光固化自修复聚氨酯弹性体制备及性能

Preparation and performances of UV curable self-healing polyurethane elastomer

光固化弹性体因其独特的物理化学性质而被广泛应用于柔性传感器、电子皮肤、生物医学等领域。然而目前市售光固化弹性体强度低,受损后难以实现自修复,极大限制了该类弹性材料的承载能力和应用范围。为解决上述问题,以甘油聚醚多元醇和异佛尔酮异氰酸酯作为分子结构中的软段和硬段,并以2-(叔丁基氨基)甲基丙烯酸乙酯(TBEMA)封端合成了具有动态受阻脲键(HUB)的聚(氨基甲酸酯)脲丙烯酸酯(PUUA)低聚物,然后将封端剂TBEMA作为稀释剂加入PUUA中以制备光敏树脂,通过探究PUUA预聚体和稀释剂比例对材料性能的影响,选出最优配比。之后将制备的光敏树脂进行3D打印,得到光固化自修复聚氨酯弹性体,并分析不同PUUA含量对弹性体性能的影响。结果表明,由于共聚物之间的共价交联及动态可逆和氢键等相互作用,当PUUA质量分数为50%时,弹性体表现出7.3 MPa的高拉伸强度和1 032%的断裂伸长率,并且在经历1 000次的循环加载试验后仍保持稳定的力学性能,断裂的拉伸试样在自修复10 h后拉伸强度的修复效率可达到86.6%。实验证明制备的弹性体具有优异的力学性能和出色的自修复能力,同时所具有的较低玻璃化转变温度使其可在低温环境下保持稳定的物理特性,显示了具有HUB的弹性体在柔性材料领域的潜在应用。

Light cured elastomers are widely used in fields such as flexible sensors,electronic skin,and biomedicine due to their unique physical and chemical properties.However,currently available light cured elastomers have low mechanical strength and are difficult for self-repairing by self after damage,greatly limiting the load-bearing capacity and application range of the elastic materials.To solve the above problems,poly(aminoformate)urea acrylate(PUUA)oligomer with dynamically hindered urea bond(HUB)was synthesized by using glycerol polyether polyol and isophorone isocyanate as the soft and hard segments in the molecular structure,and 2-(tert butylamino)methyl methacrylate ethyl ester(TBEMA)as the end capping agent.Then TBEMA was added as a diluent to prepare a photosensitive resin,the optimal ratio was selected by exploring the influences of PUUA prepolymer and diluent ratio on material properties.Afterwards,the 3D printing of the prepared photosensitive resin was done for preparing UV curable self-healing polyurethane elastomer,and the effects of PUUA contents on the performances of the elastomer were analyzed.The results show that,due to the covalent crosslinking,dynamic reversibility,and hydrogen bonding interactions between copolymers,the elastomer exhibits a high tensile strength of 7.3 MPa and a elongation at break of 1032%.After undergoing 1000 cyclic loading tests,it still maintains stable mechanical properties.The repair efficiency of the tensile strength of the fractured specimen can reach 86.6%after self-healing for 10 h.Experimental results have shown that the prepared elastomer exhibits excellent mechanical properties and self-healing ability,while its lower glass transition temperature enables it to maintain stable physical properties in low-temperature environments,demonstrating potential application of the elastomer with HUB in the field of flexible materials.