| Self-healing material can heal own damage from internal or external.The material can eliminate the hidden danger in time and prolong the service life of material.Therefore,selfhealing materials have a great development prospect and application value in some important engineering fields,and become one of the hot spots in the intelligent research of polymer composites.At present,there are many ways of self-healing of polymer composites,in which thermal reversible covalent bond of Diels-Alder(DA)reaction implant material in bulk structure is an effective method.The polymer material implanted with DA covalent bond can repair the damage site of polymer composite material by the interaction of Diels-Alder inverse reaction and Diels-Alder reaction in the molecular chain,and the self-healing efficiency is high.In the first step,Dihydroxyl group chain extender containing furan ring was synthesized from propylene oxide and furan.After co complete chain extension reaction with DMPA,then react with bismaleimide with bifunctional degree,the self-healing material of waterborne polyurethane containing DA covalent bond was prepared In the second step,WPU-DA/CO self-healing composites were prepared by mixing graphene oxide with WPU-DA in ultrasonic oscillations.The synthesis of the product was confirmed by Fourier transform infrared spectroscopy(FTIR).Differential scanning calorimeter(DSC)was used to study the thermal reversible properties of waterborne polyurethane(WPU-DAA)and WPU-DA/CO composites.The self-repairing process of knife marks on WPU-DA film and WPU-DA/CO film at 120 ? was observed by polarizing microscope(POM).The results showed that the knife mark on WPU-DA film and WPU-DA/CO film with knife mark could be completely disappeared within 5 minutes.Finally,the mechanical properties of the composites show that the self-repairing properties of the composites can reach 70%. |
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