Effect of temperature on the preparation of epoxy nanocomposites with nanoclays

摘要

Epoxy nanocomposites based on layered silicates have received much attention recently. Unlike thermoplastic-based nanocomposites, thermoset-based nanocomposites are subject to certain constraints in their preparation because of the high reactivity of the monomers or oligomers used in their formation. This paper concentrates on the effects of mixing temperature and time on the formation of epoxy-based nanocomposites. Different commercial organo-nanoclays were used at different concentrations, and both solvent-based and direct mixing processes were used to prepare the nanocomposites. The sample prepared with the use of solvent was taken as a reference for this study. Differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spec-troscopy were used to characterize the mixtures obtained. It was found that organo-clay treated with primary amine can play a role as a catalyst for the homopolymerization of the epoxy resin, whereas organo-clay treated with quaternary amine does not do so. It is important to take this into account in preparing the resin-clay mixtures. Thus the quaternary-amine-treated clay can be mixed with epoxy resin at temperatures up to 140°C without risk of polymerization. In the case of the primary-amine-treated clay, however, mixing at 140°C should be limited to less than one hour to avoid significant polymerization, although mixing at 100°C implies little risk. Further on-going experiments will answer additional questions on the effect of mixing conditions on the exfoliation of the nanoclays and the performance of the resulting nanocomposites.