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交联型单分散聚苯乙烯微球的制备 总被引:1,自引:0,他引:1
以聚乙烯吡咯烷酮(PVP)为分散剂,偶氮二异丁腈(AIBN)为引发剂,乙醇为分散介质,二乙烯基苯(DVB)为交联剂进行了苯乙烯(St)的分散聚合;讨论了引发剂、交联剂、分散剂、单体用量对聚合物粒径及分布的影响,制备了交联型单分散聚苯乙烯微球。实验表明:当交联剂质量分数达到单体质量分数的1%时,微球依然可以保持良好的单分散性。在聚合体系中引入抗坏血酸,使其与微量的氧结合,有效地提高了微球的均匀度。 相似文献
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连续法制备单分散聚苯乙烯微球及粒径影响因素的研究 总被引:1,自引:0,他引:1
以苯乙烯为单体,偶氮二异丁腈(AIBN)为引发剂,聚乙烯吡咯烷酮(PVP)为分散剂,采用连续分段添加引发剂的方法制备微米级的聚苯乙烯微球。研究了引发剂的添加方式,各组分用量变化对聚苯乙烯微球粒径和粒径分布的影响。结果表明:在反应过程中不断地补加引发剂可以保持活性自由基的生成速率,对聚苯乙烯微球的粒径和粒径分布有着重要的影响。在此基础上,通过改变各组分的用量可以制备出表面光洁,粒径在1.3μm左右的聚苯乙烯微球,且单分散性良好,单分散系数在1.02左右。 相似文献
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采用无皂乳液聚合法制备了亚微米级聚苯乙烯(PS)微球,考察了苯乙烯(St)单体浓度、引发剂过硫酸钾(K2S2O8)浓度、离子强度(氯化钠浓度)与PS微球粒径及其分布的关系。然后通过加入微量乳化剂或β-环糊精对无皂乳液聚合法进行改进,研究了改进效果。结果表明,PS微球的粒径随St单体浓度和氯化钠浓度的增加而增加、随K2S2O8浓度的增加而减小,通过调节这3种原料的浓度,可制得粒径在450~1000 nm且单分散系数小于0.08的PS微球,但产品收率较低,仅为30%左右。在相同的合成条件下,加入微量乳化剂可制得粒径在100~350 nm且单分散系数小于0.05的PS微球,产品收率提高到75%左右;加入微量β-环糊精可制得粒径在300 nm左右且单分散系数小于0.08的PS微球,产品收率可达80%且反应时间大幅缩短,由原来的12 h缩减到5 h。 相似文献
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以苯乙烯(St)和含氟单体(G04)为原料、聚乙烯吡咯烷酮(PVP)为分散剂和乙醇/水为混合溶剂,采用分散聚合法制备出PS-F(含氟聚苯乙烯)微球;然后以苯丙乳液提供的附着力、PS-F微球提供的疏水性能,制备PS-F疏水涂层。结果表明:制备PS-F微球的最佳工艺条件是m(总单体)=m(St+含氟单体)=20 g且m(St):m(含氟单体)=18:2、w(AIBN)=1.5%、w(PVP)=7.5%、V(乙醇)=108 mL、V(H_2O)=72mL、反应温度70℃和反应时间10 h,此时PS-F微球的粒径为0.4~1.0μm;当w(PS-F微球)=60%时,疏水涂层的水接触角为130。左右;含氟单体含量和苯丙乳液含量对水接触角的影响不大,涂层疏水性能主要与PS-F微球大小、涂层表面粗糙度有关。 相似文献
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以苯乙烯和甲基丙烯酸为单体、PVP为分散剂,AIBN为引发剂,在异丙醇-水介质中,用分散聚合方法制备了微米级单分散的聚(苯乙烯-甲基丙烯酸)[P(St-MAA)]微球。结果表明,采用反应初期低温、中后期升温的聚合工艺可制得单分散的聚合物微球,并提高聚合反应的速率和转化率。P(St-MAA)微球的粒径及其分布可通过改变介质组成来控制。分散介质中异丙醇质量分数降低,聚合反应速率增大,转化率升高,微球的粒径减小。当分散介质中异丙醇的质量分数降低到60%时,聚合反应中有凝胶生成,粒径分布呈多分散性。 相似文献
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Using PVP K-30 as steric stabilizer and AIBN as initiator, uniform polystyrene (PS) particles were
prepared by dispersion polymerization of styrene in ethanol/water and isopropanol/ water media. The effects
of initiator and stabilizer concentration, alcohol/water volume ratio on the average sizes and size range
of PS particles were investigated. Unifrom PS particles in the size range of 0.7-1.7 μm were obtained.
