SUSTAINABLE BIOPLASTICS FOR FOOD PACKAGING

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1014122
• Project Start Date: Oct 1, 2017
• Project End Date: Sep 30, 2022
• Program Code: [(N/A)]- (N/A)

Recipient Organization
OHIO STATE UNIVERSITY
1680 MADISON AVENUE
WOOSTER,OH 44691

Performing Department
Food Science & Technology

Non Technical Summary
Bacteria and enzymes can degrade aliphatic polymers with hydrolyzable carbon backbones, such as bacterially synthesized poly-(3-hydroxybutyrate) (PHB), thus alleviating landfill saturation.5-8 PHB is produced by nutrient-deprived microorganisms, which accumulate the polymer as an intracellular form of energy storage.4-9 However, commercial use of PHB is limited due to thermal degradation, and brittleness at room temperature 4-9 , in addition to its higher production costs. During the growth stage of PHB homo-polymer, incorporation of propionic or pentanoic acid, while restricting dissolved oxygen, leads to the formation of 3-hydroxyvalerate (PHV). PHBV, although a promising bio-plastic, has poor thermal and mechanical properties above 160ºC.10-12 Additionally, high processing temperatures within the extruder resulted in thermal degradation of the polymer near or above the melting temperature (171ºC) of the PHBV.10 Hevea brasiliensis (the para rubber tree) is a source of natural rubber (NR), The incorporation of dispersed rubber particles into a brittle PHBV thermoplastic matrix is known to improve both the impact resistance and toughness properties with minor decreases in modulus. 13,14 However, these studies incorporated the rubber as a particulate filler. Natural rubber polymers have not been blended with PHBV to form a visually uniform blended material nor have they been used in food packaging applications.Various unique requirements need to be met when considering a material for food packaging applications that encompass the dynamic interaction between food, packaging material and the environment15. Additionally, other more common properties such as gas and water vapor permeability, mechanical changes, sealing and thermoforming capabilities, machinability, transparency, anti-fogging, printability, resistance to light, water, acid, grease, availability and of course cost all are important factors16.

Animal Health Component

30%

Research Effort Categories

Basic

20%

Applied

30%

Developmental

50%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
511	5010	2020	100%

Knowledge Area
511 - New and Improved Non-Food Products and Processes;

Subject Of Investigation
5010 - Food;

Field Of Science
2020 - Engineering;

Keywords

bioplastics

food packaging

phbv

rubber blends

Goals / Objectives
To fabricate PHBV blended with high molecular weight natural rubber (HMW-NR), and assess the physico-chemical properties of the new materials.Test the flexural, sealing, and drop impact resistance properties of the packaging material developed.Investigate the effects of freezing and microwaving with low and high pH food systems using the packaging developed.Investigate the scale up production of these materials.

