Christian Koulic

Controlled synthesis of anthracene-labeled ω-amine polystyrene to be used as a probe for interfacial reaction with mutually reactive PMMA

Anthracene-labeled polystyrene (PS) endcapped by a primary amine has been synthesized by atom transfer radical copolymerization of styrene with 3-isopropenyl-α,α-dimethylbenzyl isocyanata (m-TMI). The m-TMI co-monomer (5.7 mol-%) does not perturb the control of the radical polymerization of styrene. The pendan isocyanate groups of the copolymer chains of low polydispersity (M w /M n = 1.25) and controlled molecular weight (up to 35 000) have been derivatized into anthracene by a reaction with 9-methyl(aminomethyl)anthracene. The anthracene-labeled PS (ca. 2 mol-% label) has been conveniently analyzed by size-exclusion chromatography with a UV detector (SEC-UV). Moreover, the ω-bromide end-group of the copolymer chains has been derivatized into a primary amine, making the labeled PS chains reactive towards non-miscible poly(methyl methacrylate) (PMMA) chains endcapped by an anhydride. The interfacial coupling of the mutually reactive PS and PMMA chains has been studied under static conditions (i.e., at the interface between thin PS and PMMA films) and successfully analyzed by SEC-UV.

Premade versus in situ formed compatibilizer at the PS/PMMA interface: contribution of the Raman confocal microscopy to the fracture analysis

The interface of a two-layer assembly of polystyrene (PS) and poly(methyl methacrylate) (PMMA) was modified by an intermediate layer of either a premade poly(styrene-g-methyl methacrylate) copolymer (P(S-g-MMA)) or a preblend of mutually reactive PS and PMMA synthesized by atom transfer radical polymerization (ATRP). No significant difference was found in the interfacial fracture toughness measured by the double cantilever beam test, although the morphology of the interfacial region was not the same when observed by transmission electron microscopy. The premade copolymer formed a distinct interphase, in contrast to the sharp interface that was observed in the case of the reactive system. The analysis of the fracture surfaces by Raman confocal microscopy showed that the fracture occurred alternatively in the PS phase and either at the PS/copolymer interface for the non reactive system or at the PS/PMMA interface for the reactive one.