Preparation And Application Of Intrinsic Self-healing Polymer

Polymer materials with self-healing properties(self-healing polymers)can overcome the problems of traditional polymer materials such as short service lifespan and limited working environment,and become one of the new smart materials in the21 st century.According to their repair mechanism,self-healing polymers can be divided into two categories: Extrinsic self-healing polymers that introduce other chemical substances for polymerization reactions to achieve repairing,and intrinsic self-healing polymers that use the reversible covalent bond or non-covalent bond of the polymer material itself as self-repair sites to achieve repairing.Intrinsic selfhealing polymer replaces extrinsic self-healing polymer in repair times,preparation process,parameter adjustment,etc.Therefore,from the perspective of intrinsic selfhealing polymers,this paper selects two self-healing polymer systems based on reversible imine bonds and disulfide bonds as repair sites for research.The self-healing polymers prepared are applied to energy harvesting and transformation,metamaterials and flexible sensors.Related work and results of the subject are as follows:(1)A compound tri-[(4-formylphenoxy)methyl]ethane containing three aldehyde functional groups was designed and synthesized,it was subjected to Schiff base reaction with amino-terminated polydimethylsiloxane to obtain a self-healing polymer with dynamic imine bond as the repair site.Nuclear magnetic resonance(NMR)and infrared spectroscopy(IR)data proved that the polymer was successfully synthesized.Real-time optical microscope observation and mechanical property test proved that the self-healing polymer could achieve structural and property recovery after reparing at room temperature for 6 h.Using the self-healing polymer as a substrate,a fully flexible nano-energy collection device-electret friction nanogenerator is prepared.First,prepare the sandwiched structure and the fully flexible electret film,and assemble and set up the corona polarization device to inject a large amount of electric charge into the electret,and apply liquid metal(Ga In Sn)to the side of the self-healing polymer to act as an electrode and encapsulate the electret to obtain a nanogenerator,which can be used as an energy harvester to collect the mechanical energy of the experimenter and convert it into electric energy drives dozens of LED lights to work,and can also be used as a self-powered sensor to distinguish walking,running and other postures.After the device is repaired,various performances are restored to the original level.(2)Polysulfide polymer and epoxy resin are used to prepare a self-healing polymer based on reversible dynamic disulfide bond.The polymer can be completely repaired after standing at 60°C for 4 hours.Due to the high conductivity and high fluidity of the liquid metal in the room,it is extremely strong repairability,and then use a self-healing polymer-encapsulated liquid metal resonance ring as a metamaterial for application of electromagnetic wave absorption.It has an electromagnetic wave absorption greater than 90% at 10 GHz,and the metamaterial has the same absorbing performance before damage and after repair;at the same time,the self-healing polymer is used to encapsulate liquid metal to prepare a fully flexible self-healing sensor.The test shows that the electrical signal law of changes in multiple parts of the body under different tensile deformations is obvious,and the signal output ability is completely restored after repair.