Performance of eco-friendly soy protein adhesive reinforced by aldehyde sodium alginate

• Published in: International journal of adhesion and adhesives 2024-05, Vol.131, p.103649, Article 103649
• Main Authors: Li, Zhuqi, Niu, Wenxi, Cai, Li, Li, Jianzhang, Chen, Hui, Gao, Qiang
• Format: Article
• Language: English
• Subjects: Adhesive; Bonding strength; Soy protein isolate; Viscosity; Water resistance
• ISSN: 0143-7496
• DOI: 10.1016/j.ijadhadh.2024.103649

Faced with many challenges such as energy crisis and environmental protection issues, biomass soy protein-based adhesives for replacing aldehyde-based adhesives have gradually become one of the research hotspots for wood industry upgrading. However, soy protein-based adhesives still have many shortcomings. Low bonding strength, poor water resistance and high viscosity restrict their widespread industrial application. In this work, a modified soy protein isolate (SPI) based adhesive with strong water-resistant bonding strength and low viscosity was prepared. Oxidized sodium alginate (OSA) and calcium ions were employed in SPI adhesive system. Results showed that cross-linking between OSA, calcium ions and SPI occurred successfully. The mechanical properties of SPI were significantly improved. The dry and wet bond strengths were 2.05 MPa and 0.97 MPa, respectively, in 65.3 % and 49.2 % increments for comparison. The adhesive samples also showed a reduction in viscosity and an increase in thermal stability. It can be developed as a facile method for preparing bio-adhesives. [Display omitted] •Oxidized sodium alginate and Ca2+ were employed to modify SPI adhesive.•The adhesive shows high bond strength, good water resistance and viscosity.•The wet shear strength reaches 0.97 MPa.•Schiff bases reaction improves the cross-linking density of adhesive.•Hydrogen bonding network provides additional cohesion.