无皂乳液聚合法合成聚苯乙烯微球的研究

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。     

石蜡聚苯乙烯微球的制备

用悬浮聚合法制备石蜡聚苯乙烯微球。研究了合成过程中搅拌器的位置、搅拌速度、升温速度和反应时间等对微球粒径分布及其产率的影响。     

多孔性聚苯乙烯磁性微球的制备

以磁流体颗粒为核,采用乳液聚合法合成了聚苯乙烯磁性微球.用该微球作为种子,采用分散聚合法,以乙二醇/水为分散介质,聚乙二醇为分散剂,甲苯为制孔剂,进行二乙烯苯-丙烯酸-苯乙烯三元共聚物的合成,最终合成了粒径大小均匀、具有强磁响应性的多孔聚苯乙烯磁性微球.     

石蜡聚苯乙烯微球的制备Ⅱ.分散剂及复合介质的影响

通过悬浮聚合法合成了石蜡聚苯乙烯微球,研究了合成过程中复合介质的配比和用量以及分散剂种类和用量对微球粒径及其分布的影响。结果表明:采用聚乙烯醇作分散剂,更有利于合成小粒径高产率的石蜡聚苯乙烯微球,悬浮聚合体系中水-乙醇复合介质的最佳体积配比和用量分别为1:2.5和150mL。     

磁性多孔聚苯乙烯微球的制备

在磁流体存在的情况下,采用改进了的乳液聚合法合成了具有磁核的微米级高分子聚苯乙烯微球。以该微球为种子,采用分散聚合法,以乙二醇／水为分散介质、聚乙二醇为分散剂、甲苯为制孔剂,进行苯乙烯-丙烯酸-二乙烯苯的三元共聚物的合成,最终合成出粒径分布均匀、磁响应性强的磁性多孔聚苯乙烯微球。     

无皂乳液聚合法合成单分散性阴离子聚苯乙烯微球

采用无皂乳液聚合法制备了粒径大小可控且均一的聚苯乙烯微球,研究了反应过程中SDS加入量、反应温度、引发剂加入量及反应介质对聚苯乙烯微球粒径大小及分布的影响。利用傅立叶变换红外光谱仪对微球结构进行了表征。     

交联型聚苯乙烯微球的制备

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。     

乳液法制备OVPOSS/PS复合微球及其热性能的研究

采用普通乳液聚合法制备了八乙烯基倍半硅氧烷(OVPOSS)交联的聚苯乙烯(PS)纳米复合微球,分析该纳米复合微球的化学结构、晶体结构及热性能。结果表明:通过自由基乳液聚合法可实现苯乙烯与OVPOSS的共聚,复合微球的粒径约为80nm,且尺寸分布较均匀;引入POSS可以显著提高复合粒子的耐热性和玻璃化转变温度。     

分散剂及复合介质对石蜡-聚苯乙烯微球合成的影响

通过悬浮聚合法合成石蜡-聚苯乙烯微球,研究了合成过程中复合介质的配比和用量以及分散剂种类和用量对微球粒径及其分布的影响。实验结果表明:采用聚乙烯醇作分散剂,更有利于合成小粒径、高产率的石蜡-聚苯乙烯微球,悬浮聚合体系中水-乙醇复合介质的最佳体积配比和用量分别为1:2.5和150mL。     

石蜡聚苯乙烯微球的制备

通过悬浮聚合技术合成了石蜡聚苯乙烯微球，研究了合成过程中引发剂浓度及交联剂用量对微球粒径及其分布的影响。     

Preparation of monodisperse magnetic polystyrene microspheres and its surface chemical modification

Monodisperse magnetic polystyrene (PS) microspheres were prepared in the presence of PS seed particles and styrene‐based magnetic colloid by the method of magnetic colloid swelling polymerization. The PS seed particles were prepared in advance by soap‐free emulsion polymerization. Styrene‐based magnetic colloid was used for swelling the PS seed particles in the magnetic colloid swelling polymerization process. After polymerization, functional amino groups were introduced onto the surface of the magnetic PS microspheres by surface Friedel‐Crafts acylation reaction. The morphology, size distribution, and magnetic properties of magnetic PS microspheres were characterized with scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM), respectively. SEM showed that the magnetic PS microspheres had an average size of 1078 nm with a narrow size distribution. VSM showed that the magnetic PS microspheres were superparamagnetic, and saturation magnetization was found to be 5.714 emu/g. The concentration of functional amino groups on the surface of magnetic PS microspheres was measured by atomic absorption spectroscopy and UV−Vis spectroscopy, and the concentration of amino groups was found to be 0.168 mmol/g. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Experimental investigation on the role of PVA in eliminating inhibition phenomenon of carbon black during the synthesis of polystyrene/carbon black composite particles

