Preparation And Research Of Low Temperature Self-healing Graphene Thermal Conductive Composite Material

In recent years,the application of highly integrated electronic devices in some extreme environments has greatly increased,so the use conditions of materials are more severe.At present,some smart materials have the characteristics of light weight,easy processing and self-healing,so they have become the key materials used in severe environments.In addition,in order to obtain high-performance thermal interface materials,graphene has become the first choice for highly thermally conductive fillers due to its highly regular six-membered ring structure.In view of the low self-healing efficiency and low thermal conductivity of the polymer under low temperature conditions,polydimethylsiloxane cross-linked polymer network（H₂PDMS）with multiple hydrogen bonds was prepared by polydimethylsiloxane and malonyl chloride polycondensation on the amino end of flexible molecular chains.2-urea-4[1H]pyrimidone grafted graphene oxide（UGO）was prepared by functional modification of graphene.After composite,low-temperature self-healing thermal conductive composites were obtained,and their physical and chemical properties,self-healing properties and thermal conductivity were studied.The main results are as follows:（1）Using polydimethylsiloxane（PDMS）and malonyl chloride with flexible molecular chains as the main raw materials,a self-healing H₂PDMS polymer is prepared by condensation polymerization,which is realized by supramolecular hydrogen bonding cross-linking network self-healing,through the reversible fracture and formation of multiple hydrogen bonds between N-H and C=O to achieve self-healing function,after repairing at-25℃for 40 min,the tensile modulus of polydimethylsiloxane cross-linked polymer can be repaired by 97%,which has certain reference significance for the preparation of hydrogen-bonded low-temperature self-healing polymers.（2）Introduce 2-ureido-4[1H]pyrimidinone-grafted graphene oxide（UGO）to prepare H₂PDMS/UGO composite materials.Not only effectively improves the strength of the polymer material,but also through the mutual cooperation of multiple hydrogen bonds,the composite material can also be self-healing at low temperature（0℃）,and the filling of functionalized graphene makes the thermal conductivity of the polymer material improve 5 times,and also showed good self-healing ability in the process of heat transfer.