Cationic Dyeable Polyester Research Articles

Study on the dyeing and moisture absorption and quick-drying performance of Porel spandex core-spun yarns

Replacing cotton fiber with cationic dyeable modified polyester may effectively alleviate the pressure of cotton resource shortage. Porel is a new generation of cotton-like cationic dyeable polyester fiber with reduced modulus, rigidity, pilling, and improved softness. In this work, cationic dye dyeing process and hygroscopic and quick-drying property tests were conducted on Porel products. The findings indicated that 100 °C and 30 mins were the ideal dyeing temperature and time for Porel spandex core-spun yarns. Fastness to rubbing and washing achieved 4.5 grade, and fastness to sunlight reached 6–7 grade. Compared with cotton spandex core-spun yarn, the overall cost per ton of Porel spandex core-spun yarn can be saved by 35%. Furthermore, Porel denim was proven to have excellent moisture absorption and quick drying properties. This study introduces a novel approach to addressing the challenges associated with cotton scarcity through the development of functional cotton-like products.

Crystallization Behavior of Copolyesters Containing Sulfonates.

The polar sulfonate groups in cationic dyeable polyester (CDP) lead to complex crystallization behavior, affecting CDP production's stability. In this study, cationic dyeable polyesters (CDP) with different sulfonate group contents were prepared via one-step feeding of sodium isophthalic acid-5-sulfonate (SIPA), terephthalic acid (PTA), and ethylene glycol (EG). The non-isothermal crystallization behavior of these copolyesters was analyzed by differential scanning calorimetry (DSC). Results show that the crystallization temperature of the sample shifts to lower values with the increase in SIPA content. The relaxation behavior of the molecular chain is enhanced due to the ionic aggregation effect of sulfonate groups in CDP. Therefore, at low cooling rates (2.5 °C/min and 5 °C/min), some molecular chain segments in CDP are still too late to orderly stack into the lattice, forming metastable crystals, and melting double peaks appear on the melting curve after crystallization. When the cooling rate increases (10-20 °C/min), the limited region of sulfonate aggregation in CDP increases, resulting in more random chain segments, and a cold crystallization peak appears on the melting curve after crystallization. The non-isothermal crystallization behavior of all samples was fitted and analyzed by the Jeziorny equation, Ozawa equation, and Mo equation. The results indicate that the nucleation density and nucleation growth rate of CDP decrease with the increase in SIPA content. Meanwhile, analysis of the Kissinger equation reveals that the activation energy of non-isothermal crystallization decreases gradually with the increase in SIPA content, and the addition of SIPA makes CDP crystallization more difficult.

Smart emulsion system driven by light‐triggered ionic liquid molecules and its application in eco‐friendly water‐saving dyeing

AbstractThe smart emulsification and demulsification system with the light response is a useful tool in various industries, including green chemistry, catalytic reaction, pharmaceuticals, and environmental remediation. Herein, an ionic liquid crystal compound with a light triggered switch based on the azobenzene group [(4‐{3‐methyl‐1‐[3‐(8‐octyloxyoctyl)oxy‐4‐oxobutanoyl]imidazo‐lium‐1‐yl}octyl)oxy] ‐N‐(4‐methylphenyl)benzene‐1,2‐diazene bromide (MOIAzo), was designed and synthesized, which could cause reversible transition between emulsification and demulsification through the light trigger. The ionic liquid has an efficient photoinduced liquefaction process, which dramatically lowers the melting point of ionic liquids from 79 to 9.2 oC. This significantly broadens the liquid state temperature of the ionic liquid crystal. The ionic liquid crystal MOIAzo exhibits both photoinduced and thermally induced nematic liquid crystal properties. The smart emulsion system was effectively employed in an eco‐friendly water‐saving dyeing process of cationic dyes for cationic dyeable polyester (CDP) fabrics, which used only half the amount of water compared with the conventional water bath dyeing method. After dyeing, the oil and water phases can be efficiently separated through the light irradiation, and the oil phase can be reused for the subsequent dyeing process. This novel smart emulsion dyeing method greatly reduces the water consumption and wastewater discharge. MOIAzo as a light‐triggered ionic liquid molecule opens up new dimensions in green chemistry.

