Synthesis And Properties Of Novel Polycarboxylate-based Comb-like Polymers

Comb-like random terpolymers were synthesized with AA, PMEM (Mn=950 g/mol)and 2-EHA by free radical emulsion copolymerization method in this thesis. The main research works are outlined as follows:The influence of reaction time, reaction temperature, monomer concentration,initiator concentration and concentration of chain transfer agent on the conversion rate was explored,so as to establish the best reaction conditions. As the reaction time was 4 h,monomer total concentration was 20%, The concentration of initiator was 1.5% of the total monomer concentration, chain transfer agent was 3% of the total monomer concentration, reaction temperature was 70℃, the conversion of double bond was above 95%. The molecular weight of comb-like polymers was determined by GPC. The structures of the product were characterized by the FT-IR and 1H NMR spectra. Based on the FT-IR and 1H NMR, it can be demonstrated that PAE-Na terpolymers were prepared successfully.Series of different monomer ratios of comb-like polymers were synthesized in the optimum condition. Surface activities and aggregation behaviors of polymers were studied by means of surface tensiometer, TEM and DLS. The experimental results show that PAE-Na has higher surface activity and stronger aggregation ability compared with the common polymer surfactants. The ratio of hydrophilic and hydrophobic group of products has certain influences on CAC and γCAC. It can be seen that spherical aggregates are formed in aqueous solution by means of TEM and DLS. Also, the distributions of aggregates are inhomogeneous and the diameters of aggregates increases with the increasing of concentrations.Furthermore,the dispersion properties of polymers with different PEG density and different PEG chain length were studied by means of titration, MS2000 laser granulometer, TEM and theoretical calculation. The results show that dispersibility of terpolymers has an increasing trend while increasing the PEG density and PEG chain length. The aggregations of CaCO3 particles are significantly improved after adding PAE-Na as the dispersants. The little diameters of CaCO3 particles correspond to large dispersion amounts. Theoretical calculation shows that RAC and EFlory increase with the increasing of the chain length and density of PEG. Larger RAC and EFlory means higher steric hindrance and coverage for solid particles.Finally, the application performance of products was studied. Comb-like polymer which has best dispersibility, was added into standard liquid detergent. The whiteness and sedimentary ash performance were studied. The results show that the addition of comb-like polymers can improve the whiteness effectively. Also, comb-like polymers have strong aiti-redepositing power.