Research On The Synthesis And Performance Of Polymers Based On Active Methylene Compounds

Biomedical materials have developed into an important part of contemporary materials science.Nowadays,biomedical materials with multiple functions have become the goal of people's pursuit.In this paper,based on active methylene compounds(AMCs),through the study of carbon-carbon bonds,two types of biomedical materials with excellent biological properties,polymer materials and hydrogel materials were synthesized.The results are as follows:(1)Based on AMCs,a synthesis method of carbon-carbon single bonds under ambient conditions was explored,which belongs to active carbon anionic polymerization.A model polymerization was first conducted between ethylene glycol diacrylate and methyl cyanoacetate,and an organic superbase 1,8-diazabicyclo[5.4.0]undec-7-ene was used as a catalyst to verify the feasibility of the reaction.Eight AMCs were selected and a highthroughput parallel synthesizing instrument was used to synthesize a series of polymers via a Michael type polyaddition.The obtained polymers had low cell cytotoxicity.Secondly,dihalogen compounds were also explored to polymerize with AMCs via a polyalkylation.The pendent cyanogen or ester groups of the polymers could be reduced to amino groups and hydroxyl groups by lithium aluminum hydride,and the reduction products with multiple NH2 and OH may have a great application in gene delivery and antibacterial materials.What's more,elastomers with cyanogen groups could be prepared,which may be applied in flexible electronic and shape memory materials.(2)Based on the active methylene compound poly(ethylene glycol)dicyanoacetate and water-soluble poly(vanillin acrylate),the dynamic C=C bond formed by the Knoevenagel condensation reaction was studied and this reaction was used to prepare injectable hydrogels.The gelation time ranged from seconds to minutes and was highly tunable by changing catalyst(phosphate buffer saline,metal organic framework material and tertiary amine).Due to the reversibility of the Knoevenagel condensation reaction,the formed hydrogel was a dynamic hydrogel,which had self-healing properties and could be used in flexible electronics.This found a new dynamic covalent chemistry for the preparation of self-healable materials.What's more,the hydrogel precursors and hydrogels had low cytotoxicity.He La cells were embedded in the hydrogels for 3D cell culture,which proved that the hydrogels could be used as good cell carrier material.