The Preparation Of Zwitterionic Block Polymer By RAFT Polymerization Method And Its Performance Research

In recent years,reversible addition-fragmentation chain transfer polymerization(RAFT)has attracted much attention in the field of polymer synthesis,which is a kind of controlled/"living" radical polymerization with mild reaction conditions and a wide range of application.The purpose of this article is to use the activity controllable characteristics of RAFT polymerization to prepare zwitterionic block polymers,which were based on poly(2-acrylamido-2-methylpropane sulfonic acid)(PAMPS)by directly adding a second comonomer.We preliminarily study the difference between the properties of the solution of the zwitterionic block polymers and the zwitterionic random polymers and the difference in the adsorption behavior of the two types of polymers on the clay.The paper consists of four parts and specific content as follows:1.Preparation of macromolecular chain transfer agent Marco-AMPS.Macromolecular chain transfer agents Macro-AMPS was synthesized though RAFT polymerization using chain transfer agent S-1-dodecyl-S'-(a,a'-dimethyl-a"-acetate)trithiocarbonate(DDMAT)and anionic monomer 2-acrylamido-2-methylpropanesulfonic acid(AMPS).We investigated the influence of time,[DDMAT]0/[I]0,solvent ratio,and solute content on the polymerization of AMPS.The reasonable experimental conditions as following:the ratio range of[DDMAT]0/[I]0 was from 4 to 5,w(methanol):w(water)= 8:2,the proportion range of monomers was from 20 wt%to 25 wt%,pH<7,the range of temperature was from 65 ? to 75 ?,the chain transfer agent DDMAT could quickly control AMPS for RAFT polymerization,The PDI was<1.3.2.Preparation of zwitterionic block polymers PAMPS-b-PMAPTAC.The block polymers PAMPS-b-PMAPTAC were synthesized through RAFT polymerization using cationic monomer(3-methacrylamidopropyl)trimethylammonium chloride(MAPTAC)and Macro-AMPS.The polymers were characterized by FT-IR,1H NMR and GPC.The results proved that the PAMPS-b-PMAPTAC was successfully synthesized,the PDI was less than 1.4 and the controllability was strong.3.Comparison of the properties of zwitterionic block polymer PAMPS-b-PMAPTAC solution and zwitterionic random polymer P(AMPS/MAPTAC)solution.We examined the effect of temperature,NaCl,and CaCl2 on the polymer solution by measuring the specific viscosity of the solution,the microscopic morphology was tested by SEM;the thermal stability of polymer was analysed by TGA.The conclusion was reached as following:(1)The increase of the molecular weight of the cationic chains in the polymer was beneficial to improve the temperature resistance of PAMPS-b-PMAPTAC;(2)The specific viscosity of the solution would show a tendency to decrease first,then increase slightly,and finally decrease when adding NaCl continuously to the block polymer solution;(3)The SEM test showed that the molecular chains of the block copolymers and the random copolymers existed mainly in the curled or folded conformation in the solution,and the molecular chains would expand to form the network structure under the action of NaCl.4.The study on the adsorption behavior of block polymer on clay.We investigated the adsorption behavior of polymers on clay in the condition of time,temperature,and salt at room temperature and elevated temperature by comparing the block copolymers,the random polymers and PAMPS,the amount of adsorption was analyzed by the elemental analysis,the stability of the polymer on the clay was analysed by XRD and TGA,and the conformation of the polymer was measured by AFM,The conclusion was reached as following:(1)The time for the polymer to reach equilibrium on the clay was 12 h at a constant temperature;(2)Block polymers with low molecular weight and high cationicity could be faster,adsorbed on clay but the adsorption capacity would decrease after reaching saturation adsorption;(3)The adsorption and desorption of polymers on clay tended to be dynamically balanced under long-term hot rolling.