多酚型改性腰果酚涂层的制备及性能研究OA

Cardanol-based benzoxazine was prepared via the Mannich reaction using cardanol(CL)as raw material,and it was further subjected to a ring-opening reaction with cardanol to synthesize high bio-based-content polyphenolic(bisphenolic and tetraphenolic)modified cardanol resins.The obtained resins were then formulated into thermosetting coatings using copper N,N'-ethylenebis(salicylideneimine)(Cu-salen)as a drier.The chemical structures of the synthesized products were characterized by Fourier transform infrared(FT-IR)and 1H nuclear magnetic resonance spectroscopy(1H NMR),while the composition,surface morphology and thermophysical-mechanical properties of the coating samples were characterized by X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and dynamic thermomechanometry analysis(DMA).The effects of the type of polyphenolic cardanol and Cu-salen loading on coating performance were examined.The results showed that the phenolic hydroxyl group of cardanol chelated with Cu2+,while the unsaturated bonds in the side chain formed a cured film through crosslinking reactions.The storage modulus of the film increased with the increases of drier content and the number of phenolic hydroxyl groups.Among the samples,tetra-cardanol with 5％Cu-salen(T-CL-Cu5)exhibited the highest storage modulus,reaching 2 303 MPa.Under conditions of 120 ℃ and 18 h,the bisphenolic cardanol coating with 5％Cu-salen achieved completely drying,with a pencil hardness of 6H and an adhesion grade of 1,whereas the tetraphenol-type coating reached full cure within just 7 h.With the increase of the drier amount,the surface morphology of the coating became smoother and more uniformed.Compared with the natural lacquer film,the hardness,adhesion and gloss of the modified cardanol coating doped with Cu-salen were further improved.