Bismaleimide (BMI)-based copolymers and IPNS: Synthesis, properties, and polymerization kinetics

Bismaleimide (BMI)-diamine systems are among the most important BMI-based thermosetting systems. In a system containing BMIs and aromatic amines, both amine addition and homopolymerization reactions play important roles in forming the polymer network. However, many important issues related to both amine addition and homopolymerization reactions have not been studied in detail.; In Part I, N-phenylmaleimide (NPM) and aniline were selected as model compounds to study the reactions between BMI and amine hardeners. In situ near-infrared (NIR) spectroscopy was employed to provide quantitative information specific to the amine and maleimide functional groups. NIR absorptions suitable for quantitative studies of the reactions between NPM and amines were identified. Furthermore, NIR spectroscopy was utilized to elucidate the mechanisms for the reactions between NPM and several aromatic secondary amines. In situ NIR spectroscopy indicated that the secondary amine reaction between NPM and N,N{dollar}spprime{dollar}-diphenylaspartimide can be neglected for temperatures as high as 220{dollar}spcirc{dollar}C.; In Part II, diffusion limitations which occur as a part of BMI homopolymerization reactions were explored via differential scanning calorimetry (DSC) studies. During early stages of reactions, the reaction rate is limited by the chemical kinetics, which can be described by empirical models commonly employed for epoxy and unsaturated polyester systems. As the reaction enters later stages of cure, the conversion data can deviate from those predicated based upon the corresponding conversion data obtained from consideration of the chemical kinetics alone. In addition, the relationship between glass transition temperature (T{dollar}rmsb{lcub}g{rcub}){dollar} and conversion is described by DiBenedetto's equation.; Finally, the application of these studies to a particular family of novel BMI-based composite materials is included in an appendix to this dissertation.