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United States Department of Agriculture

Agricultural Research Service

Research Project: THERMOCHEMICAL PROCESSING OF AGRICULTURAL WASTES TO VALUE-ADDED PRODUCTS AND BIOENERGY Title: Lipophilic super-absorbent polymer gels as surface cleaners for oil and grease from metal and non-metal surfaces

Authors
item Boddu, Veera -
item Myers, Christopher -
item Uchimiya, Sophie

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 16, 2011
Publication Date: N/A

Technical Abstract: The objective of this research is to develop a new cleaning technology based on lipophilic super-absorbent swelling gels for the removal of oil, grease and particulate matters from metal and non-metal surfaces. It is desired that the cleaner is in solid form and is VOC-exempt, HAP-free, non-toxic, non-corrosive, non-ozone depleting, recyclable, and self-generates energy necessary for the cleaning function, thereby affording a new cost-effective, environmentally friendly cleaning technology. Currently employed techniques such as vapor degreasing, solvent, aqueous, or blast cleaning processes suffer from shortcomings in environmental friendliness, personnel health and safety, cleaning efficiency, cost-effectiveness, management of contaminated cleaning media, or in maintaining the integrity of equipment material surfaces. We have developed lipophilic super-absorbent swelling gels that will not only absorb the oil and grease from these machine parts, but will also act as an automated sweeper due to the self-generating mechanical force of the gel. An octadecylacrylate-co-ethylene glycol dimethacrylate (ODA-co-EGDMA) lipophilic polyelectrolyte gel (EG-18) and commercially available alkylstyrene copolymer (imbiber beads) were evaluated for swelling and oil sorption capacity. Along with the imbiber beads and EG-18 gel, poly(stearylacrylate-co-ethyleneglycol dimethacrylate) (SA-co-EGDMA) lipophilic neutral gel (NG-18), another lipophilic super-absorbent gel, was synthesized and evaluated in the laboratory. For each gel, the swelling degree and oil absorption capacity were quantitatively investigated at 0-60°C using a variety of polar and nonpolar solvents. The mechanical strength of each gel was studied by cleaning and measuring compression strength of the swollen gel. The cross-linking of the polymers was studied using infrared spectroscopy. The cleaning tests were performed using metal coupons. NG-18 and EG-18 gels remove particulate contaminants and absorb oils and grease on metal and non-metal surfaces without causing abrasion. A recycling process was determined such that the gels can be used multiple times before needing to retired. The gel cleaning was compared with cleaning with trichloroethylene (TCE), a standard cleaning solvent, following ASTM test methods and MIL-PRF-680B procedure with MIL-PRF-10924 test grease. The results indicate that polymer gel cleaning quality is comparable to the TCE cleaning process; however the kinetics are a bit slower, taking about 10 minutes compared to the 5 minutes for the TCE cleaning. While slower, the ability to recycle the gel allows for a considerably more cost effective solution for cleaning metal and non-metal surfaces. The need for extensive use of VOC and HAP containing solvents can be eliminated with the superabsorbent polymer gel cleaning process.

Last Modified: 11/27/2014
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