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| - New Polymer Syntheses. 100. Multiblock Copolyesters by CombinedMacrocyclic Polymerization and Silicon-Mediated Polycondensation
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| - Using 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP) as cyclic initiator the macrocyclicpolymerizations of ε-caprolactone were conducted in bulk at 80 °C at monomer/initiator ratios of 20/1.The resulting tin-containing supermacrocycles were reacted in situ with an excess of isophthaloyl chloride,and this reaction mixture was polycondensed with silylated Bisphenol A at temperatures between 150and 300 °C. The characterization of the isolated copolyesters by DSC measurements and 1H NMR and13C NMR spectroscopy proved that they possess a perfect multiblock structure up to a reaction temperatureof 240 °C. At higher temperatures transesterification causes a more or less perfect randomization of thesequence. In a second series of combined ring-opening polymerizations and ring-opening polycondensations(ROPPOC) silylated methylhydroquinone and 1,10-bis(4-chlorophenoxy)decane were used as comonomersof the macrocyclic poly(ε-caprolactone). The isolated multiblock copolyesters showed a two phasic meltwith an isotropic phase containing the polylactone blocks and a nematic phase consisting of the aromaticblocks. The relationship between block lengths and phase separation is discussed.
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