原位乳液聚合法制备二氧化钛/聚苯乙烯复合微球

采用原位乳液聚合法制备了TiO2 PS(二氧化钛 聚苯乙烯)复合微球,探索了复合微球的制备条件,并采用红外、透射电镜和差热分析等分析手段对其结构进行了表征。结果表明,采用原位乳液聚合法可制备出粒径分布均一的不同粒径的TiO2 PS复合微球,反应条件对微球的形成及粒径影响很大,介质pH>7以及乳化剂用量小于临界胶束浓度是形成复合微球的必要条件;复合微球粒径随苯乙烯浓度增加而增大。     

细乳液聚合制备磁性复合微球研究进展

介绍了细乳液聚合的特点、细乳液聚合制备磁性复合微球的一般步骤;从制备影响因素角度,对近年来国内外细乳液聚合制备磁性复合微球的研究进行了综述。磁性复合微球主要采用正相细乳液聚合,影响微球制备的主要因素有乳化剂类型和用量、磁性纳米粒子表面修饰、超声分散、助稳定剂类型、交联剂引发剂和磁流体用量等。今后,细乳液聚合制备磁性复合微球的研究仍将关注提高复合微球性能(高磁响应性能、粒子大小可控且均匀、具有表面功能基团)及产率(磁性粒子包覆率)等方面。     

无皂乳液聚合制备SiO_2/PMMA纳米复合胶体微球

采用半连续无皂乳液聚合方法在未经硅烷偶联剂改性的230 nm亲水性SiO2微球表面聚合甲基丙烯酸甲酯(PMMA)壳层,制备以SiO2粒子为核、PMMA为壳层的复合胶体微球。研究微球表面形貌、组成、粒径变化规律,探索聚合反应的成核过程和PMMA进料流量对复合微球粒径的影响。结果表明,在未经硅烷偶联剂改性的纳米SiO2表面可形成稳定规整的PMMA壳层,SiO2/PMMA复合胶体微球球型度接近1.0,单分散性较好,多分散度指数(PDI)小于0.04。聚合反应受甲基丙烯酸甲酯(PMMA)单体含量控制,随着PMMA进料流量增加,乳胶粒子成核过程由均相成核过渡为胶束成核,复合微球粒径加速增大,多分散性增强,其粒径可通过调节PMMA进料流量控制。     

无皂乳液聚合制备多孔聚苯乙烯纳米微球

苯乙烯(St)单体、过硫酸钾(KPS)和二乙烯基苯(DVB)通过无皂乳液聚合,在70℃下反应8 h,合成聚苯乙烯(PS)纳米粒子,PS磺化,得到磺化聚苯乙烯(SPS),通过正庚烷和乙醇溶胀后,水进入粒子内部发生相分离,形成多孔聚苯乙烯PS,在-30 k Pa负压条件下,负载缓蚀剂苯丙三氮唑(BTA)。考察单体量和反应时间对粒子形态的影响。结果表明,采用10 g St,0.05 g KPS,100 mL去离子水,反应2 h后加入0.05 g DVB,可以得到粒径合适、球形完整的PS纳米微球。PS微球磺化6 h,n(乙醇)∶n(水)∶n(正庚烷)=5∶5∶1,造孔10 h时,可得到形貌和孔径合适的多孔SPS纳米微球。SEM、TEM和FTIR表明,多孔SPS微球表面和内部负载上了一定量的缓蚀剂BTA。     

细乳液聚合制备单分散性超顺磁性Fe_3O_4/聚苯乙烯复合微球

采用共沉淀聚合制备出单分散性的油酸改性的磁性纳米粒子,将制备的磁性纳米粒子加入到细乳液聚合的油相中,制备出单分散性超顺磁性的Fe_3O_4/聚苯乙烯复合微球。研究了不同乳化剂和引发剂条件下所制备的磁性复合微球的形貌,并采用透射电镜(TEM),热重分析(TGA)和振动样品磁强计(VSM)对Fe_3O_4/聚苯乙烯复合微球进行了表征,结果表明,不同的乳化剂条件下乳液具有不同的稳定性,而不同的引发剂下所制备的聚合物复合微球的形貌不同。其中采用阴离子型的十二烷基硫酸钠(SDS)为乳化剂,油溶性的偶氮二异丁腈(AIBN)为引发剂制备出的复合微球磁含量较高,可以达到19. 74%;振动样品磁强计的测试表明,所制备的磁性微球都具有超顺磁性,复合微球的饱和磁强度值可达到39. 8 emu/g。     

