共查询到20条相似文献,搜索用时 125 毫秒
1.
采用辛醇和乳化剂(OS)作为复合分散剂,用悬浮聚合法制备了4-氨基吡啶分子印迹聚合物微球。采用无皂乳液聚合法对分子印迹聚合物种子微球的制备与性能进行了研究。结果表明,辛醇与极少数乳化剂复合使用,提高了乳液的稳定性,改善了种子微球粒径大小及粒径分布。当辛醇用量为单体质量的3.0%、丙烯酸乙醋与苯乙烯质量比为1:0.229、反应温度为85℃、pH值为8.0时,能够制备出期盼的分子印迹聚合物微球。 相似文献
2.
3.
4.
5.
6.
7.
通过沉淀聚合制备聚脲微球,主要研究反应时间、反应温度及单体添加量对聚脲微球粒径、粒径分布及形态结构的影响。结果表明,在其他条件不变,反应时间在80~110 min时,聚脲微球的粒径分布呈现双粒径分布,120min时体系为单粒径分布,微球平均粒径由2. 1μm增加到5. 9μm;其他条件不变,反应温度在30~45℃时,粒径由5. 9μm增加到7. 0μm,粒径变异系数(CV)控制在5%以内。当温度到达50℃时,微球CV大于5%;其他条件不变,单体投入量在2%~5%时,微球粒径由5. 8μm逐步增加到8. 4μm,CV小于10%,当质量分数为7%时,CV为52%。通过对反应时间、反应温度及单体添加量的研究,得到了一系列制备粒径及形态可控聚脲微球的规律,为制备出粒径及形态可控的聚脲微球奠定实验和理论基础。 相似文献
8.
乳液聚合法制备中空乳胶粒的研究 总被引:1,自引:0,他引:1
采用多段乳液聚合法制备了聚(甲基丙烯酸甲酯-丙烯酸正丁酯-甲基丙烯酸)/聚(苯乙烯-丙烯腈)核壳乳液,然后用碱溶胀处理得到了单分散性较好的中空聚合物微球.以透射电子显微镜(TEM)和扫描电子显微镜(SEM)对各阶段乳液聚合的胶粒大小和分布以及形貌行了表征.研究了种子乳液聚合反应时间、搅拌速度、单体滴加速度等因素对中空聚合物微球的形态及粒径分布的影响.结果表明:当单体的滴加速度控制在0.1~0.2g/min,搅拌速度控制在80~120 r/min时,可以制备中空形态较好的中空聚合物微球. 相似文献
9.
《胶体与聚合物》2016,(2)
采用W/O/W乳液法制备了多孔聚合物微球(聚苯乙烯-二乙烯基苯)(PSDS),通过扫描电子镜、激光粒度仪、孔径及比表面积分析仪等对微球进行了表征,研究了乳化剂类型、分散剂用量及搅拌速率等对PSDS微球形貌、粒径等性能的影响。结果表明:不同种类乳化剂(Span-80、十六烷基三甲基溴化铵、OP-10)均能得到聚合物微球,以Tween-80为乳化剂,形成的PSDS不规则,以Span-80为乳化剂,PSDS的粒径分布较窄;分散剂用量增加,PSDS微球粒径变小,粒径分布变窄;搅拌速率越快,PSDS微球的粒径越小,粒径分布越窄;典型PSDS的比表面积为175.3m~2/g,孔容为0.35cm~3/g,平均孔径为0.86 nm。 相似文献
10.
选用无皂乳液聚合法合成了聚苯乙烯微球乳液,并对无皂乳液聚合的最新研究动态及应用进行了介绍和总结。为了得到制备单分散微球的有利反应条件,本文研究了无皂乳液聚合体系中反应温度、单体用量、引发剂用量、反应时间等因素对聚苯乙烯微球的粒径及粒径分布的影响,同时通过透射电子显微镜(TEM)对聚苯乙烯微球进行了表征分析。实验结果表明:无皂乳液聚合法可以制备出大小均一、单分散性好的PS微球乳液;反应温度在80~95℃范围内时,温度升高,微球粒径减小,且粒径范围在300~500 nm之间;改变单体用量可以制备粒径大小不同的聚苯乙烯微球乳液;改变引发剂用量也是制备不同粒径微球的一种有效途径;延长反应聚合时间,主要是为了提高转化率,而对微球的聚合度基本没有影响。 相似文献
11.
