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首页> 外文期刊>Journal of Applied Polymer Science >The effects of isocyanate index on the properties of aliphatic waterborne polyurethaneureas
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The effects of isocyanate index on the properties of aliphatic waterborne polyurethaneureas

机译：异氰酸酯指数对脂肪族水性聚氨酯脲性能的影响

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摘要

The aliphatic waterborne polyurethaneureas (WPU) with different isocyanate index (R) were synthesized by isophorone diisocyanate (IPDI) and polyester glycol via prepolymer mixing method. The effects of the R value on the structure and the properties of the resultant polymers have been analyzed. The polymer with a certain R value (R = 1.44) exhibited excellent mechanical properties with both high tensile strength (55 MPa) and high elongation at break (1400%). The water resistance and the thermal stabilities of WPUs have been improved with the increase of R. The results were interpreted in terms of the structures associated with the micro-phase separation. According to differential scanning calorimeter (DSC) analysis, the microphase separation degree was elevated by increasing R value. FTIR spectrum showed the more R value, the more hydrogen bonded urea groups. No crystallinity was found in X-ray diffraction (XRD) patterns showing the typical amorphous morphologies of IPDI-based WPUs. Thus the primary driving force for microphase separation was the hydrogen bonding between urethane and urea groups, making significant influence on the properties of WPUs, as shown in dynamic mechanical analyzes.
机译：通过异佛尔酮二异氰酸酯（IPDI）和聚酯二醇经预聚物混合法合成了异氰酸酯指数（R）不同的脂肪族水性聚氨酯脲（WPU）。分析了R值对所得聚合物的结构和性质的影响。具有一定R值（R = 1.44）的聚合物表现出优异的机械性能，同时具有高拉伸强度（55 MPa）和高断裂伸长率（1400％）。随着R的增加，WPU的耐水性和热稳定性得到了改善。结果用与微相分离有关的结构来解释。根据差示扫描量热仪（DSC）分析，通过增加R值提高了微相分离度。 FTIR光谱显示R值越大，氢键结合的脲基团越多。在显示基于IPDI的WPU的典型非晶形态的X射线衍射（XRD）模式中未发现结晶度。因此，如动态力学分析所示，微相分离的主要驱动力是氨基甲酸酯和尿素基团之间的氢键，这对WPU的性能产生重大影响。

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