Project Methods
During fabrication and testing of the materials, the following instrumentation and procedures will be used to determine the proporties that would make for adequate food packaging applications:Differential Scanning Calorimetry (DSC)monitors changes in physical or chemical properties of a material as a function of temperature by detecting the heat changes associated with such processes.This method is critical to understand melting and other transitions of the material and thus processing limitations and compatibility of polymersThermal Gravimetric Analysis (TGA) is a technique used to understand weight loss and rate of weight loss of a material with increased time or temperature. This is critical in understanding material stability with storage and temperature abuse.Dynamic Mechanical Analysis (DMA)is a micro-rheological technique in which a dynamic stress is applied and the resulting strain is monitored. Food polymers are mostly viscoelastic with stress and strain being out of phase with respect to each other by the sinusoidal angle delta. This instrument is important to understand mechanical properties and handelability of materials4. Rheology Rheology determines the deformation of a liquid and semi liquid material when a stress/strain is applied and is used to understand flow behavior. This instrument can be used to guide processing conditions of new materials 4. Nuclear Magnetic Resonance (NMR) The various NMR techniques are critical for identifying structure of materials as well as molecular mobility in a material. The latter is critical for stability as well as uniformity of new materials developed.a. 1H CR-NMRA 600 MHz Bruker spectrometer (Bruker Instruments, Billerica, MD) will be used.b. 13C CPMAS NMRA 600 MHz spectrometer (Bruker Instruments, Billerica, MD) equipped with an IBM solids unit will be used to acquire the data. Cross polarization (CP) and magic angle spinning (MAS) will be applied.5. Flexural, sealing integrity, and drop impact resistance properties of the materials will be determined according to ASTM D790-15, ASTM F3039-15, and ASTM D2463-156. The color of the food/tray after treatment will be measured and the results will be compared with the pre-set color difference target color to obtain color difference. Uniform, acceptable color is important for consumer acceptability.Results from all these methodologies will be used to optimize material properties and determine applications.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Our group has interacted with various companies, working with them on more sustainable packaging solutions. These include small and multinational companies that are looking for films, trays and adhesives that decrease the imapct to the environment. Changes/Problems:Due to COVID epidemic resulting in laboratory closure, we had some delays in our different projects and needed extensions What opportunities for training and professional development has the project provided?We have also been working on innovative ways for reuse of waste plastics. A workshop "Making Matter" was offered to students in architecture to explore methods for embedding granulated waste plastic into concrete, plaster and other mineral substrates to make new composite materials. These efforts were aided by the involvement of 6 undergraduate students that focused on different parts of the project and will result in publications. Additionally, a postdoc from chemistry has been working on our projects, translating molecular findings to real bioplastic applications. We have other undergraduates, mainly from material science and engineering,working in our laboratories aiding in all facets of our research. How have the results been disseminated to communities of interest?We have expanded our team to include a variety of areas related to this project where expertise form other OSU researchers would be of value. As such, the team has elected to form a MAC (Multidisciplinary Applied Collaborative) named Alternative Matters (https://u.osu.edu/alternativematters/) that will highlight and promote our activities. Notably, the team also won OSU's coolest story of the year (https://news.osu.edu/biodegradable-plastics-is-coolest-ohio-state-science-story-of-2019/) showcasing the public interest in this critical area. We have published several papers and plan to present our findings in future related conferences. What do you plan to do during the next reporting period to accomplish the goals?Our main goal for the next year is to continue dialogue with potential industry collaborators to translate our bioplastics into the commercial market.

Impacts
What was accomplished under these goals? This year, our multidisciplinary team has accomplished various of its objectives as well as built a solid foundation for expanding its efforts. The team used a bacterial fermentation derived polymer blended with natural rubber as an alternative for both plastics and films. To achieve greater strength, invasive plant species from the Olentangy wetlands were used as fiber reinforcement. Additionally, epoxides derived from spent coffee grounds were added to improve chemical interaction between the different components. We are now working with various companies for specific applications and to scale up the process. Similarly, the same blend with added corn-derived bioplastic was used for film manufacturing. A need for greater water barrier properties of the film was addressed by investigating chemically modified cellulose. A method was optimized for assessing the stretchability of the film to assure it can be used in scale up equipment. Additionally, studies on a water- soluble natural rubber latex adhesive were conducted, and significant progress was made this year although continued efforts are needed to optimize its role to role spreadability properties.Efforts began on utilizing spent coffee ground waste by converting extracted oil to a novel bioplastic.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, X., Venoor, V., Koelling, K., Cornish, K. and Vodovotz, Y. 2019. Bio?based blends from poly(3?hydroxybutyrate?co?3?hydroxyvalerate) and natural rubber for packaging applications. Journal of Applied Polymer Science. 136(15)47334
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, X., Cornish, K. and Vodovotz, Y. 2019. Synergistic mechanisms underlie the peroxide and coagent improvement of natural rubber toughened poly (3-hydroxybuty-rate-co-3-hydroxyvalerate) mechanical performance. Polymers.11:565-585.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, X., Ji, K., Koelling, K., Cornish, K. and Vodovotz, Y. 2019. Optimal Mechanical Properties of Biodegradable Natural Rubber-Toughened PHBV Bioplastics Intended for Food Packaging Applications. Food Packaging and Shelf Life. 21:100348.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhao, X., Cornish, K. and Vodovotz, Y. 2020. Narrowing the gap for bioplastic use in food packaging-an update. Environmental Science and Technology. 54, 4712-4732

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:This research is targeted at the food packaging industry, government agencies interested in food packaging and other researchers in this field Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Several undergraduate students participated in optimizing the biobased blend. How have the results been disseminated to communities of interest?Data and results were published and presented at various conferences What do you plan to do during the next reporting period to accomplish the goals?We aim to continue to work on the biodegradable, biobased materials concentrating on the water impermeable films

