Grantee Research Project Results
Final Report: Sustainable Packaging Solutions based on Biodegradable Plastics
EPA Grant Number: SU835535Title: Sustainable Packaging Solutions based on Biodegradable Plastics
Investigators: Nagarajan, Ramaswamy , MohdAris, Zarif Farhana , Singh, Ankita , Connor, Sean , Ponrathnam, Timothy , Bavishi, Vishal , Xia, Zhiyu
Institution: University of Massachusetts - Lowell
EPA Project Officer: Packard, Benjamin H
Phase: I
Project Period: August 15, 2013 through August 14, 2014
Project Amount: $14,994
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2013) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Chemical Safety , P3 Awards , Sustainable and Healthy Communities
Objective:
Flexible packaging was a $74 billion market globally in 2012 and is expected to grow to $100 billion in 2018 [1]. While food packaging has dominated this market, flexible packaging is also being used extensively in the pharmaceutical sector. Unfortunately despite all efforts, less than 10 % of plastic waste generated is successfully recycled in the U.S.A [2]. About 5.8 million tons of flexible-packaging waste is generated annually in the U.S.A (40 lbs per capita). The vast majority of plastic waste generated ends up in landfills. Improper disposal has also resulted in the accumulation of billions of pounds of plastic in vast ocean gyres. While biodegradable polymers such as corn starch derived poly(lactic acid) [PLA] are available commercially, the oxygen and water vapor barrier properties of these polymers are extremely poor and hence they cannot be used directly for food packaging. Metallization of biodegradable plastics using aluminum can improve moisture and oxygen barrier properties [ 3 ]. However studies investigating effect of aluminum in contact with food indicate leaching and contamination problems especially in the case of packaging of acidic food such as coffee beans. Multiple coatings or lamination (with often non-biodegradable films) is essential to prevent direct contact of aluminum with the food. Metallization also causes problems with biodegradation of the films and metals or metal oxides are released into the composting environment [4]. There is an immediate need for the development of biobased and biodegradable films with improved barrier properties suitable for food packaging.
Objectives:
The objective of the proposed research effort is to develop novel biobased coatings and appropriate processes to significantly enhance the gas barrier properties of bio-derived flexible packaging films such as PLA. This novel, packaging solution will lead to the creation of biodegradable films with good oxygen and moisture barrier properties suitable for food packaging, as a sustainable alternative to petroleum-based non-biodegradable films. The proposed research utilizes biobased materials like chitosan (derived from exoskeletons of crabs) and beeswax to enhance the barrier properties of these plastics. This project seeks to support the three pillars of sustainability – people, prosperity and planet by addressing a huge problem caused by environmentally-persistent plastics packaging waste. Specific goals of the first phase of the project are stated in the list below:
- Use of Renewable, non-toxic and biodegradable starting materials for coating PLA in accordance to the principles of green chemistry and engineering. The selected starting materials should be low cost and abundantly available (such as chitosan and beeswax).
- Develop method for modifying the surface energy of the films (corona treatment) to facilitate electrostatic layer-by-layer deposition of Chitosan from solution.
- Optimize the coating thickness by systematically varying concentration and pH of the Chitosan solution so that appropriate oxygen barrier properties and surface chemistry for the coating of the subsequent layer(s) can be achieved.
- Develop appropriate moisture barrier layers based on fatty acids or biodegradable beeswax and a process for coating it.
- Optimize coating materials and processes to achieve an Oxygen transmission rate (OTR) of less than 50.0 cm3/m2 day and Water Vapor Transmission Rate (WVTR) of less than 8 g/m2 day at (38°C, 90% RH) – the specification for coffee bean packaging application.
- Characterize the film with the coatings at every stage: Film thickness measurement using optical profilometry or deposition of coatings on a quartz crystal microbalance. Surface activity and wettability of film through contact angle measurement. Determine barrier properties of the coated film using oxygen and water vapor transmission rate analyzers.
Summary/Accomplishments (Outputs/Outcomes):
Summary of Findings (Outputs/Outcomes):
- Corona Surface treatment of PLA films increased the surface energy of the substrate from 42 dyne/cm to 56 dyne/cm, which helped improve the wettability of chitosan solution onto the PLA substrate.
- The pH of the chitosan solution had a significant effect on thickness and oxygen transmission rate (OTR). There was a direct relation between solution pH and thickness of the coating over the range studied. Increase in coating thickness reduces the OTR.
- Coating PLA with chitosan significantly reduces the OTR from 1042 cm3/(m2.day.atm) to 14.3 cm3/(m2.day.atm).
- Incorporation of the fatty acid layer reduces the water vapor transmission rate (WVTR) significantly from greater than 80 g/(m2.day.atm) to 15.24 g/(m2.day.atm).
- Coating of fatty acid layers does not provide significant reduction in WVTR. The films turn brittle when the coating thickness is increased.
- Incorporation of a hydrophobic beeswax coating significantly reduced the WVTR to 1.02 g/(m2.day.atm) exceeding the targeted WVTR of < 8 g/(m2.day.atm).
- Relative humidity even as high as 85% did not have any significant negative effect on the OTR.
- Tensile properties of the chitosan and fatty acid coated PLA films remain unchanged. However, the beeswax coating reduced the transparency of the film.
Conclusions:
In first phase of the project, the P3 Team has successfully demonstrated the development of a biobased coating on biodegradable films to achieve the target oxygen transmission rate and the water vapor transmission rate necessary for coffee bean packaging application. These biobased coatings cause a significant reduction in OTR of PLA films from 1000 cc/(m2.day.atm) to 10 cc/(m2.day.atm) and WVTR from 375 g/(m2.day.atm) to 1g/(m2.day.atm) respectively. The barrier properties achieved by this project meet the targeted requirement for packaging of coffee beans provided by Mesoamerican Development Institute (MDI).
In phase II, the P3 team would develop this coating technology to be broadly applicable to other types of biobased films and demonstrate scalability of the technology through a continuous rollto- roll process in collaborations with industrial partners. Prototype bags for coffee packaging will be fabricated and tested in collaboration with MDI. It is believed that this initiative will open more opportunities for the use of this sustainable packaging solution in other substrates such as paper, cellulose and starch-based packaging. This would be a significant step in replacing petroleum based non-biodegradable plastic from food packaging supply chain. The team will also work closely with Massachusetts Toxics Use Reduction Institute (TURI) to ensure all materials used for the coating process are safe from a human health and environmental perspective.
Journal Articles:
No journal articles submitted with this report: View all 1 publications for this projectSupplemental Keywords:
Biobased, Biodegradable, Packaging, Barrier, Sustainable Development, Chitosan, PLA, BeeswaxRelevant Websites:
http://www.uml.edu/Research/CAM/epa-programs/green-packaging/default.aspx
http://faculty.uml.edu/rnagarajan/Research2.htm
The 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.