木薯淀粉-聚乙烯醇胶黏剂的合成与性能OA北大核心CSTPCD

Since starch is a macromolecular polymer,adhesives directly prepared from starch typically exhibit poor water resistance.To improve its water resistance,the authors selected three types of acids as catalysts(formic acid,acetic acid,and sulfuric acid)to hydrolyze cassava starch,and then polymerized it with polyvinyl alcohol to prepare formaldehyde-free cassava starch-polyvinyl alcohol(CS-PVA)wood adhesives for wood products.The effect of formic acid concentration on the adhesive's performance was explored by evaluating its basic properties,including viscosity and solid content.Structural analysis was carried out using X-ray diffraction(XRD),Fourier-transform infrared spectroscopy(FTIR),carbon nuclear magnetic resonance spectroscopy(13C-NMR),X-ray photoelectron spectroscopy(XPS),and scanning electron microscopy(SEM).Differential scanning calorimetry(DSC)and thermogravimetric analysis(TGA)were employed to characterize the curing performance,while wettability was assessed through contact angle measurements.The results showed that acid-catalyzed starch degradation significantly increased its interaction with PVA,promoting the formation of cross-linked structures through ether and hydrogen bonds.These cross-links effectively inhibited the penetration of water molecules,thereby improving the resin's water resistance.SEM observations indicated that the structure of the degraded CS-PVA adhesive was denser and more stable than that of the non-degraded counterpart.Notably,when 1％formic acid was used as the catalyst,the plywood samples exhibited dry shear strength,24-hour cold-water shear strength,and 3-hour hot-water(63℃)shear strength values of 2.45 MPa,1.31 MPa,and 0.93 MPa,respectively,which met the requirements of the national standard GB/T 9846-2015"Plywood for general use"for Type II plywood.These shear strengths represented improvements of 41.6％,151.9％,and 66.1％,respectively,compared to plywood bonded with non-degraded starch resin.These findings indicate that starch degradation significantly enhances the water resistance of CS-PVA adhesives while maximizing their environmental friendliness and strength.