Preparation and Performance of Self-healing Polyurethane based on Two Kind of Disulfide Bonds
Yan Wenkang, Wan Liying
School of Materials Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China
摘要：以异佛尔酮二异氰酸酯(IPDI)和双(2-羟基乙基)二硫醚(DTBO)为硬段，聚四氢呋喃(PTMG)为软段，β-巯基乙醇(ME)为封端剂，制备巯基封端且含双硫键的聚氨酯(PUR)预聚物，利用巯基易氧化的特点，用H2O2/NaI进行氧化，合成分子链内和分子链端均含有双硫键的自修复交联PUR。采用傅立叶变换红外光谱仪、差示扫描量热仪、热重/差热综合热分析仪和电子拉力试验机等手段，研究了PUR的结构及PTMG与ME的物质的量之比对PUR热性能、力学性能和自修复性能的影响。结果表明，合成的系列交联PUR都具有一定的自修复能力和良好的热性能，当DTBO和PTMG物质的量分数分别为总二元醇的40%和60%时，PUR的拉伸强度达到最大值，为2.6 MPa，在60℃热处理8 h条件的自修复率为80.8%，且该试样经三次自修复后，自修复率仍可达到50.0%。
Abstract：With isophorone diisocyanate (IPDI) and double (2-hydroxy ethyl) sulfide (DTBO) as hard segment, polyethylene tetrahydrofuran (PTMG) as soft segment, β-mercaptoethanol (ME) for the end capping agent, the sulfhydryl-terminated polyurethane (PUR) prepolymer containing disulfide bonds was prepared. Sulfhydryl groups were oxidized using H2O2/NaI, and self-healing PUR with cross-linked structures were synthesized. The double sulfur bonds were existed within and at the ends of PUR molecular chains. Fourier transform infrared spectrometer, differential scanning calorimeter, thermogravimetric/differential thermal analyzer, and electronic tensile testing machine were used to research the effects of the PUR structure and ratio of PTMG and ME on the thermal, mechanical and self-healing properties of PUR. The results show that a series of cross-linked PUR synthesized has self-healing ability and good heat resistance. When amount of substance fractions of DTBO and PTMG is 40% and 60% of the total glycol respectively, the tensile strength of PUR reaches the maximum value of 2.6 MPa, and the self-healing rate of heat treatment at 60℃ for 8 h is 80.8%. After three times of self-healing of the same specimen, the self-healing rate can still reach 50.0%.
Keywords：polyurethane; disulfide bonds; sulfhydryl group; self-healing
Yan Wenkang，Wan Liying. Preparation and performance of self-healing polyurethane based on two kind of disulfide bonds[J]. Engineering Plastics Application，2021，49(2)：34-39.