Property modifications of finished textiles by a cationic surfactant

Fabrics made of 100% cotton, 100% polyester and a 50/50 cotton/polyester blend with and without functional finishes were treated in aqueous solutions of the cationic surfactant distearyldimethylammonium bromide (DSDMAB). Finishes chosen were dimethyloldihydroxyethyleneurea (DMDHEU), a durable press finish, and poly(acrylic acid), a soil release finish. Selective sorption of the cationic surfactant by finished and unfinished fabrics was quantified. Cotton takes up much larger amounts of DSDMAB than does polyester. In general, acrylic finished fabrics take up more DSDMAB, while DMDHEU finished fabrics take up smaller amounts of DSDMAB as compared to their unfinished controls. These findings indicate that ionic interaction forces play an important role in the sorption process. In order to investigate this, acid numbers were used as a relative measure of negative sorption sites on fabrics. A direct relationship between DSDMAB sorption and the acid numbers of the fabrics was established. Perceived fabric softness is generally improved by treatments with DSDMAB for all test fabrics. Although cotton fabrics finished with DMDHEU were perceived to be less soft than unfinished cotton, treatment with DSDMAB restored the softness level to that of unfinished cotton. The softness of both cotton and polyester fabrics was greatly lowered by the acrylic finish. The presence of even large amounts of DSDMAB did not restore softness ratings to levels comparable to unfinished controls. Electrical resistivity and electrostatic clinging measurements were used to assess the effectiveness of DSDMAB as an antistatic agent. DSDMAB reduced the electrical resistivities of all test fabrics. However, relative humidity played a much larger role in reducting the electrical resistivity of fabrics. Clinging times were also reduced by DSDMAB treatments. DSDMAB was particularly efficient in reducing the clinging time of polyester. Additional moisture related properties were investigated. The presence of DSDMAB on the test fabrics did not significantly alter moisture regain. The application of DSDMAB from aqueous solutions resulted in lower water retention values of the test fabrics after centrifuging at ag-factor comparable to home washing machines. This leads to energy savings during drying from 10–24%, depending on the fabric and finish type. However, energy savings due to fiber type were more significant than those due to the cationic surfactant treatment.