Sustainable Triblock Copolymers with Supramolecular Interactions for Improved Performance

University Of Houston, Houston TX

Investigators

Abstract

PART 1: NON-TECHNICAL SUMMARY Our society's dependence on petroleum feedstocks for polymers has drawbacks of a limited raw material supply, generation of harmful environmental emissions and plastic waste, and unpredictability in feedstock prices and availability. Though many prior studies have developed routes to sustainable materials from a variety of resources such as plant sugars, plant oils, plant terpenes, carbon dioxide, polysaccharides, rosins, and microbial polyesters, challenges still persist in their broad implementation in society. One significant challenge is that new polymers must meet the performance and property expectations of existing materials in order to be adopted. However, new polymers developed from sustainable sources are rarely simple drop-in replacements for conventional polymers. The persistent challenge that this project addresses is that many sustainable polymers have features which significantly and adversely impact their properties and limit their use. The knowledge developed in this project will provide a route to overcoming these limitations, enabling the potential of widespread adoption in applications. This project will also use outreach programs to cultivate knowledge among students and the general public on the important role of polymers in society and their environmental impacts. The Materials Day at UH program, providing opportunities for hands-on laboratory experiences, will be expanded with new modules in sustainable polymers. Undergraduate and graduate students will gain valuable experiences through involvement in the research projects. Finally, demonstrations on sustainable polymers will be developed for the Houston Energy Day festival. PART 2: TECHNICAL SUMMARY Developing advanced polymeric materials from sustainable sources with superior physical properties and greater function is a fundamentally important challenge in reducing the environmental impact of polymers. Vegetable oils and their fatty acids are convenient sources for polymers due to their wide availability, ease of functionalization, and lack of toxicity. The long alkyl chains of the fatty acids comprising vegetable oils have a large impact on the resulting polymer properties, which are tunable through choice of vegetable oil feedstock. Unfortunately, polymers with bulky constituents, such as the long alkyl side-chains of fatty acid-derived polymers, typically exhibit poor mechanical performance due to lack of entanglements. In this project, supramolecular interactions will be incorporated into the vegetable oil-derived polymers as a route to improve their mechanical behavior. The central hypothesis of this work is that the incorporation of supramolecular interactions in sustainable triblock copolymers will lead to a new class of sustainable materials with enhanced physical properties. Long-chain poly(meth)acrylates will be modified with functional groups to promote hydrogen bonding and ionic interactions. These materials will be incorporated as the midblock of ABA triblock copolymers. The effective crosslink density and viscoelastic properties of the materials will be quantified. Finally, relationships between the strength, dynamics, and type of supramolecular interactions and the polymer physical properties will be established. These materials will be explored as thermoplastic elastomers, shape memory materials, and self-healing materials. . 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.