Thesis Details

Thesis Title: Co-Presence of Durable Flame Retardant and Repellent Nano-Finishes
Thesis Author: Jonathan C. Halbur
Abstract: Due to the costs associated with processing and materials, and the inherent difficulties of applying durable flame retardant and/or repellent finishes, alternatives to conventional finishing methodologies are of large interest in the textile industry. Surface modification of textile substrates using mixed silanes and ceramic nanoparticles have become of interest as a means of functionalizing textiles. Blended 50/50 polyester/cotton fabrics were treated with a combination of ceramic nanoparticles, hydrophobic silanes (such as hexadecyltriethoxysilane), silane crosslink enhancers [such as 1,3 bis(triethoxysilyl)ethane], and flame retardants [such as tetrakis(hydroxymethyl)phosphonium chloride (THPC) and urea]. These fabrics were treated using conventional pad-dry-cure laboratory scale processing. Following finishing, fabrics were evaluated for flame resistant performance using a vertical flame chamber. Fabrics were also evaluated for repellency through the use of a goniometer. After initial testing, all fabrics were laundered, dried, and re-tested to evaluate the durability of both flame resistance and repellency. Results of this work show that the use of organofunctional silane crosslink enhancers, hydrophobic silanes, ceramic nanoparticles, and THPC/Urea flame retardants was successful in creating fabrics with durable flame resistant and water repellent properties. When ceramic nanoparticles were added to the finish, the flame resistance and repellency of the finished fabrics both increased, even at concentrations as low as 0.1% by weight, and the char length, afterflame time, and water contact angle were all enhanced as the concentration of ceramic nanoparticles increased. When the titania concentration was 1-3%, the use of THPC/Urea was much lower than the recommended level for commercial THPC based FR's. It was also found that titania treated fabrics had better flame resistance than did fabrics treated with silica, but no apparent difference was seen between titania or silica nanoparticles with respect to repellency. In addition, the use of traditional silane crosslink enhancer (such as tetraethoxysilane and 1,3 bis(triethoxysilyl)ethane) were successful in creating finishes that maintain repellency after laundering, but the durability of flame resistance of treated fabrics needed improvement. In order to improve the durability of flame resistance, organofunctional silane crosslink enhancer 3-isocyanatopropyltriethoxysilane was used. It was found that treated fabrics were durable to laundering and maintained flame retardance even at concentrations as low as 30%, which is 10% lower than the recommended concentration for THPC based flame retardants. For example, prior to laundering, fabrics treated with 5% 3-isocyanatopropyltriethoxysilane, 2% hexadecyltriethoxysilane, 1% titania, and 30% THPC/Urea had average char lengths of 3.2 inches and average contact angles of 141 o; after laundering, average char length was 3.4 inches and average contact angle was 135 o. The retention of both flame resistance and repellency after laundering shows much promise for the use of multifunctional silanes, ceramic nanoparticles, and phosphorus based FR’s in finishing fabrics to create dual functionality. It is suggested that future work should focus on further increasing the durability of the finish to laundering, as well as incorporating the finish on different types of fibers. Additional organofunctional silanes, flame retardants, and curing processes should be investigated also.