Collaborative Research: Interfacial Phenomena of Functional Solutes Impregnated into Cellulose Packaging Substrates

包装在日常生活中是必不可少的。它保护我们的食品和药品，并促进全国和世界各地的货物安全运输。塑料包装已经变得流行起来，因为它提供了比传统纸质包装更好的阻隔性能，这有助于保护包装产品的质量和安全。尽管塑料包装有好处，但糟糕的报废特性和回收挑战往往会导致环境污染。这项研究项目旨在开发一种可持续和功能性的纸基塑料包装替代品，可以使用可再生原料和绿色化学技术来制造。从农业废物中提取的生物基化合物将被浸入纸张中，以改善材料的功能和阻隔性能。将研究纸张和生物基化合物之间的分子水平相互作用，以开发一种具有竞争力和可持续的塑料包装替代品。为了增加STEM领域的多样性和促进经济繁荣，该项目将吸引来自STEM领域传统上代表性较低的背景和群体的高中、本科生和研究生。此外，外展活动将提高公众对可持续包装实践的认识。该项目由界面工程计划和既定的激励竞争研究计划(EPSCoR)共同资助。这项研究的目的是通过设计具有更好的阻隔性能的纤维基材来开发具有良好性能和寿命结束特征的下一代可持续包装材料。这将使用超临界浸渍(SCI)方法来实现，即使用超临界二氧化碳(SsCO2)将生物衍生的溶质浸渍到纤维素基质中。将确定控制溶质在纤维素纤维上吸附的基本界面现象。选择了两个模型溶质体系--脂肪族和芳香族--和共溶剂来表示来自农业残渣的化学物种。脂族溶质体系有望为包装材料提供理想的疏水性能，芳香族溶质体系有望赋予紫外线吸收性能。使用最先进的石英晶体微天平(QCM-D)仪器测量溶质在纤维素纤维上的初始吸附动力学，并对其进行建模，以量化工艺条件对速率常数的影响。在OPERANDO近红外(NIR)光谱研究中，将阐明促进纸张基材SCI的基本键合和分配过程，包括界面纤维素纤维的氢键，scCO2-助溶剂相互作用对氢键的影响，以及scCO2-助溶剂-纤维素相互作用对溶质分配到纤维素中的影响。最后，将通过数字成像分析来评估溶质扩散机制和所产生的溶质在整个纤维素基质中的分布之间的关系，并分别通过测量两个系统的接触角和透光率来评估功能的改善。这项研究以多种方式为社会做出贡献，包括开发可持续包装材料，提高生物衍生溶质作为包装添加剂的潜力，为未被充分代表的学生提供研究机会，并通过外展活动教育社区有关可持续包装的好处。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Packaging is essential to everyday life. It protects our food and medicine and facilitates the safe transport of goods across the country and around the world. Plastics-based packaging has become popular because it offers better barrier properties than traditional paper-based packaging, which helps preserve the quality and safety of packaged products. Despite the benefits of plastic packaging, the poor end-of-life characteristics and recycling challenges often lead to environmental pollution. This research project seeks to develop a sustainable and functional paper-based alternative to plastic packaging that can be manufactured using renewable feedstocks and green chemistry technologies. Bio-based compounds extracted from agricultural waste will be impregnated into paper to improve the material’s functionality and barrier properties. The molecular-level interactions between paper and bio-based compounds will be examined to develop a competitive and sustainable alternative to plastic packaging. To increase diversity in STEM fields and promote economic prosperity, this project will engage high school, undergraduate, and graduate students from backgrounds and groups traditionally underrepresented in STEM fields. Additionally, outreach events will enhance public awareness of sustainable packaging practices.This project is jointly funded by the Interfacial Engineering program and the Established Program to Stimulate Competitive Research (EPSCoR). The research aims to develop next-generation sustainable packaging materials, with favorable performance and end-of-life characteristics, by engineering cellulosic substrates with improved barrier properties. This will be accomplished using the supercritical impregnation (SCI) methodology, where supercritical carbon dioxide (ssCO2) is used to impregnate bioderived solutes into cellulose matrices. The fundamental interfacial phenomena governing solute adsorption onto the cellulosic fibers will be determined. Two model solute systems – aliphatic and aromatic - and cosolvents have been chosen to represent the chemical species derived from agricultural residues. The aliphatic solute system is expected to yield desirable hydrophobic properties for the packaging material, and the aromatic solute system is expected to impart UV-absorbent properties. The initial adsorption kinetics of the solutes onto the cellulosic fibers will be measured using state-of-the-art quartz crystal microbalance (QCM-D) instrumentation and modeled to quantify the impact of the process conditions influencing rate constants. In operando near-infrared (NIR) spectroscopic studies will elucidate fundamental bonding and partitioning processes that facilitate SCI of paper substrates, including the hydrogen-bonding of interfacing cellulosic fibers, the influence of scCO2-cosolvent interactions on hydrogen-bonding, and the impact of scCO2-cosolvent-cellulose interactions on solute partitioning into cellulose. Lastly, relationships between solute diffusion mechanisms and the resultant distribution of solutes throughout cellulosic matrices will be evaluated via digital imaging analyses, with functional improvements assessed via contact angle and light transmittance measurements for the two systems, respectively. This research contributes to society in multiple ways, including developing sustainable packaging materials, advancing the potential of bioderived solutes as packaging additives, providing research opportunities for underrepresented students, and educating the community on sustainable packaging benefits through outreach events.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.