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1.
High‐solids, low‐viscosity, stable polyacrylamide (PAM) aqueous dispersions were prepared by dispersion polymerization of acrylamide in aqueous solution of ammonium sulfate (AS) using poly (sodium acrylic acid) (PAANa) as the stabilizer, ammonium persulfate (APS) or 2,2′‐Azobis (N,N′‐dimethyleneisobutyramidine) dihydrochloride (VA‐044) as the initiator. The molecular weight of the formed PAM, ranged from 710, 000 g/mol to 4,330,000 g/mol, was controlled by the addition of sodium formate as a conventional chain‐transfer agent. The progress of a typical AM dispersion polymerization was monitored with aqueous size exclusion chromatography. The influences of the AS concentration, the poly(sodium acrylic acid) concentration, the initiator type and concentration, the chain‐transfer agent concentration and temperature on the monomer conversion, the dispersion viscosity, the PAM molecular weight and distribution, the particle size and morphology were systematically investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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The copolymer of acrylamide (AM) and 2‐acrylamido‐2‐methyl‐1‐propane sulfonate (AMPS) was synthesized through the free radical dispersion polymerization in an aqueous solution of ammonium sulfate and in the presence of poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonate) as stabilizer. The average particle size of the copolymer ranged from 1 to 4 μm, and the molecular weight was from 2.0 × 106 to 7.0 × 106 g mol?1. By analyzing apparent viscosity and particle size, the swelling property of the dispersion copolymer was studied. When the dispersion was diluted with salt water in which the ammonium sulfate concentration kept equal with that of the original dispersion, particle size and particle size distribution of the diluted dispersion changed a little, compared with that of the original dispersion. While diluted with deionized water, particle size and particle size distribution could expand several times. The effects of varying concentrations of the stabilizer, the monomer, the salt and the initiator on particle size, and molecular weight of the copolymer were investigated, respectively. The reaction conditions for preparing stable dispersion were concentrations of 20–28% of the salt, 6–14% of monomers, and 1.8–2.7% of the stabilizer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2379–2385, 2006 相似文献
3.
The terpolymer of acrylamide (AM), dimethylaminoethyl methacrylate methyl chloride (DMC), and acrylic acid (AA) was synthesized with their molar ratio of 70 : 15 : 15 through dispersion polymerization in aqueous solution of ammonium sulfate (AS), using poly(dimethylaminoethyl methacrylate methyl chloride) (PDMC) as stabilizer and 2,2′‐azobis(2‐amidinopropane) dihydrochloride (V‐50) as initiator. The particle size of the terpolymer ranged from 5 to 8 μm and the intrinsic viscosity was from 5.5 to 11.6 dL g?1. The terpolymer had anti‐ polyelectrolyte effect under low AS concentration, but polyelectrolyte effect with the concentration beyond 10%. Polymerization dispersion with low apparent viscosity, uniform particles, good stability, and high molecular weight terpolymer was obtained in single stage. The effects of varying concentrations of salt, stabilizer, and monomers on particle morphology and intrinsic viscosity were investigated. With increasing concentration of AS and PDMC, the intrinsic viscosity of terpolymer increased, then decreased afterward. However, it increased gradually with increase in monomer concentration. The particle size was enlarged with increasing of AS and monomer concentration and decreasing of PDMC concentration. The optimum condition was the concentrations of salt, stabilizer, and monomers 28%, 3.0%, and 8% to 15%, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
4.
阳离子聚丙烯酰胺“水包水”乳液的制备研究 总被引:2,自引:0,他引:2
在硫酸铵溶液中,以相对分子质量为7.44×10~5~1.21×10~6的聚甲基丙烯酰氧乙基三甲基氯化铵为分散剂,在偶氮二异丁脒盐酸盐引发剂的作用下,通过分散聚合进行了丙烯酰胺和甲基丙烯酰氧乙基三甲基氯化铵的二元共聚。分别探讨了分散剂浓度、无机盐浓度、单体总浓度及其配比、引发剂浓度、反应温度等对分散聚合的影响,找出了各影响因素之间的协同规律,最终确定出最佳的合成条件和体系配比。在上述条件下制备出颗粒分散性较好、流动性较好、稳定性较高、特性黏数及黏均分子量较高的阳离子聚丙烯酰胺"水包水"乳液。 相似文献
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Branched polyacrylonitriles were prepared via the one‐pot radical copolymerization of acrylonitirle and an asymmetric divinyl monomer (allyl methacrylate) that possesses both a higher reactive methacrylate and a lower reactive allyl. RAFT technique was used to keep a low‐propagation chain concentration via a fast reversible chain transfer euilibration and thus the cross‐linking was prevented until a high level of monomer conversions. This novel strategy was demonstrated to engenerate a branched architecture with abundant pendant functional vinyl and nitrile groups, and controlled molecular weight as a behavior of controlled/living radical polymerization characteristics. The effect of the various experimental parameters, including temperature, brancher to monomer molar ratio, and chain transfer agent to initiator molar ratio, on the control of moleculer dimension (molecular weight and polydispersity indices) and the degree of branching were investigated in detail. Moreover, 1H NMR and gel permeation chromatography confirm the branched architecture of the resultant polymer. The intrinsic viscosity of the copolymer is also lower than the linear counterpart.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
8.
