| Epoxy resin has excellent comprehensive performance.One-component epoxy resin based on latent curing agent has good storage stability,and has huge application demand and commercial value in adhesives,coatings,electronic packaging and composite materials and other fields.The development of latent curing agent adapts to modern industrial large-scale production mode,which can increase efficiency work,reduce environment pollution,more importantly,obtain stable quality of industrial products.However,the latent curing agent depends on non-renewable fossil resources which mining also lead environmental pollution.Thus,the development of green-sourced and environment-friendly latent curing agent has become an important research topic.In view of the above issues,we carried out research on the new latent curing agent based on biomass resources.First,a latent curing agent,imidazole phytate PAIM,was prepared by the reaction of imidazole and phytic acid.The curing agent possessed good solubility in the bisphenol A epoxy resin DER331,and was blended into epoxy resin to prepare one-component epoxy resin.Differential scanning calorimeter and rotary rheometer were used to systematically study the storage and curing behavior of one-component epoxy resin system,which has the characteristics of low-temperature storage stability and high-temperature curing reactivity.And then gradually heating to complete the curing reaction to obtain cured epoxy resin.The cured exhibited high T_g(～205℃)and superior thermal stability.Then,we exploited amino acids a new type latent curing agent.The curing kinetics and latent curing mechanism of epoxy resin were investigated by non-isothermal DSC scanning and small molecular model of compound amino acids,which is indicative of the potential of amino acids as type latent curing agent.Through the design and synthesis of amino acid’s chemical structure,the properties of cured epoxy resin can be improved and regulated.Amino acid containing amide bond(PDA-MAH)was synthesized from bioresources,and mixed with itaconic acid epoxy monomer(EIA)to obtain fully bio-based one-component epoxy resin(PDA-MAH-EIA).In order to study the effect of amide bond in the network on properties,AAD-EIA was used as the control group.The results showed that the mechanical and thermal properties of PDA-MAH-EIA samples were much better than AAD-EIA,which was due to the fact that the amide bonds contained in amino acids made epoxy network be rich in hydrogen bonds.In addition,due to the large number of ester bonds in the epoxy network,the cured products exhibited certain degradability under alkaline conditionsIn summary,this thesis developed bio-derived latent curing agents for epoxy resin,studied the latent curing behavior of one-component epoxy resin,and obtained the epoxy network with adjustable performance,which is of great significance for the development of latent curing agent in the future. |
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