DEVELOPING A CHEMICAL PLATFORM BASED ON COTTONSEED OIL TO DEVELOP FUNCTIONAL FINISHES FOR CELLULOSIC SUBSTRATES

The overarching goal of this project is to develop a chemical platform based on cottonseed oil to produce novel functional, non-allergenic and sustainable products that can be used as finishing agents (softeners and durable press agents) for cotton apparel and wet-strength agents for paper. These new applications will create economic value for cottonseed oil that is sustainable and profitable within the current plant oil based chemical industry. Green reactions to epoxidize the cotton seed oil will be utilized. The new applications for epoxidized cotton seed oil will take advantage of the properties of cotton seed oil that include a high palmitic/linolenic ratio, resistance to thermally induced oxidation, and a lack of allergenicity, which will differentiate the products from other seed oil products. We will characterize cottonseed oil, epoxidize the oil, aminate the oil, create oil in water emulsions, and then apply emulsions to fabrics and paper. We aim to develop unique, renewable and green durable press agents for fabrics and wet strength additives for paper. Chemical analysis of the oils and modified oils, as well as the treated fabrics and paper will be used to interpret and optimize the systems. Soybean oil will be the control material. Outcomes will include new technologies to create functionalized cotton seed oil, to produce stable oil in water emulsions, to treat fabrics for wrinkle resistance, dimensional stability, and to treat paper to develop water resistance and wet strength properties for containerboard.The project is a collaboration between researchers at North Carolina State University, Cotton Inc., and an industrial fabric finish manufacturer. The proposed research addresses key issues pertinent to the A1811 program AFRI Commodity Board Co-funding Topic 5 by developing improved cotton byproduct utilization which will improve the resilience of the cotton production system.

Objective 1: Characterization of the refined cotton seed oil and soybean oil as a control. Three samples of refined cottonseed oil will be acquired from commercial suppliers such as Venture Foods (Lou Anna), ADM, Hunt Wesson, Kraft, and Bunge to reflect the expected range of oils. In addition, we will also investigate 2-3 experimental cottonseed oils grown or processed to increase unsaturation and decrease saturated fatty acids, as sourced by Cotton Incorporated . We will also procure and evaluate soybean oil as a reference material since the palmitic/linolenic ratio is very different for CSO and soybean oil. The cottonseed oils and reference oil will be analyzed by Gas Chromatography (GC) and High-Performance Liquid Chromatography (HPLC). GC is used to determine fatty acid composition of oils after conversion to fatty acid methyl esters (FAMEs) .Objective 2: Evaluate the reaction of peroxide with the unsaturated bonds to form epoxide on the alkyl chains using two different pathways. We propose to achieve the epoxidation reaction using an alternative method to standard methods by using alumina as a solid catalyst . Results will be compared to the procedure described in the preliminary data that used peracetic acid. For the reaction using alumina, we proposed to explore variables such as activation temperature of the catalyst, amount of catalyst, temperature and time of reaction, and ratio of reactants to optimize the protocol. The analytical process will be the same for both pathways: titration for iodine value and oxirane oxygen, FT-IR and 1H NMR.Objective 3: Understand how the formulation and preparation steps impact the stability of an aqueous emulsion of the epoxidized cottonseed oil. We will initially investigate an emulsification system using a mixture of sorbitan monolaurate (Span 20, HLB 8.6) and polysorbate 80 (Tween 80, HLB 15). These were chosen because they are derived from sorbitol (a sugar alcohol) an environmentally benign and biodegradable compound. These surfactants are approved for cosmetic and food applications. The parameters will be changed one variable at a time. In the first set of experiments, different surfactant concentrations will be evaluated using a fixed Tween 80 to Span 20 ratio. Usually, HLB (Hydrophilic-Lipophilic Balance) values for oil-in-water emulsifying agents are between 8 to 16. Based on the individual HLB of these surfactants, it is proposed to use a Tween 80 to Span 20 ratio of 1.8, with a resultant HLB of 12.7. The surfactant mixture will be incorporated in the aqueous phase, as well as potential additives. In each experiment, 20mL of the emulsion will be prepared by adding the oil mixture to the water mixture, at the desired ratio, under constant strong stirring with an Ultra-Turrax lab-scale homogenizer for 2 minutes. The stability of samples will be evaluated as the time required to visually observe the separation of half of the aqueous phase from the emulsion in a tall glass vial. The objective is to have an emulsion that does not break up for approximately 90 days for fabric finishes and paper additives.Objective 4: Determine the effect that application and reaction conditions of the ESCO have on its use as a durable wrinkle-resistant finish on cotton fabrics. The finishes described in Objectives 2 (ECSO) and 6 (aminated ESCO) will be evaluated for their performance as a cotton fabric finish. Selected finishes from each objective will be diluted, blended with a suitable wetting agent (surface active and cationic), and pad applied to knitted and woven cotton fabric available at Cotton Inc. In some cases manual applications will be utilized if more practical. The treated fabrics will then be dried using frame restrained temperature-controlled dryers at a prescribed temperature and time; through extended times, this will also be used as a curing process. It is anticipated that experimentation will be required to ascertain optimum pH and curing temperatures when ECSO application reactions are desired. This will be performed by applying the ESCO to the fabrics at different loadings, pH and curing temperatures and then evaluating the reaction with cellulose using hexane extraction followed by FT-IR or HPLC to determine the amount of ECSO in the extract using an experimentally designed matrix of conditions 28,42. The solvent is expected to only remove the unreacted material. We will also test commercially available finish products (durable press finish with formaldehyde-based dimethylol dihydroxy ethylene urea (DMDHEU)11; softener silicone based 43, as well as epoxidized soybean oil and apply them to cotton fabrics as controls. Fabric physical and mechanical properties will be analyzed before and after multiple launderings. Along with others, a key consideration will be given to shade change and strength changes caused by the utilization of these new compounds. The experiments will first be performed with the knit fabric and then a limited number of experiments with promising conditions will be performed on the woven fabrics. Extensive testing on both knitted and woven cotton fabrics will be conducted on several conditions (3-5) that showed high reaction efficiency of the ESCO compound with cellulose. Durable press rating (AATCC 124), shrinkage (AATCC 135), and crease retention rating (AATCC 88C) will be performed to evaluate the performance as a durable press finish. Also, physical properties such as tensile strength, tear strength, burst strength, smoothness, and abrasion resistance will be utilized to fully characterize developed finishes on fabrics. Softness will be evaluated using an Emtec TSA softness tester as well as a Kawabata Evaluation System and a Cusick drape test. Additionally, color characterization will be determined by evaluation of samples with a spectrophotometer.Objective 5: Determine how the ECSO emulsion can be applied to paper substrates to produce effective wet strength properties. We will apply the emulsions to pulp fibers and then form handsheets and then test the handsheet properties. The application in containerboard and food containers will be evaluated experimentally and the recyclability of such paper products will also be characterized in lab experiments.Objective 6: Develop fabric softeners based on ECSO modified with amines and investigate how the chemical composition and application methods impact the softening properties and durability of the developed softener. Hypotheses: Modification of ECSO with amines will yield a complex molecule with unique multifunctionality. Differing amounts of modification (amine/epoxide ratio) will yield finishes that lend different balances of properties.