用氧化还原引发体系在低温下研究了丙烯腈与丙烯酸乙酯的乳液共聚合。考察了聚合温度、乳化剂浓度和分子量调节剂浓度对聚合的影响 ,结果表明 ,随温度升高 ,乳化剂浓度增大 ,单体转化率和分子量增大 ,乳液更稳定 ;链转移剂十二烷基硫醇浓度增加 ,分子量显著降低 ,转化率有所降低 ,表明十二烷基硫醇在调节分子量的同时也起着缓聚剂的作用。用激光粒径分析仪考察了 2 0℃时聚合过程中乳胶粒子大小的变化 ,发现聚合过程的成核和增长均在胶束中进行的。用凝胶渗透色谱法研究了十二烷基硫醇对聚合物分子量的影响 ,发现聚合时加入分子量调节剂 ,活性链寿命较短并呈单峰分布 :聚合时不加入分子量调节剂 ,活性链寿命较长并呈双峰分布。 DSC结果表明 ,随聚合体系中软单体含量增加 ,共聚物的玻璃化温度降低。 相似文献
9.
The copolymer of acrylamide (AM) and 2-acrylamide-2-methyl-propane sulfonate (AMPS) was synthesized through free radical dispersion
polymerization in an aqueous solution of ammonium sulfate and poly(2-acrylamide-2-methyl-1-propane sulfonate) as a steric
stabilizer. The average particle size of the copolymer ranged from 1.0 μm to 4.0 μm, and the molecular weight was 2.0 × 106 ~ 7.0 × 106 g mol−1. The swelling property of the dispersion copolymer was studied by characterizing the apparent viscosity and particle size
distribution. When the dispersion was diluted with salt aqueous solution in which the ammonium sulfate concentration kept
equal with that of the original dispersion, particle size and particle size distribution of the diluted dispersion changed
little, compared with that of the original dispersion. While diluted with deionized water, particle size and particle size
distribution could expand several times. The effects of the AMPS/AM molar ratios, the molecular weight of stabilizer, and
the initiation temperature were investigated. It was found that with the increase of the AMPS/AM ratios, the molecular weight
of copolymers increased, and then decreased. The particle size and conversion of monomers increased. The stability of the
copolymer dispersion increased with increasing the molecular weight of stabilizer for a fixed stabilizer concentration. With
the increase of the initiation temperature, the molecular weight of copolymer increased at first and then decreased gradually,
but the particle size and conversion increased. The optimum conditions for the stable AMPS/AM dispersion were as follows:
the AMPS/AM molecular ratio was 15/85, the molecular weight of the PAMPS stabilizer 3.0 × 105 ~ 4.0 × 105, and the initiation temperature 50 °С, respectively. 相似文献
10.
采用偶氮二异丁脒二盐酸盐(AIBA·2HCl)和NaHSO3(RH)组成的引发体系,研究了引发剂浓度、溶液的pH值、引发剂复配和加料方式等因素对二甲基二烯丙基氯化铵(DMDAAC)-丙烯酰胺(AM)共聚合反应规律的影响.结果表明:在30 ℃、nAM∶nDMDAAC=4∶1、ω(monomer) =30%和引发剂AIBA·2HCl-RH的浓度为1.0×10-4 mol·L-1的条件下, pH=7.0时, DMDAAC-AM共聚物的特性黏数达11.56 dl·g-1;pH=10.0时,特性黏数最高达13.60 dl·g-1.采取连续加料方式,可获得阳离子度38.8%,特性黏数达11.61 dl·g-1的共聚物.进一步测得该引发体系30 ℃下,聚合反应的表观活化能为33.25 kJ·mol-1,单体的竞聚率为γAM=6.800,γDMDAAC=0.174. 相似文献
11.