The results showed that higher stabilizer concentration led to PS particles with smaller average sizes,
and higher initiator concentration caused greater average particle sizes. It was also found that the
average sizes reduced and size ranges became narrow as the polarity (solubility parameter) of dispersion
medium employed was increased. 相似文献
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反应体系组成对纳米SiO2/PS复合粒子粒径及分布的影响 总被引:1,自引:1,他引:0
研究了在纳米SiO2粒子表面的苯乙烯原位聚合反应中,反应体系的组成(单体、引发剂、稳定剂及纳米SiO2粒子用量)对纳米SiO2/PS复合粒子的形态、粒径大小及分布的影响。结果表明,当纳米SiO2粒子与单体质量比为5%,苯乙烯质量分数为25%,引发剂及稳定剂用量分别为单体用量(质量比)的0.15%和1.5%时,制备出的纳米SiO2/PS复合粒子呈球形,表面光滑无明显缺陷,颗粒之间分散性很好,粒径为0.923μm,分散系数为0.108。 相似文献
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The research was to design a carrier used in tissue engineering and drug-release system. In this article, a new dispersion polymerization system without organic solvent was described to prepare poly(ethylene glycol) diacrylate/2-hydroxyethyl methacrylate (PEG-DA/HEMA) copolymer hydrogel microspheres as carrier, which introduced chitosan (CS) as reaction medium and costabilizer, polyvinylpyrrolidone (PVP) as steric stabilizer and benzoy peroxide (BPO) as initiator. The effects of mass ratios of monomers, concentration of stabilizer and initiator on partilcle size and polydispersity index (PDI) of microspheres were investigated. Furthermore, bovine serum albumin (BSA) as protein model, the composition of copolymer, size, and polydispersity index of microspheres were employed to study the amount and released ratio of loaded BSA in this article. The results showed that hydrogel microspheres with 3.26 ± 0.24 μm in particle size and 1.03 ± 0.008 in PDI, obtained with mass ratios of PEG-DA 60/HEMA 40, 2 wt % of stabilizer content and 2 wt % of initiator content (relative to total mass of monomers), had 124.57 ± 3.14 mg/g in the amount of loaded BSA and 59.09 ± 1.43% of released ratio. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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The dispersion polymerization of n‐butyl acrylate (BA) was investigated using alcohol/water mixtures as the dispersion medium, 4,4′ ‐azobis‐(4‐cyanopentanoic acid) as the initiator, and polyvinylpyrrolidone (PVP) as the stabilizer. The effects of polymerization parameters, such as the alcohol/water ratio in the medium and the type and concentration of the polymeric stabilizer, on the resulting particle size and size distribution were studied. The final particle size and the stability of the dispersion system were found to be greatly influenced by the type of alcohol used in the mixture; that is, methanol or ethanol, even though the apparent solubility parameters are almost the same for the two types of mixtures. Poly(butyl acrylate) particles with controlled size and size distribution (monodisperse), and gel content were successfully prepared in a 90/10 methanol/water medium. It was found that the particle size decreased with increasing initiator concentration. This is the opposite of what was previously reported in the dispersion polymerizations of styrene and methyl methacrylate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2692–2709, 2002 相似文献
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Uniform polystyrene (PSt) particles with the size of 1.9 μm were first prepared via dispersion polymerization, and then used as the seeds in a second‐stage dispersion copolymerization of styrene (St) and methacrylic acid (MAA) to produce carboxyl‐carrying microspheres. The PSt seed particles were swollen by monomer mixture of St and MAA, including an oil‐soluble initiator 2,2′‐azobisiso‐butyronitrile (AIBN), before polymerization. Finally, uniform PS/P(St/MAA) (polydispersity index, PDI = 1.02) microspheres with the size of 2.2 μm were obtained. The average particle size and size distribution of the final microspheres were investigated. MAA contents between 54 and 97 mg/g were detected from the PS/P(St/MAA) particles produced under different conditions. Dispersion medium has great influence on the kinetics of polymerization, due to its effect on the partitioning of monomers, solvents, and initiator in the particle phase, probably as well as on the conformation of the dispersion agent on the surface of the particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3586–3591, 2006 相似文献
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In this study, monosized polystyrene (PS) latices were prepared by dispersion polymerization of styrene in isopropanol-water media using poly(acrylic acid) (PAA) as a steric stabilizer and 2,2′-azobisizobutyronitrile (AIBN) as an initiator. The effects of initiator and stabilizer concentrations, alcohol/water and monomer/dispersion medium ratio on the polymerization kinetics, and the size and monodispersity of PS latices were experimented with in a stirred reactor system. Monosize PS beads in the size range of 1.0–3.0 μm were obtained. The PS latex obtained in the first step having a diameter of 2.3 μm were used as the seed latex, and styrene/acrylate monomers, acrylic acid (AA), 2-hydroxyethyl methacrylate (HEMA), and dimethylaminoethyl methacrylate (DMAEMA) were copolymerized onto the PS latex particles. The incorporation of functional groups to the surface and bulk structure of PS was confirmed by IR, FTIR, XPS, and zeta potential measurements. © 1994 John Wiley & Sons, Inc. 相似文献
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Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2'-azobisisobutyronitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of 1μm with superparamagnetic characteristics. The saturation magnetization was found to be 4.5emu·g-1. There was abundance of epoxy groups with density of 0.028 mmol·g-1 in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology. 相似文献