共查询到19条相似文献,搜索用时 109 毫秒
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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
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采用无皂乳液聚合法制备了单分散亚微米级聚苯乙烯微球。考查了偶联剂的种类和用量对聚苯乙烯微球形貌、粒径、粒径分布及溶解性能的影响。结果表明:采用N,N-亚甲基双丙烯酰胺为偶联剂制备的聚苯乙烯微球为亚微米级,并且呈现单分散性;增加偶联剂的用量,聚苯乙烯微球的粒径先减小后增大,单分散指数变大。FT-IR谱图表明合成了聚苯乙烯微球。 相似文献
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通过无皂乳液聚合法制备羧基化的聚苯乙烯(PS)微球,并讨论了甲基丙烯酸(MAA)用量、引发剂过硫酸铵(APS)用量对单体转化率、微球粒径及其分布的影响。分别使用漂浮自组装法、单基片垂直沉积法和双基片垂直沉积法对聚合物微球进行自组装。结果表明:当MAA的摩尔分数为2%~8%,APS用量为0.168~0.504 g时,可制备单分散性良好的聚合物微球,且随着MAA,APS用量的增加,单体转化率增大,聚合物微球的粒径减小。与漂浮自组装法和单基片垂直沉积法相比,使用双基片垂直沉积法,当乳液固体质量分数为1.0%,微球自组装效果好,排列规整有序。 相似文献
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《日用化学工业》2015,(1)
以分散聚合合成的单分散聚苯乙烯微球作为种子微球,采用两步种子溶胀法制备多孔聚苯乙烯-二乙烯苯微球,并吸附玫瑰香精制备了香精多孔微球。利用马尔文激光粒度仪、比表面积孔径分布测定仪(BET)、热重分析仪(TGA)、扫描电镜(SEM)对种子微球和多孔微球的粒径、比表面积和孔结构、缓释性能、表观形貌进行了分析表征。结果表明:种球的粒径随着分散介质中无水乙醇体积分数的增大而增加;随着溶胀剂邻苯二甲酸二丁酯(DBP)用量的增加,多孔微球的平均粒径变大,分布变宽;随着交联单体二乙烯苯(DVB)用量增加,多孔微球平均粒径减小,分布变窄;以甲苯为致孔剂制备的多孔微球单分散性最好。当V(DBP):m(种球)=3:1,V(DVB):V(苯乙烯)=4:0时,制备的多孔微球的平均粒径约为4μm。以此多孔微球负载玫瑰香精,可以减缓香精的释放速率,提高起始分解温度,实现对香精的缓释。 相似文献
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《化工科技》2015,(6)
以苯乙烯(St)为单体,正庚烷为致孔剂,偶氮二异丁腈(AIBN)为引发剂,聚乙烯醇(PVA)为分散剂,用悬浮聚合法制备聚合物微球,在转速和分散剂一定的条件下,研究致孔剂用量对聚苯乙烯微球粒径和密度的影响。结果表明,微球的粒径和密度均受致孔剂含量的影响。致孔剂含量影响初始液滴大小、致孔剂均匀分布、液滴中致孔剂和聚苯乙烯比例、相分离难易和微球的溶胀度等方面,这些因素共同影响微球粒径和密度。在实验条件范围内,V(致孔剂)∶V(St)=0.40时制备的微球粒径最大,平均粒径1.6mm;V(致孔剂)∶V(St)=0.80时微球密度最低,为0.899 8g/cm3,漂浮率最高,为96.29%。 相似文献
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采用半连续乳液聚合法合成了以丙烯酸丁酯和甲基丙烯酸甲酯为成核单体,丙烯酸丁酯(MAA)、甲基丙烯酸甲酯(BA)、丙烯酸(AA)和γ―甲基丙烯酰氧基丙基三甲氧基硅烷为成壳单体的核壳结构乳液。采用马尔文纳米粒度仪等研究了乳液的粒径及其分布与引发剂和乳化剂用量之间的关系,粒径对乳液稳定性的影响以及乳液粒径与温度的关系,通过透射电镜对乳液微粒形态进行了分析。结果表明,乳液的粒径随着引发剂和乳化剂用量的增加而减小,乳液粒径在30~60℃时较为稳定,当引发剂过硫酸铵质量分数为0.55%,乳化剂十二烷基苯磺酸钠质量分数为2%时,制得的乳液粒径在120 nm左右,具有明显的核壳结构和较好的稳定性。 相似文献
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The effects of some polymerization conditions on poly(vinyl chloride) (PVC) particles produced by the suspension polymerization process were studied on a laboratory scale. The different stages of vinyl chloride suspension polymerization were investigated experimentally by using an on-line sample withdrawal technique during reaction. It was found that the method of addition of initiator has a great effect on the PVC particle uniformity as well as the size distribution. Furthermore, when the initiator was predispersed in the continuous phase, some latex particles were formed. The effect of the type of stabilizer was also studied with two different types of PVA [partially hydrolyzed poly(vinyl acetate)]. It was found that by changing the stabilizer, the particle size, the porosity, and the morphology could change. When H80 (PVA with a degree of hydrolysis of 80% and a molecular weight of 259,000) stabilizer was used, the rigidity of the PVC particles was weak. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 127–134, 1997 相似文献
