An investigation on curing rheokinetics of a nadic end-capped MDA-BTDA-ODA copolyimide resin by dynamic mechanical analysis

Abstract

Abstract The curing behavior of a nadic end capped MDA-BTDA-ODA copolyimide resin was investigated using dynamic mechanical analysis in the shear mode. The studied copolyimide consists of 3,3′,4,4′-benzophenonetetracarboxylic acid dianhydride (BTDA) with a 50:50 M combination of 4,4′-diaminodiphenylmethane (MDA) and 3,4′-oxydianiline (ODA) monomers. The effects of curing temperature and time on the rheological properties of the resin were examined. At the beginning of the network formation process, an increase in the storage modulus, loss modulus and complex viscosity was observed. The gelation temperature, Tgel, was determined from the intersection points of the temperature-dependent storage and loss moduli curves. It was found that the rate of gelation of the resin was increased with increasing temperature. In terms of mechanical curing condition, the kinetics of isothermal network formation process at different isothermal curing temperatures were monitored by using Kamal-Sourour model. The model fitted well with experimental data. Therefore, mechanical conversion at different temperatures can be well predicted by the kinetics data.