| Silicone softeners with excellent softness, smoothness and film-forming ability, are widely applied to the finishing of various d kinds of textile fibers and finishing. Among them, amino-modified silicone softeners (aminosilicones) are on a large-scale use and have the advantages of high cost-effectiveness and versatility. However, aminosilicones are subjected to some problems, such as poor product stability and yellowing of textiles finished with them under high temperature, which limit their applications. In this work, an aminosilicone polyether block copolymer was synthesized using the linear block copolymerization. This aminosilicone is the representative of today’s silicone softeners, and a promising product in the future. The combination introduction of polyether, amino and quaternary ammonium groups in the skeleton of silicones gives a new product which makes textiles finished with it exhibit soft handle and hydrophilicity better than those of textiles finished with conventional aminosilicones, and show lower yellowing during the high temperature finishing.In order to obtain an aminosilicone polyether block copolymer, a series of synthetic reactions and steps were carried out as follows:synthesis of the terminal hydrogen-containing silicone through the reaction of octamethylcyclotetrasiloxane (D4) as a monomer and1,1,3,3-tetramethyldisiloxane as blocking agent in the presence of concentrated sulfuric acid as a catalyst; synthesis of the diterminal hydrogen-containing silicone with different molecular weights obtained by the adjustment of the ratio of D4and1,1,3,3-tetramethyldisiloxane; syntheis of the terminal epoxy polyether-containing silicone through the reaction of diterminal hydrogen-containing silicone and terminal allyl side epoxy polyether under the ethylene glycol monobutyl ether solvent in the presence of chloroplatinic acid as a catalyst; and synthesis of aminosilicone polyether block copolymer through the reaction of terminal epoxy polyether-containing silicone, polyether amine and N,N,N’,N’-methyl-1,6-hexamethylenediamine acetate. The final product (Silicone BW), was obtained through the adjustment of the ratio of reacting substances, and its chemical structure was confirmed by infrared spectroscopy. The product possessed the merits of good soft handle, hydrophilicity and low extent of yellowing. The non-ionic emulsifiers were employed to the emulsification of aminosilicone polyether block copolymer. The transparent pan-blue light silicone softener emulsion was obtained under the optimum emulsification condition determined by the experiments of selection and combination of emulsifiers, adjustment of pH, and optimization of emulsifier dosage. The analyses of the light transmission and average particle size of the emulsion showed that Silicone BW had the same emulsion stability as that of the similar product Derma NT manufactured by the foreign company. In addition, Silicone BW had self-emulsifying ability, and did not need the addition of an emulsifier during emulsification.Silicone BW and Derma NT were applied to the soft finish of cotton fabric. The whiteness, breaking strength, tear strength, hydrophilicity and softness of the finished fabrics were measured and compared. The results showed that the fabric finished with Silicone BW exhibited obviously reduced yellowing and remarkably enhanced hydrophilicity, and remained good handle. The antibacterial test showed that the finished cotton fabric had good antibacterial activitiy against Escherichia coli. Silicone BW was also applied to the finishing of polyester fabric and polyester/cotton blend. The tests showed that the two finished fabrics exhibited obviously improved hydrophilicity and antistatic properties.In summary, after finished with the aminosilicone polyether block copolymer, the fabrics can exhibit good softness, anti-yellowing and hydrophilicity, and are endowed with antibacterial and anti-static effects. Thus, the aminosilicone polyether block copolymer is a new kind of promising excellent softener. |
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