聚丙烯酸-羧甲基纤维素合成及其对豆胶性能影响OA

In recent years,as a sustainable alternative to traditional urea-formaldehyde resins,the development of soy protein-based adhesives has gained significant attention in the wood-based panel industry.Among various modification approaches,crosslinking modification has proven particularly effective in enhancing the water resistance of soy protein adhesives,enabling its application in commercial production.However,conventional crosslinking agents often induce excessive brittleness in the adhesive layer,compromising the long-term bonding stability of the resulting materials.To address this limitation,this study developed a novel modifier through the esterification reaction between polyacrylic acid(PAA)and carboxymethyl cellulose(CMC),aiming to incorporate a robust hydrogen bond network into the soy protein adhesive system.This research focused on synthesizing polyacrylic acid-carboxymethyl cellulose(PAA@CMC)and systematically investigating its effects on both the bonding performance of adhesives and the toughness of cured adhesive layers.Using defatted soy powder as the base material,triglycidylamine(TGA)as the crosslinking agent,and the synthesized PAA@CMC as the toughening modifier,this study developed a dual modification mechanism.The epoxy groups of TGA reacted with amino groups in soy protein to form a dense crosslinked network,effectively reducing the concentration of hydrophilic groups and thereby decreasing the material's susceptibility to water intrusion.Simultaneously,PAA@CMC interacted with hydroxyl and amino groups in the protein matrix through hydrogen bonding,significantly improving both the adhesive strength and the adhesive layer toughness.The results showed that at an optimal PAA@CMC content of 5%(mass fraction),the soy protein adhesive achieved significant performance improvements.The dry bonding strength increased to 2.33 MPa and wet bonding strength reached 0.97 MPa,fully meeting the requirements of the Class Ⅱ plywood standards specified in GB/T 9846-2015"Plywood for general use".Additionally,the hygroscopicity decreased 17.3%.Most notably,the modified adhesive exhibited substantially improved toughness,which provided an effective strategy for improving the toughness of the adhesive layer.This study introduced a PAA@CMC hydrogen-bonded network to modify soy protein adhesive,which not only meets the Class Ⅱ plywood standards specified in Chinese National Standard but also effectively addressed the brittleness issue associated with conventional crosslinking agents.The successful integration of crosslinking and toughening modifications presents a promising pathway for the large-scale industrial application of soy protein adhesives in the wood composite industry.The findings provide significant technical support for the practical application of eco-friendly adhesives in industrial settings.