Grantee Research Project Results
2023 Progress Report: Elimination of microplastics and per- and polyfluoroalkyl substances (PFAS) problems upon the disposal of single-use packaging
EPA Grant Number: SU840402Title: Elimination of microplastics and per- and polyfluoroalkyl substances (PFAS) problems upon the disposal of single-use packaging
Investigators: Rabnawaz, Muhammad , Hamdani, Syeda Shamila , Mestry, Jayesh , Emch, Hannah , Isherwood, Jacob , Alford, Alexandra
Institution: Michigan State University
EPA Project Officer: Spatz, Kyle
Phase: I
Project Period: July 1, 2022 through June 30, 2023 (Extended to December 30, 2023)
Project Period Covered by this Report: July 1, 2022 through June 30,2023
Project Amount: $24,991
RFA: 18th Annual P3 Awards: A National Student Design Competition Focusing on People, Prosperity and the Planet (2021) RFA Text | Recipients Lists
Research Category: P3 Awards , Chemical Safety for Sustainability
Objective:
The proliferation of microplastics as well as per- and poly(fluoroalkyl) substances (PFAS) has become an environmental and health risk. Approximately 50% of ocean plastics (which are precursors for microplastics) originate from single-use packaging. Similarly, the usage of PFAS in paper coatings for food wrappers, molded fiber containers, and so forth is a significant contributor to the accumulation of PFAS in the environment and human bodies. This project is aimed to develop PFAS-free and fully biodegradable coated paper with water- and oil-resistance as an alternative to single-use plastic and PFAS-coated products. These alternatives, at the end of their service lifetimes, will: 1) become converted into water and CO2 if they leach into the environment, thanks to their fully biodegradable nature; and 2) can be converted into fertilizers under controlled composting conditions. Thus, this project can mitigate two major environmental problems, namely the proliferation of microplastics and PFAS.
The main objective of this work is to create water- and oil-resistant coatings without generating microplastics and PFAS at the end of their service lifetimes. In phase I, two specific objectives were pursued.
Objective #1 was aimed toward the synthesis of biodegradable aliphatic polyesters and their corresponding latexes (water-borne polymers).
Objective #2 was focused on the coating of paper substrates with starch (as the base layer) and latex (as the top layer), and subsequent property assessments of these samples (e.g., long-term water- and oil-resistance, thermal sealing, physico-mechanical properties, etc.).
Progress Summary:
Outputs:
- Biodegradable aliphatic polyesters were synthesized, and some were acquired commercially.
- Biodegradable aliphatic polyesters were converted into latexes by a dissolutionevaporation method with a blend of poly(vinyl alcohol) (PVOH) as an emulsifier.
- The latexes were coated onto uncoated as well as starchcoated kraft paper with around 30 wt% coating load.
- Latex formed a nice coating on uncoated kraft paper.
- The water resistance of the latexcoated paper was measured, and its Cobb1800 value was 15.55 ± 0.07 g/m2. This was compared to the water resistance of uncoated kraft paper, which had a value of 87.30 ± 0.97 g/m2.
- The oil resistance of the latex coated paper was excellent (12/12 kit rating).
- The water vapor transmission rate (WVTR) of the coated paper was reduced by approximately 80% in comparison to uncoated paper.
- The mechanical properties of the coated paper were found to be excellent.
- A comparison with several commercial products indicated that the latexcoated paper had kit ratings on par with commercial benchmarks, but superior water resistance compared to at least two of them.
Outcomes:
- Protocols were developed for polyester latexes using the dissolutionevaporation method.
- Coated paper was fully biodegradable, PFASfree, and has good water and oil resistance suitable for packaging applications such as disposable cups, plates, etc.
- The coated paper retained its desirable mechanical properties.
- The coated paper demonstrated outstanding thermal sealing capabilities and offer a suitable alternative for food storage.
- A major drawback of this coated paper is the very coating load (~30 wt%), which needs more work to bring the coating load to 10 wt% or below.
Future Activities:
Aliphatic polyesters, both synthesized and commercially acquired, provide a promising avenue for the development of latexes that are suitable for PFAS-free and biodegradable paper coatings. The dissolution-evaporation method, paired with PVOH as an emulsifier, is an effective protocol for producing polyester latexes. The latex coating significantly enhanced the water and oil resistance of the kraft paper. A reduction in the water vapor transmission rate (WVTR) by about 80% was achieved, making them a promising candidate for packaging moisture-sensitive products. The coated paper maintained excellent mechanical properties as well as excellent thermal sealing. Benchmarks with commercial products reveal that latex-coated paper not only offer matching oil resistance (kit ratings) but also excel in water resistance, positioning them competitively in the market. The improved water resistance and retained mechanical properties suggest that the latex-coated paper is good for packaging applications, including disposable items such as cups and plates. However, the current coating load is high (~30%), which will lead to higher costs.
In phase II, we aim to significantly reduce the current coating loads from 30 wt% to below 10 wt%, thus lowering the cost and enhancing the commercial viability of this coated paper.
Objective #1: Use of poly(butylene succinate) blends (PBS-blends) for paper coating: Here, PBS will be blended with low surface energy biodegradable materials to provide strong water resistance at low coating loads. These PBS-blends will then be used as coatings for paper substrates and various aspects of their performance will be evaluated, such as water and oil resistance, thermal sealing capabilities, and other essential physico-mechanical properties.
Objective #2: Dual-Layer Coating Strategy: The second objective pivots towards using a dual layer coating strategy as a way to reduce the overall coating load. The dual layer-coated paper will be tested for its water and oil resistance, thermal sealing capabilities, and other essential physico-mechanical properties.
At the end of Phase II, we expect to have developed PFAS-free and biodegradable paper that is water and oil resistant and has a coating load of 10 wt% or below.
Journal Articles:
No journal articles submitted with this report: View all 3 publications for this projectSupplemental Keywords:
Thermoplastics, biodegradable, water-resistant, oil-resistant, thermal sealing.Relevant Websites:
MSU Sustainable Materials Group Exit
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.