Thermoplastic graft copolymer elastomers with chain‐folding or bifurcated side chains
Thermoplastic graft copolymer elastomers with chain‐folding or bifurcated side chains
复制标题
具有链折叠或分叉侧链的热塑性接枝共聚物弹性体
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
T. Heinemann
中科院分区：
文献类型：
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作者：
C. Eisenbach;T. Heinemann
通过远爪聚醚与相应的α，α′-双官能度聚氨酯大分子单体的取代缩聚反应，合成了主链为聚氧四亚甲基、接枝分子均匀的聚氨酯接枝共聚物。侧链的特征在于由一个内置的宪法单位，允许一个对称的链折叠或分叉与两个同样长的寡氨基甲酸酯分支。差示扫描量热法、小角X射线散射和动态力学分析表明，该材料为具有半结晶聚氨酯硬畴的微相分离体系，为热塑性弹性体。这些数据和比较研究的模型化合物的特殊结构的接枝和聚（醚-氨基甲酸酯）与对称链折叠的片段说明，这些聚氨酯弹性体的形态和性能可以完美地模仿的接枝共聚物与分叉的侧链。
Graft copolymers with a poly(oxytetramethylene) main chain and molecularly uniform oligourethane grafts were synthesized by substitution polycondensation of a telechelic polyether and the corresponding α,α′-bifunctional oligourethane macromonomer. The side chains were either characterized by a built-in constitutional unit allowing a symmetrical chain fold or by bifurcation with two equally long oligourethane branches. Differential scanning calorimetry, small-angle X-ray scattering and dynamic mechanical analysis proved a microphase-separated system with semicrystalline oligourethane hard domains, and the materials were thermoplastic elastomers. These data and the comparative study of model compounds for the specially structured grafts and of poly(ether-urethane)s with symmetrically chain-folded segments illustrated that the morphology and properties of these polyurethane elastomers could be perfectly mimicked by a graft copolymer with bifurcated side chains.