端—OH聚氨酯增韧环氧树脂的制备与性能研究

Study on preparation and properties of hydroxyl-terminated polyurethane toughened epoxy resin

以聚乙二醇(PEG)400和异佛尔酮二异氰酸酯(IPDI)为主要原料,分别采用分步法和一步法合成端—OH聚氨酯(PU)预聚体,将其用作改性增韧剂,以脂肪族三乙烯四胺为固化剂,制备系列的EP增韧材料,并对其力学性能和热性能进行研究.结果表明,两种方法合成的端—OHPU的红外谱图形状大致相同;当端-OHPU中—OH与—NCO当量比6GA6FA5,添加量为15份时,改性EP材料的断裂伸长率为11.1%,拉伸剪切强度为14.9MPa,冲击强度为25.7kJ/m^2,分别较未改性的EP材料提高了0.8倍、1.3倍和1.9倍,韧性和粘接性能都得到了明显提升;端-OHPU增韧EP材料为均相和微分相体系(端-OHPU添加量<15份)时,端—OHPU降低了EP材料的Tg;出现相分离(端—OHPU添加量≥15份)后,端—OHPU对EP材料Tg的影响减小.一步法合成的端-OHPU实现了EP的高效增韧,分子结构中避免了常用方法中苯环的存在,既提高了EP的耐候性又能够在室温条件下实现增韧EP的快速固化,为EP的增韧与快速固化提供了一条新途径.

The epoxy resin (EP) was toughened by the hydroxyl-terminated polyurethane (PU) which was synthesized by polyethylene glycol (PEG) 400 and isophorone diisocyanate (IPDI) with step-by-step and one-step methods. Toughened EP materials were prepared by EP, hydroxyl-terminated PU and triethylene tetramine. The mechanical properties and thermal properties of toughened EP were investigated. Results showed that the infrared spectra of hydroxyl-terminated PU synthesized by the two methods were approximately the same in shape.When the addition of hydroxyl-terminated PU(equivalent ratio of-OH and - NCO 6 GA6FA 5) was 15 phr,the elongation at break was 11.1%, the tensile shear strength was 14.9 MPa and the impact strength was 25.7 kJ/m^ 2 , which were 0.8 times,1.3 times and 1.9 times higher than those of pure EP, respectively. The toughness and bonding performance of EP were significantly improved. The T g of hydroxyl-terminated PU toughened EP materials decreased when it was homogeneous phase and microphase separation system (hydroxyl-terminated PU content <15 phr). After phase separation (hydroxyl-terminated PU content ≥15 phr), the influence of hydroxyl-terminated PU on EP material's T g decreased. The hydroxyl-terminated PU synthesized by one-step method realized EP's high-efficiency toughening and avoided the presence of benzene ring in the molecular structure, which not only improved EP's weather resistance, but also realized the rapid curing of toughened EP at room temperature. The method provides a new way for EP's toughening and rapid curing.