以苯乙烯(St)为单体,十二烷基硫酸钠为乳化剂、过硫酸钾为引发剂,碳酸氢钠和氢氧化钠为复合缓冲剂,通过乳液聚合反应,合成了粒径分布均匀的聚苯乙烯纳米微球(PSt)。在确定缓冲剂用量及引发剂滴加方式的条件下,经正交实验优选出最佳合成工艺条件如下:蒸馏水与苯乙烯的体积比为1.5:1、乳化剂用量为苯乙烯质量的1.0%、引发剂用量为苯乙烯质量的1.2%、反应时间为8h,反应温度为80℃。在此条件下转化率为94.58%,并用扫描电镜(SEM)和红外光谱(FTIR)对其进行了表征。 相似文献
12.
中空聚合物微球的制备——酸含量的影响 总被引:5,自引:0,他引:5
采用预乳化滴加工艺结合多段乳液聚合方法先制备聚(甲基丙烯酸甲酯-丙烯酸丁酯-甲基丙烯酸)/聚(苯乙烯-甲基丙烯酸)核壳乳液,随后以碱/酸溶胀处理得到了单分散性优异且中空度为30%的中空聚合物微球.以动态光散射(DLS)、透射电子显微镜(TEM)和场发式扫描电子显微镜(FESEM)等对各阶段乳液聚合的胶粒大小和分布以及形态结构进行了表征.实验考察了种子酸含量对种子和核壳乳胶的特性以及中空聚合物微球形态的影响规律.结果表明,种子制备时的酸用量以30%~35%为宜,核壳胶粒中约85%的酸单元存在于核聚合物内部.另外,探讨了核壳胶粒在碱/酸溶胀处理过程中的中空形成机理. 相似文献
13.
Uniform molecularly imprinted polymer beads were synthesized by precipitation polymerization for separation of triazine herbicides. A series of imprinted polymers were prepared using ametryn as template and divinylbenzene as crosslinking monomer, in combination with three different functional monomers under different solvent conditions. Under optimized reaction conditions, we obtained uniform molecularly imprinted polymer microspheres that display favorable molecular binding selectivity for triazine herbicides. The imprinted polymer beads synthesized using methacrylic acid as functional monomer in a mixture of methyl ethyl ketone and heptane showed the best results in terms of particle size distribution and molecular selectivity. Compared with nonimprinted polymer microspheres, the imprinted microspheres displayed significantly higher binding for a group of triazine herbicides including atrazine, simazine, propazine, ametryn, prometryn, and terbutryn. For the first time, precipitation polymerization has been used to produce highly uniform imprinted microspheres suitable for affinity separation of triazine herbicides. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
14.
Narrow‐dispersion or monodisperse polymer microspheres with active hydroxyl groups were prepared by distillation–precipitation polymerization in the absence of any stabilizer. The monomer hydroxyethyl methacrylate (HEMA) was copolymerized with either commercial divinylbenzene (DVB) (containing 80 % of DVB isomers) or ethyleneglycol dimethacrylate (EGDMA) as crosslinker by distillation–precipitation polymerization technique with 2,2′‐azobisisobutyronitrile (AIBN) as initiator in neat acetonitrile. The effects of the crosslinker and the crosslinking degree on the morphology and the loading of the active hydroxyl group of the resultant microspheres were investigated. The agitation caused by distilling off a portion of the polymerization solvent during the polymerization avoided coagulation and resulted in the narrow‐dispersion or monodisperse polymer microspheres for the distillation precipitation technique. Copyright © 2005 Society of Chemical Industry 相似文献
15.
