Preparation and performances of UV curable self-healing polyurethane elastomer
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 elas-tomer exhibits a high tensile strength of 7.3 MPa and a elongation at break of 1 032%.After undergoing 1 000 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.
3D printingself-healingelastomerglycerol polyetherpolyurethane
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