Miscibility enhancement in blends of polystyrene and polyisoprene modified with electron donor-electron acceptor groups

John M G Cowie, Alexi Demaude

Research output: Contribution to journalArticle

Abstract

The use of electron donor-electron acceptor groups to enhance miscibility in polymer blends has been investigated, using the immiscible binary pair polystyrene and polyisoprene as the basic materials. These polymers have been modified by copolymerization with monomers that are either donor or acceptor groups. The copolymers synthesized were poly(styrene-stat-N-itaconimidyl-3,5-dinitrobenzoate), which contains the electron acceptor, and poly[isoprene-stat-N-(2-hydroxyethyl) carbazole methacrylate], which contains the electron donor. Blends were examined using differential scanning calorimetry and dynamic mechanical thermal analysis. The criterion of miscibility was taken to be the presence of only one glass transition temperature in the binary blend, and it was established that at least 20 mol% of the donor-acceptor units had to be incorporated into each chain before a stable one-phase blend was obtained. Miscible blends were observed to undergo a 'decomplexation' reaction above the blend Tg, to form partially phase separated blends, with each phase rich in one component and diluted by the second. The value of the blend Tg was above that expected from a weighted average of those of the components, indicating that specific intermolecular interactions, probably charge-transfer complexes, which led to nonbonding crosslinking were present in the blend and stabilized the one-phase system.

Original languageEnglish
Pages (from-to)178-183
Number of pages6
JournalPolymers for Advanced Technologies
Volume5
Issue number3
DOIs
Publication statusPublished - Mar 1994

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