College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University , Chengdu 610065, China.
ACS Appl Mater Interfaces. 2014 Feb 26;6(4):2497-507. doi: 10.1021/am4056694. Epub 2014 Feb 6.
In the present work, a series of thermoplastic polyurethane (TPU)/microfibrillated cellulose (MFC) nanocomposites were successfully synthesized via in situ polymerization. TPU was covalently grafted onto the MFC by particular association with the hard segments, as evidenced by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The adequate dispersion and network structure of MFC in the TPU matrix and the strong interfacial interaction through covalent grafting and hydrogen bonding between MFC and TPU resulted in significantly improved mechanical properties and thermostability of the prepared nanocomposites. The tensile strength and elongation-at-break of the nanocomposite containing only 1 wt % MFC were increased by 4.5-fold and 1.8-fold compared with that of neat TPU, respectively. It was also very interesting to find that the glass transition temperature (Tg) of TPU was decreased significantly with the introduction of MFC, indicating potential for low-temperature resistance applications. Most importantly, compared with TPU nanocomposites reinforced with other nanofillers, the TPU/MFC nanocomposites prepared in this work exhibited excellent transparency and higher reinforcing efficiency.
在本工作中，通过原位聚合成功合成了一系列热塑性聚氨酯（TPU）/微纤化纤维素（MFC）纳米复合材料。通过与硬段的特殊缔合，TPU 被共价接枝到 MFC 上，这一点通过傅里叶变换红外光谱、X 射线光电子能谱和热重分析得到了证实。MFC 在 TPU 基体中的充分分散和网络结构，以及 MFC 和 TPU 之间通过共价接枝和氢键形成的强界面相互作用，导致所制备的纳米复合材料的力学性能和热稳定性得到显著提高。与纯 TPU 相比，仅含 1wt% MFC 的纳米复合材料的拉伸强度和断裂伸长率分别提高了 4.5 倍和 1.8 倍。有趣的是，还发现随着 MFC 的引入，TPU 的玻璃化转变温度（Tg）显著降低，表明其具有耐低温应用的潜力。最重要的是，与用其他纳米填料增强的 TPU 纳米复合材料相比，本工作制备的 TPU/MFC 纳米复合材料表现出优异的透明度和更高的增强效率。
