High-amylose starch-based gel as green adhesive for plywood: Adhesive property, water-resistance, and flame-retardancy

Yaoxing Chen, Yongjing Rao, Peng Liu, Linlin Wu, Guojie Zhang, Jianguo Zhang, Fengwei Xie

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Abstract

The escalating demand for environmentally sustainable and cost-effective adhesives in the wood processing and manufacturing sector has prompted exploration into innovative solutions. This study introduces a novel gel adhesive composed of chemically unmodified high-amylose starch (G70, with 68 % amylose content) with a minimal proportion of urea-formaldehyde (UF) (UF/starch = 1:10, w/w). This G70/UF gel demonstrates remarkable adhesive capabilities for wooden boards under both dry conditions (with a shear stress of 4.13 ± 0.12 MPa) and wet conditions (with a shear strength of 0.93 ± 0.07 MPa after 2 h of water soaking). The study unveils that the elevated amylose content in the starch, coupled with a meticulously controlled isothermal process during bonding, is crucial for these enhancements. Specifically, the robust cohesion of amylose chains expedites phase separation between starch and UF, while the isothermal process facilitates the migration and enrichment of UF molecules at the gel-board and gel-air interfaces. Lacking these mechanisms, conventional amylopectin-rich starch/UF gels (27 % amylose content) show minimal improvement. Moreover, the G70/UF gel showcases exceptional fire retardancy. In all, the G70/UF gel presents a promising alternative for plywood production, reducing reliance on unhealthy UF resin while offering satisfactory bonding resistance in diverse conditions and superior flame retardancy.

Original languageEnglish
Article number122247
JournalCarbohydrate Polymers
Volume339
Early online date8 May 2024
DOIs
Publication statusE-pub ahead of print - 8 May 2024

Data Availability Statement

Data will be made available on request.

Keywords

  • Biopolymer-based gels
  • High-amylose starch
  • Starch-based adhesives
  • Water-resistance
  • Wood flame retardancy

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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