Submitted to: Industrial Crops and Products International Conference Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/29/2000
Publication Date: 7/8/2001
Citation: Foulk, J.A., Bunn, J.M. Properties of compression molded, acetylated soy protein films. Industrial Crops and Products International Conference Proceedings. 2001. v.14(1). p.11-22.
Interpretive Summary: Synthetic materials have gradually replaced metal, wood, natural fibers, glass and paper in suitable applications. Such materials have led to one of today's major disposal needs and created interest in biodegradable polymers produced from natural products. Selective use of degradable natural products may help ease waste disposal problems. Demand for biodegradable polymers produced from renewable natural resources grow as environmental concerns increase. This study examined how acetylated soy protein isolate performed as a thermoplastic and how the properties of films made from it were affected by composition and morphology. Compression molded thermoplastics produced from acetylated soy protein isolate appear as a possible commercial thermoplastic. The results are important to U.S. farmers and future soy protein markets because use of soy protein in these biopolymers could aid U.S. based farms and industries in their goal to succeed globally.
Technical Abstract: Demand for biodegradable polymers produced from renewable natural resources grow as environmental concerns increase. The objective of this study is to examine how acetylated soy protein isolate performed as a thermoplastic and how the properties of films made from it are affected by composition and morphology. SUPRO 620 and 660 were modified and acetylated to produce SY7 and SY23 thermoplastic films. These films were formed under various compression molding conditions to form films of two thicknesses and relative molecular weights. No plasticizers were used in forming these films. Molded films were then evaluated for total and volatile solids, nitrogen content, chemical oxygen demand, flow rate, solubility, X-ray diffraction, 1H and 13C NMR, differential scanning calorimetry, infrared analysis, tensile properties, oxygen and water vapor permeability. A comparison of melt flow index values, nitrogen content, total solids, volatile solids, and chemical oxygen demand showed no statistical differences between films, but significant differences from SUPRO 620 the base material used to form SY7. The SY7 films had lower solubility, lower "wet" tensile strength, and higher oxygen permeability than the SY23 films. Both SY7 and SY23 films formed at higher conpression molding temperatures had higher tensile strengths, increased "wet" elongation, and lower water vapor permeability than films formed at lower compression molding temperatures. X-ray diffracction, 1H and 13C NMR, differential scanning calorimetry, and infrared analysis showed slight or no differences between the SY7 and SY23 films. Compression molded thermoplastics produced from acetylated SUPRO 620 and 660 appear similar and a possible commercial thermoplastic.