Novel hybrid copolymer by incorporating POSS into hard segments of thermoplastic elastomer SEBS via click coupling reaction

A novel organic-inorganic hybrid copolymer has been achieved by incorporating polyhedral oligomeric silsesquioxanes (POSS) into the hard polystyrene segments in thermoplastic elastomer of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) via click coupling reaction of alkyne group in POSS with azido groups in SEBS by Cu(I)-catalyzed 1,3-dipolarcycloaddition. The alkyne-functionalized POSS could be synthesized via thiol-ene facile click reaction and subsequent amidation reaction with high conversion near to 100%. Azido-functionalized SEBS (SEBS-CH2N3) with different functionalities could be synthesized by chloromethylation of phenyl groups and subsequent azido reaction. The obvious POSS inorganic phase aggregates of around 30 nm in size formed and homogeneously dispersed in SEBS matrix. The SEBS-g-POSS copolymer presented a good hydrophobic property with contact angle of 94.8°. The final decomposition temperature was increased by c.a. 20 °C in comparison with that of SEBS. SEBS-g-POSS makes a contribution to improvements in tensile stress and modulus of PS/SEBS-g-POSS composites due to the hard core with Si-O-Si inorganic structure of POSS. Compared to parallel PS/SEBS composite without any inorganic phase, tensile strength and modulus of PS/SEBS-g-POSS (90/10) blend could be increased by 35% and by 10% respectively.

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