Experimental Studies on the Phase Separation Behavior of Molten Benzenesulfonate-Modified PET/PA6 Blends

In this work, nylon 6 (PA6) and cationic dyeable polyester (CDP) modified with benzenesulfonate groups were reactively blended in a twin-screw extruder. The well-mixed CDP/PA6 blends were re-molten and statically kept for various amounts of time. The morphology evolution caused by phase separation was observed by a scanning electron microscope (SEM) and an atomic force microscopy-infrared (AFM-IR) technique. In the absence of shear force, the homogeneously mixed blends were found to separate rapidly into two phases because of the poor miscibility between polyester and polyamide. In the early stage, the dispersed phase was small in size and irregular in shape. With prolongation of the phase separation time, the dispersed phase turned into larger and spherical particles to minimize the interface between phases. The phase separation process typically lasted 2 to 7 min. This means that the effects of phase separation on the morphology of the blends cannot be ignored in injection molding, compression molding, or other processing processes short of shear force. The effects of the ratio between polyester and polyamide, the benzenesulfonate content, and the molecular weight of polymers on phase separation behavior were investigated.

Absorption kinetics and thermodynamics of cationic dyeing for poly(ethylene terephthalate) copolyester modified by 2,2-dimethyl-1,3-propylene glycol (NPG)

The copoly(ethylene terephthalate) (ENCDP) were successfully prepared with 2,2-sodium-5-sulfo-bis-(hydroxyethyl)-isophthalate (SIPE), poly(ethylene glycol) (PEG) and 2,2-dimethyl-1,3-propylene glycol (NPG), named as cationic dyeable polyester. The dyeing properties consisted of adsorption kinetics and thermodynamics of cationic blue X-BL on the ENCDP fabric were investigated. The T-Vickerstaff hyperbolic adsorption model could be used to explain the adsorption kinetics and predict the equilibrium rate constant k, equilibrium dye sorption capacity (C∞), the half dyeing time (t1/2) and diffusion coefficient (D) at different temperatures. According to the adsorption activation energy (Ea)> 40KJ/mol, it is judged that the isotherm adsorption conforms to the langmuir isotherm and possessed the higher correlation. Moreover, the determined thermodynamic parameters including the positive value of adsorption affinity (-Δµ°) and enthalpy change (ΔH°) showed that the dye adsorption onto ENCDP was a chemisorption process of spontaneous and endothermic.

Regenerated cationic dyeable polyester deriving from poly(ethylene terephthalate) waste

In this paper, sodium-5-sulfo-bis(hydroxyethyl)-isophthalate (SIPE) comonomer, which could copolymerized with bis(hydroxyethyl) terephthalate (BHET) for dyeability modification of poly(ethylene terephthalate) (PET), was prepared through transesterification reaction of sodium dimethyl 5-sulfoisophthalate (SIPM) and ethylene glycol (EG). The obtained SIPE was then polycondensation reacted with BHET which was extracted from waste PET fiber depolymerization under nitrogen atmosphere with excess EG as glycolysis agent and zinc acetate (Zn(Ac)2) as catalyst, to achieve regenerated cationic dyeable polyester (rCDP). Chemical structure, thermal properties, intrinsic viscosity and thermal properties of rCDP were analyzed and compared with virgin CDP (vCDP). Effects of SIPE on rheological property and dyeability of rCDP were also investigated.

Dyeing Properties of Berberine on Cationic Dyeable Polyester

The natural cationic colorant berberine was used to dye cationic dyeable polyester (CDP) fibers. Its dyeing properties, namely color strength ( K/ S) of dyed CDP and percent exhaustion ( E%) of berberine, on CDP were explored at various dyeing pH levels, temperatures, time, and concentration of berberine. Furthermore, dyeing kinetic and thermodynamic studies were also carried out to evaluate the adsorption properties and mechanism. It was found that the E% of berberine on CDP fibers and the rate of adsorption increased with increasing dyeing temperature, while the influence of pH was extraordinarily small. In addition, the adsorption isotherm of berberine on CDP fibers was in line with the Langmuir model.

Thermal, electrical, mechanical and fluidity properties of polyester-reinforced concrete composites

Polyester particles in concrete are preferred because they provide thermal, chemical and water resistance. In this study, thermal conductivity, electrical resistivity, mechanical strength and water resistance properties of concretes containing polyester granules such as flame-retardant polyester, cationic dyeable polyester and polyester with a low melting point-filled concrete have been analyzed using a full factorial design via Minitab® version 17. The effect of the most influential factors on thermal conductivity of polyester aggregate reinforced concrete composite has been determined as an interaction between the cationic dyeable and low-melt–point polyester. This mixture is suitable for production of thermal insulating concrete. Moreover, it is concluded that cationic dyeable polyester is the highest corrosion- and water-resistant product among the polyesters used in this study. The recovery rate of 33.94% in the thermal conductivity and 214.89% in the electrical resistivity of polyester-reinforced concrete composites has been obtained with a 28-day compressive strength loss of 41.94% according to the reference concrete in the full factorial design application. These results indicate that the polyester-reinforced concrete composites are quite effective in achieving thermal and corrosion resistance concrete but with noticeable compressive strength loss.

