Substitution Of Poly(Vinylalcohol) Sizes Using Biodegradable Soy Proteins

In this research, the additives with multi hydroxyl groups, non-linear molecular structure andelectric charge were used to modify soy protein sizes to replace Poly (Vinyl Alcohol)(PVA) forhigh speed weaving of cotton, poly-cotton and polyester fabrics. PVAsizes are known as the bestsizing agent for polyester and their blends. However, PVAis poorly biodegradable and is a majorcontributor to high chemical oxygen demand in textile effluents (COD1,700mg/g and BOD30–80mg/g). In order to substitute PVAand reduce the environmental pollution caused by PVAsize effluent, various modified starch sizing agents and acrylate-based sizes have been developed.However, most of modified starch still could not provide cotton yarns with enough protection inhigh speed weaving or weaving of high-count cotton fabrics as PVAdoes, and eventually affectproductivity and quality of cotton fabrics.Acrylate-based sizing agents have high cost and lowbiodegradability (COD1,350–1,650mg/g and BOD of50mg/g). Therefore, global textileindustry, companies manufacturing textile chemicals and national environmental administrationsare endorsing the need for biodegradable， high performance and low cost sizing chemicals toreplace PVA.Soy proteins, extracted from bio-diesel or edible oil byproducts, have potential to be textilesizing agents due to their large quantities, low cost and biodegradability. However, soy proteinsfilms are too brittle to protect yarns during high speed weaving.This paper studied the effect of various chemicals, such astriethanolamine, diethanolamine,ethanolamine, propanolamine, butanolamine and glycerol, on the tensile properties of soy protein films. TEA-soyproteins(TEASP) showed much better improvement in tensile properties offilms than soy proteins, and even have98.8%and83.3%increase in films strength andelongation compared to GLY-soy proteins. Industrial weaving results showed TEASP had62.1%and14.6%higher weaving efficiency than the physical modified starch and PVA sizes. Industrialweaving results showed TEA-soy proteins (TEASP) had3%and10%higher relative weavingefficiency than PVA and modified starch sizes on poly-cotton fabrics, and had similar relativeweaving efficiency to PVA on polyester fabrics, although at3%to6%lower add-on.In addition,TEASP size had a5-daybiochemical oxygen demand/chemical oxygen demand ratio of0.44compared to0.03for PVA indicating that TEASP sizes were easily biodegradable in activatedsludge. High weaving efficiency and good biodegradability from industrial trials indicate TEASPare promising sizing agents for cotton to replace modified starch and PVA for high quality andhigh speed weaving.