Synthesis Of Cationic Polyacrylammide By Inverse Suspension Polymerization

With the extensive application of cationic polyacrylamide in wastewater treatment,papermaking process,and oil production,the preparation process has been rapidly developed.Among them,polymerization methods ba sed on solution polymerization have been industrialized,but there are also disadvantages such as low cationicity,slow dissolution rate,and low molecular weight.Therefore,the development of new preparation methods has become one of the important direct ions.In this chapter,a cationic polyacrylamide with different cationic degree was synthesized by inverse phase suspension polymerization using acrylamide and acryloxyethyl trimethylammonium chloride as monomers in the presence of?NH₄?₂S₂O₈/NaHSO₃/V44 as complex initiators.The effects of type and concentration of initiator,monomer concentration,pH,reaction temperature,reaction time,cationic degree,N₂ inlet time,drying temperature and time on the molecular weight of P?DAC-AM?and conversion of mono mers were systematically investigated.And the effects of stirring speed,dispersion system,dispersant concentration and oil-water mass ratio on the particle size and particle size distribution of polymer particles were studied.At the same time,the retention and filter aid performance and flocculating effect of the polymer under different cation conditions were analyzed.The optimum reaction conditions for the low-cationic of P?DAC-AM?were as follows:concentration of initiator V44 and?NH₄?₂S₂O₈/NaHSO₃ was 40ppm and 60ppm,m?Span60/Span80?:m?cyclohexane?=3:97,m?oxidant?:m?reductant?=1:1,monomer concentration 40%,p H=6,reaction temperature 50?,m?oil?:m?water?=1.5:1,N₂ inlet time 30min,drying temperature was 60?,drying time was 2h,the concentration of EDTA-2Na was 60ppm and the stirring speed was controlled at 300r/min.Under above conditions,the cationic polyacrylamide with molecular weight of 1.05×10⁷Da was prepared and monomer conversion reached 97.5%,dissolution time 45min,the particle size of about 0.9-2 mm.The structure of P?DAC-AM?was characterized by FTIR and ¹H NMR under the above conditions,which proved that the obtained polymer was truly a copolymer of AM and DAC.TG analysis was used to study the thermal stability of P?DAC-AM?,which proved that P?DAC-AM?has good thermal stability in the temperature range of 0²00?.The best conditions for retention and drainage were the dosage of polymer is 700 ppm,p H=10,the viscosity average molecular weight of8.0×10⁶ Da.Under above conditions,the resulting filler retention rate of up to 75%or more,close to 800 g of water quality.The optimum reaction conditions for the high-cationic of P?DAC-AM?were concentration of initiator V44 and?NH₄?₂S₂O₈/Na HSO₃ was 40 ppm and 60 ppm,dispersant concentration 5%,m?oxidant?:m?reductant?=1:1,monomer concentration 40%,pH=6,reaction temperature 50?,m?oil?:m?water?=1.5:1,N₂ inlet time 30 min,drying temperature was 50?,drying time was 3 h,the concentration of EDTA-2Na was 60ppm and the stirring speed was controlled at 350 r/min.Under above conditions,the cationic polyacrylamide with molecular weight of 8.2×10⁶ Da was prepared and monomer conversion reached 97.4%,dissolution time 30min,the particle size of about0.9-2 mm.And the obtained optimum conditions for flocculation experiments were wastewater dosage of flocculant 2 ppm,p H=6,molecular weight of flocculant 5.0×10⁶Da,cationic degree 40%.Under above conditions,the transmittance of treated wastewater the flocculating rate and flocculation rate were 97%and 85%.