the modified resin is reduced to 0%, which means that it is compatible with liquid oxygen, and the elongation at break of the resin is improved by 24.8% toughness compared with the pure resin. These results indicate that HBPSi modified epoxy resin can effectively enhance its liquid oxygen compatibility and toughness.