Discussion on Avoidance of Staining Problem in Cotton/CDPET Dyeing

In this research, a novel approach has been proposed to remove stain problem from blended fabrics as an alternative option with traditional reduction clearing process. For this purpose, cationic dyeable polyester and cotton blended fabrics were dyed as traditional technique based on formulations approach and the colour strength (K/S), dye uptake (%) and the whiteness index properties were evaluated. The results of color strength indicated that dye was more uniformly absorbed by the blended fabric compared to the untreated fabric. In addition, when untreated fabric was dyed in the presence of a leveling agent (Lyogen DFTN), the K/S and levelness of dye uptake (%) values were enhanced. Finally, very less staining was observed that proved by CIE Whiteness Index values and indicates that formulation (F-IV) has more beneficial to reduce staining from Cotton/CDPET blended fabric (65/35).

Alkaline hydrolysis and pretreatment of trilobal high dimethyl 5-sulfoisophthalate sodium cationic dyeable polyester

Lower glass transition temperature and crystallinity degree of trilobal high dimethyl 5-sulfoisophthalate sodium cationic dyeable polyester (THCDP) led to its more sensitivity to strong alkali and high temperature than regular Poly(ethylene terephthalate) (PET). The kinetic behaviors of alkaline hydrolysis of THCDP and PET were further explored, and the kinetics equations determined by regression analysis manifested that THCDP with high content of dimethyl 5-sulfoisophthalate sodium salt (SIP) was more prone to alkali hydrolysis and had higher weight loss rate. A comparatively lower power consumption pretreatment process of THCDP knitted fabrics benefited from the synergistic effect of various additives was applied in this study by response surface methodology and the optimum process with less auxiliaries, especially with less caustic treatment avoided large strength loss of fabric, as well as lower manufacturing cost in an environmentally friendly way.

Preparation and characterization of poly(ethylene terephthalate) copolyesters and fibers modified with sodium-5-sulfo-bis-(hydroxyethyl)-isophthalate and poly(ethylene glycol)

New copolyesters were successfully prepared with SIPE and PEG units designated as cationic dyeable polyester and easy cationic dyeable polyester. The number average molecular weight of PEG unit is 6000 (abbreviated as PEG6000). Corresponding copolyesters were spun into fibers with melt spinning method. Chemical and crystalline structures were characterized by the NMR and WAXD measurement, and thermal properties were tested by Differential Scanning Calorimetry and Thermogravimetric Analysis, respectively. NMR experimental results indicated the actual molar ratio of comonomers was basically consistent with the correlative feed ratio. WAXD results showed that crystalline structures of prepared copolyesters were similar to that of Poly(ethylene terephthalate). Moreover, the glass transition temperature, melting temperature, and thermal degradation temperature were found to decrease with the increase in weight ratio of PEG6000 units since the incorporation of higher PEG6000 content brought more ether bonds into molecular chains, which increased the asymmetry and irregularity of molecular chains and led to lower crystallinity. Besides, when content of PEG6000 increased, the breaking tenacity and initial modulus were reduced, yet elongation at break enhanced. It suggested that PEG6000 segments reduced the symmetry of molecular chains and decreased the orientation degree of fibers. In addition, because the incorporation of higher weight percentage of PEG6000 led to more hydroxyl end groups and ether bonds in molecular chains, the moisture regain of fibers increased, manifesting fibers had better hydrophilicity with increasing weight ratio of PEG6000 components.

