Smith Dallin L, Rodriguez-Melendez Danixa, Montemayor Maya D, Convento Miguel O, Grunlan Jaime C
Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States.
Department of Mechanical Engineering, Texas A&M University, College Station, Texas 77843, United States.
Biomacromolecules. 2025 Feb 10;26(2):1141-1148. doi: 10.1021/acs.biomac.4c01467. Epub 2025 Jan 5.
Chitosan is one of the most abundant biopolymers on earth. It is used as a nontoxic alternative in a wide range of medicines, packaging, adhesives, and flame retardants. Chitosan is poorly soluble in neutral or alkaline solutions, but it dissolves in solutions of weak acids, such as acetic acid or citric acid, both of which occur naturally. As a replacement for formaldehyde-containing resins in engineered wood, a chitosan-acid mixture acts as a low-cost, nontoxic adhesive for natural wood that also offers fire protection by forming a char barrier. Pentaerythritol was studied as an additive due to its similarity to glycerol (a common plasticizer for chitosan) and its potential flame retardant benefit. The properties of chitosan adhesives produced with acetic acid and citric acid are compared, and moderate thermal treatment is applied to facilitate covalent bonding (e.g., Maillard reaction) that improves water resistance. Tensile shear strengths of >1 MPa are obtained on lap joints. The unique combination of fire protection and adhesion for wood makes these low cost, biobased systems very appealing.
壳聚糖是地球上最丰富的生物聚合物之一。它在广泛的药物、包装、粘合剂和阻燃剂中用作无毒替代品。壳聚糖在中性或碱性溶液中溶解性较差，但可溶于弱酸溶液，如天然存在的醋酸或柠檬酸。作为人造木材中含甲醛树脂的替代品，壳聚糖 - 酸混合物用作天然木材的低成本、无毒粘合剂，还通过形成炭质屏障提供防火保护。由于季戊四醇与甘油（壳聚糖常用的增塑剂）相似且具有潜在的阻燃益处，因此对其作为添加剂进行了研究。比较了用醋酸和柠檬酸生产的壳聚糖粘合剂的性能，并进行适度热处理以促进共价键合（如美拉德反应），从而提高耐水性。搭接接头的拉伸剪切强度大于1兆帕。这些低成本、生物基体系对木材具有防火和粘合的独特组合，非常有吸引力。