微乳液聚合和细乳液聚合

分别从微乳、细乳体系的形成,聚合机理及聚合特点等方断对两者进行了比较,并对各自的应用前景进行了展望。     

Pickering乳液聚合制备共价键连接的磁性复合微球

以先后用TEOS和KH570改性的表面含双键的Fe3O4纳米粒子为唯一乳化剂,以甲基丙烯酸甲酯(MMA)为单体,制备了稳定的Pickering乳液,并通过Pickering乳液聚合制备了以PMMA为核、Fe3O4为壳的Fe3O4/PMMA磁性复合微球。用粒度分析仪、光学显微镜、扫描电镜、傅立叶红外光谱仪、热失重分析仪、振动样品磁强计对所制备的改性Fe3O4纳米粒子和磁性复合微球的结构、形态和性能进行了表征。结果表明:通过Fe3O4表面双键与单体的共聚,使微球表面的Fe3O4通过化学键与PMMA连接,所制备磁性复合微球粒径为15～20μm、磁含量为4.9%、比饱和磁化强度为2.38emu.g-1,可在外磁场下方便地分离。     

细乳液聚合法制备含结晶紫微球乳液的研究

本研究采用过硫酸钾为水溶性引发剂,利用细乳液聚合来制备含结晶紫油溶性染料功能化乳液。反应完成后,用称量法测定其转化率,用紫外-可见光吸收光谱进行表征,用动态光散射测试粒径大小,并通过扫描电镜观察了纳米粒子形貌,用TG表征其热稳定性能,最终得到了制备含结晶紫纳米聚合物微球彩色乳液的一般方法。     

乳液聚合法制备单分散性PS磁性微球的研究

用改进的乳液聚合法,以乙醇／水为反应介质,十二烷基苯磺酸钠为乳化剂,过硫酸钾为引发剂,制备出单分散性聚苯乙烯磁性微球。通过SEM观察其表面形貌、粒径大小及分布,表明具有良好的球形度和一定均匀性。为了制备出粒径小、粒径分布均匀的聚苯乙烯磁性微球,设计了正交实验来优化实验条件;探讨了反应聚合温度、引发剂用量、乳化剂用量及醇水比对微球粒径及粒径分布的影响。实验表明在实验范围内,较低的反应温度、较低的引发剂用量、较高的乳化剂用量、较低的醇水比有利于得到小粒径、高均匀性的PS磁性微球。     

细乳液聚合制备聚丙烯腈/纳米SiO2复合粒子

由含甲基丙烯酸-3-三甲氧基硅烷(MPS)改性纳米SiO2的丙烯腈细乳液聚合制备聚丙烯腈/纳米SiO2复合粒子.研究了纳米SiO2的改性及含量、十二烷基硫酸钠(SDS)乳化剂和十六烷(HD)助乳化剂浓度对细乳化液滴粒径的影响.结果表明,直接采用未改性纳米SiO2,细乳化后出现双峰分布,纳米SiO2粒子未有效进入单体液滴;用10%MPS改性纳米SiO2后,细乳化液滴呈单峰分布.随着纳米SiO2粒子含量的增加,细乳化液滴的平均粒径增大,分布变宽.含纳米SiO2粒子的细乳化液滴体的平均粒径随SDS浓度和HD浓度增大而减小.透射电镜观察发现,细乳液聚合产物的连续相中无纳米SiO2粒子分布,复合粒子呈非规整结构,纳米SiO2>粒子在聚丙烯腈基体中基本呈初级粒子分布.     

Nucleation mechanism and morphology of polystyrene/Fe3O4 latex particles via miniemulsion polymerization using AIBN as initiator

In this study, oil‐based magnetic Fe₃O₄ nanoparticles were first synthesized by a coprecipitation method followed by a surface modification using lauric acid. Polystyrene/Fe₃O₄ composite particles were then prepared via miniemulsion polymerization method using styrene as monomer, 2,2′‐azobisisobutyronitrile (AIBN) as initiator, sodium dodecyl sulfate (SDS) as surfactant, hexadecane (HD) or sorbitan monolaurate (Span20®) as costabilizer in the presence of Fe₃O₄ nanoparticles. The effects of Fe₃O₄ content, costabilizer, homogenization energy during ultrasonication, and surfactant concentration on the polymerization kinetics (e.g., conversion), nucleation mechanism, and morphology (e.g., size distributions of droplets and latex) of composite particles were investigated. The results showed that at high homogenization energy, an optimum amount of SDS and hydrophobic costabilizer was needed to obtain composite particles nucleated predominately by droplet nucleation mechanism. The morphology of the composite particles can be well controlled by the homogenization energy and the hydrophobicity of the costabilizer. The magnetic composite particles can be made by locating Fe₃O₄ inside the latex particles or forming a shell layer on their PS core surface depending on the aforementioned polymerization conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

