Structured thermoplastic/thermoset blends using block copolymers

Abstract

Thermoplastic/thermoset blends have been compatibilized by block copolymers. The thermoplastic is poly(phenylene ether) and the thermoset precursors are a liquid epoxy, diglycidyl ether of bisphenol A (DGEBA) and an aromatic diamine (4,4′ methylene bis [3 chloro 2,6 diethylaniline], MCDEA). The triblock poly(styrene-b-butadiene-b-methyl methacrylate), SBM has been chosen because (i) PS blocks interact very favourably with PPE (ii) PMMA blocks remain miscible with the thermoset during the whole curing process, and (iii) PB mid blocks are expected to cover the interface. Morphologies of blends were observed by Transmission Electron Microscopy and phase composition evaluated by Dynamic Mechanical Thermal Analysis. It was observed that the strong repulsion between PPE and PMMA blocks governs the organization of the blend before and during the curing process. During polymerization a purification of the matrix is induced. As expected, a large proportion of block copolymer is at the interface between the matrix and nodules. It was demonstrated that the number of SBM micelles and their degree of dispersion is the main parameter controlling the mechanical properties. Copyright © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.