This proposal seeks to support NDSC’s mission, vision, and core values by using soybean extracts as corrosion inhibiting additives to commercially available poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) coatings. The soybean extracts will be obtained through a technically and economically feasible extraction approach developed by our research group. The addition of soybean extracts to PVDF-HFP coatings is expected to increase the fluoropolymer’s corrosion resistance and overall surface adhesion strength.
We believe that this newly proposed utility of soy is important to the ND soybean farming community as the increasingly specific end-use and environmental requirements are currently influencing the growth of demand for green anti-corrosion additives made from sustainable natural resources. In 2021, the global corrosion inhibitor market value was worth US$ 8 billion and is projected to garner by US$ 2 billion in the year 2026. Likewise, the global market for corrosion resistant coatings was valued at US$ 13.5 billion in 2020 and is estimated to increase to up to US$ 20 billion in 2027. The corrosion inhibiting additives that we will be developing from soybeans can benefit from these market growths and increase soybean demand, which will further the farmers’ productivity and revenue.
My research group at NDSU specializes on the fabrication of advanced protective coatings, development of new groups of corrosion-preventing materials, and utility of electrochemical approaches to evaluating coatings’ corrosion protection. If successful, the obtained soybean extracts can be used as less expensive and more eco-friendly corrosion inhibiting additives to many fluoropolymers and other low adhesion strength polymer coating materials.

Our proposed work seeks to focus on the use of soybean extracts as anticorrosive additives to PVDF-HFP coatings. The supporting objectives are to (1) obtain high purity and high yield soybean extracts through a combined extraction-distillation process using eco-friendly extracting solvents; (2) investigate the effect of added soybean extracts in varying amounts on the corrosion resistance of PVDF-HFP coating system using electrochemical measurements; (3) examine the influence of soybean extracts on the surface adhesion strength of PVDF-HFP coatings.

The anticipated deliverables for the proposed project include (1) high purity and high yield soybean extracts obtained from a combined extraction-distillation process, (2) PVDF-HFP coating systems composed of varying amounts of soybean extract additive, (3) electrochemical and surface adhesion properties of extract-containing PVDF-HFP coatings. We anticipate that 1-2 peer-reviewed journal publications will result from this proposed project. The key scientific and theoretical findings will also be presented at a soybean-related research or regional/national conference.

Update:
The mid-year report for this project is attached.

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Updated June 28, 2024:
The final reports are attached.

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Fluoropolymers display interesting properties including high mechanical integrity, thermal stability, water repellency, and chemical resistance. However, their nonstick property limits their applications as it often results in poor film adhesion to various surfaces including metals. While many approaches have been explored to enhance their adhesion, their practical application remains restricted due to their complexity, cost, and environmental impact. This study used soybean extract (SE), obtained using water as an eco-friendly extracting solvent, to enhance the adhesion and corrosion protection properties of the fluoropolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) on mild steel. Results showed that the inclusion of SE increased the affinity between the fluoropolymer coating and the metal surface. This improvement is attributable to the presence of abundant heteroatoms and pi-electrons from isoflavones in SE and their capability to facilitate interactions at the coating-metal interface. Even with minimal SE loading, the fluoropolymer coatings demonstrated excellent corrosion resistance even after 7 days of continuous immersion in a 3.5 wt% NaCl solution. Findings also revealed that the coating adhesion on the metal surface was enhanced at higher SE concentrations, without compromising the thermal stability and hydrophobicity of the fluoropolymer. Based on electrochemical results, the fluoropolymer coating with 0.5 wt.% SE showed the best performance, indicating an optimal SE dispersion. This SE loading provided strong adhesion without forming hydrophilic (or water-loving) pathways that could facilitate the diffusion of water through the coating layer. The results obtained were supported by various analytical techniques including microscopy, spectroscopy, wettability assessments, mechanical tests, and thermal stability analyses, as well as cyclic corrosion tests, and simulation studies. This study highlights SE additives as a sustainable, economical solution for improving the performance of fluoropolymer coatings and potentially other coatings with low adhesion strength. Overall, our strategic approach highlights the beneficial use of SE additives toward formulating cost-effective, sustainable, and high-performance fluoropolymer coatings for a wide range of surface protection applications.

The obtained soybean extracts can be used as less expensive and more eco-friendly corrosion inhibiting additives to many fluoropolymers and other low adhesion strength polymer coating materials. Hence, the economic benefits of these green anticorrosive additives from the ongoing market value growth of corrosion inhibitors and protective coatings may potentially open a new income-generating activity for the whole ND soybean farming community. Potential commercialization and increased demand for high volume production of soybeans can be seen because of the extract additives’ eco-friendliness and renewability. Farmers will also become acquainted with this new use of soybeans, encouraging them to be more productive in soybean farming. Combined with renewability and several environmental advantages, the developed soybean extract additives are expected to economically benefit from the polymers’ anticipated market value growth, promoting the productivity and revenue of the soybean farmers.