用分散聚合法制备水溶性两性离子共聚物

Preparation of Water Soluble Amphoteric Copolymer by Dispersion Polymerization

为了扩大分散聚合所合成聚合物的应用领域,在硫酸铵水溶液中以丙烯酰胺(AM)、丙烯酸(AA)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)为单体,聚乙烯吡咯烷酮(PVPK12)为分散剂,2,2'-偶氮双(2-甲基丙脒)二盐酸盐(V-50)为引发剂,合成了可作为降滤失剂的两性离子共聚物。研究了硫酸铵浓度、AMPS浓度和单体总浓度对分散液表观黏度、颗粒粒径大小和聚合物特性黏数的影响,用红外光谱仪和核磁共振仪对共聚物的结构进行了表征,评价了聚合物的降滤失性能。结果表明,在单体加量为15%、单体摩尔比n(AM)∶n(AA)∶n(DMC)∶n(AMPS)=2∶5∶1∶2、V-50加量为0.0426%(以单体质量计)、PVPK12加量为1.4%(以水质量计)、温度55℃、p H=5的条件下制备的聚合物分子结构与设计相符,分散液中的聚合物颗粒为球形,分布均匀,粒径分布窄,在室温下存储稳定时长超过一年。硫酸铵和AMPS加量对分散液表观黏度和粒径的影响相同,均为随着加量的增大先降低后增加;随着硫酸铵浓度增大,聚合物的特性黏数先增加后降低,AMPS则相反。随着单体浓度增大,分散液表观黏度和颗粒粒径均增大。聚合物的降滤失性能较好。随着聚合物加量的增加,膨润土浆的中压滤失量、高温高压滤失量均逐渐减小并趋于稳定。采用分散聚合法制备的两性离子聚合物可作为降滤失剂用于钻井施工。

In order to develop the application field of polymers synthesized by dispersion polymerization,amphotericcopolymer which could be used as filtrate loss reducer was synthesized in ammonium sulfate solution by acrylamide(AM),acrylic acid(AA),2-acrylamido-2-methyl propane sulfonic acid(AMPS)and methacryloyloxyethyltrimethyl ammonium chloride(DMC)as monomers,polyvinylpyrrolidone(PVPK12)as dispersing agent,and 2,2’-azobis(2-methylpropionamide)dihydrochloride(V-50)as initiator. The effects of different concentration of ammonium sulfate,AMPS,monomers on the apparent viscosity and particle size of dispersions and intrinsic viscosity of polymers were discussed. The structure was characterized by FTIR and 1H-NMR,and the filtration reduction property of copolymer in bentonite slurry was evaluated. The results showed that the structure of polymers was consistent with the designed one synthesized on following conditions:15% monomers concentration,2∶5∶1∶2 monomer ratio of AM∶AA∶DMC∶AMPS,0.0426% V50 dosage(in terms of total monomers),1.4% PVPK12 dosage(in terms of total water),55℃ temperature,5 p H value. Polymers in dispersion were spherical and distributed uniformly which had a narrow diameter distribution. The dispersion could be stored beyond one year at room temperature. The ammonium sulfate and AMPS concentration had same effects on the apparent viscosity and particle size of dispersion. With increasing dosage of ammonium sulfate and AMPS,these two variables were decreased first and then increased. When the concentration of ammonium sulfate increased,the intrinsic viscosity number of polymer increased first and then decreased,while AMPS had the contrary effect on intrinsic viscosity number.With increasing concentration of monomers,the apparent viscosity and particle size of dispersion were both increased. The polymer had a good performance on filtrate loss reducing. With increasing dosage of polymers in bentonite slurry,the API and HTHP fluid loss decreased and became stable gradually. Amphoteric copolymer synthesized by dispersion polymerization in ammonium sulfate solution could be used as filtrate loss reducer in drilling operation.