Influence of the addition of polystyrene-b-poly(methyl methacrylate) block copolymer (PS-b-PMMA) on the morphologies generated by reaction-induced phase separation in PS/PMMA/epoxy blends

E.GIRARD-REYDET; A. SÉVIGNON; J.P. PASCAULT; C. E. HOPPE; M. J. GALANTE; P. A. OYANGUREN; R. J. J. WILLIAMS

MACROMOLECULAR CHEMISTRY AND PHYSICS

Wiley-V C H Verlag GMBH

Lugar: Weinheim, Germany; Año: 2002 vol. 203 p. 947 - 952

1022-1352

Homogeneous solutions of polystyrene (PS) and poly(methyl methacrylate) (PMMA) in diglycidylether of bisphenol A (DGEBA), containing about 8 wt % total thermoplastic (PS and PMMA in different ratios), and including or not 0.5 wt % of a PS-b-PMMA block copolymer, were polymerized either in the presence of a tertiary amine (benzyldimethylamine, BDMA), or using a stoichiometric amount of a diamine (4,4’-diaminodiphenyl sulfone, DDS). A double phase separation was recorded by light transmission during polymerization. A PS-rich phase was separated at low conversions and a PMMA-rich phase was segregated at more advanced conversions. The addition of the block copolymer produced significant changes in the morphologies generated. For the BDMA-initiated polymerization, the presence of the block copolymer made the small PMMA-rich domains clearly discernible in TEM micrographs. For the DDS-cured system, the addition of the block copolymer led to a dispersion of small PS-rich particles encapsulated by PMMA shells. The possibility of generating a stable dispersion of biphasic particles by polymerization-induced phase separation, opens a new way to modify thermosetting polymers for toughening purposes.