Thesis Details

Thesis Title: The effects of polyurethane additives on the mechanical properties of durable press finished fabrics
Thesis Author: Chris Caldwell
Abstract: While durable press cotton goods have been available since the 1960s, their poor mechanical properties have limited their use almost exclusively to bottom weight goods in the United States. Research indicates that the mechanical losses associated with resin finishing are due to two independent phenomena. The rigid linking of neighboring polymer chains inhibits load sharing, and cotton fabric is weakened due to acid hydrolysis of the cellulose by the cross-linking catalyst. This research investigated the effects of increasing flexibility of the cross-link by incorporating polyurethane compounds into a typical DMDHEU durable press resin formulation. Four polyurethanes at two concentrations were evaluated to determine the level of tensile strength, tear strength, and abrasion resistance of the dyed only cotton fabric that could be retained. Additionally, the resin concentration and curing temperature were varied to optimize the finish bath formulation and to determine which factors most affected the mechanical properties of the finished fabric. The test fabric was finished with a typical durable press treatment and retained only 46% of the tensile strength, 63% of the tear strength, and 9% of the original abrasion resistance. The same fabric treated with the durable press resin and polyurethane retained 82% of the tensile strength, while increasing both tear strength and abrasion resistance to a level above that of the dyed only, cotton fabric. The smoothness rating of the fabric treated with the durable press finish and polyurethane was 0.5 units lower than fabric finished without the polyurethane additive. The cost increase associated with this change in chemistry was about 19.3 cents per pound. For the test fabric, this equates to $0.065/ square yard.