Cationic dyeable poly(ethylene terephthalate) (CD-PET) was formed by copolymerizing dimethylterephthalate (DMT),5-sodium sulfonate dimethyl isophthalate (SIPM) with a molar ratio of 2% and ethylene glycol (EG). Blends of regular poly(ethylene terephthalate) (PET) and CD-PET were spun into hollow fibers. The fibers were then treated with aqueous NaOH. This study investigated the physical properties of PET/CD-PET polyblend hollow fibers and their kinetic behavior of alkaline hydrolysis using differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), the density gradient method, a gel permeation chromatograph (GPC), a rheometer, and regression analysis of the statistical method. For the alkaline hydrolysis kinetics equation of PET, CD-PET, and PET/CD-PET polyblend materials: Ϫ dW/dt ϭ KC ␣ A ␤ , ␤ values of chip and POY/ FOY hollow fibers are equal to 1. Moreover, R 2 of the kinetics equation of chip/POY/FOY for a from 1.09 -1.35/ 1.08 -1.32/1.06 -1.29 were better than those of a ϭ 1. Experimental results indicate that the rate constant of alkaline hydrolysis was CD-PET hollow fiber Ͼ PET/CD-PET polyblend hollow fibers Ͼ PET hollow fiber and FOY Ͼ POY Ͼ Ͼ Chip.

This study investigated the physics and kinetics of three cationic dyeable poly(ethylene terephthalate) (CDPET) and four polyethylene glycol (PEG)-modified cationic dyeable PET (PEG-modified CDPET) polymers using differential scanning calorimetry, thermogravimetric analysis, the density gradient method, gel permeation chromatography, a rheometer, and statistical regression analysis. The molar ratios of dimethyl 5-sulfoisophthalate sodium salt (SIPM) for three CDPET polymers were 2, 6, and 10%, respectively. For four PEG-modified CDPET polymers, with molar ratios of SIPM of 2%, the PEG content and the number-average molecular weights (M n ) of PEG were 3/6 (wt %) and 400/2000 (g/mol), respectively. Experimental results revealed that the crystallinities of CDPET and PEG-modified CDPET polymers declined as the SIPM and PEG contents increased. The crystallinity of the PEG400 -CDPET polymer exceeded that of the PEG2000 -CDPET polymer with the same SIPM and PEG contents. The SIPM and PEG segments did not change the original PET unit cell. The -SO 3 Na functional group and the PEG molecules gathered only on the crystal surface and in the amorphous regions. In the kinetic equation of the alkaline hydrolysis of PET, CDPET, and PEG-modified CDPET polymers, ␤ equals 1. Furthermore, the R 2 of the kinetic equation for ␣ from 1.09 to 1.25 was better than that of ␣ ϭ 1. The rate constants of alkaline hydrolysis were in the order CDPET-10 Ͼ CDPET-6 Ͼ PEG2000-6-CDPET-2 Ͼ PEG2000-3-CDPET-2 Ͼ PEG400-6-CDPET-2 Ͼ PEG400-3-CDPET-2 Ͼ CDPET-2 Ͼ PET. Clearly, the rate constant of the alkaline hydrolysis of CDPET and PEG-modified CDPET polymers increased with SIPM/PEG content and the M n of the PEG increased.

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Poly(trimethylene terephthalate) (PTT) and cationic dyeable poly(trimethylene terephthalate) (CD-PTT) were extruded (in the proportions of 80:20, 60:40, 40:60, and 20:80) from one melt twin-screw extruder to prepare four PTT/CD-PTT polyblended fibers. The molar ratio of 5-sodium sulfonate dimethyl isophthalate (5-SSDMI) for CD-PTT polymer was 2%. This study investigated the thermal and mechanical properties of PTT/CD-PTT polyblended fibers using gel permeation chromatograph, differential scanning calorimetry (DSC), thermogravimetric analysis, potentiometer, a rheometer, the density gradient, wide-angle Xray diffraction, extension stress-strain measurement, and scanning electron microscope (SEM). Melting behavior of PTT/CD-PTT polyblended polymers exhibited positive-deviation blends, and the blend of PTT/CD-PTT between 60:40 and 40:60 showed a maximum value of the melt viscosity. Experimental results from the DSC indicated that PTT and CD-PTT molecules formed a miscible system. The tenacity of PTT/CD-PTT polyblended fibers declined as the 5-SSDMI content increased. Crystallinities and densities of PTT/CD-PTT polyblended fibers were also found decrease as the 5-SSDMI content increased. The surface of PTT/CD-PTT polyblended fibers exhibited a uniform morphology, from the SEM observation. It indicated that PTT and CD-PTT polymers were identified to be a miscible system. Though there is a good interfacial adhesion between PTT and CD-PTT polymer, the mechanical properties of PTT/CD-PTT ployblended fibers were largely affected by the 5-SSDMI content.

This investigation explores the kinetics of the alkaline hydrolysis of regular poly(ethylene terephthalate) (PET) solid fibers and PET micro-porous hollow fibers, using statistical regression analysis. Statistical regression analysis results concerning the kinetics of the alkaline hydrolysis of regular PET solid fibers and PET micro-porous hollow fibers yielded a b value of 1. The R 2 of the kinetic equation for a values from 1.07 to 1.16 exceeded that for a ¼ 1. The rate constants of alkaline hydrolysis followed the order PET micro-porous hollow fibers ) regular PET solid fibers. A morphology of large pores of diameter 0.1-3.5 lm was observed following alkali treatment of the PET micro-porous hollow fibers. The weight loss percentage of the hollow fibers was around 20%. The hollowness of the PET micro-porous hollow fibers after alkali treatment was between 30 and 32%. The PET micro-porous hollow fibers exhibited simultaneous water-absorption/release and keep-warm functions.