Epoxy plus liquid crystalline epoxy coreacted networks: II. Mechanical properties

The effect of coreacting diglycidyl ether of bisphenol F (DGEBP-F) with diglycidyl ether of 4,4'-dihydroxybiphenol (DGE-DHBP) on mechanical properties is investigated. DGE-DHBP shows a liquid crystal (LQ transition upon curing. Tensile, impact and fracture toughness test results are evaluated. Dynamic mechanical analysis is conducted to determine the effect of the DGE-DHBP component. Scanning electron microscopy of fracture surfaces shows changes in failure mechanisms compared to the pure components. The results indicate that the mechanical properties of these blended samples are significantly improved at 10-20% by weight of DGE-DHBP. This is a consequence of the rigidity of the LC component which thus provides the reinforcement. (C) 2001 Elsevier Science Ltd. All rights reserved.