Abstract In this study, thermoplastic polyurethanes (TPUs) containing trisilanol isooctyl polyhedral oligomeric silsesquioxane (POSS), a reactive nanofiller, were synthesized and characterized rheologically and morphologically, and the effects of POSS content on the melt thermal stability of the TPUs are investigated. Samples containing 0, 0.23, 0.57, 1.14, and 2.23% (w/w) POSS were synthesized by reactive extrusion and characterized by Fourier transform infrared spectroscopy (FTIR), oscillatory and extensional rheometry, atomic force microscopy (AFM), and small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). The rheological properties of molten TPU are time-dependent and the melt thermal stability of the TPU is maximal at 1.14% of POSS. The addition of 0.23 and 0.57% POSS promotes strain-hardening at low extensional strain rates (0.01 and 0.10 s−1), not affecting the extensional characteristics at higher strain rates. The addition of increasing amounts of POSS leads to the formation of POSS-rich clusters well dispersed in the TPU matrix. SAXS and WAXS results show that the POSS domains are amorphous and that POSS does not modify the crystalline structure of TPU. Therefore, this work indicates that synthesizing TPU in the presence of trisilanol isooctyl POSS can increase the melt thermal stability of the polymer, facilitating its processing.

中文翻译：

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三硅烷醇异辛基POSS含量对热塑性聚氨酯（TPU）结构、形貌和流变性能的影响

摘要 在本研究中，合成了含有三硅烷醇异辛基多面体低聚倍半硅氧烷 (POSS) 的热塑性聚氨酯 (TPU)，一种反应性纳米填料，并对其进行了流变学和形态学表征，并研究了 POSS 含量对 TPU 熔体热稳定性的影响。含有 0、0.23、0.57、1.14 和 2.23% (w/w) POSS 的样品通过反应挤出合成，并通过傅里叶变换红外光谱 (FTIR)、振荡和拉伸流变仪、原子力显微镜 (AFM) 和小-和广角 X 射线散射（分别为 SAXS 和 WAXS）。熔融 TPU 的流变特性与时间有关，TPU 的熔体热稳定性在 POSS 的 1.14% 时达到最大值。0.23 和 0 相加。57% POSS 在低拉伸应变率（0.01 和 0.10 s-1）下促进应变硬化，在较高应变率下不影响拉伸特性。添加越来越多的 POSS 导致形成良好分散在 TPU 基质中的富含 POSS 的簇。SAXS 和 WAXS 结果表明 POSS 域是无定形的，并且 POSS 不会改变 TPU 的晶体结构。因此，这项工作表明在三硅烷醇异辛基 POSS 存在下合成 TPU 可以增加聚合物的熔体热稳定性，促进其加工。SAXS 和 WAXS 结果表明 POSS 域是无定形的，并且 POSS 不会改变 TPU 的晶体结构。因此，这项工作表明在三硅烷醇异辛基 POSS 存在下合成 TPU 可以增加聚合物的熔体热稳定性，促进其加工。SAXS 和 WAXS 结果表明 POSS 域是无定形的，并且 POSS 不会改变 TPU 的晶体结构。因此，这项工作表明在三硅烷醇异辛基 POSS 存在下合成 TPU 可以增加聚合物的熔体热稳定性，促进其加工。