Preparation And Properties Of Cardanol Benzoxazine Polymers

Benzoxazine,as a new type of phenolic resin,has excellent thermal properties,mechanical properties,flexible molecular design capabilities,and other advantages,while it still has problems such as large brittleness and improvement of adhesion.This paper deals with the preparation of sustainable biobased-benzoxazines with cardanol,formaldehyde and different amine components（ethanolamine,2-amino-1,3 propanediol,tris,octylamine and butylamine）,and explores its potential as an anti-corrosion substrate,which provides theoretical and experimental basis for expanding and upgrading the application field and practical value of benzoxazine resin.1.The benzoxazine monomer C-o was successfully prepared by solvent-free method using cardanol and octylamine which have flexible long side chains,and paraformaldehyde.We added CuCl₂ to accomplish the process of the ring opening at a lower temperature to form the octylamine-based benzoxazine copper polymer（PBzn）.Results showed that copper ions participated in coordination polymerization.It was found that the PBzn was dried at room temperature and had excellent impact strength,adhesion and flexibility because of cardanol and octylamine with flexible long side chains.2.Preparation of polyimides（R1 and R2）as corrosion inhibitors with pyromellitic anhydride,1,4,5,8-naphthalenetetracarboxylic anhydride and benzidine.R1 and R2 were respectively added in an amount of 0.1 wt%,0.5 wt%,1 wt%,and a polyimide-octylamine benzoxazine copper polymers were obtained by using PBzn as a matrix.The TG analysis showed that the thermal stability of the copolymer films was enhanced by the addition of polyimides,and the Tafel curve and EIS impedance showed that polyimide could effectively improve the corrosion resistance of PBzn.3.Preparation of thermosetting polybenzoxazine with cardanol,paraformaldehyde and different amines including butylamine,ethanolamine,2-amino-1,3 propanediol and tris.The effect of hydroxyl groups on the adhesion of polymers was studied.Results showed that as the number of hydroxyl groups in the amine source increased,the contact angle decreased,indicating an increase in the number of hydroxyl groups on the surface of the coating.The introduction of hydroxyl groups could improve the adhesion of the coating,and the adhesion of the coating increased with the increase of the number of hydroxyl groups,and the PCT had exhibited excellent adhesion on the metal substrate in strong acid and alkali environment.