Impacts
What was accomplished under these goals? Incorporation of natural rubber (NR) into poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) through melt blending improves PHBV flexibility and toughness but sacrifices tensile strength, due to low NR modulus and insufficient compatibility between NR and PHBV. These unbalanced mechanical properties restrict NR/PHBV use in packaging applications. A response surface methodology (RSM), with a Box-Behnken design, was used to optimize the mechanical properties of PHBV/NR blends enhanced with synergistic use of TMPTA coagent and peroxide. Notched impact strength (toughness) of the blends increased with increasing coagent and peroxide, maximal at 15 wt. % rubber loading. Tensile strength increased with increasing coagent, decreased with increasing rubber content, but was independent of peroxide. In contrast, flexibility, which also was independent of peroxide, decreased with coagent and increased with rubber loading. The optimal PHBV/NR blend was obtained at 15 wt. % NR, 4.2 phr peroxide, and 3 phr coagent, with a tensile strength of 28.1 MPa, notched impact strength of 27.5 J/m, flex modulus (1% secant modulus) of 8,679 MPa. The blends degraded by ˜15% in 53 days in a lab-scale aerobic composting system at 58 °C. Trays made from the optimized PHBV/NR blend had water vapor permeability and sealability comparable to polypropylene (PP), and migration studies indicated that the trays were safe for food-contact applications.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, X., Venoor, V., Koelling, K., Cornish, K. and Vodovotz, Y. 2019. Bio?based blends from poly(3?hydroxybutyrate?co?3?hydroxyvalerate) and natural rubber for packaging applications. Journal of Applied Polymer Science. 136(15)47334.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, X., Cornish, K. and Vodovotz, Y. 2019. Synergistic mechanisms underlie the peroxide and coagent improvement of natural rubber toughened poly (3-hydroxybuty-rate-co-3-hydroxyvalerate) mechanical performance. Polymers.11:565-585
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Zhao, X., Ji, K., Koelling, K., Cornish, K. and Vodovotz, Y. 2019. Optimal Mechanical Properties of Biodegradable Natural Rubber-Toughened PHBV Bioplastics Intended for Food Packaging Applications. Food Packaging and Shelf Life. 21:100348

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:Our novel bioplastics are designed to replace petrolium-based packaging and therefore are of interest to bioplastics consumers and manufacturers. Changes/Problems:The bioplastic raw material, PHBV, is not well regulated as far as valerate content of the final polymer. During our studies, the valerate content in the polymer decreased from 4-5% to 1-2%, changing the inherent physical properties. Our group had to reformulate the polymer blend with NR to achieve the desired properties with the lower valerate content PHBV. What opportunities for training and professional development has the project provided?The graduate student primarily in charge of the project was able to train 2 undergraduate enigneering students in research as well as help the technician learn about the novel blend How have the results been disseminated to communities of interest?Through publications and oral/poster presentations What do you plan to do during the next reporting period to accomplish the goals?Continue optimization of the bioplastic blend, assess biodegradability and physical properties

Impacts
What was accomplished under these goals? In this phase, 2-25 wt. %NR (natural rubber) was incorporated into Poly-(β-hydroxybutyrate-co-valerate), PHBV, through reactive extrusion in the presence of peroxide to improve PHBV flexibility and toughness. The PHBV/NR blends had two phases with crosslinked rubber being dispersed in PHBV matrix. Rubber addition restricted PHBV crystallization and decreased its degree of crystallinity. The blend had improved flexibility, toughness, thermal stability, and melt strength, but decreased tensile strength than pristine PHBV. The blend performance had clear rubber loading-dependent differences.

Publications

• Type: Journal Articles Status: Accepted Year Published: 2018 Citation: Zhao, X., Venoor, V., Koelling, K., Cornish, K. and Vodovotz, Y. Peroxide Induced Dynamically Vulcanized Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/Natural Rubber Blends for Food Packaging Applications. European Polymer Journal.
• Type: Journal Articles Status: Submitted Year Published: 2019 Citation: Zhao, X., Ji, K., Koelling, K., Cornish, K. and Vodovotz, Y. Optimal Mechanical Properties of Biodegradable Natural Rubber-Toughened PHBV Bioplastics Intended for Food Packaging Applications. Food Packaging and Shelf Life
• Type: Theses/Dissertations Status: Accepted Year Published: 2018 Citation: Zhao, X. Natural Rubber Toughened Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) Bioplastic for Food Packaging Applications. PhD. Dissertation. Department of Food Science and Technology. The Ohio State University. 2018.