基于两种双硫键自修复聚氨酯制备及性能

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%。

Preparation and Performance of Self-healing Polyurethane based on Two Kind of Disulfide Bonds

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 selfhealing 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%.