U.S.-Egypt Cooperative Research: Ionic Crosslinking - A Novel Method for Fabric Stabilization

North Carolina State University, Raleigh NC

Investigators

Abstract

0513828 Smith Description: This project supports a collaborative research between Dr. C. Brent Smith, Department of Textile Chemistry, North Carolina State University (NCSU) and Dr. Mohamed Hashem, National Research Center, Cairo, Egypt. The PIs will consider new chemical systems for treating cotton, that give enhanced performance without using harmful chemicals like formaldehyde, by using ionic crosslinking agents that don't release formaldehyde. The goal is to provide better wet and dry wrinkle recovery (WRA) for cellulosic fabrics, as well as other advantages, such as antimicrobial activity and enhanced dyeability. The research will cover the ionic crosslinking method to produce non-wrinkle durable-press effects for cotton. This will involve treating cotton with either an anionic material, then reacting with a polycation; or reacting with a cationic material, then applying a polyanion. They will make anionic cotton by reacting cellulose with chloroacetic acid (CAA) to attach negative anionic sites to the cellulosic fibers, and treat the anionic cellulose with a wide variety of positive cations to get improved WRA performance. They also will treat cellulosic fabric with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHTAC) to attach positive cationic sites to the fiber, and then treat the cloth with a wide variety of negative anions. Intellectual Merit: When treated with formaldehyde-based crosslinkers, cellulosic fabrics show improved mechanical stability, crease recovery angle (CRA) and durable press performance. But resin treatment also causes fabrics to lose strength, and later to release formaldehyde, a known human carcinogen. The PIs have discovered that ionic crosslinks can be used to stabilize cellulose using high molecular weight reactive ionic materials that do not release hazardous reactive chemicals, but at the same time provide outstanding CRA as well as complete strength retention in treated goods. The PIs plan to study the physical and chemical mechanism of this stabilization and to test a wide variety of ionic crosslinking agents and methods for producing these crosslinks in cellulosic textile materials. This requires: 1) basic research in the chemical laboratory, and 2) implementation of the best chemical principles in a commercial production setting. The results have the potential for positive environmental impacts. Broader impacts: To stabilize cotton textile products, which are widely used nearly everywhere, they are universally treated with resins that later release formaldehyde, a known human carcinogen. These resins also can cause strength loss and color change. A long-standing goal of textiles producers is to produce easy care, wrinkle-resistant cellulosic fabrics without the use of formaldehyde-based reactants. Also, the presence of ionic charges on cotton can allow much higher exhaustion of dyes of the opposite charge. This give a possible solution to the two greatest problems facing cotton dyers: (1) Excessive color waste and color pollution in the wastewater from textile dyeing operations, and (2) aquatic toxicity caused by massive amounts of salt that are currently used to dye cotton goods. The project provides an opportunity for the Egyptian scientists to expand a type of expertise that could serve their country well over time, and since Egypt is a cotton producer, this could lead to economic and technical advances in that country. The project will involve support for at least one post-doctoral student, and will also involve graduate students at NCSU. The PIs will interact with other academic investigators, as well as chemical manufacturers and textile manufacturers. This project is being supported under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to carry out these cooperative activities.