Amphoteric polyacrylamide of acrylamide, acryloyloxyethyl trimethylammonium chloride, sodium acrylate, and acrylic acid was synthesized by foamed copolymerization. The effects of monomer concentration and composition, initiator concentration and composition, sodium bicarbonate and stabilizer content on the polymer intrinsic viscosity and monomer conversion were examined. The monomer conversion increased with increasing initiator concentration, sodium bicarbonate and stabilizer content. The polymer intrinsic viscosity decreased with increasing initiator concentration. The structure and low molecular weight of the amphoteric polymer were identified by fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC), respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
12.
以(NH4)2S2O8/Na2SO3/CuSO4为氧化-还原引发体系、十二烷基硫酸钠(SDS)为乳化剂,采用间歇乳液聚合合成氯乙烯/异丁基乙烯基醚(VC/IBVE)共聚物。结果表明,当投料单体中IBVE质量分数增加时,相同聚合时间的聚合转化率和共聚物特性粘度明显降低。当转化率小于70%时,共聚物平均组成变化不大;聚合温度增加使聚合速率增加,但共聚物特性粘度减小;SDS浓度对聚合速率和共聚物特性粘度的影响很小;随引发体系浓度增加.聚合速率增加,共聚物特性粘度变化不大。 相似文献
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F. J. Escudero Sanz J. R. Ochoa Gómez P. M. Sasia E. Díaz de Apodaca P. Río 《应用聚合物科学杂志》2007,103(5):2826-2836
Acrylamide/2‐acryloxyethyltrimethyl ammon‐ium chloride copolymers in inverse microemulsion, with a cationic charge density of 60% and a concentration of active matter of 30 wt %, of interest as flocculants have been obtained by inverse microemulsion copolymerization. Interesting inverse microemulsion formulations from both industrial and economical standpoints were selected from pseudoternary phase diagrams. These formulations were polymerized by semicontinuous free radical copolymerization in inverse microemulsion using sodium disulfite and ammonium persulfate as initiators. Influence of initiators and initiator addition conditions (specific flow rate and concentration) on semicontinuous polymerization and final product properties as flocculants have been studied. A strong difference in copolymer solution viscosity has been found when an aqueous solution of sodium disulfite is used as initiator instead of sodium disulfite/ammonium persulfate couple redox, specially for low sodium disulfite solution feeding flow. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2826–2836, 2007 相似文献
14.
Micron‐size functional crosslinked poly(methyl methacrylate) (PMMA) particles with narrow size distribution in the range of 1~5 µm were prepared by dispersion copolymerization in polar media with poly(N‐vinylpyrrolidone)(PVP) as steric stabilizer, 2,2′‐azobisisobutyronitrile(AIBN) as initiator and ethylene glycol dimethylacrylate (EGDMA) as crosslinking agent. The effects of functional comonomer acrylic acid (AA) concentration, contents in AIBN, EGDMA and PVP, media polarity as well as reaction temperature on the particle size and size distribution were investigated. Particle size initially increased, and then decreased with increasing AA concentration in the range of 0.7~3.5 mol l?1, having a maximum of 5.01 µm at the concentration of 2.1 mol l?1, while size distribution became broader. This was regarded as the result of different roles of PAA in the process. Particle size increased with decreasing media polarity and stabilizer concentration, and with increasing initiator concentration and reaction temperature. The resulting particle shapes were observed by transmission electron microscopy and the presence of carboxyl groups on the surface of the particles was confirmed by Fourier‐transform infrared spectroscopy. Copyright © 2003 Society of Chemical Industry 相似文献
15.
Yajun Yang Qingzhi Dong Zi Wang Cuihui Shen Zhengfeng Huang Hui Zhu Tao Liu Chun Pu Hu 《应用聚合物科学杂志》2006,102(6):5640-5648
Dispersion copolymerization of acrylonitrile‐vinyl acetate (AN‐VAc) had been successfully performed in supercritical carbon dioxide (ScCO2) with 2,2‐azobisisobutyronitrile (AIBN) as a initiator and a series of lipophilic/CO2‐philic diblock copolymers, such as poly(styrene‐r‐acrylonitrile)‐b‐poly(1,1,2,2‐tetrahydroperfluorooctyl methacrylate) (PSAN‐b‐PFOMA), as steric stabilizers. In dispersion copolymerization, poly(acrylonitrile‐r‐vinyl acetate) (PAVAc) was emulsified in ScCO2 effectively using PSAN‐b‐PFOMA as a stabilizer. Compared with the precipitation polymerization (absence of stabilizer), the products prepared by dispersion polymerization possessed of higher yield and higher molecular weight. In addition, the particle morphology of precipitation polymerization was irregular, but the particle morphology of dispersion polymerization was uniform spherical particles. In this study, the effects of the initial concentrations of monomer and the stabilizer and the initiator, and the reaction pressure on the yield and the molecular weight and the resulting size and particle morphology of the colloidal particles were investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5640–5648, 2006 相似文献
16.
