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首页> 外文期刊>Journal of Applied Polymer Science >Effect of diisocyanate isomer composition on properties and morphology of polyurethanes based on 4,4 prime -dicyclohexyl methane diisocyanate and mixed macrodiols (PDMS-PHMO)
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Effect of diisocyanate isomer composition on properties and morphology of polyurethanes based on 4,4 prime -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-伯-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态的影响

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摘要

Three series of polyurethanes were prepared having 42 wt % hard segments based on 4,4 prime -dicyclohexyl methane diisocyanate (H12MDI) 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), α,ω-bishydroxyethoxypropyl polydimethylsiloxane (PDMS, MW 940), and two mixed macrodiol compositions consisting of 80 and 20% (w/w) PDMS. H12MDI with 35, 85, and 95% trans,trans isomer contents were obtained from commercial H12MDI (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 H12MDI with trans,trans contents of 35% or higher yielded materials insoluble in N,N-dimethylformamide (DMF) and were generally opaque. Mechanical properties, such as tensile strength and elongation at break, decreased with increasing trans,trans content, while the Young's modulus and Shore hardness increased. The polyurethanes based on mixed macrodiols 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 (80/20) and a hard segment based on commercial H12MDI 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 H12MDI with high trans,trans isomer were very highly phase separated, exhibiting characteristic hard segment melting endotherms as high as 255 °C. The other materials were generally phase mixed. FTIR spectroscopy results corroborated DSC results.
机译：基于4，4-伯-二环己基甲烷二异氰酸酯（H12MDI）制备具有42wt％的硬链段的三系列聚氨酯，其反式，反式异构体含量在13至95mol％范围内，并且具有1，4-丁二醇扩链剂。所述软链段基于大二醇聚（六亚甲基氧化物）（PHMO，MW 696），α，ω-双羟基乙氧基丙基聚二甲基硅氧烷（PDMS，MW 940），以及两种混合的由80和20％（w / w）PDMS组成的大二醇组合物。通过分步结晶从市售H12MDI（13％反式，反式）中获得具有35％，85％和95％的反式，反式异构体含量的H12MDI，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，通常可得到透明的透明材料。反式，反式含量为35％或更高的基于H12MDI的聚氨酯产生的材料不溶于N，N-二甲基甲酰胺（DMF），通常是不透明的。力学性能，例如抗张强度和断裂伸长率，随着反式，反式含量的增加而降低，而杨氏模量和肖氏硬度却增加。基于混合大分子二醇的聚氨酯比基于单个大分子二醇的材料具有更高的拉伸性能。对于由基于PDMS-PHMO（80/20）的软链段和基于商业H12MDI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H12MDI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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