ζ-Potential of Ultrafine Polyester Fiber and Deposition of Polymer Latices on Its Fiber

Interfacial electrical properties of ultrafine polyester fiber and regular polyester fiber and deposition of polymer latices onto these fibers were studied. The polymer latices used were polystyrene [PS] and polystyrene/acrylamide [P(St/AAm)] copolymer latices, both prepared without emulsifier. Conductometric titration and ζ-potential measurement of these fibers showed that acidic groups are much more abundant on the ultrafine fiber polyester much more than on the regular polyester fiber, and that acidic groups of the former are likely to be strong acids, while those of the latter are weak acids. The relative swelling degree of the ultrafine polyester fiber was greater than that of the regular polyester fiber. These facts indicate that the ultrafine polyester fiber is more hydrophilic than the regular polyester fiber. The ζ-potential decreased and deposition of latices onto the both fibers increased at acidic pHs. The deposition of the latices onto the ultrafine polyester fiber were much greater at acidic pHs than a neutral and alkaline pHs. The same tendency was observed with the regular polyester fiber. The P(St/AAm) latex deposited onto the ultrafine polyester fiber more strongly than the PS latex. This tendency was the same as with the regular polyester fiber. These results indicate the bridging effect between the polymer chain of P(St/AAm) latex and these fibers.