INFRARED STUDIES OF SEGMENTED POLYURETHANE ELASTOMERS .2. INFRARED DICHROISM
INFRARED STUDIES OF SEGMENTED POLYURETHANE ELASTOMERS .2. INFRARED DICHROISM
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DOI：
10.1021/ma60022a018
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发表时间：
1971-01-01
期刊：
影响因子：
5.5
通讯作者：
COOPER, SL
中科院分区：
文献类型：
--
作者：
ESTES, GM;SEYMOUR, RW;COOPER, SL
本文报道了聚乙烯弹性体薄膜的应变二向色性实验。温度和应变历史对嵌段聚合物链不同链段中分子取向的影响的研究为解释力学性能数据提供了基础。提出了一个两相模型来表示聚氨酯的形态。该模型设想了两个几乎纯域-一个包含氨基甲酸酯嵌段，另一个包含预聚物链段-这是不连续和互穿的。特征结构域尺寸为50 μ m，这与已知的嵌段分子量非常一致。含有芳族氨基甲酸酯嵌段的较高模量域起到增强橡胶状预聚物相的作用，并且由于两相是互穿的，两者都通过施加的应力而变形。当载荷被移除时，软域松弛到接近各向同性的状态，而刚性相保持塑性变形。增强相的不可恢复变形引起应力软化现象。
Strain dichroism experiments on thin films of polyurethaneelastomers are reported. Studies of the effect of temperature and strain history on molecular orientation in different segments of the block-polymer chain provide a basis for the interpretation of mechanical property data. A two-phasemodel is proposed to representthe polyurethane morphology. The model envisions two nearly pure domains—one containing the urethane blocks and the other the prepolymer segments—which are semicontinuous and interpenetrating. A characteristic domain dimension is 50 Á, which agrees closely with the known block molecular weights. Higher modulus domains containing the aromatic urethane blocksact to reinforce the rubbery prepolymer phase, and since the two phases are interpenetrating, both are deformed by the applied stress. When the load is removed, the soft domains relax to a nearly isotropic state, while the rigid phase remains plastically deformed. The nonrecoverable deformationof the reinforcing phase gives rise to the phenomenon of stress softening.