Soy-Based Adhesives Functionalized with Pressure-Responsive Crosslinker Microcapsules for Enhanced Wet Adhesion
Soy-Based Adhesives Functionalized with Pressure-Responsive Crosslinker Microcapsules for Enhanced Wet Adhesion
复制标题
DOI：
10.1021/acsapm.0c01295
复制
发表时间：
2021-01-20
影响因子：
5
通讯作者：
Chen, Nairong
中科院分区：
文献类型：
--
作者：
Yin, Hao;Zhang, Erbing;Chen, Nairong
甲醛基胶粘剂以其优异的粘接性能被广泛应用于木质材料的生产。然而，这些粘合剂可能会对人类健康和环境造成危害。本文通过构建具有核壳结构的压敏交联剂体系，制备了一种环保型大豆基胶粘剂（SBA）。以异佛尔酮二异氰酸酯（IPDI）为芯材，以聚氨酯为壳材，通过阻止大豆蛋白与IPDI之间的交联反应，避免了胶粘剂粘度的增加。微胶囊中的IPDI作为SBA的交联剂和固化剂，在外加压力作用下可释放出来，引发IPDI与木材和大豆蛋白的原位交联，促进SBA的固化反应，在SBA与木材之间建立化学桥，从而降低固化温度，提高SBA的耐水性。用压敏交联剂体系改性的SBA表现出改善的湿剪切强度、适中的粘度、较低的固化温度和非常低的细胞毒性，显示出作为基于甲醛的粘合剂的替代品的巨大潜力。此外，压力响应性微胶囊交联剂体系也已成功地应用于官能化许多其他生物质衍生的粘合剂（即，棉籽蛋白、花生粕、氧化淀粉和海藻酸钠），以显著改善它们的耐水性和机械性能。这项工作为开发无甲醛、可持续和高性能的生物基粘合剂提供了一种通用策略。
With excellent bonding performance, formaldehyde-based adhesives have been widely used for the production of woody materials. However, these adhesives could potentially cause harm to human health and the environment. Herein, we report an eco-friendly soy-based adhesive (SBA) by constructing a pressure-responsive crosslinker system with a core-shell structure. Isophorone diisocyanate (IPDI) was encapsulated in microcapsules as the core, and a shell mainly consisting of polyurethane was used to hinder the crosslinking reaction between the soy protein and IPDI, thus avoiding an increase in viscosity of the adhesive. As the crosslinker and curing agent for the SBA, the encapsulated IPDI in the microcapsules could be released under an external pressure, which induces in situ crosslinking of IPDI with wood and soy protein, promoting the curing reaction of the SBA and building chemical bridges between the SBA and wood, thereby decreasing curing temperature and improving water resistance of the SBA. The SBA modified with the pressure-responsive crosslinker system exhibited improved wet shear strength, moderate viscosity, low curing temperature, and very low cytotoxicity, showing great potential as an alternative to formaldehyde-based adhesives. Furthermore, the pressure-responsive microcapsule crosslinker system has been also successfully applied to functionalize many other biomass-derived adhesives (i.e., cottonseed protein, peanut meal, oxidized starch, and sodium alginate) to dramatically improve their water resistance and mechanical properties. This work provides a versatile strategy to develop formaldehyde-free, sustainable, and high-performance bio-based adhesives.