In this study, the role of polyvinyl alcohol (PVA) in eliminating the inhibition phenomenon of modified light‐weight carbon black (CB) during the synthesis of polystyrene/modified light‐weight carbon black (PS/MLCB) composite particles was examined. It was interesting to note that the polymerization time was largely shortened in the presence of a certain PVA. And the effect of PVA dosage on the polymerization time and the macromorphology of obtained PS/MLCB composite particles were systematically investigated, as well as the correlation between PVA dosage, polymerization time, and MLCB content. In addition, the potential mechanism about the role of PVA in eliminating the inhibition phenomenon of MLCB during the suspension polymerization of styrene was also proposed and analyzed in detail. The PS/MLCB composites particles were studied in terms of surface morphology, thermal stability, and molecular weight. Scanning electron microscopy images of the resulting PS/MLCB composite particles demonstrated that CB was well dispersed in the PS matrix. And the thermal stability of obtained PS/MLCB composite particles was significantly enhanced with the incorporation of MLCB, and increased with the increasing content of MLCB. This synthesis technique brought about a promising future in the large‐scale production of black expandable polystyrene. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Investigation on particular phase morphology of immiscible polyamide 12 and polystyrene blends prepared via anionic ring‐opening polymerization

In this article, the particular phase morphology of immiscible polyamide 12/polystyrene (PA12/PS) blends prepared via in situ anionic ring‐opening polymerization of laurolactam (LL) in the presence of polystyrene (PS) was investigated. Scanning electron microscopy (SEM) and Fourier Transform infrared Spectroscopy (FTIR) were used to analyze the morphology of the blends. The results show that the PS is dispersed as small droplets in the continuous matrix of PA12 when PS content is 5 wt%. However, when the PS content is higher than 10 wt%, two particular phase morphologies appeared. Firstly, dispersed PS‐rich particles with the spherical inclusions of PA12 can be found when PS content is between 10 and 15 wt%. Then the phase inversion occurred (the phase morphology of the PA12/PS blends changed from the PS dispersed/PA12 matrix to PA12 dispersed/PS matrix system) when PS content is 20 wt% or higher, which is unusual for polymer blends prepared via conventional methods such as mixing, hydrolytic polycondensation and so on. The formation of this particular phase morphology development was simply elucidated via a phase inversion mechanism. Furthermore, the stability of the phase morphology of the PA12/PS blends after annealing at 230°C was also investigated via SEM. POLYM. ENG. SCI., 52:1831–1838, 2012. © 2012 Society of Plastics Engineers     

Highly crosslinked micron‐sized,monodispersed polystyrene particles by semicontinuous dispersion polymerization. II. Semicontinuous,delayed addition and seeded semicontinuous processes

A highly crosslinked, monodispersed polystyrene (PS) particle was prepared by the seeded semicontinuous dispersion polymerization using ready‐made monodispersed PS seed particles. The effects of Styrene (in 2nd stage)/Styrene (in PS seed) ratio, addition point and feeding time of divinylbenzene (DVB), concentration of DVB and polymerization temperature on the particle size, size distribution and morphology of the resulting particles were investigated. Monodispersed PS particles with 15 wt % of the DVB were prepared at 1/1 in St/St ratio, In comparison, highly crosslinked monodispersed and smooth‐surfaced PS particles containing up to 70 wt % of the DVB were effectively prepared at 0/1. 5% weight loss of the PS particles determined by TGA occurred from 353.3 to 389.6°C and the degree of swellability in toluene decreased from 113 to 101% as the DVB concentration increased from 10 to 70 wt %, implying increased thermal stability and solvent resistance due to the increase of the crosslink density. This study demonstrates that the seeded semicontinuous process, primarily with the starved condition at the second stage, is an efficient way to obtain highly crosslinked, monodispersed PS particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