Cationic dyeing properties of trilobal high dimethyl 5-sulfoisophthalate sodium salt (SIP) content cationic dyeable polyester (THCDP) fabrics

To make the polyester ionically dyeable, trilobal high dimethyl 5-sulfoisophthalate sodium salt (SIP) content cationic dyeable polyester (THCDP) was developed in this study which aimed to investigate its structural and dyeing properties. Its lower glass transition temperature and crystallinity degree contributed to lower dyeing temperature. A low-cost and environmentally friendly dyeing solution was applied in this study and the dyeing temperature of newly THCDP fabric could be reduced to 90°C, distinctly different from the previous cationic dyeable polyester which needed more than 100°C to reach dyeing standard. Meanwhile, THCDP showed its higher dyeing saturation value than normal acrylic fabric and cationic dyeable polyester with the Cationic Red X-GRL dyestuff. In present, both pure THCDP and blend textiles were developed. A series of THCDP/Cotton blends’ (20/80, 35/65, 65/35, 80/20) dyeing behaviors were tested, and found they could be dyed at 90°C with good color fastness and levelness.

Dyeing behaviour of THCDP and its blend with cotton at low temperature

Tg and crystallinity of trilobal cationic dyeable polyester (THCDP) and poly(ethylene terephthalate) through X-ray diffraction and differential scanning calorimetry were tested respectively, and the results manifest that lower Tg and percent crystallinity of THCDP contribute to lower dyeing temperature. The dyeing behaviours of cationic black X-FDL on THCDP were studied, demonstrating that dyeing temperature of newly THCDP fabric can be reduced to 90°C, different from the previous cationic dyeable polyester, which needs >100°C to reach dyeing standard. A series of THCDP/cotton blend (20/80, 35/ 65, 65/35, 80/20) dyeing behaviours were tested successively via online monitoring dyeing system, and it has been found that they can be dyed at 90°C with good colour fastness and levelness.

Preparation and characterization of poly(ethylene terephthalate) copolyesters modified with sodium‐5‐sulfo‐bis‐(hydroxyethyl)‐isophthalate and poly(ethylene glycol)

ABSTRACTTwo types of poly(ethylene terephthalate) (PET) copolyesters were successfully prepared with sodium‐5‐sulfo‐bis‐(hydroxyethyl)‐isophthalate (SIPE) and poly(ethylene glycol) (PEG) units with different molecular weights named as cationic dyeable polyester and easy cationic dyeable polyester. Their chemical and crystalline structures were characterized by the nuclear magnetic resonance (NMR), wide angle X‐ray diffraction (WAXD), and small angle X‐ray scattering measurement, and their thermal properties were tested by differential scanning calorimetry and thermogravimetric analysis, respectively. NMR experimental results showed that the actual molar ratio of comonomers was basically consistent with the correlative feed ratio. WAXD results indicated that the crystalline structures of prepared copolyesters were similar to that of PET. Moreover, the glass transition temperature, melting temperature, and thermal degradation temperature were found to decrease with the reduction of the of PEG units as the incorporation of lower of PEG units brought more ether bonds into molecular chains, which increased the irregularity of molecular chain arrangement and led to lower crystallinity. In addition, because the incorporation of PEG units with lower molecular weight led to more ether bonds and hydroxyl end‐groups in molecular chains, the value of contact angle of PET copolyesters dropped, manifesting PET copolyesters had better hydrophilicity with the decreasing molecular weight of PEG units.© 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39823.

Study on the dyeing properties of hemicyanine dyes. II. Cationic dyeable polyester

The absorption spectra of two hemicyanine fluorescent dyes, namely, trans‐4‐[p‐(N,N‐di(2‐hydroxyethyl))‐amino‐styryl]‐N‐ethyl pyridinium bromide (DHEASPBr‐C2) and trans‐4‐[p‐(N,N‐di(2‐hydroxyethyl))‐amino‐styryl]‐N‐octyl pyridinium bromide (DHEASPBr‐C8), were studied at various levels of pH and high temperatures, and were then employed to dye cationic dyeable polyester. Their dyeing properties, fluorescent reflectance and colorimetric properties were explored. The novel fluorescent dyes existed in two forms of monocation and dication in solutions at low pH and high temperature. Overall, the influence of pH on colour depth and the maximum reflectance of dyed cationic dyeable polyester was extremely small. The adsorption mechanism of DHEASPBr‐C2 and DHEASPBr‐C8 on cationic dyeable polyester fibres was in good accord with the Langmuir type. Compared with DHEASPBr‐C2, DHEASPBr‐C8 exhibited comparatively faster adsorption rate, higher affinity and dye uptake, while its fluorescence shown by cationic dyeable polyester was slightly weak.

ChemInform Abstract: The Synthesis of Disperse and Cationic Dyes from Acid Dye Structures.

