Engineering Lignocellulosic Surfaces for Adhesion

尽管拥有世界上10%的森林资源，加拿大人必须为我们的木材找到新的、更高附加值的用途。非常有前途的举措包括在复合材料和涂料中使用纳米纤维素晶体和纤维。然而，任何有潮湿地下室或旧甲板的人都知道，水是许多纤维素基材料的致命弱点。本研究的重点是设计规则（科学知识）和新方法（技术）的发展，以控制纤维素表面的粘附性能，特别是在潮湿时。****三位博士生将追求三个相互关联的关键目标：****纤维素表面适合粘合剂：关键思想是建立基于实验证据的机制模型，预测醛、羧基和磺酸基的表面分布对粘合剂粘合的影响。通过使纤维素表面更具活性，可以使用更环保、更便宜的粘合剂。目前缺乏的是预测纤维素表面官能团的最佳密度和类型所需的理解，从而获得最佳的耐水性。****2。用于纤维素的超韧水凝胶粘合剂：在这里，我们量化了用互穿聚合物网络（ipn）取代均质粘合聚合物网络的效果。最近在水凝胶文献中报道了基于ipn的超韧水凝胶。在这个项目中，我们探索是否有价值使用这种外来结构作为促进湿纤维素粘附的基础。****3。迈向基于不稳定纤维素粘合剂的农业用纸：目标是开发粘合剂网络，在刺激或时间下进行自毁编程。这种材料可以有许多用途，例如作为向加拿大田地运送种子和控释肥料和/或杀虫剂的载体带。****研究生将使用麦克马斯特生物界面研究所最先进的表面表征和高通量设备-为我们提供纤维素表面的前所未有的化学知识以及它们如何与聚合物粘合剂相互作用***

Although blessed with 10% of the world's forests resources, Canadians must find new, higher value-added uses for our wood. Very promising initiatives include the use of nanocellulose crystals and fibers in composites and coatings. However, anyone with a wet basement or an old deck knows that water is the Achilles heal of many cellulose-based materials. This research focuses on the development of design rules (scientific knowledge) and new approaches (technologies) for controlling adhesion properties of cellulose surfaces particularly when wet.****Three Ph.D. students will pursue three key objectives, which are inter-related:****1. Cellulose Surfaces Tuned For Adhesives: The key idea is to develop mechanistic models, based on experimental evidence, that will predict the influence of the surface distribution of aldehyde, carboxyl and sulfonic acid groups on bonding to adhesives. By making the cellulose surface more reactive, greener and less expensive adhesives can be employed. Currently lacking is the understanding required to predict the optimum density and types of cellulose surface functional groups giving the best water resistance.****2. Ultra-tough Hydrogel Adhesives for Cellulose: Here we quantify the effects of replacing the homogenous adhesive polymer networks with interpenetrating polymer networks (IPNs). Recent developments reported in the hydrogel literature describe ultra-tough hydrogels based on IPNs. In this project we explore whether or not there is value in using such exotic structures as a basis for promoting wet cellulose adhesion.****3. Towards Agricultural Papers Based on Labile Cellulose Adhesives: The goal is to develop adhesive networks, programed to self-destruct with a stimulus or time. Such a material could have many applications, for example as carrier tapes for delivering seeds and controlled release fertilizers and/or pesticides to Canadian fields.****The graduate students will employ state-of-the-art surface characterization and high throughput facilities in the McMaster Biointerfaces Institute - giving us unprecedented chemical knowledge of cellulose surfaces and how they interact with polymeric adhesives***