Effect of epoxidized liquid CTBN on thermal, mechanical, and rheological properties of epoxy resin

Liquid rubbers are widely used as reinforcement fillers and toughening agents for improvment of toghness and modification of epoxy resins. In the present work, epoxy groups were introduced into the liquid carboxyl terminated poly butadiene-acrylonitrile (CTBN) liquid rubber by an epoxidation reaction to increase the resin/rubber interaction. Epoxidation reaction was performed with hydrogen peroxide and acetic acid in the presence of sodium tungstate. The prepared epoxidized CTBN (ECTBN) was used as a reinforcment filler in the matrix of epoxy resin. The thermal, mechanical, and rheological properties of epoxy resin were examined in the presence of ۵-۲۰ phr CTBN and ECTBN liquid rubbers as modifiers. The neat epoxy resin had a higher thermal resistance than the rubber-filled samples due to its higher crosslinking density. The epoxy resin containing ECTBN exhibited a higher thermal resistance and slower degradation rate than the epoxy resin containing CTBN. Epoxidation caused the Tg of the rubber and the epoxy resin to shift to higher temperatures. The sample containing ECTBN rubber has a higher initial viscosity than the sample containing CTBN rubber. As the amount of rubber is increased, the initial viscosity is enhanced and the curing rate is reduced. The results also demonstrated that the epoxidation of rubber can change the elastic modulus, ultimate strength, elongation at break, and other properties of epoxy resin.

کلیدواژه ها:

Epoxy resin ، Liquid rubber ، CTBN ، Epoxidation ، Crosslinking density