基于细乳液聚合法TiO2/PMMA纳米复合粒子的制备及其性能

采用细乳液聚合法制备了二氧化钛/聚甲基丙烯酸甲酯（TiO2/PMMA）纳米复合粒子,考察了引发剂、助乳化剂、乳化剂、单体结构和种类对TiO2/PMMA纳米复合粒子性能的影响。结果表明与十二醇和十六醇相比,十六烷（HD）更能抑制甲基丙烯酸甲酯（MMA）液滴的Ostwald熟化效应,当MMA占TiO2质量分数的60%,HD对单体质量分数的6%,可聚合乳化剂1-烯丙氧基-3-(4-壬基苯酚)-2-丙醇聚氧乙烯(10)醚硫酸铵（DNS-86）占整个体系的质量分数为2%时,制备TiO2/PMMA纳米复合粒子分散体的粒径为185nm,此时TiO2/PMMA纳米复合粒子与细乳液粒径差距较小;采用TiO2/PMMA纳米复合粒子制备白色涂料墨水的稳定性和遮盖力明显优于同等条件下TiO2所制备的涂料墨水。     

Preparation of epoxy resin/acrylic composite latexes by miniemulsion polymerization method

Epoxy resin/acrylic composite latexes were prepared by miniemulsion polymerization. Epoxy resins have a functional epoxy group in them and excellent characteristics, such as heat resistance and good adhesion. Acrylic latexes have weather and water resistance. Combining the epoxy resin and the acrylic latex was an attempt to actualize these advantages. The miniemulsion polymerization method was effective in obtaining the composite latex. A less than 500‐nm droplet size for the monomer preemulsion was necessary to obtain the latex in a stable manner. Dimethylaminoethylmethacrylate and methacrylic acid as the reactive functional monomer with an epoxy group were introduced to the latexes. The effect of the polymerization method of these functional groups on the properties of latexes and their films was investigated. The latex prepared by the two‐stage polymerization method had good polymerization stability, storage stability, and solvent resistance. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 128–133, 2001     

Particle morphology development in hybrid miniemulsion polymerization

Incompatibility between polymer phases resulting from hybrid minienulsion polymerization of acrylic monomers in the presence of alkyd resin leads to interesting particle morphologies. In this paper, morphology was deduced through crosscomparison of results from several forms of microscopy. For the combination of methyl methacrylate and alkyd, a derivative of core/shell morphology was observed through the combination of transmission electron microscopy, scanning electron microscopy, and spin diffusion NMR. A raspherry-like shell was found to form on the hybrid particle surface consisting of a full coverage of small (roughly 25 nm) polymethyl methacrylate spheres anchored to the particle surface through grafting with the alkyd core. Migration of the spheres to tha surface is thought to be induced by phase separation, and the size of the spheres precludes their origin from homoparticles from homogeneous nucleation. Homopolymethyl methacrylate particles were also detected in the particle distribution, resulting from the aqueous-phase initiator and hydrophilicity of methyl methacrylate monomer. For copolymer/alkyd systems (either methyl methacrylate/butyl acrylate/acrylic acid/alkyd or methyl methacrylate/butyl acrylate/alkyd), more traditional core/shell morphologies were observed with a lesser degree of homonucleated particles. A significantly different result was found in the combination of butyl acrylate and alkyd, resulting in a continuous particle-phase of polylbutyl acrylate and small internally dispersed island domains of alkyd. This is likely due to the lesser incompatibility between polybutyl acrylate and alkyd along with their similar hydrophobicity and glass transition temperatures. A higher degree of grafting between the alkyd and polybutyl acrylate also contributed to the compatibility between the two components, when compared to hybrid methyl methyl methacrylate/alkyd systems.     

