吡啶基聚氨酯的制备及其自修复性能研究

Preparation and self⁃healing performance of pyridine⁃containing polyurethane

为探究氢键对聚氨酯性能的影响,以聚四氢呋喃、异氟尔酮二异氰酸酯、4,4’-二羟基联苯(HBD)和N^(3),N^(5)-双(4-羟基苯基)吡啶-3,5-二甲酰胺(HPD)制备了2种类型的聚氨酯,并利用红外光谱仪(FTIR)、热重分析仪(TG)、万能力学试验机等对2种聚氨酯的化学结构、热稳定性、力学性能和自修复性能等进行了表征和测试。结果表明,2种聚氨酯均表现出了优异的自修复性能;60℃下,两者均30 min即可完成自修复;相较于以HBD为扩链剂制备的聚氨酯,以含有吡啶基团和酰胺基团的扩链剂(HPD)制备的聚氨酯表现出更优异的力学性能(拉伸强度为1.2 MPa)、更优异的热稳定性能(热降解活化能为230.3 kJ/mol)及更高的残炭率(800℃残炭率约为5%)。

To explore the effect of hydrogen bonds on the properties of polyurethane,two types of polyurethanes were syn-thesized using polytetrahydrofuran,isophorone diisocyanate,4,4’-dihydroxybiphenyl,and N^(3),N^(5)-bis(4-hydroxyphenyl)pyridine-3,5-diformamide as raw materials.Their chemical structure,thermal stability,mechanical properties,and self healing properties were investigated by Fourier-transform infrared spectroscopy,thermogravimetry analysis,and a universal material testing machine.The results indicated that the two polyurethanes presented excellent self-healing performance,and both of them could completely self-heal the damages after healing at 60℃for 30 min.As a chain extender,the polyurethane synthesized with N^(3),N^(5)-bis(4-hydroxyphenyl)pyridine-3,5-dicarboxamide exhibited a better mechanical property than that with 4,4’-dihydroxybipheny,exhibiting higher tensile strength of 1.2 MPa,superior thermal stability with thermal degradation activation energy of 230.3 kJ/mol,and a higher carbon residual yield of 5 wt%at 800℃.