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以苯乙烯(St)为单体、偶氮二异丁腈(AIBN)为引发剂、聚乙烯吡咯烷酮(PVP)为分散稳定剂,在乙醇-水反应介质中,采用分散聚合法制备了微米级单分散聚苯乙烯(PS)微球。分别用电镜扫描和激光粒度仪表征了PS微球表面形貌、粒径及粒度分布,探讨了影响PS微球粒径及粒度分布的诸多因素。结果表明,AIBN用量(以单体质量计,下同)大于5.0%或PVP用量(以单体质量计,下同)小于2%时,PS粒子间有聚并现象;当St浓度为10%、AIBN用量为2.5%、PVP用量为5.5%、醇水质量比为90∶10、聚合温度为70℃时,制备的PS微球粒径为1.612μm、粒度分散系数为0.357,微球单分散性及球形度最佳。 相似文献
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Soapless emulsion polymerization of n‐butyl methacrylate (BMA) was carried out through microwave heating with potassium persulfate (KPS) as an initiator at 73 ± 2°C. The influence of the monomer amount, the initiator amount, and the addition of ethanol on the monomer conversion, the particle size, and its distribution were studied. The results indicate that microwave polymerization had a much higher rate and produced smaller particles with a slightly broader size distribution compared with normal polymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2455–2459, 2001 相似文献
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VAc/MA/AA三元无皂乳液共聚的研究 总被引:4,自引:1,他引:4
以过硫酸钾(KPS)为引发剂,对VAc/MA/AA三元无皂乳液共聚进行了研究。探讨了引发剂用量、功能单体用量(AA)对乳液稳定性、胶乳粒子粒径、粒径分布及胶乳粘度、粘接强度等性质的影响。结果表明: 引发剂用量小于单体总质量的0.7%时,随着KPS用量的增加,胶乳粒子粒径减小,粒径分布变窄;引发剂用量大于单体总质量的0.7%时,随着KPS用量的增加,胶乳粒径及分布都增大,KPS用量为单体总质量的6%时,单分散性好;共聚乳液的粒径随AA用量的增加而增加,粒径分布则随AA用量的增加而减小,乳液粘度随AA用量增大而降低,而粘接强度随AA用量增大而增加,耐水性下降。 相似文献
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Poly(styrene‐co‐divinylbenzene) microspheres with size ranging from 1.6 to 1.8 μm were prepared in acetic acid by precipitation polymerization. The particle size and particle size distribution were determined by laser diffraction particle size analyzer, and the morphology of the particles was observed with scanning electron microscope. Besides, effects of various polymerization parameters such as initiator and total monomer concentration, divinylbenzene (DVB) content, polymerization time and polymerization temperature on the morphology and particle size were investigated in this article. In addition, the yield of microspheres increased with the increasing total monomer concentration, initiator loading, DVB concentration and polymerization time. In addition, the optimum polymerization conditions for synthesis of monodisperse crosslinked poly(styrene‐co‐divinylbenzene) microspheres by precipitation polymerization in acetic acid were obtained. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
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聚合条件对丙烯酸酯微乳液粒径及其分布的影响 总被引:2,自引:1,他引:1
以烯丙氧基壬基酚聚氧乙烯(10)醚硫酸铵(DNS-86)为阴离子型反应性乳化剂、过硫酸钾(KPS)为引发剂,制备丙烯酸酯微乳液。研究了聚合工艺、乳化剂、引发剂和单体等对微乳液的粒径及其分布的影响。结果表明:随着DNS-86、KPS用量的不断增加,乳胶粒的粒径逐渐减小,但过多加入KPS时会导致乳胶粒的粒径增大;乳胶粒的粒径均呈双峰分布,并且双峰随单体用量增加均向大粒径方向偏移;当w(DNS-86)=11%、w(KPS)=0.5%和m(单体)∶m(水)=6∶14时,采用种子预乳化半连续聚合法,可以制备出粒径小(平均粒径为39 nm)、分布窄(粒径分布指数为0.202)的丙烯酸酯微乳液。 相似文献
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Ultrasound‐assisted emulsion polymerization of poly(methyl methacrylate‐co‐butyl acrylate): Effect of initiator content and temperature
