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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]

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]

Soymeal, which contains natural plasticizer and tackifier, has been used to fabricate biodegradable and low-cost warp sizes, with potential for replacing non-biodegradable polyvinyl alcohol (PVA) sizes for large-quantity industrial applications. Warp sizes from soyprotein isolates (SPI) have been reported as a potential substitute for PVA sizes, which contribute to high chemical oxygen demand in textile effluents and cause serious water pollution. However, sizes from SPI are high in cost and need additional plasticizers to overcome brittleness of films. In this research, the developed low-cost soymeal sizes contain soyprotein as majority and saccharides/saponified-oil from soymeal as minorities. Comparing to films from triethanolamine-plasticized SPI sizes, the soymeal size had about 30.1, 25.2 and 8.3% higher film flexibility, adhesion to yarns and abrasion resistance, respectively. Saccharides in soymeal and saponified oil formed during size extraction functioned as plant-based additives with capability of improving adhesion of protein sizing pastes to cotton and/or polyester yarns and increasing elongation of protein-based size films. Successful utilization of soymeal in textile sizing will lead to its large-quantity application, resulting in high value addition to agricultural byproducts and profound impact on soybean industry and textile industry. [ABSTRACT FROM AUTHOR]