Abstract
© 2015.A methylnadic anhydride-cured diglycidylether of bisphenol A, is prepared and characterised and a mono-epoxy POSS reagent added (0.5-4wt-%) to produce a series of nanocomposites. Two reaction mechanisms are observed involving esterification at lower temperatures (60-180°C) and etherification at temperatures above 180°C. Using the Ozawa and Kissinger methods, the activation energy for the first reaction was found to be 87-90kJ/mol and 122-124kJ/mol for the second reaction. Incorporation of POSS into the epoxy-anhydride network increases the Tg and cross-link density, indicating a more rigid network, but the values do not follow a trend based solely on POSS content. The char yield increases with POSS content with very little change in the degradation temperature. Incorporation of POSS (1wt-%) can reduce the moisture uptake in the cured resin by ~25% at 75% relative humidity. This is accompanied by a lower impact on glass transition temperature: the Tg is reduced by 10K at saturation, compared with 31K for the unmodified epoxy.