Influences of Expanding Monomer on Carbon Fiber Reinforced Epoxy Composites II.

摘要

In this investigation it was confirmed that copolymerization of dinorbornene spiroorthocarbonate (DNSOC) with epoxy can eliminate sample shrinkage and even produce sample expansion. To maximize control of shrinkage, it is important to bring epoxy to the gel stage before the DNSOC begins to copolymerize. DGEBA epoxy was cured with m-phenylenediamine (mPDA) and DNSOC-epoxy samples were cured with mPDA and BF3. diethylenetriamine (BF3 was used to catalyze polymerization of the DNSOC). As compared with carbon fiber reinforced epoxy, the sample with 5% DNSOC showed 33% reduction in interfacial shear stress as measured by the nanoindentation test, and reduction in residual stress perpendicular to the plies by interferometry. However, the significant differences in fiber volume fraction between the epoxy samples can account for some of this apparent reduction. The resin itself showed increases in both tensile strength and tensile modulus when 5% DNSOC was incorporated, and the sample showed no shrinkage.