A rapid anionic synthesis of well-defined star polymers has been developed and found to be less sensitive to the molecular weight (MW) of the arm and the reaction stoichiometry.  The method was based on the addition of living anionic polymers (PSLi) to octavinylPOSS in benzene.  The reaction proceeded rapidly to completion (within 5 min for MW up to 239 k), forming predominantly eight-arm star polymers which then were purified by fractionation and fully characterized by 1H NMR, 13C NMR, 29Si NMR, and MALDI-TOF mass spectrometry.  More strikingly, the stoichiometry of the reactants seemed to has less effect on the product distribution.  Even at 1:2 ratio between PSLi and octavinylPOSS, the major product is high addition products with average arm number around 6.   An aggregation-addition mechanism was invoked to account for this unusual phenomenon.  The method has general implications in the understanding of reactive nature of the living anionic polymers and may find practical application in the synthesis of diverse functional star polymers of distinct composition.

Rapid anionic synthesis of well-defined star polymers: A process that is less sensitive to arm molecular weight and stoichiometry

243rd National Meeting (2012)

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