Soy protein (SP) possesses promising physico-chemical properties in terms of film formation, however, main shortcomings of SP films are poor water-resistance and brittleness which limit SP applications. Due to sustainability, abundance and low cost, SP attracts interest for the development of food packaging materials, but needs to be modified to balance mechanical properties, as well as to provide very low permeability.
This project is motivated by encouraging experimental results obtained during currently supported by North Dakota Soybean Council work which shows feasibility of combining SP with latex polymers from soybean oil-based vinyl monomer (SBM, developed at NDSU) to improve permeability and mechanical performance of resulted bioplastic films. However, in two-component system, compatibility between SP and SBM-based latex polymers limits incorporation extent of latexes into the SP films, and, thus, latex effect on films properties and performance.
The basic concept of this project is to engineer one-component material via grafting (attachment) of SBM polymer chains to the SP. The goal is to render new materials, SP-SBM copolymers, with targeted physico-chemical, mechanical and film-forming properties.
Specific aims include i. grafting of SBM polymer chains of various lengths at various grafting densities to SP to yield new SP-SBM copolymers; ii. formation of SP-SBM films and their further characterization to demonstrate feasibility as bioplastics.
Identifying industrial partners to help with evaluating performance of SP-SBM films is targeted. Biodegradable plastics market was estimated at $2 billion in 2015, and projected to reach $3.4 billion in 2020, growing at about 11% per year. Protein-based films are currently thought as a great alternative in food packaging industries.

(measurable) Series of 20-30 µm thick films made up of at least 90% plant building blocks, biodegradation about 80% of the bioplastic after one month. Oxygen permeability target is <10 cm3 µ mm-2 day-1 kPa-1. Targeted mechanical properties (tested at 20-25oC, RH=50%, and at -18oC): Elastic modulus and tensile strength ranges, depending on the specific application, are targeted at 100-1000 MPa.

1. Process development for grafting of SBM polymer chains to SP.
2. SP-SBM film formation, characterization and testing to determine their feasibility as bioplastics for food packaging applications.
Longer term goal is to test films from SP-SBM copolymers at industrial partner facilities (will be identified during this project) to evaluate perspectives for new product commercialization.

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Research conducted
Being expanded over the past few decades, industry of food packaging targets maintaining food quality, improving food shelf-life, providing safe environment for food storage and transportation. Both consumers and regulatory agencies indicate the demands to less polluting, more environmentally friendly, renewable plastic materials, particularly, for food packaging. For specific applications, compostable or biodegradable plastics (either naturally derived or made from sustainable resources) could replace traditional petroleum-based polymeric food packaging materials. By degrading with microorganisms, such plastics help to reduce the solid waste environmental concerns.
One of the targeted renewable raw materials to be used for bioplastics manufacturing are plant proteins (including soy protein), natural polymers formed from amino acids linked by peptide bonds in long chains. Plant proteins-based films are considered as a great alternative in food packaging industries. In this work, we demonstrate feasibility of using soy protein (in combination with soybean oil) in synthesizing bioplastic films which can be applied for food packaging.

Why the research is important to ND soybean farmers
The proposed research aims to provide the feasibility of using soybean protein and soybean oil produced in the state of North Dakota for high value and high profit food packaging materials. The proposed technology has the ability to add more value to the crop and make it more profitable for farmers. Newly developed materials can diversify soy-based products with increased demand for soy protein and soybean oil in manufacturing of bioplastics.
The market will be given soy-based food packaging materials. This will also help the state of North Dakota economy to attract new investors and other new soy processing industries.

Final findings of the research
We show that bioplastic films from all-soy-one component bioplastics (soy protein/soy oil grafted copolymers) are not only feasible and provide decent film-forming ability, but also possess mechanical properties which can be attractive in achieving enhanced material performance in variety of applications. Overall, new materials, in combination with recently developed by us “two-component systems” (where soy protein was modified by soybean oil-based latexes), can be considered as versatile biobased platform, alternative to the traditional petroleum-based plastics.

Benefits/Recommendations to North Dakota soybean farmers and industry
This work benefits the North Dakota soybean farmers and industry by establishing additional uses for multiple derivatives of the soybean, including soy protein and soybean oil.
This technology focuses on the use in food packaging applications, however, advances may be turned to other agricultural applications as well (in particular, agricultural mulch, other bioplastic films), thus benefitting the farmers and industry even further by providing a sustainable biodegradable, environmental friendly options for various agricultural technologies and products.

This proposal aims to advance the feasibility of using crops produced in the state of North Dakota for high value and high profit polymer materials for food packaging. Using SP and soybean oil for making new bioplastics has the ability to add more value to the crop, thereby make it more profitable for farmers. Thus, ability to produce all soy-based bioplastics from crop grown in state of North Dakota certainly strengthens the proposed concept. Obtained results are expected to benefit North Dakota soybean farmers because the findings will diversify soy-based products with increased demand for SP and soybean oil. The market will get all soy-based bioplastics for food packaging applications. It will also help the state of North Dakota economy to involve investors and other soy processing industries.