Research Progress on Formaldehyde‐Free Wood Adhesive Derived from Soy Flour

Abstract

Soy-based adhesives have been regarded as the most suitable candidates for wood industry. For a widespread use of soy-based adhesives, new technologies need to be developed to improve the water resistance. An overview on the methods to improve water resistance of soy-based adhesives is presented. Denaturants were once considered necessary to modify soy protein. However, water-resistant soy adhesives could be prepared by simply removing water-soluble carbohydrates and low molecular peptides from soy flour. In addition, proper grafting and cross-linking agents help to prepare water-resistant soy-based adhesives, which are used widely to bond interior wood composites. In particular, a new type of polyamidoamine (PADA) resin and an itaconic acid-based polyamidoamine-epichlorohydrin (IA-PAE) resin were synthesized to perform as cross-linking agents for soy-based adhesives. This review concludes that soybased adhesives have great potential for use in numerous applications. However, future work is still needed to make soy-based adhesives more competitive with synthetic adhesives.

A Review of Strategies to Enhance the Water Resistance of Green Wood Adhesives Produced from Sustainable Protein Sources

“…Protein adhesives especially soy-based adhesives are expected to witness significant growth with a compound annual growth rate of around 7% from 2019 to 2025 [11]. The expansion is due to the environmental benefits offered by the products which is the major factor for the increasing demand [30].…”

A formaldehyde-free adhesive for particleboards based on soy flour, magnesium oxide, and a plant-derived enzymatic hydrolysate

“…Denaturation of soy protein is performed with various chemicals, such as acids, alkalis, detergents, salts, and chaotropic agents, with the aim of exposing more polar groups for improved solubility and interaction via hydrogen bonds (Vnučec et al 2017). Water resistance of soy protein adhesives is imparted by soy protein molecular modifications, i.e., grafting reactive groups onto protein molecules (Qin et al 2013;Gui et al 2016). These groups react with the polar groups of soy protein during hot pressing and form a crosslinked network in the course of curing (Kim and Sun 2014;Zhu and Damodaran 2014).…”

Estimation of Formaldehyde Emissions of Plywood Treated With Fire Retardant Chemicals by Artificial Neural Network

“…Literatürde yapılan çalışmalara göre, bu yöntemler dört başlık atında toplanabilir. Bunlar; (1) tutkal reçinesindeki formaldehit içeriğinin azaltılması (Myers, 1984), (2) formaldehit tutucuların veya diğer formaldehit yakalayıcı bileşiklerin kullanılması (Kim, 2009;Moubarik et al, 2010;Gangi et al, 2013;Costa et al, 2013) (3) boyalar, cilalar, kaplamalar ve kağıtlar ile levhaların yüzeylerinin işlenmesi (Roffael, 1982;Myers, 1986;Costa et al, 2013) ve (4) alternatif tutkal türleri ve sistemlerinin kullanılmasıdır (Gui et al, 2016). Yangın geciktirici kimyasalların, kendileriyle işlenen malzemelerin diğer fiziksel, mekanik ve bazı teknolojik özellikleri üzerinde etkili olduğu bilinmektedir (Ustaömer, 2008).…”