分散聚合法制备亚微米级单分散聚苯乙烯微球

以醇和水的混合液为分散介质,聚乙烯基吡咯烷酮（PVP）为分散剂、偶氮二异丁腈（AIBN）为引发剂,利用分散聚合法制备亚微米级的单分散聚苯乙烯（PS）微球。分别讨论分散剂的用量以及分散介质的溶解度参数对PS微球粒径的影响。结果表明,当分散介质溶解度参数和单体苯乙烯的溶解度参数越接近时,所制得的PS微球粒径越大,反之越小;随着分散剂PVP量的增加,微球的粒径减小,粒径分布变窄;所制得的聚苯乙烯微球表面光滑,呈均匀的球形。     

Preparation of polyaniline coated polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) microparticles and the further fabrication of hollow polyaniline microspheres

In this article, the microparticles of polystyrene‐poly(styrene‐co‐sodium 4‐styrenesulfonate) (PS‐PSS) coated by polyaniline (PANI) were prepared and hollow PANI microspheres were further obtained by dissolving the core. First, surface‐sulfonated monodispersed PS was prepared by copolymerization of sodium 4‐styrenesulfonate (SSS) and styrene with dispersion polymerization method. Then aniline was polymerized on the surface of the surface‐sulfonated PS (PS‐PSS) by chemical oxidative polymerization. After purification, we prepared core‐shell (PS‐PSS)/PANI particles. Hollow PANI microspheres were prepared by dissolving the plastic PS core of the (PS‐PSS)/PANI particles in chloroform. The growth process of PANI on the surface of PS‐PSS particles was investigated and the hollow PANI microspheres were characterized. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of PNIPAM/PS core/shell particles

Crosslinked, monodisperse PNIPAM particles were synthesized by precipitation polymerization. The particle size was measured by dynamic light scattering (DLS), capillary hydrodynamic fractionation (CHDF), and transmission electron microscopy (TEM). Two different polymerization methods were used to prepare PNIPAM/PS core/shell particles, both above and below the volume phase transition temperature (VPPT) using either a semibatch or seeded semibatch polymerization process. In both processes, uniform “raspberry” structures were obtained in which polystyrene formed small domains on the surface of the PNIPAM particles. The resulting core and shell structure was confirmed by temperature‐dependent particle size and density gradient experiments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Uniform Polystyrene Particles by Dispersion Polymerization in Different Dispersion Medium

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.     

A convenient approach to synthesize stable silver nanoparticles and silver/polystyrene nanocomposite particles

In this study, silver nanoparticles were prepared by the reduction of silver nitrate in SDS+ isopentanol/styrene/H₂O reverse microemulsion system using sodium citrate as reducing agent. The Ag/PS nanocomposite particles were prepared by in situ emulsion polymerization of the styrene system containing silver nanoparticles that did not separate from the reaction solution. The polymerization dynamic characteristic was studied, at the same time, silver nanparticles and the encapsulation of composite particles were characterized by Fourier‐transform‐infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X‐ray diffraction (XRD) measurement, UV–vis diffuse reflectance spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The results of TEM and UV–vis absorption spectra showed that well‐dispersed silver nanoparticles have a narrow size distribution. XRD showed that Ag and Ag/PS nanocomposite particles were less than 10 and 20 nm in size, which is similar to those observed by TEM. The results of XPS spectra revealed that the microemulsion system can stabilize the silver nanoparticles from aggregation and provided supporting evidence for the polystyrene encapsulated silver nanoparticle structure. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

种子聚合法制备PS/PAA核壳微球的研究

设计制备了以疏水性聚苯乙烯(PS)为核、以亲水性聚丙烯酸(PAA)为壳的PS/PAA核壳结构复合微球。首先利用无皂乳液聚合法制备了亚微米级的PS微球,再以其为种子,利用种子无皂乳液聚合法制备PS/PAA核壳微球。在种子聚合阶段,选用AIBN当引发剂,经过红外光谱(IR)表征,表明当使用油溶性引发剂偶氮二异丁腈(AIBN),使其最终形成PS/PAA核壳结构微球。这种方法解决了亲水性较强的单体在以水为介质时在PS微球溶于少量的苯乙烯(St),并在引发聚合之前经过充分的吸附溶胀,可使亲水性单体AAc在PS种子微球表面聚合生成壳层,解决表面不容易直接聚合生成壳层的问题。