Abstract This paper is concerned with the conversion of some mono- and di-sulfonated naphthol azo dyes to disperse dyes suitable for poly(ethyleneterephthalate) fibers, and cationic dyes for cationic dyeable polyester and acrylic fibers. The chemical structure of these new dyes has been confirmed by 1H-NMR, FAB or DCI mass spectrometry, and in some cases by elemental analysis. Some fastness properties and absorption spectral data of both types of dyes are also reported, as well as an interesting limitation in the naphthalene-based acid dyes suitable for the described conversion.

Thermal properties and chemical changes in blend melt spinning of cellulose acetate butyrate and a novel cationic dyeable copolyester

AbstractA novel cationic dyeable copolyester (MCDP) containing purified terephthalate acid (PTA), ethylene glycol (EG), 2‐methyl‐1,3‐propanediol (MPD), and sodium‐5‐sulfo‐isophthalate (SIP) was synthesized via direct esterification method. The chemical structure of modified cationic dyeable polyester (MCPD) was confirmed by FTIR and 1H‐NMR. The thermal properties of MCDP and cellulose acetate butyrate (CAB) blends with different blend ratios were investigated by DSC. The results revealed that MCDP and CAB were immiscible polymer blends, and the glass transition temperature of CAB in blend fibers was higher than that of CAB in blend chips because of the strengthening hydrogen bonding. The chemical changes of MCDP and CAB in blend melt spinning were analyzed. It was found that the thermal hydrolysis reaction of ester side groups of CAB occurred in blend melt spinning, which resulted in that the acid gas was produced and the hydroxyl group content of CAB was increased. Furthermore, the moisture absorption of blend fibers was improved about three times than pure MCDP fiber even after washing 30 times. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Ozone‐gas treatment of cationic dyeable polyester and poly(butylene terephthalate) fibers

AbstractCationic dyeable polyester and poly(butylene terephthalate) fabrics were treated with ozone gas under atmospheric pressure and at a pressure of 0.1 MPa. The effect of the ozone‐gas treatment was investigated on the basis of electron spectroscopy for chemical analysis, Fourier transform infrared spectrum, X‐ray diffraction, moisture regain, water absorption, and dyeing properties. The ozone‐gas treatment caused an increase in the oxygen content of each fiber. From the wave separation of C1s, the oxygen was incorporated in the form of CO and COO on the fiber surface, and also, despite an increase in the water absorption, the fiber density as an index of crystallinity increased a little with the treatment. As the result, we concluded that the treatment caused a change not only on the fiber surface but also in the internal structure of both fibers. Then, it seemed that the treatment brought about an effect on the dyeing properties. The apparent dyeing rate with the cationic dye increased remarkably with the ozone‐gas treatment, whereas that with the disperse dye increased slightly. Therefore, it was clear that the ozone‐gas treatment caused a change not only in the fine structure but also in the dyeing behavior. These phenomena were the same as those of poly(ethylene terephthalate) fibers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2423–2429, 2007

Analytical Technique for Characterizing the Initial Stage of the Dyeing Process

A convenient experimental apparatus is developed for analyzing the initial stage of several seconds at the start of the dyeing process under rapid adsorption conditions. A cationic dyeable acrylic fiber is dyed at 90°C and pH 6.4 with 0.002% methylene blue solution at a 500:1 liquor ratio. The fiber is left in the 90°C steamed atmosphere for 30 minutes before dyeing. The wavelength of the 668 nm monochromatic light beam transmittance is detected with multiple optical glass fibers inserted directly in the dye bath. Six percent of the dye uptake in the fibers after 2 hours' dyeing is adsorbed before I second. In case of a cationic dyeable polyester fiber, 9% is adsorbed in the same period.

The effect of heat setting on the dyeability of differentially dyeable polyester fibres

Apparent diffusion coefficients of two disperse dyes for so‐called easily dyeable/cationic‐dyeable polyester (ED‐CDPET) and cationic‐dyeable polyester (CDPET) fibres of identical linear density and sulphonic acid group content have been calculated. It was found that the diffusion coefficients of dyes for ED‐CDPET were far greater than those of dyes for CDPET. The dyeability at the boil without carrier, using disperse and cationic dyes on various ED‐CDPET and CDPET fibres, has been studied. ED‐CDPET was found to have higher dyeability at all levels of heat setting (irrespective of the dye used). The finest ED‐CDPET fibres showed maximum dye uptake as a result of increased surface area. Heat setting in the taut condition reduced dye uptake.