Chemical and physical changes during the homopolymerization of DGEBA

M. YG Tackie, G. C. Martin

Research output: Contribution to conferencePaper

Abstract

The curing reaction of the diglycidyl ether of bisphenol-A (DGEBA) with boron trifluoride monoethylamine (BF3-MEA) was investigated. The purpose of the work was to model kinetics and network growth so that physical properties could be related to time, temperature and reactant concentrations. A tetrafunctional epoxy system with a simple reaction mechanism was chosen for this purpose. Results of experiments to confirm the BF3-MEA reaction mechanism, to measure rheology before and during gelation are discussed. BF3-MEA undergoes a rapid thermal conversion to HBF4, which is the catalytic species. After the thermal conversion, there is a fast complex formation reaction between HBF4 and the epoxy, which produces OH absorbances in the FTIR spectrum, and a carbocation from which the epoxy homopolymerization proceeds. The curing mechanism results in a non-free radical system where gel formation occurs at 7%, much less than the 33% expected for a tetrafunctional monomer which is not free-radical cured. An explanation of why the network develops as it does is presented. Significantly, the initial appearance of the gel does not result in a rise in viscosity; macroscopic gelation occurs at 34% conversion, close to the theoretically predicted value of 33%.

Original languageEnglish (US)
Pages1560-1563
Number of pages4
StatePublished - Jan 1 1991
Event49th Annual Technical Conference -ANTEC '91 - Montreal, Que, Can
Duration: May 5 1991May 9 1991

Other

Other49th Annual Technical Conference -ANTEC '91
CityMontreal, Que, Can
Period5/5/915/9/91

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Polymers and Plastics

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    Tackie, M. YG., & Martin, G. C. (1991). Chemical and physical changes during the homopolymerization of DGEBA. 1560-1563. Paper presented at 49th Annual Technical Conference -ANTEC '91, Montreal, Que, Can, .