INFLUENCE OF A QUATERNARY AMMONIUM SURFACTANT ON ALKALINE-HYDROLYSIS OF HEAT-SET POLY(ETHYLENE-TEREPHTHALATE) FIBERS

The hydrolytic behavior of heat-set poly(ethylene terephthalate) (PET) fibers is compared in the presence and absence of a quaternary ammoni um compound, dodecylbenzyldimethylammonium chloride (DBDMAC). Alkaline hydrolysis without DBDMAC depends on the heat-setting temperature, sh owing a minimum weight loss at around 140 degrees C and becoming more marked with increased NaOH concentration, hydrolysis temperature, and time. Alkaline hydrolysis is accelerated by DBDMAC for all PET fibers over the whole range of heat-setting temperatures. The fibers set at l ower temperatures, however, have much larger increases in weight loss than those set at higher temperatures by alkaline hydrolysis in the pr esence of DBDMAC. The rate enhancement of alkaline hydrolysis by DBDMA C decreases with increased heat-setting temperature or degree of cryst allinity of the fiber, and may preferentially occur in the amorphous r egions of the fiber.