Modification Of Hyperbranched Polymer And Its Application On Dyeing And Finishing Of Textiles

Hyperbranched polymers are torispherical irregular macromolecules with highly branched architecture, a large number of terminal functional groups and inner cavities, showing low viscosity, high solubility and chemical reactivity. Due to their unique chemical and physical properties, interest in hyperbranched polymers is growing rapidly. A great progress has been made in the synthesis and characterization methods during the past two decades. Investigations on the modification of hyperbranched polymers to obtain various functional materials become a new research direction.A number of hyperbranched polymers have been synthesized, among which hyperbranched polyester is commercially available. Hyperbranched polyester is one of the most widely used hyperbranched polymers because of the activity of the terminal hydroxyl groups. Quaternary ammonium surfactants are widely used in dyeing and finishing of textiles because of their excellent performance. In this dissertation, a series of quaternary ammonium functionalized hyperbranched polyesters (QHPEs) with different lengths of the alkyl chain were synthesized. In addition, the applications of QHPEs on the alkaline hydrolysis of polyethylene terephthalate (PET) fabrics, dye wastewater treatment and color fixing effectiveness on direct-dyed cotton fabrics were studied. The details and key conclusions are described as follows:1. Synthesis, characterization and properties of QHPEsA novel kind of macromolecule, QHPE was synthesized by the reaction of hyperbranched polyester (HPE) and 2,3-epoxypropyl alkyl dimethyl ammonium chloride. Aliphatic hyperbranched polyester Boltorn H20 or H30 was chosen in this study. After modification, the hydroxyl terminal group of hyperbranched polyester was converted into ammonium functional group.The optimum reaction conditions of the synthesis of QHPE were determined by the reaction of H20 and (2,3-epoxypropyl)trimethyl ammonium chloride (GTA). The reaction conditions, such as the solvent, catalyst, the molar ratio of the reactants, and reaction time and temperature were investigated, and feasible conditions were indicated for the synthesis of QHPE. FTIR,1H NMR,13C NMR, and elemental analysis (EA) were used to characterize the products. The results showed that under the conditions of n(H20)/n(GTA)=1:16, n(NaOH)/n(H20-OH)=0.5, reaction temperature 50℃and reaction time 24 h, the product was obtained in yield of 61.11%.In order to obtain a novel kind of quaternary ammonium surfactant, a series of amphiphilic QHPEs with different lengths of the alkyl chain was synthesized. The synthesis of QHPE was carried out in two steps. In the first step, long chain alkyl epoxypropyl dimethyl ammonium chloride (EDAC) was prepared by the reaction between epichlorohydrin and long-chain alkyl dimethyl tertiary amine (C8, C12, C14, C16 and C18). In the second step, HPE (H20 or H30) was modified by EDAC to transfer the hydroxyl terminals to the ammonium functional groups. A series of water-soluble QHPEs was obtained by adjusting the molar ratio of EDAC to HPE. QHPEs were written as H20CxN or H30CxN, where x= 8,12,14,16, and 18, is the lengths of the alkyl chain in the quaternary ammonium groups. All compounds were characterized and confirmed by FTIR,1H NMR,13C NMR, EA, and TGThe results showed that all of the QHPEs were soluble in common polar solvents like water with poor solubility in non-polar or weak polar solvents. With increasing length of the alkyl groups in the quaternary ammonium salt part, the solubility of the QHPEs increased at first, and then decreased because of the hydrophobicity of the long alkyl chain. In addition, with increasing molar ratio of EDAC to HPE, QHPEs showed better solubility in polar solvents.The thermal degradation properties of QHPEs were changed after modification because of the introduction of the quaternary ammonium groups. We have noted indeed that all of the QHPEs began to degrade at 175-230℃, whereas the unmodified hyperbranched polyester had high degradation temperature.The foaming properties of QHPE solutions indicated surface activity. The surface activity of QHPE was evaluated by critical micelle concentration (CMC). As expected, a decrease in the CMC values was observed with increasing length of the alkyl chain modified on HPE (H20 or H30).2. Application of QHPEs on the alkaline hydrolysis of PET fabricsAlkaline hydrolysis (or "silk-like") treatment is an important method for modifying chemical and physical properties of PET fabrics. It improves the handling, wettability, resistance to abrasion damage, and soil resistant properties of the fabrics. A series of QHPEs with different lengths of the alkyl chain (H30C8N, H30C12N, H30C16N and H30C18N) was used as the polycationic accelerator for the alkaline hydrolysis of PET fabrics to impart silk-like handling.The effects of the structure and concentration of the accelerator QHPE, NaOH concentration, and hydrolysis time and temperature on the weight loss of PET fabrics were discussed. The results indicated that the length of the alkyl chain of the accelerators influenced their catalytic performance. Accelerators with longer lengths of the alkyl chain showed higher hydrolysis rates. With increasing length of the alkyl chain, the reduction of the surface tension became greater, the accelerators were more easily absorbed onto the fiber surface, and the hydrolysis reaction occurred more rapidly. The equilibrium concentration of the accelerator