The formation of asymmetric polystyrene/saponite composite nanoparticles via miniemulsion polymerization

The synthesis of asymmetric spherical nanoparticles has attracted great interest because their anisotropic structure can be used as unique building blocks for constructing advanced materials. In this article, we report the formation of hemispherical or truncated polystyrene/nanosaponite composite particles via one‐pot miniemulsion polymerization. It was found that the morphology of final composite latex particles strongly depends on the size of the nanoclay and its surface properties. Hemisphere or truncated sphere is the dominant morphology if the size of the nanoclay is larger than 100 nm. With the increase of the nanoclay content (up to 30 wt %), the fraction of hemispherical or truncated polystyrene/nanosaponite composite latex particles increased accordingly. The formation of hemispherical particles is possibly attributed to either the asymmetric growth of polymer chains on one side of the hydrophobically modified clay or the mechanical peeling‐off of large spherical particles between polymer and saponite. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation of polystyrene/poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐p‐phenylenevinylene] fluorescent microspheres by miniemulsion polymerization

Fluorescent microspheres have great potential for use as probes in biological diagnostics. In this context, poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐p‐phenylenevinylene] (MEH‐PPV), a conjugated polymer which has high quantum yield, controllable emitting wavelength and facile processing in manufacture, was used as a fluorescent material for the preparation of polystyrene (PS)/MEH‐PPV fluorescent microspheres via miniemulsion polymerization. We demonstrate that the emitting wavelength of the PS/MEH‐PPV fluorescent microspheres can be regulated by changing the amount of azobisisobutyronitrile initiator in the polymerization process. Using acrylic acid comonomer, poly[styrene‐co‐(acrylic acid)]/MEH‐PPV fluorescent microspheres with functional carboxyl groups were also prepared. All the microspheres were characterized using transmission electron microscopy, scanning electron microscopy, fluorescence microscopy and fluorescence spectrophotometry. The functional carboxyl groups were characterized using Fourier transform infrared spectroscopy. This work provides a novel platform for the preparation of conjugated polymer fluorescent microspheres for biological applications. © 2012 Society of Chemical Industry     

细乳液聚合制备含氟丙烯酸酯聚氨酯共聚物

采用细乳液聚合法,制备了稳定的含氟丙烯酸酯聚氨酯细乳液。用FT-IR表征了丙烯酸酯聚氨酯预聚体及其共聚物的结构组成;考查了细乳液的稳定性;用透射电子显微镜(TEM)观察了乳胶粒的形态;用接触角法表征了乳胶膜对水和正十六烷的接触角。     

二氧化钛纳米管稳定Pickering乳液制备PS/TiO2纳米管复合微球

利用γ-甲基丙烯酰氧基丙基三甲氧基硅烷（KH-570）,对水热法制备的TiO₂纳米管进行了表面改性,并用改性的纳米管为稳定剂,采用Pickering乳液聚合法制备了聚苯乙烯/TiO₂纳米管复合微球。采用红外光谱（IR）、光学显微镜、高分辨透射电镜（HRTEM）、高分辨扫描电子显微镜（FESEM）、X射线光电子能谱（XPS）等分析手段,对改性前后TiO₂纳米管以及复合微球的结构和形貌进行了表征,用三相接触角仪测试并优化了TiO₂纳米管的表面润湿性。研究结果表明,当m_KH-570/m_TiO2=15%时,改性TiO₂纳米管表面润湿性最佳,能很好地稳定Pickering乳液聚合,聚合后可以得到壳层为致密均匀TiO₂纳米管,核为聚苯乙烯的复合微球。     

PS/TiO2核壳型微球和空心TiO2微球有序排列的制备

利用纳米级二氧化钛（TiO₂）溶胶微粒与聚苯乙烯（PS）胶体颗粒的混合悬浮液,以垂直共沉积的方法制备了核壳型PS/TiO₂微球的有序排列。当利用煅烧的方法去除PS胶粒晶体模板后,可以形成空心TiO₂微球的三维有序排列。考察了混合悬浮液中两种胶体颗粒的体积比（PS∶TiO₂=R）对空心TiO₂微球有序排列形成的影响。实验结果表明,合适的R值（6∶1）对于空心微球有序排列的形成至关重要。与此同时,浸渍填充法对照实验的结果表明,煅烧过程中TiO₂纳米颗粒晶型转化引起的收缩是造成TiO₂空心球产生的主要原因。     

Preparation and properties of magnetic polystyrene microspheres

Magnetic polystyrene nanospheres were efficiently prepared by using a new indirect process based on miniemulsion polymerization of styrene. The samples were characterized by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), and vibrating‐sample magnetometry (VSM), respectively. The experimental results clearly show that the 3‐methacryloxypropyltrimethoxy silane was anchored onto the surface of the magnetic particles to form the vinyl end. The size of the magnetic particle is about 6–30 nm. The size of the magnetic particle capped with polystyrene is about 1–2 μm. The magnetic polystyrene spheres exhibit multidomain character, whereas the pure magnetic particles show single domain character. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3660–3666, 2007