Pressure Dependence of the Curing Behavior of Epoxy Resin

Abstract

ABSTRACT:Epoxy resin of bisphenol A type/aromatic diamine system was cured under high pressure up to 1,000 MPa. Pressure dependence of the mechanical and thermal properties of cured epoxy resin was investigated. Mechanical properties such as Young's modulus, tensile strength and elongation at break, and the glass transition temperature decreased with increasing curing pressure, though high pressure showed no effect on density. The swelling ratio of the cured resin with toluene increased with increasing curing pressure, and the IR absorption band assigned to epoxy group remained for the epoxy resin cured at high pressure. These results show that high curing pressure increases the glass transition temperature, restricts the diffusion and collision of molecules and the rate of curing reaction slow down. Poor mechanical and thermal properties for the epoxy resin cured under high pressure are considered to be due to insufficient curing of these resins.KEY WORDS Ultrahigh Curing Pressure/ Epoxy Resin/ Thermal Property / Mechanical Property / Curing Behavior / substances. Epoxy resin is used in many important fields as an excellent thermosetting adhesive and protective for metals and semiconductors. A lot of studies on the curing mechanism of epoxy resin 1 and also on the residual stress 2 at the interface between metal and epoxy resin were reported, but little is known about the effects of pressure on curing behavior. It is well known that many reactions which could not be carried out under normal pressure, for example, polymerization of ethylene, can be carried out under high pressure. 3 Pressure is considered to take part in various reactions for a many In this study, epoxy resin was cured under an ultrahigh pressure up to 1000 MPa, and the pressure dependence of the mechanical and thermal properties of cured epoxy resin was investigated. EXPERIMENT AL MaterialsA liquid diglycidyl ether of bisphenol A type epoxy resin (Epikote 828; Shell Chemical Co.;

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