Preparation Of Cationic Dyeable Poly(Trimethylene Terephthalate)(CDPTT)/Poly(Trimethylene Terephthalate)(PTT) Fiber And Kinetics Studies Of Its Dyeing

Poly(trimethylene terephthalate)(PTT) has been introduced as commercial polyester for textile fiber, and in particular it combines many advantages of other polymers. Although PTT fiber exhibits better dyeability than PET fiber, only disperse dyes can adopted for PTT fibers dyeing which need high temperature and pressure. While 90% of domestic dyeing equipments can not meet the high requirement and it limits the development of PTT in our country. Furthermore, such as low absorption of dyestuff, large quantity of wastewater yielding, monotonic color and so on are also the big problems for PTT fiber dyeing. In this thesis, a kind of cationic dyeable poly(trimethylene terephthalate) (CDPTT) fiber was prepared and tried to solve the above problems.In this thesis, CDPTT with different contents of 5-sodium sulfonate dimethyl isophthalate(SIPT) was synthesized and its copolymerization technics and properties was studied. Based on the knowledge of CDPET synthesis, an advanced copolymerization technics for CDPTT was proposed from the economical views and considering the compatibility. SIPT solution was prepared through the transesterification of ethyleneterephalate-co-sodium-5-sulfo-isophthalate (SIPM) and 1,3-propylene glycol (PDO) and added after ending of direct esterification of PTA and PDO. It was found that CDPTT with ideal intrinsic viscosity(IV) could be obtained with reasonable adding technics of SIPT and suitable choice of catalysts and other additives. The structure and thermal behavior of CDPTT were studied through nuclear magnetic resonance (NMR) and differential scanning calorimetry(DSC) analysis etc. The molar fraction of SIPT in the CDPTT chains was close to its feedings from NMR analysis. The intrinsic viscosity(IV), melting point(T_m) and the degree of crystallinity(X_c) decreased and the dye uptake increased with the increase of SIPT content for the chain regularity destroying after SIPT adding.CDPTT-10 with 10% molar content of SIPT and PTT in different blending ratio were melt blended by twin-screw extruder to prepare CDPTT/PTT chips. The effects of blending temperature and time on the thermal degradation of CDPTT/PTT chips were also studied. The results showed that the existence of SIPT suppressed the degradation in some extent and the CDPTT/PTT=20/80 has the lowest instrinic viscosity decrease. The structure and crystalline morphology of CDPTT/PTT were also studied by ~1H NMR, DSC and hot-stage polarized optical microscopy (POM). Similarly, the crystallinity degree X_c, melting point T_m and heat crystallization temperature T_c were decreased with increase of CDPTT/PTT blending ratio for the strong polarity and of SIPT. While small quanitity of SIPT could act as plasticizer and favored the nucleation. Furthermore, the intrinsic viscosity (IV) of all CDPTT/PTT chips were dropped with a certain degree during the extrusion.Based on the research of melt blending of CDPTT/PTT, CDPTT/PTT=20/80 as-spun fibers and stretched fibers were prepared through melt spinning and drawing in different ratio. The breaking strength, orientation, sonic modulus and crystallinity degree of as-spun and stretched fibers decreased and the breaking elongation and boiling water shrinkage increased as introducing SIPT with comparison of PTT fiber.Dyeing experimental kinetics with cationic red SD-GRL for CDPTT/PTT and PTT as-spun and stretched fibers were studied. The effect of drawing ratio, dyeing temperature and time, bath ratio and pH on dye uptake were focused. It is founded that the stretch ratio plays a little important role in dyeing, while SIPT has a great impact on dyeing. From the diffusion coefficient and half dyeing time, the best dyeing technics was founded that the dyeing temperature and dyeing time are 97℃, 60 minutes respectively, and the dye uptake can reach 84.9% for CDPTT/PTT fiber, which is about 3 times of PTT fiber. Diffusion coefficient and half dyeing time were measured. At same dyeing temperature, the diffusion coefficient increased at first and then decreased with dyeing time, a maximum diffusion coefficient at 20min dyeing time was obtained. While the diffusion coefficient increased with the increase of dyeing temperature at same dyeing time. The half dyeing time had the inversed relationship with diffusion coefficient.