Polymerizability, copolymerizability, and properties of cyanoacrylate-telechelic polyisobutylenes II: copolymerization of three-arm star cyanoacrylatetelechelic polyisobutylene with ethyl cyanoacrylate

摘要

This research concerned the synthesis and characterization of novel conetworks containing polyisobutylene (PIB) and polyethyl-2-cyanoacrylate [poly(Et-CA)] sequences. The syntheses involved the copolymerization of CA-telechelic three-arm star PIB [Φ(PIB-CA){sub}3] with ethyl-2-cyanoacrylate (Et-CA) mediated by nucleophiles or by living tissue (fresh eggs). The conetworks were characterized by swelling in hexanes, tetrahydrofuran (THF), and acetone, and the results indicate co-continuous PIB and poly(Et-CA) domains. The conetworks exhibit two T{sub}gs indicating phase-separation between PIB and poly(Et-CA). The outstanding oxidative resistance of the conetworks was demonstrated by exposure to concentrated nitric acid. The tensile strengths, moduli, and elongations of a series of conetworks with different overall compositions were investigated and the findings interpreted in terms of covalently linked rubbery and glassy domains. AFM also suggests the presence of phase-separated rubbery and glassy domains. DMTA spectra of aΦ(PIB-CA){sub}3 homonetwork, andΦ(PIB-CA){sub}3/Et-CA conetworks were analyzed and interpreted in terms of coexisting rubbery and glassy domains. Observations made during the exposure ofΦ(PIB-CA){sub}3/Et-CA mixtures to proteinaceous tissue, in combination with characterization data, were used to propose a structural model for the conetworks.