NSF Award
2229091
The need for highly functional flexible packaging for food, medical products, and consumer goods is growing worldwide, but single-use plastics are also contributing to environmental pollution. Current materials are not recyclable because of their heterogeneity and related challenges in collection, separation, cleaning, and reprocessing. While chemical recycling methods are rapidly evolving, these approaches require high energy input, and the intrinsic material value is lost. This project will enable increased recycling of flexible films through creation of a manufacturing process for high performance barrier films from a single polymer type. Industrial, economic, and societal benefits respectively include: (1) enhanced functional properties in films for high volume applications, (2) cost competitiveness driven by technologies that are compatible with current processing systems, and (3) greatly enhanced plastics recycling enabled by simplified material systems. The research plan includes industry workshops for advancing the novel plastics processing technologies as well as educational webinars to impact plastics sustainability more broadly.<br/><br/>This research will investigate new materials processing strategies designed to replace traditional multilayer packaging systems with polyethylenes of varying molecular weight, branching structures, and crystallinity to achieve properties superior to known best-in-class barrier films. These strategies require improved understanding and control of polymer morphology, specifically: (1) characterization of the melt-mastication dynamics, (2) scale-up with layer multiplying sonication, and (3) developing structure-process-property correlations to reproducibly induce high crystallinity and tortuous hierarchical structures starting from a range of polymer chain architectures. The research on future processing strategies will inform the use of single polymer types serving multiple purposes in a product design, reducing the number of polymers employed across the industry as well as other materials such as metallized foils, paper layers, and additives that adversely impact the recyclability of flexible packaging. By the end of the project, we aim to: (1) demonstrate technical feasibility of all-polyolefin barrier films using layer multiplying melt-mastication, (2) deliver a predictive model relating polymer and film structure to process conditions and performance in melt-masticated polymer multilayers, and (3) produce a model of the energy and life cycle characteristics of the process. The research plan includes educational workshops for advancing plastics sustainability knowledge, and community webinars to impact plastics sustainability more broadly. Recruitment of students from underrepresented groups, targeted manufacturing education activities, and outreach to local communities for workforce development training will enrich the research, increase its relevance, and result in tangible diversity, equity, and inclusion outcomes.<br/><br/>This Future Manufacturing award was supported by co-funding from the Chemical, Biological, Environmental Engineering and Transport Systems Division, and the Civil, Mechanical and Manufacturing Innovation Division in the Directorate for Engineering, and the Division of Materials Research in the Directorate for Mathematical and Physical Sciences.<br/><br/>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.
