Search

Abstract Spinnability and rheological properties of soy protein are studied for potential application in food products. It has been considered impossible to spin globular proteins due to the difficulty in extending the molecules to achieve high degree of intermolecular entanglement. In order to improve the spinnability of globular proteins, other polymers were incorporated. This paper shows a good spinnability of 100% globular soy protein. In this work, aqueous urea/reductant system is selected for efficient stretch and entanglement globular soy proteins for fiber spinning. In this system, hydrogen bonds, hydrophobic and electrostatic interaction were disrupted by urea, while disulfide bonds were cleaved by reductants. Moreover, the backbones of globular soy proteins were not severely destroyed, rendering the stretched globular protein spinnable and the spun fibers mechanically robust. Relationship between rheological properties and spinnability of globular soy protein solutions is quantified. In order to be spinnable, globular soy proteins should be highly stretched, and thus entangled with preserved backbones. Graphical abstract Image 1 Highlights • Globular soy protein could be spun to fibers after proper dissolution. • A solvent system selected for efficient intermolecular entanglement of soy protein. • Relationship quantified between rheological property and spinnability of soy protein. • Soy protein fibers are potential candidates for various food applications. [ABSTRACT FROM AUTHOR]

Fully biodegradable textile sizes with satisfactory performance properties were developed from soy protein with controlled hydrolysis and dis-entanglement to tackle the intractable environmental issues associated with the non-biodegradable polyvinyl alcohol (PVA) in textile effluents. PVA derived from petroleum is the primary sizing agent due to its excellent sizing performance on polyester-containing yarns, especially in increasingly prevailing high-speed weaving. However, due to the poor biodegradability, PVA causes serious environmental pollution, and thus, should be substituted with more environmentally friendly polymers. Soy protein treated with high amount of triethanolamine was found with acceptable sizing properties. However, triethanolamine is also non-biodegradable and originated from petroleum, therefore, is not an ideal additive. In this research, soy sizes were developed from soy protein treated with glycerol, the biodegradable triol that could also be obtained from soy. The soy sizes had good film properties, adhesion to polyester and abrasion resistance close to PVA, rendering them qualified for sizing applications. Regarding desizing, consumption of water and energy for removal of soy size could be remarkably decreased, comparing to removal of PVA. Moreover, with satisfactory degradability, the wastewater containing soy sizes was readily dischargeable after treated in activated sludge for two days. In summary, the fully biodegradable soy sizes had potential to substitute PVA for sustainable textile processing. [ABSTRACT FROM AUTHOR]

For the first time, rheological behavior of soy protein isolate (SPI) solution with high concentration for fibers and films was studied. The results showed that SPI could be readily dissolved in urea/sodium sulfite aqueous system, and the SPI solution is suitable for wet spinning and film casting. The effects of concentration, temperature, and shear rates on the rheological properties of SPI solution were studied. Viscosity of SPI solution decreases with increasing temperature, which is good for the preparation of solution with high concentration and regenerated SPI fibers/films with good properties. All solution samples exhibited thixotropic behavior, which were different from traditional polymer solution for wet spinning and film casting process. Both in forward and backward measurements were carried out by the Power Law model. Under constant shear rates (80-160 s −1 ), 18 wt% SPI solution was chosen to study the dependence of viscosity on time. Second order structural kinetic model, Weltman model, first-order stress decay models with zero and none-zero equilibrium stress values were used to fit the rheological data. Among the four models, Weltman model is more appropriate to fit the thixotropic data. [ABSTRACT FROM AUTHOR]

All-green textile sizes with satisfactory weaving performance and biodegradability were developed from soy protein and glycerol, two major byproducts from soy-based biodiesel production. Polyvinyl alcohol has long dominated textile sizing chemical market due to its excellent sizing performance, despite its non-biodegradability. Efforts have been devoted to replace polyvinyl alcohol for a more sustainable textile industry. Recently, substitute size developed from soy protein after using high amount of petro-based triethanolamine showed acceptable sizing properties. However, triethanolamine was not an eco-friendly additive, due to its petroleum origin and non-biodegradability. In this research, glycerol was used to plasticize soy protein to develop all-green soy size. Glycerol interrupted hydrogen bonds in the soy globulin, allowing them to extend in the films. Resultantly, the soy size films possessed high stretchability and work of rupture. Lab-scale experiments and industrial weaving proved that the all-green soy size had similar or better weaving performance and remarkably better degradability, comparing to polyvinyl alcohol and triethanolamine plasticized soy protein size. For the first time, a possible logarithmic relationship was found between work of rupture of the size film and relative weaving efficiency. [ABSTRACT FROM AUTHOR]

Graft polymerization of acrylic acid endowed soy protein films with good tensile properties and water solubility without sacrificing biodegradability. In this research, soy protein was grafted with acrylic acid and cast into biodegradable films as substitutes of non-biodegradable Poly(vinyl alcohol) (PVA) films. The grafted soy protein films had 318%, 114%, 60% and 9% higher tensile strength, elongation, dissolving rate and transmittance, compared to ungrafted ones, respectively. Acrylic acid grafting provided soy protein films with biodegradability, flexibility, and adhesion to yarns substantially higher than PVA, while water solubility and abrasion resistance similar to PVA, leading to high potential applications of the grafted soy proteins in the fields of water soluble packaging films and slashing to substitute PVA. [ABSTRACT FROM AUTHOR]