06/12/2025
By Danielle Fretwell

The Francis College of Engineering, Department of Plastics Engineering, invites you to attend a Doctoral Dissertation defense by Kerry Candlen on: "The Impact of Polyolefins on the Environment and More Sustainable Solutions for Ration Packaging and Agricultural Mulch Film."

Candidate Name: Kerry Candlen
Degree: Doctoral
Defense Date: Wednesday, June 18, 2025
Time: 10 a.m. - noon
Location: ETIC 445

Committee:

  • Advisor: Wan-Ting (Grace) Chen, Associate Professor, Plastics Engineering, University of Massachusetts Lowell
  • Amy Peterson, Professor, Plastics Engineering, University of Massachusetts Lowell
  • Jo Ann Ratto, Adjunct Professor, Plastics Engineering, University of Massachusetts Lowell
  • Genevieve Flock, Research Microbiologist, Combat Feeding Directorate, DEVCOM SC

Abstract:
Production rates and pollution concerns surrounding flexible packaging continue to rise despite a lack of understanding of how plastics interact with the environment and an underdeveloped bioplastic market for alternative materials. This work at large aims to protect global water sources by implementing more sustainable materials for flexible packaging and agricultural mulch films applications. Firstly, Chapter 4 investigates the interaction between microbes and polypropylene (PP) films to better understand polyolefin degradation in aquatic environments. Filtered, fresh, and marine water samples were used as incubation medium for PP films under ambient and accelerated aging conditions. Chemical and morphological changes to the film surface reveal that biofilm will not only grow on PP, but it will also initiate surface degradation, indicated by biofilm removal and carbonyl index (CI) measurements. From a mitigation standpoint, Chapter 5 reevaluates the performance metrics necessary to meet shelf life and durability requirements for U.S Military Meal, Ready-to-eat (MRE) applications so ration packaging can be better designed for end of life. Barrier metrics were evaluated via storage study and sensory analysis, while mechanical metrics were evaluated by simulated distribution testing. Results suggest that though the current water vapor transmission rate (WVTR) requirement may be excessively stringent, commercially available more sustainable materials still struggle to meet the newly defined barrier metrics. Minimum tensile properties, puncture resistance, and seal strength metrics are also proposed for survivability in the supply chain. Moreover, Chapter 6 investigates the performance of edible film for primary ration packaging applications. In this study, cheesecake bars of differing water activity (Aw) and aromas were wrapped in carboxymethyl cellulose (CMC) edible films, overwrapped in the current non-retort MRE pouch, and then subjected to storage at 27 °C. While Aw and moisture content measurements of the cheesecake bars suggest moisture migration through the edible packaging, no aroma migration was detected by sensory analysis after one month in storage. Seal strength data suggests stable mechanical performance throughout the storage study as well. Finally, Chapter 7 further investigates sustainable film alternatives by evaluating a biodegradable mulch film fabricated from poly(butylene adipate-co-terephthalate) (PBAT), poly(lactic acid) (PLA), and 10% soy waste (PBAT/PLA/Soy). The film was subjected to an accelerated storage study, as well as field trials and respirometry, to evaluate its performance and biodegradation characteristics. PBAT/PLA/Soy films exhibited 49.6±1.1% mineralization according to ASTM D5338, as well as 49% higher plants heights compared to unfilled PBAT/PLA. Results herein reveal the potential for more sustainable materials as film and packaging solutions in response to growing global waste concerns and known detrimental effects on the environment. Ultimately, this work encourages the use of highly engineered, sustainable materials to optimize packaging design and reduce end-of-life burdens on the consumer.