针对辽河油田注水区块现有颗粒类深部调驱堵剂耐温、抗剪切性能差,成胶强度低,有效期短,压力提升幅度有限等问题,采用丙烯酰胺与天然橡胶胶乳、乙烯基吡咯烷酮通过自由基共聚,经胶体干燥、造粒得到具有良好柔韧性和粘弹性能的柔性凝胶颗粒,并确定了最佳聚合反应条件:单体浓度30%,丙烯酰胺:天然橡胶胶乳:乙烯基吡咯烷酮质量比为1:0.8:0.3,交联剂浓度0.05%,引发剂(甲醛合次硫酸氢钠与过硫酸铵质量比为1:2)浓度0.6%,聚合反应温度65℃。同时确定了用于悬浮凝胶颗粒的凝胶配方体系:聚合物800 mg/L、交联剂400 mg/L、稳定剂80 mg/L,得到了凝胶颗粒现场应用的合理粒径中值为2 mm,最佳使用浓度范围1%~3%。现场试验结果表明:凝胶颗粒对调驱压力提升作用明显,具有很高的可行性和实用性,为注水区块稳油控水提供了有力的技术保障。 相似文献
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采用偶氮二异丁脒二盐酸盐(AIBA·2HCl)和NaHSO3(RH)组成的引发体系,研究了引发剂浓度、溶液的pH值、引发剂复配和加料方式等因素对二甲基二烯丙基氯化铵(DMDAAC)-丙烯酰胺(AM)共聚合反应规律的影响.结果表明:在30 ℃、nAM∶nDMDAAC=4∶1、ω(monomer) =30%和引发剂AIBA·2HCl-RH的浓度为1.0×10-4 mol·L-1的条件下, pH=7.0时, DMDAAC-AM共聚物的特性黏数达11.56 dl·g-1;pH=10.0时,特性黏数最高达13.60 dl·g-1.采取连续加料方式,可获得阳离子度38.8%,特性黏数达11.61 dl·g-1的共聚物.进一步测得该引发体系30 ℃下,聚合反应的表观活化能为33.25 kJ·mol-1,单体的竞聚率为γAM=6.800,γDMDAAC=0.174. 相似文献
19.
Cheng Yang Xiaoqing Song Chao Sun Mingqing Chen Yulan Xu Xiaoya Liu Zhongbin Ni 《应用聚合物科学杂志》2006,102(4):4023-4029
Graft copolymers of soybean protein isolate (SPI) and methacrylic acid (MAA) were prepared in an 8 mol/L urea aqueous solution with ammonium persulfate (APS) as an initiator, β‐mercaptoethanol as an unfolding agent for SPI, and a chain‐transfer agent. Evidence of grafting was obtained by the comparison of the Fourier transform infrared and NMR spectra of SPI with those of the SPI‐grafted MAA copolymer [SPI‐g‐poly(methacrylic acid) (PMAA)]. A possible copolymerization mechanism of SPI and MAA was determined, and the copolymerization rate equation was derived. The effect of β‐mercaptoethanol content, APS content, and reaction temperature on the graft copolymerization was studied by the determination of the grafting parameters, including grafting percentage and grafting efficiency. Dynamic laser light scattering was used to investigate the effect of the pH value on the hydrodynamic radius of SPI and the grafted SPI aggregate in aqueous solution. The average hydrodynamic radius of SPI‐g‐PMAA aggregate was much smaller than that of the SPI aggregate at about the isoelectric point of SPI and a high pH value, and the hydrodynamic radius distribution of the SPI‐g‐PMAA aggregate was narrower than that of the SPI aggregate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4023–4029, 2006 相似文献
20.
赵洪池;吴秀亭;高姗姗;高玲玲;宋智伟;白海英 《中国塑料》2010,24(8):32-36
以苯乙烯(St)、γ-甲基丙烯酰氧丙基三甲氧基硅烷(TMSPMA)为单体,十二烷基硫酸钠和辛基酚聚氧乙烯醚为复合乳化剂,通过乳液聚合法制备了St-TMSPMA共聚物。用傅里叶变换红外光谱仪对共聚物进行了表征,1090 cm-1处Si-O-Si键的吸收峰和1723 cm-1处羰基的伸缩振动吸收峰表明TMSPMA与St发生了共聚反应;并研究了反应温度、引发剂浓度、乳化剂浓度和TMSPMA浓度对乳液共聚反应速率的影响,结果表明,升高反应温度、增大引发剂或乳化剂浓度以及降低TMSPMA浓度都可以提高聚合反应速率。 相似文献