| Recently, quaternary ammonium antimicrobial agent was widely used in China and at abroad, but its antibacterial effect was greatly reduced for the long-term application. However, quaternary phosphonium salt, which structure was similar to quaternary ammonium salts, was a novel antimicrobial agent which had good antibacterial property, low toxicity, broad-spectrum antibacterial activities and good stability, so it can be widely used in many areas. Especially in the industrial circulating water and oilfield water injection system, it has been described as the substitute of traditional quaternary ammonium salt bactericide, because of its low foam, strong slime stripping ability and wide application range of pH. But it has not been reported about the application of textile antibacterial finishing in our country. Therefore, in order to gain the washingfastness and antibacterial performance, this article synthetized a novel quaternary phosphonium salt, which was fixed on the fabric by the reaction of fibers with-Si-OH hydrolysised from alkoxy silane groups.In this paper, the new quaternary phosphonium salt was synthesized through SN2reaction, using triphenylphosphine and r-chloropropyl triethoxysilane. The structure of quaternary phosphonium salt was characterized by IR、1H NMR and31P, and the results showed that the product was quaternary phosphonium salt what we expected. Then the effects of the reaction factors were studied. The results showed that the optimal reaction conditions were as follows:reaction medium was40mL benzyl alcohol, molar ratio of triphenylphosphine to chloropropyl triethoxysilane was1:1.1, reaction temperature was135℃and reaction time was27h. It was also confirmed that KI can greatly improve the conversion rate of triphenylphosphine, and the top conversion rate can reached up to91.6%.Cotton fabric was treated with quaternary phosphonium salt by padding method. The content of silicon and phosphorus element on the treated fabric was measured by EDS and elemental analysis, and the results confirmed that phosphonium salt has reacted with the fabric. Shaking flask method was used to study the antibiotic properties of treated fabric to Escherichia coli and Staphylococcus aureus, and we observed the impact of some factors on the antibacterial properties, such as quaternary phosphonium salt dosage, incubation time and soaping washing times. The results showed that the antibiotic effect got better and better with the the dosage increases of quaternary phosphonium salts. When the dosage of quaternary phosphonium salts was5%, the antibacterial rates to Escherichia coli and Staphylococcus aureus were82.9%and98.9%respectively. If the finished fabrics contacted with the bacteria for more than18h, antibacterial rates to Escherichia coli were higher than80%, while antibacterial rates to Staphylococcus aureus were more than90%. And antibacterial rates of fabric finished by10%of quaternary phosphonium salt were72.8%and93.1%, after4washing cycles.Considering the effect that phosphorus elements had on the thermal stability of fabric, we used horizontal burning method, SEM and thermogravimetric analysis to study it. And the results showed that the quaternary phosphonium salt can improve the thermal stability and the flame retardant properties of fabric to some extent, by promoting the formation of coke. At the same time, we also found that the UV protective properties were also improved. In addition, it had little change in the capillary effect and whiteness, and tensile strength and tear strength increased. The results showed that the finishing had no effect on the mechanical properties of cotton fabric, so the novel phosphonium salt is expected to become a very good fabric finishing agent. |
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