The goal of this study is to employ bio-based dialdehyde starch (DAS), derived from in situ polymerization and the resultant microphase separation structure, to improve the strength of melamine–urea–formaldehyde (MUF) resin, as well as enhance the properties that affect its adhesive performance. Thus, we evaluated the effects of DAS on the chemical structure, toughness, curing behavior, thermal stability, and micromorphology of the MUF resin. Furthermore, the wet shear strength and formaldehyde emissions of a manufactured, three-layer plywood were also measured. Results indicate that DAS was chemically introduced into the MUF resin by in situ polymerization between the aldehyde group in the DAS and the amino group and hydroxymethyl group in the resin. Essentially, polymerization caused a DAS soft segment to interpenetrate into the rigid MUF resin cross-linked network, and subsequently form a microphase separation structure. By incorporating 3% DAS into the MUF resin, the elongation at break of impregnated paper increased 48.12%, and the wet shear strength of the plywood increased 23.08%. These improvements were possibly due to one or a combination of the following: (1) DAS polymerization increasing the cross-linking density of the cured system; (2) DAS modification accelerating the curing of the MUF resin; and/or (3) the microphase separation structure, induced by DAS polymerization, improving the cured resin’s strength. All the results in this study suggest that the bio-based derivative from in situ polymerization and microphase separation can effectively toughen and enhance the properties that affect adhesive performance in highly cross-linked thermosetting resins.

Soy-based adhesives inherently possess low water resistance and brittleness, which limit their application on plywood fabrication. This investigation involves using a long chain cross-linker, neopentyl glycol diglycidyl ether (NGDE), to produce an intrinsic toughening effect to reduce the brittleness and improve the water resistance of a soybean meal–based adhesive. The solids content, viscosity, functional groups, fracture surface micrographs, and thermal stability of the adhesives were measured. Three-layer plywood was fabricated using the resultant adhesive, and the tensile shear strength of the plywood was measured. All adhesive properties were compared with a soybean meal/polyamidoamine-epichlorohydrin (PAE) adhesive and commercial melamine urea formaldehyde resin. The results showed that adding 6 g NGDE improved the water resistance of the soybean meal-based adhesive by 12.5%. This improvement is attributed to the following reasons: (1) a dense cross-linked network is formed by the chemical reaction between NGDE and protein molecules; (2) the toughness of the adhesive increases and a smooth and homogeneous fracture surface is created, which effectively prevents moisture intrusion; (3) the addition of NGDE increases the thermostability of the cured adhesive. The tensile shear strength of the plywood bonded with the soybean meal-based adhesive with 6 g NGDE was 286.2% higher than that without NGDE and attained 1.12 MPa, which was attributed to the reduction in the adhesive’s viscosity, and the improvement in the water resistance and toughness of the adhesive. The tensile shear strength of the plywood bonded with 6 g NGDE was 19.1% higher than that with 6 g PAE and was similar to the MUF resin, which validated the novel adhesive being suitable for use as an industrial plywood adhesive.

To solve the problem of fresh fish and meat being prone to spoilage and deterioration during storage and transportation, thus causing great economic losses, we investigated the efficacy based on the synergistic antibacterial effect of chlorine dioxide and chitosan. This paper developed an ice temperature storage technology for the preservation of fresh sturgeon fillets. The research results showed that among the five common different freezing point regulators, only NaCl, glucose, and sucrose displayed negligible effects on the texture of fish slices. The optimal ratio obtained through response surface optimization was 3.07 g/100 mL NaCl, 3.25 g/100 mL glucose, and 4.05 g/100 mL sucrose, which could lower the freezing point of fish fillet to −2.50°C. Based on the changes in volatile base nitrogen, thiobarbituric acid reactants, pH value, and total viable bacteria during storage, the spoilage endpoints of sturgeon fillets stored at ice temperature (−2°C) and low temperature (4°C) were determined to be 9–12 days and 3–6 days, respectively. Based on high‐throughput sequencing and traditional culture‐isolation techniques, four dominant spoilage bacteria were successfully isolated and identified during stored at ice temperature, including Chryseobacterium sp., Microbacterium sp., Empedobacter falsenii , and Bacillus cereus . For the three components (chitosan, sodium alginate, and poly‐L‐lysine HCl) of the coating, the response surface optimization results showed that the optimal fresh‐keeping ratio was 2.12 g/100 mL of chitosan, 0.72 g/100 mL of sodium alginate, and 1.02 g/100 mL of poly‐L‐lysine HCl. Under optimal storage conditions, the TVB‐N, TBARS, pH, and other parameters in fish meat would be significantly decreased.