高强度自修复聚氨酯弹性体的制备及性能

针对自修复材料力学性能和自修复性难以兼顾的问题，采用传统预聚体法，引入含双硫结构的交联剂，制备得到既具有一定力学强度、又具有良好自修复性的聚氨酯弹性体。采用红外光谱进行化学结构表征;采用邵氏硬度计进行硬度测定;采用万能力学试验机考察了不同条件下的自修复效率;通过三维视频显微镜和拍照记录弹性体自修复过程；采用热重分析仪对样品进行热性能表征。结果表明，双硫键被成功引入弹性体中，弹性体邵氏硬度大多可达50 HA以上。升高温度和延长时间都能提高弹性体的自修复效率:24 h时，自修复效率从25 ℃的31.3%升高到80 ℃的99.5%；在80 ℃下，自修复效率从2 h的48.4 %提高到24 h的99.5%。双硫交联剂质量分数的增加也有利于自修复，弹性体的自修复效率从PUSS 3的54.5%提高到PUSS 6的99.5%。热重分析显示，弹性体的热稳定性随双硫质量分数的增加而略有下降，但所有弹性体的5%热失重温度都高于265.0 ℃。

Preparation and Performances of Self-Healing Polyurethane Elastomers with High Strength

The polyurethane elastomers with high mechanical strength and excellent self-healing properties were synthesized by traditional prepolymer method by introducing disulfide crosslinking agent to balance contradictions between mechanical properties and self-healing properties of self-healing materials. FT-IR was used to characterize the chemical structure. The hardness were measured by Shore hardness tester. The universal testing machine was used to test the self-healing efficiency at different conditions. The healing process were recorded by three-dimensional video microscope and photographing. And the thermal properties of the samples were characterized by a thermogravimetric analyzer. The results show that the disulfide structure is successfully introduced into the polyurethane elastomer, and most of Shore hardness of elastomer can reach more than 50 HA. Increasing temperature and prolonging time can improve self-healing efficiency of the elastomer. After 24 h of self-healing, the self-healing efficiency increases from 31.3% at 25 ℃ to 99.5% at 80 ℃. And at 80 ℃, the self-healing efficiency increased from 48.4% in 2 h to 99.5% in 24 h. The increase of the content of disulfide cross-linking agent is also beneficial to self-healing, and the healing efficiency of the elastomer has increased from 54.5% of PUSS-3 to 99.5% of PUSS-6. Thermogravimetric analysis shows that the thermal stability of the elastomer decreases slightly with the increase of disulfide content, but the 5% thermal weight loss temperature of all elastomers is higher than 265.0 ℃.