Soy proteins as environmentally friendly sizing agents to replace poly(vinyl alcohol)

Abstract

An environmentally friendly and inexpensive substitute to the widely used poly(vinyl alcohol) (PVA) has been developed from soy proteins for textile warp sizing. Textile processing is the major source of industrial water pollution across the world, and sizing and desizing operations account for nearly 30 % of the water consumed in a textile plant. PVA is one of the most common sizing agents used for synthetic fibers and their blends due to PVA's easy water solubility and ability to provide desired sizing performance. However, PVA does not degrade and is a major contributor to pollution in textile effluent treatment plants. Although considerable efforts have been made to replace PVA with biodegradable sizing materials, the performance properties provided by PVA on synthetic fibers and their blends have been unmatched so far. Soy proteins are inexpensive, biodegradable, and have been widely studied for potential use in food packaging, as resins and adhesives. In this research, the potential of using soy proteins as textile sizing agents to replace PVA was studied. Polyester and polyester/cotton rovings, yarns, and fabrics sized with soy protein showed a considerably better improvement in strength and abrasion resistance compared to commercially available PVA-based size. Soy protein size had a 5-day biochemical oxygen demand /chemical oxygen demand ratio of 0.57 compared to 0.01 for PVA indicating that soy protein sizes were easily biodegradable in activated sludge. The total and ammonia nitrogen released from the proteins also did not adversely impact the biodegradability. Good sizing performance and easy biodegradability demonstrate that soy protein-based sizes have potential to replace PVA-based sizes leading to substantial benefits to the textile industry and the environment.

Low-temperature crosslinking of proteins using non-toxic citric acid in neutral aqueous medium: Mechanism and kinetic study

“…Plant proteins, such as wheat gluten, zein from corn, sorghum protein and soy protein, are byproducts or coproducts of traditional food industry, rapidly expanding bioethanol and biodiesel industries (Taheripour et al, 2010), while animal proteins, especially chicken feathers and coarse wool fibers, are wastes in poultry industry and textile industry , respectively. All these proteins were developed into films (HernandezIzquierdo and Krochta, 2008), fibers (Reddy and Yang, 2005), adhesives (Chen et al, 2013) and other forms of products, demonstrating their processability and high potential for industrial applications. However, brittleness, water/moisture sensitivity and poor dry/wet mechanical properties remain major drawbacks that restrict wide applications of protein-based materials.…”

Emerging Green Technologies and Environment Friendly Products for Sustainable Textiles

“…Likewise Stegmaier et al [85] investigated chitosan as a possible sizing agent in fabric production by appropriate modifications in the textile industry. More recently, Yang and Reddy [81] and Chen et al [86,87] are among the researchers who have demonstrated that plant proteins (such as soy proteins and wheat gluten) and chicken feathers used as sizing agents on cotton, polyester and polyester/cotton provide similar performance properties to PVA and are easily degraded in activated sludge. In a subsequent publication, Reddy et al [88] reported the use of keratin from chicken feathers as a warp sizing agent on polyester/cotton blends and polyester which can replace PVA and make the textile industry more environmentally friendly (Fig.…”

Amphiphilic and amphoteric aqueous soy protein colloids and their cohesion and adhesion to cellulose

“…As natural polyampholytes, the amphoterism of SPs was also verified by ζpotential measurements and isoelectric point determination. While SPs have served as cobinder (Erickson, 2015) and sizing (Arboleda et al, 2014b;Fahmy et al, 2010) for paper and cotton yarns (Chen et al, 2013), how colloidal SPs organize themselves in the solid forms and how they adhere to cellulose have not been reported. Hence, the structures and properties of solids dried from aq.…”