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氧化还原引发丙烯酸酯乳液共聚物的合成研究 总被引:7,自引:1,他引:7
本文以丙烯酸丁酯-苯乙烯-丙烯酸-丙烯酸羟乙酯为聚合体系,以过硫酸铵/亚硫酸氢钠为氧化还原引发剂。考察了不同氧化剂/还原剂用量、不同反应温度、不同乳化剂用量对单体转化率、特性上度、乳液稳定性的影响,并与过硫酸铵单组分引发进行了比较,用红外光谱(IR)和差热分析(DSC)对共聚物进行了表征。结果表明:采用氧化还原引发剂可以使聚合反应低温快速进行,过量的还原剂起阻聚或缓聚的作用,采用复合乳化剂体系可提高聚合反应速度和乳液的稳定性,合成的共聚物为无规共聚物。 相似文献
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自交联丙烯酸酯乳液的制备 总被引:4,自引:0,他引:4
讨论了以K2S2O8作为引发剂,使用全滴加法制备自交联丙烯酸酯—醋酸乙烯酯乳液过程中,复合乳化剂用量及相对比例,引发剂用量及滴加时间对聚合反应的影响。同热分解引发剂相比,对相同聚合体系,使用氧化—还原引发体系,可在较低温度聚合得到稳定的乳液。 相似文献
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氧化还原引发淀粉与丙烯酸接枝共聚研究 总被引:6,自引:0,他引:6
研究了马铃薯淀粉与丙烯酸的接枝共聚反应,以过硫酸钾-亚硫酸氢钠为氧化还原引发体系,考察了不同引发剂浓度、单体浓度、反应温度、反应时间等对单体转化率、接枝率和接枝效率的影响;用红外光谱对共聚物进行了表征。结果表明,采用氧化还原引发体系可使聚合反应低温快速进行,并确定反应较佳条件。 相似文献
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氧化还原引发下的淀粉、丙烯酸反相乳液聚合 总被引:3,自引:0,他引:3
以环己烷为连续相,Span20为乳化剂,采用氧化还原引发体系,通过反相乳液聚合技术,合成淀粉、丙烯酸接枝共聚物。并用红外光谱对共聚物进行了表征。研究结果表明:采用氧化还原引发剂可使聚合反应低温快速进行,在过硫酸钾为3.1mmol/L,亚硫酸氢钠为3.1mmol/L,单体丙烯酸浓度为2.6mol/L,反应温度为30℃,反应时间为3h,乳化剂浓度为5%时,单体转化率为92.6%、淀粉接枝率为43.2%、淀粉接枝效率56.4%。 相似文献
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以四氟硼酸1-丁基-3-甲基咪唑([bmim]BF4)离子液体为反应溶剂,以过氧化苯甲酰-N,N-二甲基苯胺氧化还原体系为引发剂引发聚合了丙烯酰胺。采用粘度法测定了聚丙烯酰胺的相对粘均分子量,考察了聚合反应时间、反应温度、引发剂浓度对聚合物分子量和聚合反应单体转化率的影响。结果表明,丙烯酰胺可以在[bmim]BF4离子液体中进行氧化还原聚合,聚合物分子量随反应温度的升高而下降,聚合反应速率随着温度的升高而升高,得到的聚丙烯酰胺分子量可高达7.32×107以上,且水溶性良好。 相似文献
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引发剂在乳液聚合反应中起着十分重要的作用,本文综述了水溶性氧化-还原引发剂在乳液聚合中的应用,以及引发剂对聚合反应速率,聚合物粒子形态,单体转化率的影响.通过均匀设计实验方法,研究了氧化剂与还原剂的最佳配比,采用亚硫酸氢盐/过硫酸盐(HSO3S2O2-8)氧化还原反应产生自由基来引发VAc/nBA/AA三元共聚合反应,得到了性能良好的乳液. 相似文献
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水溶性氧化—还原引发体系的乳液聚合中的应用研究 总被引:5,自引:1,他引:4
引发剂在乳液聚合反应中起着十分重要的作用,本文综述了水溶性氧化-还原引发剂在乳液聚合中的应用,以及引发剂对聚合反应速率,聚合物粒子形态,单体转化率的影响。通过均匀设计实验方法,研究了氧化剂与还原剂的最佳配比,采用亚硫酸氢盐/过硫酸盐(HSO3S2O3^2-)氧化还原反应产生自由基来引发VAc/nBA/AA三元共聚合反应,得到了性能良好的乳液。 相似文献
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研究了以Fe2+-H2O2为引发剂的木薯淀粉与醋酸乙烯酯的接枝共聚反应,并对重要的反应条件进行了讨论。结果表明:当单体与淀粉的质量配比为1.0~2.0,引发剂浓度为1.0 mmol/L,H2O2与Fe2+的摩尔比为2,反应温度为40°C,反应时间为3 h,采用Fe2+→单体→H2O2的加料顺序时,可以得到较高的转化率、接枝率、接枝效率,分别为86.47%、55.30%及31.98%,并探讨Fe2+-H2O2的引发机理。通过Srectrum One红外光谱及电镜对接枝物的结构进行了分析。 相似文献
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Graft copolymerization of acrylic acid (AAc) onto polystyrene (PS) by the solid phase graft copolymerization technique was studied. Benzoyl peroxide (BPO) was used as the free radical initiator. Acrylic acid was introduced into the reactor as an aqueous solution. Optimum reaction conditions to obtain maximum grafting were evaluated. The variables studied were temperature, initiator concentration, monomer concentration, acrylic acid-to-water ratio, and reaction time. The graft copolymer was characterized by infrared (IR) spectroscopy, and the graft level was quantified by the IR absorbance ratio technique and titration. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1001–1007, 1998 相似文献