was on the order of H30C18N< H30C16N< H30C12N.Satisfactory linear relationship was obtained between the weight loss and the hydrolysis time. The presence of the accelerators changes the activation energy (Ea). Ea= 52.98 kJ/mol for the system without accelerators. For the system containing 8 g/L NaOH and 0.16 g/L accelerators (H30C12N, H30C16N, and H30C18N), Ea was 84.43,58.78, and 69.96 kJ/mol, respectively. Moreover, SEM images indicated that the addition of accelerator did not change the basic mechanism of the hydrolysis reaction of PET fabrics in alkaline solution.The catalytic ability of alkaline hydrolysis between hyperbranched polyester quaternary ammonium salt (H30C16N) and cetyltrimethylammonium bromide (HTAB) were compared. The results showed QHPE has greater effectiveness for alkaline hydrolysis of PET fabrics compared with conventional ammonium compound with the same alkyl chain length. There were two possible reasons. First, the synergistic effect of multiple quaternary ammonium groups in the polycationic compound H30C16N showed greater electrostatic attractions to OH-in solution than HTAB. Second, compared with HTAB, H30C16N had a stronger affinity with PET fabrics because of its high film-forming properties and weaker interaction with combined OH- on the surface of the fiber because of its bigger molecular volume.As a result, QHPE was demonstrated as a kind of novel efficient accelerator for alkaline hydrolysis of PET fabric.3. Study on the flocculability of the dye wastewater with QHPEsDye wastewater is one of the most difficult constituents in textile wastewater to treat. Large quantities of dye effluents are discharged from the dyeing process with strong high chroma value that is environmentally unfriendly. The application of QHPEs (H20C1N-8, H20C1N, H30C1N and H20C12N) as novel flocculants for single and binary system dye removal was investigated. Acid Black 24 and Acid Blue 80 were used as model acid dyes and Disperse Red 73 and Disperse Blue 60 were used as model disperse dyes.The effects of the treatment conditions, such as QHPE concentration, pH value and initial dye concentration were discussed. The result showed that QHPEs are good flocculants to remove dyes in dye wastewater efficiently. The dye removal enhanced with increasing flocculant dosage in the case of flocculants with short carbon chain (H20C1N-8, H20C1N, and H30C1N). However, a restabilized phenomenon was observed in the case of flocculants with long carbon chain (H20C12N), that is, dye removal increased at first and then reduced, with increasing flocculant dosage. pH value of the dye solution had a major impact on the flocculation of dyes. The decolorization under the acidic or neutral conditions was better than the alkaline condition. With the increase of the initial dye concentration, the combining weight of flocculant and dye increased at first and then decreased.The flocculability was also influenced by the structures of the flocculants and dyes. Dye removal of the four flocculants was in the order of H20C1N-8< H20C1N < H30C1N< H20C12N. The results indicated that the higher the modification substitution is, the better the flocculation ability is; dye removal of three-generation H30C1N is higher than that of two-generation H20C1N; moreover, dye removal increased with the increasing length of the alkyl chain of QHPE. In addition, the decolorization behavior of the four kinds of eight dyes, including disperse, acid, direct and reactive dyes was compared. The results showed that dye structure had a major impact on the flocculation and flocculant QHPE had a better effect on dyes with small size and linear molecular structure.The results indicated that QHPEs had a good potential application for treating dye wastewater. The flocculation mechanism may be due to the theory of electrostatic neutralization, hydrogen bonding, trestle bridge, and encapsulation.The flocculation behavior of binary mixtures of acid dyes (Acid Black 24 and Acid Blue 80) and disperse dyes (Disperse Red 73 and Disperse Blue 60) by flocculant H20C1N and H20C12N was investigated. A synergistic effect for decolorization in binary dyes was observed where the decolorization efficiencies of binary dyes were greater than those in single dye wastewater samples. Moreover, the flocculation curves were different for each other because of the difference in the interaction between dye and flocculant. 4. Color fixing properties of QHPEs on direct-dyed cotton facricsQHPEs (H30C1N and H30C16N) were used as color fixatives to improve the wash and crock fastness of the direct-dyed cotton fabrics. Direct dyes, containing sulphonic groups, were electrostatically attracted by the ammonium groups of QHPEs, forming insoluble salts, reducing the solubility of the water-soluble dyes, therefore, improving the color fastness of the dyed fabrics. The results indicated that QHPE with longer carbon chain (H30C16N) had better fixing effectiveness, especially in improving wash fastness. The crock fastness was 1 class improved by both H30C1N and H30C16N. The best improvement in wash fastness was 1 class when fixing agent H30C16N was applied and little change occurred in the case of H30C1N.As a whole, hyperbranched polyester with hydroxyl end groups is converted into ammonium functionalities, and the product shows a great potential application on dyeing and finishing of textiles. And these studies may widen the application fields of the hyperbranched polyester and provide a new idea for the functional modification of other hyperbranched polymers.