| Backbone/teeth ratio in comb-type copolymer PAANH4-MPEO (ammonium polyacrylat-methoxy polyethylene glycol)and the length of the teeth molecular can be designed depending on the specific applied system. Therefore they can provide ideal stability for the polymer under the wide conditions and create good application.However, Researches on the detailed synthesis process parameters influencing the copolymer structure and the relationship of structure and performance of the copolymer are not so systematic or deep enough currently. So a series of type-comb copolymer PAANH4-MPEO with different side chain length and grafting rate were synthesized in the paper. One of the aims is to obtain copolymer dispersant PAANH4-MPEO with high performance and clear structure, preparation copolymer, solution properties and application performance are studied in the article. The results are potential to provide theoretical guidance and reference for designing, preparing and applying about the type-comb copolymer.Copolymerization was conducted with MPEO monoacrylate macromonomers and acrylic acid. The obtained copolymers were characterized by FTIR and NMR. The results show that the copolymerization reaction can be assigned to the typical free-radical copolymerization. The copolymization activity of MPEO monoacrylate macromonomers and acrylic acid is relatively high. The grafting rate of the comb polymer PAANH4-MPEO is found to increase along with the increase of the macromolecular monomer proportion in the feeding.Further more, the ionization behavior, dissolution behavior and conformation of copolymers with different side chain length in aqueous solution were investigated by means of acid-base titration, turbidity measurement and viscometry. It was found that, the ionization of the copolymer backbone PAANH4occurs at pH≈4.0. As pH increases, the ionization degree rise concomitantly until all ionizable groups are fully charged (α=1) at pH=9. The dissolution of polymers depends on the side chain length, ionic strength, ion valence and types more or less. All polymers concerned show good-solubility in wide range of monovalent ions concentration (Na+). In the bivalent concentration range (Ca2+, Zn2+), copolymers show better solubility relative to the homopolymer PAANH4. Similarly, in the trivalent concentration range (Al3+), copolymers are more soluble. The solubility of polymers become less sensitive to the ionic strength by increasing the length of the side chain, due to the fact that long side chains are able to shield the copolymers from counterion-induced aggregation. The conformation of homopolymer PAANH4exhibits a stronger dependence on Na+ionic strength than its comb-type counterparts. The observations also show that, as the length of the side chain MPEO increases, the comb-type copolymers are less susceptible to undergoing Na+-induced conformational change.The above comb-type copolymers with different side chain length were used in the formation of ZnO ceramics suspension. The effects of the polymer structure effects on the maximum solids content of the ZnO suspension and as well as the dispersion were examined. The results show that the polymer structure nearly had no influence on the maximum solid content of the suspension system. When compared to the homopolymer PAANH4, the copolymers PAANH4-MPEO show wider pH range and stronger resistance to Na+, and this effect is more noticeable with the longer side chain. |
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