Study On The Synthesis Of Pdmaema Star Polymers By Raft Polymerization

A large amount of CO2 will cause greenhouse effect, acid rain and other kinds of disaster, which is a significant problem affecting the current environment. The facilitated transport membrane with fixed carrier is the most interesting kind of separation membranes for this purpose. It also has the advantages of high permeation rate and high selectivity, which is unmatched by other common membrane materials. RAFT polymerization has the characteristics of mild conditions for preparation, and simple operation, which is an effective method for the synthesis of new macromolecule materials. Based on the RAFT polymerization methods, we synthesized a new kinds of membrane material prepared through blending the star polymer and Cs, and studied permeation performance of the blending membrane.Dibenzyl trithiocarbonate, S-1-Dodecyl-S’-(α, α’-dimethyl-a-acetic acid) trithiocarbonate (MTTCD), S, S’-bis (2-hydroxyethyl-2’-dimethyla crylate) trihiocarbonate (BDATC),2-cyanoprop-2-yl-dithiobenzoate (CPDB), s-(2-cyanoprop-2-yl)-s-dodecyltrithiocarbonate (CPTCD) were prepared.Macromolecules chain transfer agents (PDMAEMA-CTA) were synthesized through the reversible addition fragmentation chain transfer polymerization (RAFT) by using five RAFT agents aboved as the chain transfer agents and azobisisobutyronitrile (AIBN) as initiator, N,N-dimethylaminoethyl methacrylate (DMAEMA) as the polymerization monomer. The arms of star polymers were synthesized by using CPTCD as the RAFT agent which could provide better control over the molecular weight and the molecular weight distribution of PDMAEMA compared with other chain transfer agents. Star polymers based on the coupling reagent, namely divinyl benzene (DVB), have been successively prepared by "arm-first" method via RAFT polymerization. The chemical composition and structure of polymers were characterized by FTIR,1HNMR, XRD and GPC analysis.The blending composite membranes were prepared and their microstructures were analysed by SEM. The CO2 and N2 permeation performance of the blending composite membranes (Cs: SPDMAEMA-8=2:6) were tested at different pressure and temperature. The results showed that the resulted blending composite membrane had a CO2 permeation rate of 3.425×10-5 cm3(STP)cm-2s-1 cmHg-1 and a N2 permeation rate of 1.07×10-6 cm3(STP)cm-2s-1cmHg-1 and an ideal CO2/CH4 selectivity of 32 at a feed gas pressure of 37.5 cmHg and 30℃. We also investigated the CO2 and N2 permeation performance of the blending composite membranes with different volume ratios. It showed that the blending composite membrane (Cs:SPDMAEMA-8=4:4) had a CO2 permeation rate of 8.54×10-4 cm3(STP)cm-2s-1 cmHg-1and a N2 permeation rate of 2.42×10-5cm3(STP)cm-2s-1 cmHg-1 and an ideal CO2/CH4 selectivity of 35.2 at a feed gas pressure of 37.5 cmHg and 30℃. Compared with the pure Cs membrane, the CO2 permeation rate and ideal CO2/CH4 selectivity have improved by 31.1 and 11.1 times, respectively, but the N2 permeation rate only increased by 1.67 times.