Study On The Application Of Biomass Phenol To Prepare Thermosetting Resin

2,2-Bis(4-hydroxyphenyl)propane,called as bisphenol A(BPA),is a crucial raw material for thermosetting such as benzoxazine and epoxy resins.BPA is a petrochemical product,facing problems of resources,toxicity and environment.Thus,searching for BPA substitutes is a hot topic in the field of polymer synthesis.In this work,cardanol is used to synthesize bio-based benzoxazine,and the toughening effect on commercial benzoxazine resins are investigated.On the other hand,vanillic acid,vanillyl amine and vanillyl alcohol are used as raw materials to explore bisphenols synthesis routes such as esterification and amidation,then cytotoxicity of the resulting bisphenols and material properties of the resins are evaluated.This work contains three chapters as following:(1)This chapter used bio-based benzoxazine copolymerization approach to toughen commercial benzoxazine resins and made remarkable effects.Cardanol,aniline and paraformaldehyde via Mannich condensation reaction to synthesize cardanol-aniline benzoxazine(C-A),which was copolymerized with commercial diamine-type benzoxazine,4,4-diaminodiphenylmethane-type benzoxazine(PH-ddm)to enhance its toughness.The self-plasticizing effect of the long aliphatic chain of cardanol was used to improve the toughness of copolymer.The results show that when the molar ratio of PH-ddm/C-A is 2.5:1,the thermal stability of the copolymerized resin can remain stable while the elongation at break is 20%higher than that of the resin cured by pure PH-ddm,the toughness is significantly improved.(2)In this chapter,vanillic acid,was reacted with vanillyl amine and vanillyl alcohol to synthesized bisguaiacol amide and bisguaiacol ester respectively.The results of cytotoxicity tests confirmed that the toxicity of the two obtained bisphenols was significantly lower than that of BPA.The bisphenols were further reacted with furfurylamine and paraformaldehyde to prepared two kinds of benzoxazine with similar structure.Comparing materials properties of polybenzoxazines,the amide-based polybenzoxazine shows better performance including storage modulus,glass transition temperature(T_g),thermal stability and mechanical properties than ester-based polybenzoxazine.It could infer that biguaiacol amide can enhance the material performance effectively by providing many hydrogen bonds.Thus,amide bisphenol is more suitable for the preparation of high-performance bio-based benzoxazines to replace BPA.(3)The bisguaiacol amide synthesized in the previous chapter was demonstrated to be not significantly toxic for human by endocrine toxicity tests.Further,epoxy monomer was prepared from bisguaiacol amide and epichlorohydrin.The monomer cured with L-cysteine methyl ester,succinic anhydride,and 2-ethyl-4-methylimidazole to obtain epoxy resin,and then the material properties of the epoxy resin were characterized.Comparison of the above epoxy resins with bisphenol A-based epoxy resins revealed that the bisguaiacol amide-derived has better dynamic thermos-mechanical and mechanical properties.In particular,the epoxy resins cured by L-cysteine methyl ester could self-healing and reprocess by ester exchange reaction.The above results suggests that bisguaiacol amide is applied to the preparation of high-performance bio-based epoxy resins and can be a strong candidate to replace BPA in the preparation of high-performance polymer.