Preparation Of Self-healing And Dielectric Functional Materials Of Eucommia Ulmoides Gum

Based on the unique chemical composition and chain structure of Eucommia ulmoides gum(EUG),through epoxidation and subsequent ring-opening condensation to introduce different polar groups on the molecular chain of EUG to functional modification of EUG,then two different materials were successfully prepared,named EUG based self-healing material(FEEUG)and EUG based dielectric material(SEEUG).The microstructure changes of molecules and mechanical properties of FEEUG and SEEUG were analyzed by GPC,IR,~1H-NMR and DSC;The self-healing properties and adhesion of FEEUG were studied by tensile test and lap shear test.The aggregation structure and dielectric constant of SEEUG were studied by POM,XRD and high voltage capacitor bridge.The results of the study on FEEUG show that the FEEUG synthesized under acidic conditions tends to undergo condensation reaction between the ring-opening of the epoxy groups and the hydroxyl groups,and it tends to degrade under alkaline conditions.The triol system has a higher self-healing efficiency than the alcohol-free system and the diol system.For the triol system,with the increase of modification degree or self-healing time,the self-healing efficiency increases,and the self-healing efficiency is as high as 90.2%after self-healing at 30°C for 4 hours.The unique chain structure combined with the introduction of polar groups enhances the viscosity of the FEEUG,with reproducible and long-lasting adhesion,and the adhesion strength is only reduced by 10.9%after five repeated lap shear tests.The results of the study on SEEUG show that with the increase of reaction temperature and the extension of reaction time,the degree of modification and sulfonation increase.As the degree of modification and sulfonation increase,the mobility of the molecular chain decreases or even disappears,and the aggregate structure changes from a crystalline structure to an amorphous structure.At a certain degree of sulfonation,the introduction of sulfonic acid groups leads to the formation of new small crystal forms with enhanced and toughened effects.The tensile strength and elongation at break are as high as 22.99 MPa and 1050%,respectively.The sulfonation modification changes the electrical properties of the EUG.The maximum dielectric constant of the SEEUG reaches 3.37,which is 1.87 higher than the EUG.