Preparation Of Hyperbranched Dispersant

Pigment printing is the predominant printing application method for around 65% of prints. The main factors why pigment printing has become so widely used are the quality of the prints, the applicability to almost every kind of fibre or mixture, and the ability to avoid any washing processes after fixation. However, there are also some disadvantages such as stiffer handle than dyes, poorer fastness properties to rubbing and so on, which limit its applicability.Pigment printing is the printing method that makes pigment particles adhere to fabric with binder. Binder plays an important role in the pigment printing. Great problems of domestic pigment printing binders are hard handle and low fastness. To solve these problems, in this paper, a novel hyperbranched dispersant of hyperbranched polyesteramides-graft-mono methoxy polyethylene glycol (HP-g-MPEG) was synthesized. The hyperbranched dispersants have a large number of reactive groups at the ends, and have highly branched, globular, and unentangled structure. Owing to the particular structure, the hyperbranched dispersants can be used as dispersants and binders, and have been developed to impart the color fastness, durability and importantly, a soft"handle"to the textile that the final end user customer demands.In this paper, an AB2-like monomeric unit DH was prepared based on bis(2-hydroxypropyl)amine and cis-hexahydrophthalic anhydride as starting materials. Hyperbranched polyesteramides were obtained through the polycondendensation of DH and little excess bis(2-hydroxypropyl)amine in dimethylbenzene, which was suitable water - taking agent for the synthesis. The chemical structures of hyperbranched polyesteramides were characterized by Fourier transform infrared spectroscopy (FTIR), chemical titration and gel permeation chromatography (GPC). A degradatiove procedure for the determination of the degree of branching (DB) in hyperbranched polyesteramides was presented. After hyperbranched polyesteramides were hydrolyzed, the degree of branching was measured by high performance liquid chromatography (HPLC). The equation of reaction kinetics was demonstrated and the results showed that the polymerization process was self-catalytic. The solubility, thermostability and rheology of the polymer were also investigated. The results showed that hyperbranched polyesteramides exhibited excellent thermal stability, and had good solubility, and it was provided with low viscosity.Furthermore, a novel hyperbranched dispersant of hyperbranched polyesteramides-graft-mono methoxy polyethylene glycol (HP-g-MPEG) was synthesized by solution polymerization in ethyl acetate using 2,4-tolylene diisocyanate (TDI) as a coupling agent. The copolymers were prepared by two-step reactions. First, the isocyanate-terminated intermediate (MPEG-NCO) was prepared by introducing one NCO group of TDI onto the hydroxyl end-group of mono methoxy polyethylene glycol (MPEG). Second, MPEG-NCO was grafted onto the chains of hyperbranched polyesteramides (HP) by the reaction between the unreacted NCO group and the hydroxyls of HP, and then, HP-g-MPEG was obtained. The chemical structure of HP-g-MPEG was confirmed by using FTIR and 1H-NMR, and the yield (Y) and grafting efficiency (GE) were discussed. The results showed that the yield (Y) and grafting efficiency (GE) of HP-g-MPEG changed continuously with the ratio of HP:MPEG:TDI. At the beginning, both Y and GE increased with the increasing content of HP, Then Y and GE reached their climaxes at the optimal HP:MPEG:TDI ratio of 12.5:10:1.74. With the further increase of HP feeding ratio, the value of Y and GE decreased.The molecular conformation of hyperbranched dispersant HP-g-MPEG in dilute aqueous solution was studied by atomic force microscope (AFM) and Zetasizer Nano instrument. The results showed that surface tension isotherms of HP-g-MPEG had more than one turning point. In the very dilute solutions, hyperbranched dispersant molecules dispersed and tended to form mono-molecular micelles, which presumably consisted of a core of the hydrophobic block surrounded by a corona of the hydrophilic block. The average size of mono-molecular micelles is approximately 100nm, and they have polydisperse conformation and wide size distributions. In the dense solutions, hyperbranched dispersant molecules dispersed and tended to form the micelles containing many molecules.