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Iraj Hasanzadeh Mehdi Barikani Ali Reza Mahdavian 《Polymer Engineering and Science》2016,56(2):214-221
In this study, we propose an efficient method for preparation of large scale, monodisperse poly(methyl methacrylate‐co‐butyl acrylate) latexes by application of the low power ultrasound irradiation. The effect of polymerization temperature and initiator concentration on the polymerization nature, particle size, and particle size distribution were investigated. Results indicated that the ultrasound pulses in the first minutes of polymerization increase instant free radical to monomer ratio as well mixing efficiency which led to higher monomer conversion, improved polymerization rate (especially at first 15 min of the reaction), and remarkable decrease in molecular weight distribution. Transmittance electron microscopy (TEM) and dynamic light scattering (DLS) revealed that the particle size and particle size distribution were significantly affected, particle size decreased, and more uniform particles were obtained. Dynamic mechanical thermal analysis also showed that the initiator concentration affected glass transition temperature (Tg) of the final copolymers and in the case of ultrasound‐assisted emulsion polymerization Tg was in a very good agreement with theoretical predictions for copolymerization. POLYM. ENG. SCI., 56:214–221, 2016. © 2015 Society of Plastics Engineers 相似文献
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Semibatch emulsion copolymerization was carried out to prepare poly(butyl acrylate‐co‐glycidyl methacrylate) latexes at 75°C, using potassium persulfate as an initiator, sodium dodecylbenzene sulfonate as an emulsifier and sodium bicarbonate as a buffer. The reaction was conducted in three stages; a further stage (called the steady stage, 2 h) was added to the traditionally stages (i.e., feed and seed stages) to improve considerably the monomer conversion. The monomer conversion and particle size distribution were studied by gravimetric and laser light scattering methods, respectively. The effects of variables such as agitation speed, emulsifier concentration, initiator concentration, feeding rate and comonomers ratio were fully investigated based on the monomer conversion‐time profiles and the particle size distribution to find the optimized copolymerization conditions. Increasing the agitation speed had a negative effect on the monomer conversion, but reduced coagulation of polymer particles. Monomer conversion could be improved by increasing the initiator or emulsifier contents. Feeding rate increased the polymer particle size sharply; however, it showed no significant effect on conversion. The final conversions were as high as 97–99% and they were recognized to be independent of the comonomers ratios employed. Morphological studies by scanning electron microscopy showed nano‐sized isolated particles which were partially aggregated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献