A series of polysiloxane-based polyurethane elastomers with aliphatic and aromatic diisocyanate structures are prepared using a two-step polymerization method. First, tolylene diisocyanate (TDI); dicyclohexylmethane 4,4′-diisocyanate (H12MDI); and hexamethylene diisocyanate (HDI) separately react with polycarbonate diol (PCDL) to produce polyurethane prepolymer, and furthermore, polysiloxane (PDMS) is added to the system to produce different polymers. The effect of different diisocyanate structures on mechanical properties, thermal stability, surface topography, and hydrophobic properties are explored. The results show that when the mass loss is higher than 50% during thermal decomposition, TDIPU exhibits relatively excellent thermal stability, which may be caused by the exposure of the silicone inside the polymer. HDIPU shows high hydrophobicity and low surface free energy, which is mainly related to a large amount of Si enriched on the surface. These differences are mainly caused by different molecular structures.

中文翻译：

---

具有脂肪族和芳香族二异氰酸酯结构的聚硅氧烷基聚氨酯弹性体的表面性能和热稳定性研究

采用两步聚合法制备了一系列具有脂肪族和芳香族二异氰酸酯结构的聚硅氧烷基聚氨酯弹性体。一、甲苯二异氰酸酯（TDI）；二环己基甲烷 4,4'-二异氰酸酯 (H12MDI)；和六亚甲基二异氰酸酯（HDI）分别与聚碳酸酯二醇（PCDL）反应生成聚氨酯预聚物，此外，在体系中加入聚硅氧烷（PDMS）生成不同的聚合物。探讨了不同二异氰酸酯结构对机械性能、热稳定性、表面形貌和疏水性能的影响。结果表明，当热分解过程中质量损失大于50%时，TDIPU表现出相对优异的热稳定性，这可能是由于有机硅暴露在聚合物内部造成的。HDIPU表现出高疏水性和低表面自由能，这主要与表面富集大量Si有关。这些差异主要是由不同的分子结构造成的。