Preparation Of Polymaleic Acid By Plasma-Initiated Polymerization

The new preparation method of polymaleic acid (PMA) from maleic anhydride by plasma-initiated polymerization in aqueous solution was studied. Comparing with traditional process technology of polymaleic acid which was using of organic solvent or H2O2, the new preparation method of PMA by plasma-initiated polymerization is reported.This process is a gree synthesise Rite.The effects of discharge time, discharge power, concentration of MA, post- polymerization temperature and post- polymerization time on the conversion of MA and properties of PMA were studied. The conversion of MA could reach to 32% under the optimized conditions: discharge time 60s, discharge power 80W, mess concentration of MA 45%, post- polymerization temperature 60 ℃ and post- polymerization time 3h. The product was indentified by IR and UV-Vis. The viscosity average molecular weight of PMA was 640 and the encrustation-resistant ratio of PMA to CaCO3 could reach to 93%. It was deduced experimentally that the plasma-initiated polymerization was radical polymerization mechanism. The experimental results showed that the activity and conversion of different of allyl monomer was increaseing alongwith their stereic hindered depressing.The experimental results of plasma-initiated copolymerization of MA with sodium acrylate(AANa) in aqueous solution showed that effection seriation of kinds of factors on the disporsancy of MA-co-AANa was discharge time> discharge power> post- polymerization time> monomer ratio>post- polymerization temperature. The optimized conditions was discharge time 70s, discharge power 90W, post- polymerization time 1.5h, monomer ratio m(MA):m(AANa)=30:70 and post- polymerization temperature 90℃. The viscosity average molecular weight of MA-co-AANa was 3700 and the disporsancy of MA-co-AANa was 331 mg MnO2/100ml. the sequestration of MA-co-AANa could reach 340 mg CaCO3/g.The experimental results of plasma-initiated copolymerization of MA with acrylamide (AM) in aqueous solution showed that the optimized conditions for corrosion inhibition of MA-co-AM was discharge time 50s, discharge power 90W, post- polymerization time 2h, monomer ratio m(MA):m(AM)=35:65 and post- polymerization temperature 80 ℃. The viscosity average molecular weight of MA-co-AM was 3150 and the sequestration of MA-co-AANa could reach 352 mg CaCO3/g. The polarization curve of MA-co-AANa showed that MA-co-AANa belong to a mixed inhibtor. The mechanism of scale inhibition included chelation, threshold effect,distortion of crystal lattice and dispersion effect. The mechanism of corrosion inhibition (MA-co-AM) was adsorption membrane mechanism.