USM’s Polymer Science and Engineering: Advances in Developing Sustainable Materials

Thu, 05/18/2023 - 01:08pm | By: Ivonne Kawas, Dr. Derek Patton

Polymer science and engineering is a critical field that has potential to significantly impact and advance materials sustainability. The production and disposal of plastics, which are predominately derived from petroleum-based resources, have created significant environmental concerns, such as the depletion of non-renewable resources and the generation of plastic and microplastic pollution.

Faculty and student researchers in the School of Polymer Science and Engineering (PSE) at The University of Southern Mississippi (USM), with support from federal funding agencies such as the National Science Foundation (NSF), are exploring ways to develop sustainable polymers/plastics that are degradable, renewable, or recyclable.

Collectively, plastic recycling, degradation, and upcycling provide promising approaches to address the global plastic waste problem and promote a circular economy.

Creating 3D Printed Carbon Materials from Plastic Waste

Dr. Zhe Qiang and his team of researchers have developed an innovative method to create complex structured carbon materials using a common plastic called polypropylene (PP), as described in a paper published in the journal Advanced Materials.

Carbon materials have many useful properties, such as high mechanical strength, light weight, and high thermal/electrical conductivity, which make them essential for various technologies like energy storage, thermal management, electronics, and high-performance composites.

Paul Smith, a 3^rd year PhD student in PSE from Olympia, Wash., developed a new method involving 3D printing with polypropylene, followed by crosslinking and pyrolysis processes that transform the 3D printed plastic into carbonaceous materials. This approach allows the creation of carbon structures with complex shapes and sizes.

“My research allows us to create large, complicated structures out of carbon by 3D printing everyday plastics as precursors,” Smith explained. “We have developed a way to do this which even allows us to use plastic waste as a starting material. By doing this, we have addressed many longstanding challenges in the field and unlocked access to a whole new family of materials that could revolutionize the way we approach many technologies. “

Dr. Qiang and his team also demonstrated that this technique works with recycled polypropylene waste, such as the disposable medical masks used extensively during the COVID-19 pandemic, offering a promising solution for upcycling plastic waste and promoting a circular plastics economy.

This innovative method for producing carbon materials with programmable shape has numerous potential applications in carbon dioxide (CO2) capture and catalyst support. Its simplicity and use of low-cost, commercially available materials make it an environmentally friendly alternative to traditional manufacturing processes, paving the way for a more sustainable future.

“This innovation not only offers an alternative path for the end of life of plastic waste, but also allows those materials to become something new, with untold usefulness in sustainability and environmental remediation,” said Smith. “New generations of materials for CO2 capture, oil absorption, industrial heating, batteries and many, many more could all spring from this work at USM.”

Labmates include: Alejandro Guillen Obando (B.S., PSE 2021), Anthony Griffin (2^nd year PhD graduate student in PSE), Mark Robertson (4^th year PhD student in PSE), and  Ethan Bounds (undergraduate student in PSE).

“My time in Dr. Qiang’s Research Group has been a transformative experience for me. In the last three years I’ve had the unique opportunity to break ground in this emerging field of research,” said Smith. “Throughout this process I’ve had the pleasure to work with world-class researchers across disciplines, publish in high impact academic journals, attend national conferences, learn entrepreneurship through the NSF I-corps program, transfer technology to a patent, and build relationships in the community through outreach and mentorship,” he added.

“During these experiences my labmates, my advisor, and my USM community have worked tirelessly and intentionally to create a culture of academic and individual excellence.”

Creating Degradable/Reworkable Polymer Thermosets

Plastics are an indispensable part of modern society due to their versatility, cost-effectiveness, and durability. Arguably, plastic materials have revolutionized industries such as packaging, transportation, and healthcare, contributing to advancements in food safety, increased fuel efficiency, and improved quality of life.

However, the durability of plastic materials also has significant drawbacks, as their persistent presence in the environment creates challenges with plastic waste management and often commits valuable non-renewable resources to landfills. The plastic waste problem is particularly challenging with a class of plastics called thermosets.

Thermosets are widely used applications such as coatings, adhesives, and composites, due to their excellent mechanical and thermal properties. The chemical structure of thermosets, however, render these materials non-degradable and non-recyclable – leaving limited options of incineration and landfilling as waste management strategies.

It is in this challenging area that PSE researchers are making headway. Dr. Derek Patton, and his team of graduate and undergraduate students, are developing thermosets that can degrade under specific environmental conditions, as described in a paper published in the journal Macromolecular Rapid Communications. These thermosets are based on a class of polymers called poly (ester ketal)s, which can undergo hydrolytic degradation in the presence of water and acid.

Benjamin Alameda, a recent graduate from the PSE PhD program, synthesized these thermosets using light as an energy source and readily available ketone building blocks, including diacetyl – an organic compound responsible for the natural notes of buttery flavor in many dairy, beer, and wine products.

With continued advancements in plastic waste management strategies, these ketones are potentially recoverable upon degradation of the thermoset and can be reused to fabricate additional polymer materials – mitigating the loss of important building blocks to the environment. 

Dr. Patton and his team anticipate thesis hydrolytically degradable thermosets could provide sustainable materials with applications in areas such as degradable coatings, composites, and adhesives. Multiple graduate students in the Patton lab, including Jaylen Davis, Pritha Bhunia, Jeffrey Aguinaga, and Ethan Rose, are working on similar concepts using bioderived building blocks.

One of the students who has synthesized novel thermoset materials, Jaylen Davis, a labmate from Jackson, Miss., has been working on exploring sustainable design of degradable or reprocessable alternatives.

“My research is driven by the billions of tons of plastic waste that is evident in the environment and it seeks to find more uses for plastics at the end of their lifecycle,” Davis no­ted. “At USM, I have synthesized novel thermoset materials with a range of material properties (soft, glassy, stretchy, ductile) that contain dynamic bonds between the typical crosslinks in the molecular structure. I am now working to further understand how we can manipulate the material properties of these plastics while considering the reprocessing behaviors. With what I have completed so far along with future studies, I hope to implement reprocessable thermosets into industrially relevant needs and push for a more sustainable future.”

“Working in the Patton lab has ultimately shaped who I am not only as a scientist, but professionally as a young adult,” said Davis. “Our lab environment forces me to ask questions and keep an open mind as I navigate my research while offering the flexibility to pursue many research areas.” 

“My long-term goal is to continue research with a preference towards synthesis and characterization of sustainable materials,” said Davis. “I envision myself working for a research lab, or multiple labs, and applying what I have already learned to fit their needs, address novel questions, as well as expand my current knowledge. The research and collaboration that I am currently undergoing at USM are key components in achieving this goal.”

As the School of PSE forges ahead, it remains dedicated to addressing global challenges and promoting the development of advanced materials, sustainable solutions, and groundbreaking technologies that will shape a better tomorrow.