NC State Fabric Researchers Develop New Techniques

Written by Linda Rudd, Engineering News Services

Permanent press shirts. Flame retardant sleepwear for children. Stain-resistant furniture fabrics. We take for granted all of these products and the textile technology that made them possible. These convenient and safe products come at a price, however. The wet fabric finishing processes used to create them produce polluting effluents and consume large amounts of energy in the drying process.

An interdisciplinary team of scientists at NC State University is conducting ongoing research that could change the way fabrics are processed. Dr. Marion McCord, assistant professor of textile engineering, chemistry and science; Dr. Peter J. Hauser, associate professor of textile engineering, chemistry and science; Dr. Yiping Qiu, assistant professor of textile engineering, chemistry and science; Dr. Jerome J. Cuomo, Distinguished Research Professor of materials science and engineering; Orlando E. Hankins, assistant professor of nuclear engineering; and Mohamed A. Bourham, professor and undergraduate administrator of nuclear engineering, are involved in a project to apply plasma technology to fabric finishing.

According to Bourham, plasma is an ionized state of gas that can be used for a variety of applications. It’s easy to generate plasmas under vacuum conditions, but creating them in normal atmosphere is more difficult; very high voltage is required. “Now, using a technique of oscillating electrical fields, atmospheric plasmas can be generated using a reasonable voltage,” said Bourham. This development by the NC State team has opened new avenues for using atmospheric plasmas in industrial processes.

Using facilities in the Departments of Nuclear Engineering and Textile Engineering, Chemistry and Science, the research team is testing atmospheric plasma for fabric finishing treatments for the textile industry.

Plasma processing has several advantages over traditional wet fabric treatment. Soil resistant, flame retardant, dye and permanent press treatments can all be accomplished without creating toxic effluents. Atmospheric plasma treatments can be integrated into the production line manufacturing process, reducing pollution and energy consumption. Plasma treatment modifies the fiber surface rather than its interior, which allows the fabric to retain strength over time. According to McCord, “Surface treatments such as plasma are important to us in textiles because we want to achieve changes in surface properties without degrading the mechanical properties of the material.”

Replacing wet chemical treatment with atmospheric plasma is not feasible for industrial application yet, but in the meantime currently used processes can be enhanced by the new technology. “What we’re able to do right now is enhance wet chemical processes by pretreatment with plasma,” said McCord. “But we’re working both long and short term to help the textile industry. The long-term goal of the project is eventually to replace wet processes with processing methods such as plasma treatment.”

Currently, the main textile application for atmospheric plasma is in fabric finishing. Because new technology has made it easier to create plasma treatment conditions in the manufacturing process, Bourham and McCord hope to generate industry interest in the process. According to Bourham, “Doing everything that industry does by chemical means is a multifunctional treatment involving several steps, but if you master the atmospheric plasma process you might do the multifunctional treatment in one step, on [the production] line. That would be embraced by industry.”

Future applications of atmospheric plasma technology to the textile industry include biomaterials and medical applications. Biomaterials involves using plasma to generate thin films and to modify the surface of materials to make them more or less bioactive. Medical applications could mean creating fabrics that are sterile for bandages, implants, blood bags or surgical garments. Presterilized textiles could result in energy savings because the fabric would not have to be sterilized with high temperature and pressure before use.

For the future of plasma research at NC State, Bourham and McCord see exciting times ahead. “Our vision is looking into the future in the near term and the long term as well, so we have a very aggressive program that incorporates all of the expertise in plasma science, in materials science, in textile chemistry, in textile materials in general and in textile engineering,” said Bourham. “We are very lucky that we have all of the expertise together in one university.”

Bourham, McCord and their colleagues hope to extend the current program into an atmospheric plasma center to take advantage of this expertise at NC State. To this end, Bourham and his associates are seeking new alliances with industry. Current funding for the project comes from the National Textile Center, Cotton Incorporated, PPG Industries Inc. and the United States Department of Agriculture. A new contract with the National Textile Center is in progress for a new phase to incorporate plasma-generated nanostructures in textile materials.

The interdisciplinary aspect of this research should be very attractive to potential industrial affiliates. “This is what the new millennium looks like for research endeavors,” said Bourham. “We can argue that we have a very good start with this project by establishing formal liaisons with other departments with different expertise.”