Protection of epoxy resin against thermo-oxidation via cocuring epoxy/resole (II)

Abstract

Cocured materials based on resole/epoxy in weight ratios of 100/0, 50/50 and 0/100 were prepared by using NaOH and 4,4'-diaminodiphenylmethane (DMA) as curing agents. These cocured samples were subjected to accelerated aging at 150 degreesC in air for 45 days. Continuous increase of carbonyl IR absorption at 1700-1740 cm(-1) indicated thermal oxidation. The sample with resole/epoxy = 50/50 showed significantly retarded formation of carbonyls. Mechanical property tests of samples during the course of aging, including tensile stress-strain, modulus, and impact resistance confirmed a significant protection of epoxy by incoporating resole into the epoxy via cocuring. (C) 2001 Elsevier Science Ltd. All rights reserved.