【作者】 支晓华；

【导师】 吕亚非；

【作者基本信息】 北京化工大学 ， 材料学， 2007， 硕士

【摘要】 聚氨酯(PU)弹性体具有优良的耐磨性能、韧性、耐疲劳性、耐化学腐蚀性及高抗冲性等，是一类用途广泛的工程材料。不过，用传统原料和方法制备的聚氨酯弹性体也有着耐热性不好的弱点，因而限制了它在工程技术领域的进一步应用。通过共聚的方式将耐热性基团及刚性基团引入到聚氨酯主链中去，是改善聚氨酯弹性体耐热性能及机械性能的重要方法。扩链剂和酰亚胺部分作为硬段，多元醇作为软段，软硬结构部分在微观上形成微相分离的海岛结构，正是这种结构提供了聚氨酯酰亚胺的优异力学性能、热性能及其他性能。其中，扩链剂的结构和性质对于材料的性能影响重大。本论文合成了一种新型的三官能度的扩链剂三羟甲基庚烷，并考察了它的最佳制备工艺；另外，本论文分别考察了各种不同类型扩链剂对聚氨酯酰亚胺综合性能的影响；同时，采用主链引入硅氧键和侧链引入硅氧键的方法合成了有机硅改性的聚氨酯酰亚胺材料，并考察了材料的介电性能以及表面性能；最后，合成了两种不同键合连接的低聚酰亚胺，然后同聚氨酯预聚物进行反应制备了聚氨酯酰亚胺材料，考察了酰亚胺含量对材料性能的影响。红外光谱图证实了聚氨酯酰亚胺结构的存在。DSC图上存在低温和高温两个Tg，说明结构中微相分离的存在。力学性能测试表明，改性后的聚氨酯材料拉伸模量都有所增加，而断裂伸长率却降低，尤其是DDS扩链的PUI具有较高的模量，这主要是极性基团巨大的内聚能以及氢键作用的存在所致。TGA和DTG曲线则证明引入酰亚胺基团后材料的耐热性和热稳定性能都得到很大提高，尤其是引入DSiD扩链的聚氨酯酰亚胺材料。材料吸水性的测试表明材料具有较高的耐水性。有机硅改性聚氨酯酰亚胺的介电常数测试表明侧链引入硅氧键后材料的介电系数略微降低，而且由于硅氧键富集在材料表面因而具有较好的疏水性能。-an封端的低聚酰亚胺比-am封端的低聚酰亚胺具有更高的耐热性能，这主要是因为聚氨酯的降解都从氨酯键的断裂开始，且随着酰亚胺含量的增加，材料的耐热性能都得到提高。更多还原

【Abstract】 Polyurethanes (PU) are becoming more and more important as engineering materials due to their many excellent properties such as high abrasion resistance, chemical resistance, and high flexibility. However, it’s well known that conventional polyurethanes exhibit poor thermal stability which limits their more applications in many fields.An effective way to improve the thermal and mechanical properties of polyurethanes is chemical modification by introducing heteroaromatic groups into polyurethane backbones. The sea-island morphology caused by the incorporation of hard segment (chain-extender and imide chain) and soft segment (polyethylene glycol) provided the excellent synthesized properties of polyurethane-imides (PUI). In this work, a novel chain-extender owning three functional groups was prepared. In addition, different types of chain-extender introduced to PU chain were studied. Furthermore, the properties of dielectric constant and water resistance were studies by introducing Si-O bond into either PUI chain or PUI side chain. Finally, amine-terminated oligoimide and anhydride-terminated oligoimide were synthesized to prepare PUI. The effect of Imide content on properties of PUI was studied.The structures of PUI were confirmed through Fourier transform infrared spectra (FTIR). The existence of micro-phase separation morphology was confirmed though the results of Differential Scanning Calorimetry (DSC) analysis. Compared to conventional linear PU, the PUI exhibited higher tensile modulus but lower break elongation because of the huge cohesion energy of polar groups and interaction of H bonds. The results of Thermogravimetric analysis (TGA) and DTG disclosed that PUI owned higher degrading temperature and better thermal stabilities. PUI owning chain-extender AEAPS exhibited lower dielectric constant and higher contact angle than PUI containing DSiD, which meant better water resistance. Also, PUI synthesized from anhydride-terminated oligoimide exhibited better thermal stabilities than PUI synthesized from amine-terminated oligoimide, which showed more thermal degrading temperatures with the increase of imide content.更多还原