Effects of Pressure from High‐Pressure Homogenization on the Performance of Soybean Flour Based‐Adhesive

Abstract

A green and sustainable soybean flour (SF) adhesive is considered as a potential alternative to toxic formaldehyde‐based resins. Nevertheless, poor bond stability and low bonding strength is caused by the uneven size distribution and low reactivity of SF. Herein, SF adhesives with excellent and stable performance are synthesized via the synergistic action of high‐pressure homogenization (HPH) treatment by incorporating a green crosslinker. Specifically, an even distribution of the SF particles is obtained after the HPH treatment, from which large soy protein molecules are broken to several small and even single protein molecules. In this way, the adhesion stability is improved. Additionally, more active groups buried in proteins are exposed after the HPH treatment due to the unfolding of the protein molecules. Therefore, a more reactive SF is obtained and thus forms a denser crosslinking structure of resultant the adhesive, providing an increase in bonding strength. Particularly, the effects of homogenizing pressure on the adhesive performance are investigated. The results show that a 215.6% increase of wet bonding strength (1.01 MPa) is obtained after the HPH treatment with a homogenizing pressure of 20 MPa, meeting the standards (GB/T 9846‐2015) for interior applications.

Highly dispersed manganese dioxide nanoparticles anchored on diatomite surface by sol–gel method and its performance on soybean meal‐based adhesive

“…The first degradation peak of SM adhesive (appeared at 197 C) was attributed to the elimination of water in the initial stage up to 100 C and various gases released, such as CO, CO 2 , and NH 3 produced from the reaction between cross-linker and soy protein. 34 The second major weight loss of the SM adhesive started at approximately 214 C and ended at 284 C with one peak at 261 C, resulting from the decomposition of small molecules and the breakage of the peptide backbone. 35 The third stage of weight loss started at approximately 284 C with one peak at 317 C due to the degradation of soy meal matrix.…”

Plant Polyphenol‐Inspired Crosslinking Strategy toward High Bonding Strength and Mildew Resistance for Soy Protein Adhesives

“…[14][15][16][17] The formation of a crosslinked network is an effective approach to prepare high-performance soybean protein adhesives. Polyamine-epichlorohydrin (PAE), [18] epoxides, [19,20] and polyisocyanates [21] are common crosslinking modifiers used to construct intrapenetrating or interpenetrating networks with soy protein molecules to form tough crosslinked systems that can efficiently transfer stress and regulate cohesive interactions that improve their adhesion; however, most epoxy crosslinkers are expensive, and directly introducing them into an adhesive system may lead to severe phase separation in the protein system, resulting in poor bonding strength and toughness. [22] In marine biological systems (e.g., mussels, castle worms, and barnacles), these aquaria affix themselves to wet rocks by assembling cross-linked proteins to generate the macromolecular adhesive.…”