Thermal Studies on Chain Extended Bismaleimides-II

C. Thamaraichelvi1, A. Vanangamudi2, M. Dhanalakshmi3 and C.T. Vijayakumar3,*

1Department of Chemistry, The Standard Fireworks Rajaratnam College for Women, Sivakasi-626 123, India

2Department of PG & Research Centre in Chemistry, Ayya Nadar Janaki Ammal College, Sivakasi West-626 124, India

3Department of Polymer Technology, Kamaraj College of Engineering & Technology, S.P.G.C. Nagar, K. Vellakulam-625 701, India

Abstract

4,4'-Bismaleimidodiphenyl methane (BMIM) was synthesized by chemical imidization. Using three different aromatic diamines (4,4'-diaminodiphenyl ether (E), 4,4'-diaminodiphenyl methane (M) and 4,4'-diaminodiphenyl sulfone (S)) chain extended BMIM were prepared. The scope of present work is to study the curing and degradation studies of different chain extended BMIM resins using differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and differential thermogravimetry (DTG). Kissinger-Akahira-Sunose (KAS), Flynn-Wall-Ozawa (FWO) and Friedman (FRD) methods were followed to calculate apparent activation energy for curing and degradation studies. Exothermic transition indicative of curing was observed in DSC traces in the temperature range of 50-450 °C. Melting point and also the amount of heat released during thermal curing was considerably reduced in the chain extended BMIM. The initiation of curing reactions at temperature lower than pure BMIM’s melting point can be easily identified by the nonpresence of melting peak in the chain extended BMIM. The apparent activation energy values for the thermal degradation of the chain extended bismaleimides are significantly reduced compared to pure BMIM. From this, it is concluded that the chain extension using (4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl methane and 4,4'-diaminodiphenyl sulfone) plays an important role in pure BMIM degradation mechanism. Char yield was not significantly affected when pure bismaleimides were extended by aromatic diamines.

Keywords

Bismaleimides, Chain extension, Thermal analysis, Curing kinetics, Degradation kinetics.

  
 
  • Asian J. Mat. Chem. /
  •  2018 /
  •  3(1-2) /
  •  pp 18-27
  • DOI:10.14233/ajmc.2018.AJMC-P60