Isothermal polymerization kinetics of N,N′-bismaleimide-4,4′- diphenylmethane with cyanuric acid

Abstract

Kinetics of polymerization of N,N′-bismaleimide-4,4′-diphenylmethane (BMI) with cyanuric acid (CA) in N-methyl-2-pyrrolidone (NMP) was investigated. Both model-free and model-fitting methods were used to determine the relevant kinetic parameters. For the model-free method, the average activation energy (Eα) and pre-exponential factor (Aα) are 23±1kJmol−1 and 162±2min−1 in the α range 0.1–0.9, respectively. The Aα value obtained is a result of the model assumption with g(α)=−ln(1−α) [i.e. f(α)=(1−α)], which is based on 1H NMR measurements. As to the model-fitting method, the overall activation energy (E) and pre-exponential (A) are 23kJmol−1 and 166min−1 with g(α)=[(1−α)0.15−1]/0.15 {i.e. f(α)=(1−α)1.15}. The polymerization kinetics and mechanism of BMI/CA in NMP were characterized by DSC. Furthermore, complementary 1H NMR and 13C NMR techniques were used to identify the chemical structure of CA in the reaction medium and, therefore, the reaction mechanism (model) was predicted.