Controlled-synthesis, Properties, And Dye-fixing Mechanism Of PDMDAAC-modified Dye-fixatives

Dye-fixatives are usually used to improve the color fastness of anionic dyes on fabric, and their roles are determined by the species of fabrics and dyes, and the characteristics of dyes. The research progresses from fabric fibers, dyes for cotton fabric to resin dye-fixatives for anionic dyes on cotton fabric, were reviewed according to the literatures. The existing problems in the researches were pointed out. Based on these, the researches contents and their significations in this dissertation were illuminated. Considering the shortcomings of Poly (dimethyldiallylammonium chloride)(PDMDAAC) used as dye-fixatives for reactive dyes on cotton fabrics, the structural modifications of PDMDAAC with controlling the products’ molecular weights were done in this dissertation, and the studies on the controlled synthesis, properties, and dye-fixing mechanism of PDMDAAC-modified dye-fixatives were carried out, which were listed as follows.1. Molecular-weight-controlled synthesis, dye-fixing properties and dye-fixing mechanisms of PDMDAACIn order to to access one new way to improve dye-fixing properties, the molecular weights of PDMDAACs and their distrubtions were controlled by adjusting different synthesis conditions during polymerization, and meanwhile the structures, dye-fixing performances, and dye-fixing mechanisms of obtained PDMDAACs were also studied. The results showed, the molecular weight polydispersities and intrinsic viscosities of obtained PDMDAAC were1.22～1.92and0.18-0.81dL/g, respectively. Those PDMDAAC dye-fixatives with the controlled molecular weights represented with intrinsic viscosities of1.00-2.00dL/g and narrow molecular weight distributions could exhibit better dye-fixing properties:the dry rubbing fastness reached respectively4grades, the wet rubbing fastness reached respectively3-4grade, the color fastness to soaping and the white fabric staining both reached4-5grades, respectively. The dye-fixing fastnesses were better than those of commercial general PDMDAAC fixatives and near to that of commercial imported cationic Fixative FIX. In addition, the dye-fixing mechanisms of PDMDAAC dye-fixatives for reactive dyes on cotton fabrics showed, the molecular weights and their distributions of PDMDAAC would both play a important role in the development of the dye-fixing performances, and the basic cationic groups of PDMDAAC could form electrostatic forces with anionic dyes in the form of color lakes, but mainly form the weak Van der Waals forces with cotton fabric. Thus, it could be concluded that the dye-fixing properties of PDMDAAC dye-fixatives could be developed by controlled their molecular weights.2. Design and synthesis of cationic monomers for PDMDAAC modificationFor the further modifications of PDMDAAC, several groups of cationic functional monomers:triallylmethylammonium chloride (TAMAC),3-chloro-2-hydroxypropyltriallyl-ammonium chloride (CHTAAC), N-dially-3-hydroxy-azetidinium chloride (DHAC), and3-chloro-2-hydroxypropylmethyldiallylammonium chloride (CHMDAAC) were designed and synthesized. Their structures and copolymerization abilities with DMDAAC were also studied. The results showed, all the obtained monomers exhibited expected strucutues and could be well copolymerized with DMDAAC, which were suitable for application in PDMDAAC modifications.3. Controlled-synthesis, dye-fixing properties and dye-fixing mechanisms of slightly crosslinked PDMDAACIn order to improve the dye-fixing properties of PDMDAAC-based dye-fixatives, two series of slightly crosslinked PDMDAAC-modified dye-fixatives were synthesized by copolymerization of TAMAC or CHTAAC and dimethyldiallylammonium chloride (DMDAAC), respectively. The structures of obtained dye-fixatives could be controlled by varying molar ratios of TAMAC or CHTAAC to DMDAAC during polymerization, and their molecular weights were possibly controlled by adjusting different polymerization conditions (initial monomer concentrations and initiator amount). The results showed, the dye-fixing properties of PDMDAAC-modified dye-fixatives could be further developed by incorporation of1%molar contents of TAMAC units into the main chains of molecular-weight-controlled PDMDAAC dye-fixatives. The dye-fixing properties of obtained PDMDAAC-modified dye-fixatives were better than those of commercial general PDMDAAC fixatives and commercial imported cationic Fixative FIX. In addition, the dye-fixing mechanisms of slightly crosslinked PDMDAAC-modified dye-fixatives for reactive dyes on cotton fabrics showed that the basic cationic groups of dye-fixatives could form electrostatic forces with anionic dyes, but still mainly form the weak forces with cotton fabric. Thus, the dye-fixing properties could be usually further developed by incorporation of crosslinking units into the main chains of molecular-weight-controlled PDMDAAC dye-fixatives.4. Controlled-synthesis, dye-fixing properties and dye-fixing mechanisms of reactive PDMDAAC-modified dye-fixativesIn order to improve the dye-fixing properties of PDMDAAC-based dye-fixatives, two series of reactive PDMDAAC-modified dye-fixatives were synthesized by the copolymerization of DHAC or CHMDAAC and dimethyldiallylammonium chloride (DMDAAC), respectively. The structures of obtained dye-fixatives could be controlled by varying molar ratios of DHAC to DMDAAC during polymerization, and their molecular weights were possibly controlled by adjusting different polymerization conditions (initial monomer concentrations and initiator amount). The results showed, the dye-fixing properties of PDMDAAC-modified dye-fixatives could be further developed by incorporation of7%molar contents of DHAC units or1%-5%molar contents of CHMDAAC units into the main chains of molecular-weight-controlled PDMDAAC dye-fixatives. The dye-fixing properties of obtained PDMDAAC-modified dye-fixatives were better than those of commercial general PDMDAAC fixatives and commercial imported cationic Fixative FIX. In addition, the dye-fixing mechanisms of PDMDAAC-modified dye-fixatives for reactive dyes on cotton fabrics showed that the reactive units (DHAC and CHMDAAC) of the obtained PDMDAAC-modified dye-fixatives could bring about the expected linking reactions with the hydroxyl groups of cotton (cellulose) baked at180℃for3min, and that the basic cationic groups in the polymers could bring out the electrostatic forces with anionic dyes. Thus, the dye-fixing properties could be usually further developed by incorporation of recctive units into the main chains of molecular-weight-controlled PDMDAAC dye-fixatives.