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研究了Fe2+-H2O2-二氧化硫脲体系引发绒毛浆与甲基丙烯酸甲酯的接枝共聚。考察了该引发体系下反应温度、反应时间、过氧化氢用量、二氧化硫脲用量、单体浓度和液比对接枝率和接枝效率的影响。并用红外光谱对接枝纤维产物进行了鉴定。结果表明,二氧化硫脲的加入能有效地使接枝共聚得以顺利进行;适当地提高温度,增加单体浓度,控制合适的二氧化硫脲用量都能提高接枝率和接枝效率,并在较短的时间就能成功接枝;接枝效率几乎不受液比的影响,一般维持在90%以上,接枝过程产生的均聚物极少。 相似文献
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The graft copolymerization of styrene and methyl methacrylate onto natural rubber latex was studied under various reaction conditions using a cumene hydroperoxide redox initiator. The monomer conversion, graft copolymer compositions, and grafting efficiency were determined. The synthesized graft copolymers were purified and then characterized by proton nuclear magnetic resonance (1H‐NMR) analysis and differential scanning calorimetry (DSC). A 2 fractional factorial experimental design was applied to study the main effects on the grafting. The variables investigated in this work were the amount of the initiator and emulsifier, the presence or absence of a chain‐transfer agent, the styrene‐to‐methyl methacrylate ratio, the monomer‐to‐rubber ratio, and the reaction temperature. The measured response for the experimental design was the grafting efficiency. The analysis of the results from the design showed the sequence of the main effects on the observed response of the grafting of styrene and methyl methacrylate onto natural rubber, in ascending order. The amount of the chain‐transfer agent and the reaction temperature in the range of the test had significant effects and one marginally significant effect was the monomer‐to‐rubber ratio. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 63–74, 2003 相似文献
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The graft copolymerization of 50/50 (w/w) styrene/methyl methacrylate mixtures onto natural rubber seed latex were carried out by using cumene hydroperoxide/sodium formaldehyde sulfoxylate dihydrate/EDTA‐chelated Fe2+ as a redox initiator. The effects of the process factors such as the amount of initiator, emulsifier, and chain‐transfer agent; monomer‐to‐rubber ratio; and temperature on the grafting efficiency (GE) and grafting level (GL) are reported. The mechanism of graft copolymerization was investigated. The synthesized graft copolymers were purified and then characterized by proton nuclear magnetic resonance (1H‐NMR) analysis. Transmission electron microscopy (TEM) was used to study the morphology of the graft copolymers. It appears that the formation of graft copolymers occurs on the surface of the latex particles through a chain‐transfer process. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2993–3001, 2002; DOI 10.1002/app.2328 相似文献