This article describes the preparation of monodispersed microspheres of glycidyl methacrylate, 2-hydroxyethyl methacrylate, and triethylene glycol dimethacrylate by radical polymerization. The initial stage of the polymerization reaction began in the liquid phase. As the polymerization proceeded, a nuclear polymer chain of microspheres was generated from soluble oligomeric radicals and then solidified from the liquid phase. The radius of the microspheres was controlled by polymerization parameters, such as monomer concentration, polymerization time, and the kind of polymerization solvent. A small number of thin platelike substances may be produced by the anisotropy of the two-dimensional monomer added to the oligomeric radicals. The monodispersed microspheres were achieved through the use of the following: (1) a fluorinated tube in which the polymerization reaction proceeded; (2) a monomer concentration of about 1 mol/L; (3) a higher concentration of crosslinking regeant than used commercially; (4) the prevention of the occurrence of polymer microsphere aggregation; (5) pouring the solution mixtures into a large amount of cooled acetone after the polymerization reaction; and (6) the use of a low-temperature purification process and centrifugation at low temperature. This article describes the mechanism of microsphere formation and growth by solution polymerization. © 1995 John Wiley & Sons, Inc. 相似文献
16.
Rosin was reacted with hydroxyethyl methacrylate to produce a macromonomer. This macromonomer was used to partly replace styrene for the novel preparation of polymer microspheres with divinylbenzene via suspension polymerization. Orthogonal experiments were conducted to analyze the factors influencing the particle size, particle size distribution, swelling ratio and degree of crosslinking of the polymer microspheres. Fourier transform IR spectroscopy, thermogravimetry and scanning electron microscopy were used to examine the structures, thermal properties and morphologies, respectively, of the polymer microspheres. The results showed that the amount of dispersant had the greatest influence on particle size and distribution. On the other hand, the monomer ratio greatly influenced the swelling ratio and degree of crosslinking of the polymer microspheres. The decomposition temperature of the polymer microspheres increased upon introduction of the rosin moiety into the product. Open pores were abundant on the surface of the polymer microspheres due to the existence of the porogen, which provided a base for adsorption and separation. The present study opens a novel route for using naturally occurring rosin. Copyright © 2012 Society of Chemical Industry 相似文献
17.
聚苯乙烯单分散交联纳米微球的制备和表征 总被引:2,自引:0,他引:2
以苯乙烯为单体,二乙烯基苯为交联剂、过硫酸钾为引发剂,甲基丙烯酸为稳定剂,通过无皂乳液聚合反应,合成0粒径均匀分布的聚苯乙烯高分子微球.聚苯乙烯纳米微球由于其特定的尺寸和形貌,具有其他材料所不具备的特殊功能.采用无皂乳液聚合法制备了具有单分散性的亚微米级聚苯乙烯球,考察了聚合体系单体对微球粒径的影响.通过研究聚合物微球的自组装工艺,选出最佳条件并制备具有三维有序结构的光子材料.结果表明不同半径的聚苯乙烯微球在白光照射下会显现出不同颜色.可作为填料放到涂料中. 相似文献
18.
19.
在混合溶剂丙酮/水介质中,以纳米SiO_2粒子为Pickering乳化剂,阳离子单体甲基丙烯酰氧乙基三甲基氯化铵(MTC)为辅助单体,苯乙烯(St)和丙烯酸丁酯(BA)发生无皂乳液聚合制备了固含量高达25%的草莓型P(St-BA)/SiO_2纳米复合微球。研究了初始硅溶胶用量、软硬单体配比对复合微球形态、粒径和SiO_2吸附量的影响,并测试了乳胶膜的吸水性能。结果表明:在实验范围内制备得到的复合微球粒径在290~560 nm之间,SiO_2的吸附量介于28~34wt%之间。 相似文献
20.
以聚乙烯基吡咯烷酮(PVP)作为分散剂,以偶氮二异丁腈(AIBN)作为引发剂,在以水为溶剂的体系中以苯乙烯为单体制备出纳米级种子微球;然后利用二步溶胀法再分别以苯乙烯(St)和甲基丙烯酸甲酯(MMA)为单体,进而制备出微米级的核壳型微球。运用动态激光光散射仪对粒子半径的进行表征,其中以甲基丙烯酸甲酯为单体所制备核壳型微球粒子的半径为953 nm;以苯乙烯为单体所制备核壳型微球粒子的半径为808 nm。 相似文献