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Petroleum-derived formaldehyde resin adhesives are serious hazards to human health and depend on limited resources. Abundant, cheap and renewable biomass materials are expected to replace them. However, the contradictory mechanisms of high mechanical strength and fracture toughness affect the use of bioadhesives. Herein, a biomimetic soybean meal (SM) adhesive inspired by the structure of insect cuticles and shell pearl layer was proposed. Specifically, chitosan (CS@DA) modified 3,4-dihydroxybenzoic acid (DA, rich in catechol moiety) was anchored on molybdenum disulfide nanosheets (MoS 2 ) to construct a biomimetic structure with copper hydroxide and SM substrate (SM-MoS 2 /CS@DA-Cu). Schiff base, ionic, and hydrogen bonding strengthened the cohesion of the adhesive. The ordered alternating stacking "brick-mortar" structure stimulated the lamellar sliding and crack deflection of MoS 2 , synergistically reinforcing the toughness. Compared to SM adhesive (0.57 MPa and 0.148 J), the wet shear strength and adhesion work of the SM-MoS 2 /CS@DA-Cu were 1.68 MPa and 0.867 J, with 194.7 % and 485.8 % increases, respectively. The multiple antimicrobial effects of CS@DA, Schiff base, and Cu 2+ increased the applicability period of the adhesive to 40 days. The adhesive also displayed favorable water resistance and flame retardancy. Therefore, this peculiar and efficient biomimetic structural design inspired the development of multi-functional composites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Developing multifunctional adhesives with exceptional cold-pressing strength, water resistance, toughness, and mildew resistance remains challenging. Herein, inspired by oysters, a multifunctional organic-inorganic hybrid soybean meal (SM)-based adhesive was fabricated by incorporating amino-modified carbon dots functionalized silica nanoparticles (CDs@SiO 2 ) and dialdehyde chitosan (DCS) into SM matrix. DCS effectively enhanced the interface interactions of organic-inorganic phases and the rigid nanofillers CDs@SiO 2 uniformly dispersed in the SM matrix, which provided energy dissipation to improve the adhesive's toughness. Owing to the stiff skeleton structure and enhanced crosslinking density, the crosslinker-modified SM (MSM)/DCS/CDs@SiO 2 -2 wood adhesive exhibited outstanding cold-pressing strength (0.74 MPa), wet shear strength (1.36 MPa), and long-term water resistance (49 d). Additionally, the resultant adhesive showed superior antimildew and antibacterial properties benefiting from the introduction of DCS. Intriguingly, the fluorescent properties endowed by carbon dots further broadened the application of adhesives for realizing security testing. This study opens a new pathway for the synthesis of multifunctional biomass adhesives in industrial and household applications., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Bioplastics are considered as potential alternatives to non-renewable and non-biodegradable petroleum-based plastics. Inspired by ionic and amphiphilic properties of mussel protein, we proposed a versatile and facile strategy for the fabrication of a high-performance chitosan (CS) composite film. This technique incorporates a cationic hyperbranched polyamide (QHB) and a supramolecular system based on the lignosulphonate (LS)-functionalized cellulose nanofibrils (CNF) (LS@CNF) hybrids. The cationic QHB was synthesized by a one-step process from hyperbranched polyamide and quaternary ammonium salt. Meanwhile, the functional LS@CNF hybrids act as a well-dispersed and rigid cross-linked domain in CS matrix. Owing to the interconnected hyperbranched and enhanced supramolecular network, the toughness and tensile strength of the CS/QHB/LS@CNF film simultaneously increased to 19.1 MJ/m 3 and 50.4 MPa, 170.2 % and 72.6 % higher than the pristine CS film. Additionally, the functional QHB/LS@CNF hybrids endow the films with superior antibacterial activity, water resistance, UV shielding, and thermal stability. This bioinspired strategy provides a novel and sustainable method for the production of multifunctional CS films., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In order to optimize its production technology, response surface methodology (RSM) was used to optimize the hot-pressing process during the preparation of chitosan-modified starch adhesive film. Ranges of hotpressing temperature, hot-pressing time, and adhesive consumption were selected based on single-factor tests. A quadratic regression model of the bonding strength was obtained by fitting the response value of the bonding strength of the plywood. The results showed that the adhesive consumption and the hot-pressing temperature had a significant effect on the bonding strength of the adhesive. Also, the interaction between the temperature, time, and adhesive consumption were significant. The optimum hot-pressing process parameters for chitosan-modified starch adhesive film were a hot-pressing temperature of 145.2 °C, a hot-pressing time of 182.7 s, and an adhesive consumption of 239.3 g/m². The predicted values of the quadratic regression model fit well with the actual values of the stability test. [ABSTRACT FROM AUTHOR]

It is still a great challenge to develop soybean protein adhesives with high strength and antimildew properties through a sustainable and facile strategy. Herein, water-soluble dialdehyde chitosan (DCS) was obtained by oxidizing chitosan (CS) and used to crosslink soybean meal (SM) to fabricate protein adhesives via the Schiff base reaction. This strategy is simple, all-biomass, and without additional crosslinkers. Owing to the covalent imine bonds and non-covalent hydrogen bonds interactions, the adhesion strength of SM/DCS-4 adhesive reached 1.47 MPa, satisfying the requirement for Type II interior plywood (≥ 0.7 MPa). More importantly, the protein adhesives showed excellent antimildew properties due to the amino and aldehyde groups of DCS and the Schiff base formation. The SM/DCS-4 adhesive exhibited long shelf life (7 d), which is beneficial for industrial applications. This study helps in preparing green and fully bio-based adhesives from agricultural and fishery wastes. [Display omitted] • Dialdehyde chitosan (DCS) acted as a functional crosslinker. • Highly dense imine bonds and hydrogen bonds strengthened the adhesive network. • DCS can improve the bonding strength and antimildew properties of the adhesive. • The soybean meal (SM)/DCS adhesive exhibited long shelf life (7 d). • The SM/DCS adhesive made full use of agricultural and fishery wastes. [ABSTRACT FROM AUTHOR]

To reduce the use of formaldehyde wood adhesives, a chemical modification of starch with chitosan was explored to prepare an adhesive film for plywood with good adhesive properties, low price, non-toxic, and convenient sizing. The effect of chitosan content of the adhesive film on the shear strength of plywood was studied. The modification mechanism and bonding mechanism of the film were analyzed by FTIR, XPS, XRD and SEM. The results showed that when the amount of chitosan was 30% of starch dry weight, the dry-wet shear strength of plywood met the requirements of Chinese national class Ⅱ plywood (≧ 0.80 MPa). FTIR and XPS analysis showed that –NH 2 in the chitosan reacted with –COOH on starch and wood surface to form amide bond, which specifies the chitosan's role as a coupling agent. XRD and SEM analysis showed that the addition of chitosan disturbed the otherwise orderly arrangement of a starch structure. The structure of the attained modified film is mostly amorphous. Sizing in the form of a adhesive film solves the disadvantage of difficulty in sizing starch adhesive. Compared with commercial adhesives on the market, this adhesive film has the advantages of low price, wide source of raw materials, non-toxic, and is expected to be a good substitute for formaldehyde adhesives on the market. • Raw starch and modifier chitosan are both sustainable resources. • Chitosan is used as a special coupling agent. • The mechanism is –NH 2 and –COOH condensation reaction. • The method of adhesive film sizing is more convenient and simple. • Adhesive film cost is lower than commercial adhesives. [ABSTRACT FROM AUTHOR]