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首页> 外文期刊>Journal of Applied Polymer Science >The Effect of Diisocyanate Isomer Composition on Properties and Morphology of Polyurethanes Based on 4,4'-Dicyclohexyl Methane Diisocyanate and Mixed Macrodiols (PDMS-PHMO)
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The Effect of Diisocyanate Isomer Composition on Properties and Morphology of Polyurethanes Based on 4,4'-Dicyclohexyl Methane Diisocyanate and Mixed Macrodiols (PDMS-PHMO)

机译：二异氰酸酯异构体组成对基于4,4'-二环己基甲烷二异氰酸酯和混合大分子二醇（PDMS-PHMO）的聚氨酯的性能和形貌的影响

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摘要

Three series of polyurethanes were prepared having 42 wt % hard segments based on 4,4'-dicyclohexyl methane diisocyanate (H_12MDI) with trans, trans isomer contents in the 13 to 95 mol % range and 1,4-butanediol chain extender. The soft segments were based on macrodiols poly (hexamethylene oxide) (PHMO, MW 696), #alpha#, #omega#-bishydoxyethoxypropyl polyimehylsiloxane (PDMS, MW 940), and two mixed macrodiol compositions consisting of 80 and 20% (w/w) PDMS. H_12MDI with 35, 85, and 95% trans, trans isomer contents were obtained from commercial H_12MDI (13% trans, trans) by fractional crystallization, and all polyurethanes were prepared by a one-step bulk polymerization procedure. The polyurethanes based on the commercial diisocyanate-produced materials soluble in DMF with molecular weights in the 53, 655-75, 300 range and generally yielded clear and transparent materials. The polyurethanes based on H_12MDI with trans, trans contents of 35% or higher yielded materials insolube in N,N-dimethylformamide (DMF) and were genrally opaque. Mechanicla properties, such as temsile strength and elogation at break, decreased with increasing trans, trans content, while the Young's modulus and Shore hardness increased. The polyurethanes based on mixed macrodils yielded higher tensile properties than those of materials based on individual macrodiols. The best mechanical properties were observed for a polyurethane consisting of a soft segment based on PDMS-PHMO (8/20) and a hard segment based on commercial H_12MDI and BDO. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were employed to characterize the polyurethane morphology. DSC results confirmed that the polyurethanes based on H_12MDI with high trans, trans isomer were very highly phase separated, exhibiting characteristic hard segment melting endotherms as high as 255 deg C. The other materials were genrally phase mixed. FTIR spectroscopy results corroborated DSC results.
机译：制备了基于42，4wt％的硬链段的三系列聚氨酯，其基于4，4′-二环己基甲烷二异氰酸酯（H_12MDI），具有13至95mol％范围的反式，反式异构体含量和1，4-丁二醇扩链剂。软链段基于大分子二醇聚环氧丙烷（PHMO，MW 696），＃alpha＃，＃omega＃-双羟基乙氧基丙基聚甲基硅氧烷（PDMS，MW 940）和两种混合的大分子二醇组成，组成分别为80％和20％（w / w）PDMS。通过分步结晶从商业H_12MDI（13％反式，反式）中获得反式异构体含量为35、85和95％的H_12MDI，所有聚氨酯均通过一步本体聚合程序制备。基于可溶于DMF的市售二异氰酸酯生产的材料的聚氨酯，分子量在53、655-75、300范围内，通常可得到透明透明的材料。反式，反式含量为35％或更高的基于H_12MDI的聚氨酯在N，N-二甲基甲酰胺（DMF）中不溶于水，并且通常是不透明的。力学性能，如断裂强度和断裂强度，随反式，反式含量的增加而降低，而杨氏模量和肖氏硬度则增加。与基于单个大分子二醇的材料相比，基于混合大分子的聚氨酯具有更高的拉伸性能。对于由基于PDMS-PHMO（8/20）的软链段和基于商业H_12MDI和BDO的硬链段组成的聚氨酯，观察到了最佳的机械性能。差示扫描量热法（DSC）和傅立叶变换红外光谱（FTIR）用于表征聚氨酯的形态。 DSC结果证实，具有高反式，反式异构体的基于H_12MDI的聚氨酯具有非常高的相分离性，表现出高达255℃的特征性硬链段熔融吸热峰。其他材料通常进行相混合。 FTIR光谱结果证实了DSC结果。

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