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Miscibility enhancement in blends of polystyrene and polyisoprene modified with electron donor–electron acceptor groups
Author(s) -
Cowie John M. G.,
Demaude Alexi
Publication year - 1994
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.1994.220050306
Subject(s) - miscibility , materials science , polystyrene , electron acceptor , differential scanning calorimetry , polymer chemistry , polymer blend , electron donor , copolymer , acceptor , polymer , phase (matter) , methacrylate , glass transition , flory–huggins solution theory , chemical engineering , thermodynamics , photochemistry , organic chemistry , composite material , chemistry , physics , catalysis , engineering , condensed matter physics
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 T g , to form partially phase separated blends, with each phase rich in one component and diluted by the second. The value of the blend T g 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.