Studies On Preparation,Structure And Property Of Ureidopyrimidone Silicone Self-healing Composite Elastomer

Self-healing polymer materials have the property of being able to repair themselves to their original state after being damaged or destroyed.Thus make it has great significance in practical application requirements.As a special non-covalent bond,hydrogen bond has a unique position in the field of supramolecular chemistry and has become one of the research hotspots for self-healing polymer material.In this paper,based on the quadruple hydrogen bonding system with self-identification function,the silicone rubber is modified and used as a matrix,to which the same modified functional filler is added to achieve the enhanced purpose.At the same time,the interaction between the modified groups of both filler and the matrix was used to achieve the purpose of not damaging the self-healing properties of the composite system.In this paper,firstly,a reactive ureidopyrimidone unit?UPy-NCO?was synthesized via the reaction of hexamethyldiisocyanate?HDI?and ureidopyrimidone?UPy?.After that the silicone rubber matrix and SiO₂ nanoparticles were grafted with it.FTIR characterization demonstrated the success of synthesis and grafting reactions.The cross-sectional morphology analysis also showed that the modified SiO₂nano-particles were uniformly dispersed in the matrix;photos and micrographs of the repair process showed that the material had good self-healing properties.Comparing the original mechanical properties and self-healing mechanical properties of the samples with different added components,we can find that the original and self-healing tensile strength of the sample increased with the addition of the modified SiO₂ nanoparticles,while the repair efficiency slightly decreased.The above results demonstrate that modified SiO₂ nanoparticles have a positive reinforcing effect on the mechanical properties and self-healing properties of silicone supramolecular elastomers.Single-component and two-component composite supramolecular elastomers were prepared with layered silicate material OMMT and PANI-ATS.These fillers are inexpensive and easily available.Moreover,they have excellent mechanical properties and good compatibility with organic polymers.Characterization of FTIR and rheological properties demonstrated that C22 alkyltoluene sulfonic acid?ATS?was successfully doped with polyaniline and the product was fluid at 50 ^oC.By analyzing the mechanical properties,it was found that the original and self-healing tensile strengths of the samples increased with the increase of OMMT content,while the strength of the samples with 5%PANI-ATS at the same OMMT content was further increased.However,due to the nature of the filler itself and the large amount of filler added,the repair efficiency of the material is reduced.The graphene oxide?GO?was prepared by the Hummers method and the UPy-NCO group was grafted onto GO surface to obtain the modified graphene oxide?m-GO?.The appearance of the C=O and C-O vibrational peaks on the GO curve and the disappearance of the-NCO peak in the FTIR spectra confirm the successful preparation of GO and m-GO.The lamellar structure observed from the SEM cross-sectional topography shows that GO is uniformly dispersed in the matrix,and its compatibility with the matrix is improved after modification.Through the analysis of mechanical properties,it was found that the initial and self-healing tensile strength and tensile strain of the samples increased with the addition of m-GO,the self-healing efficiency was not affected.It is fully demonstrated that the mechanical properties and repair properties of the composite supramolecular elastomer are greatly improved with the addition of minute amounts of m-GO.The self-healing elastomer can be made into a handicraft mould to obtain a replica with complete shape and jointless seam,and can be used repeatedly.It is proved that this kind of self-repairing supramolecular elastic body has a wide application prospect in the handicraft mould field.