PREPARATION AND CHARACTERIZATION OF AFFINITY POLYMER BASIC MICROSPHERES BY SOAP-FREE EMULSION POLYMERIZATION

Poly(styrene-co-glycidyl methacrylate) latex microspheres with uniform size and high-density epoxy groups on the surface were prepared by soap-free emulsion polymerization with batch wise operation mode in the presence of 2.2′- azobis(2-methylpropionamidine) dihydrochloride as an initiator.The kinetics of soap-free emulsion polymerization and the effects of polymerization factors were examined.In addition,the optimum polymerization conditions of poly(styrene-co- glycidyl methacrylate) latex microspheres for...

Preparation of Self-crosslinked Fluorocarbon Polymer Emulsion with Core-shell Structure by the Method of Soap-free Emulsion Polymerization

Using methyl methacrylate （MMA）, butyl acrylate（BA） and hexafluorobutyl acrylate（HFBA） as main raw materials, we prepared self-crosslinked fluorocarbon polymer emulsion with core-shell structure via soap-free emulsion polymerization when the conception of particle design and polymer morphology was adopted. Moreover, the influence of mole ratio of BA to MAA, pH value on the oligomer was studied. And the effects of the added amount of oligomer, self-crosslinked monomer and HFBA, mass ratio of BA to MMA, reaction temperature and the initiator on the polymerization technology and the performance of the product, were investigated and optimized. The structure and performance of the fluorocarbon polymer emulsion were characterized and tested with FTIR, TEM, MFT and contact angle and water absorption of the latex film. The experimental results show that the optimal conditions for preparing fluorocarbon polymer emulsion are as follows： for preparing the oligomer, tool ratio of BA to MAA is equal to 1.0 ： 1.60, and pH value is controlled within the range of 8.0 and 9.0; for preparing fluorocarbon polymer emulsion, the added amount of oligmer[P（BA/MANa）] is 6%; mass ratio of BA to MMA is 40 ＂ 60; the added amount of self-crosslinked monomer is 2%, the added amount of HFBA is 15 %; reaction temperature is 80 ℃; the mixture of potassium persulfate and sodium bisulfite is used as the initiator. The film-forming stability of the fluorocarbon polymer emul- sion and the performance of the latex film, which is prepared with the soap-free emulsion polymerization, are better than that prepared with the conventional emulsion polymerization.

Influences of Electrolytes on the Soap-free Emulsion Copolymerization of St-MMA-AA

Monodisperse functional polymer microspheres with different particle size and with clean surface were prepared by batch soap-free emulsion polymerization of styrene, methyl methacrylate and acrylic acid in the presence of salts, and the influences of type and amount of electrolytes on polymerization process and particle morphology were investigated. Results showed that there was a critical concentration for different electrolyte to make polymerization process and the resultant emulsion stable, and the particle size increased with the increase of electrolyte concentration. The effect of metal ions was Ca^2＋〉〉K^＋〉Na^＋〉Li^＋, and the effect of haloids was Br〉Cl〉F. Keywords： Electrolyte, soap-free emulsion polymerization, polystyrene, latex particle morphology.

INFLUENCES OF ACID POST-TREATMENT ON THE MORPHOLOGY OF SOAP-FREE P(MMA-EA-MAA)PARTICLES PREPARED BY SEEDED EMULSION POLYMERIZATION

Soap-free poly（methyl methacrylate-ethyl acrylate-methacrylic acid） latex particles with narrow size distribution were synthesized by seeded emulsion polymerization, and the porous particles were created by a stepwise alkali/acid treatment method. Effects of acid treatment conditions on the particle morphology were investigated. Results show that one to three pores were formed inside most of particles after post-treatment. At pH 7.0, when the treatment temperature was lower than 70℃, the size of particles and the volume of pores remained almost unchanged, and these two values increased significantly when the temperature was higher than 70℃. Both the particle size and the pore volume decreased with the increase of initial pH value and treatment time in the acid treatment. As the pH was below 4.0 and the treatment time was longer than 180 min, the particles shrunk in size.

Synthesis of submicron-sized peanut-shaped poly(methyl methacrylate)/polystyrene particles by seeded soap-free emulsion polymerization

Submicron-sized peanut-shaped poly（methyl methacrylate）/polystyrene （PMMA/PS） particles were successfully synthesized by seeded soap-free emulsion polymerization of styrene on the spherical crosslinked PMMA seed particles. The obtained peanut- shaped particles showed a novel internal morphology： PS phase formed one domain which linked to the other domain having PMMA core encased by PS shell.

PREPARATION OF MICRON-SIZED NONSPHERICAL POLYSTYRENE/POLY(STYRENE-co-ETHYLENEGLYCOL DIMETHACRYLATE) PARTICLES BY SEEDED SOAP-FREE EMULSION POLYMERIZATION

Micron-sized nonspherical polymer particles having different morphologies were synthesized by seeded soap-free emulsion polymerization of styrene （St） and ethyleneglycol dimethacrylate （EGDMA, used as a crosslinker） on spherical, linear polystyrene （PS） seed particles. The morphology of the resulting PS/poly（St-co-EGDMA） particles was dependent on the crosslinker concentration and polymerization temperature.

Pickering emulsion polymerization of styrene stabilized by nanocrystalline cellulose

In this work,polystyrene-based oil-in-water Pickering emulsion stabilized by nanocrystalline cellulose(NCC)was formulated.The NCC was prepared by sulfuric-acid-catalyzed hydrolysis of microcrystalline cellulose,with a yield of 60%and an average particle size of about 152.9 nm.When the content of NCC was 5 g/L,the surface tension was 54.58 mN/m,and stable styrene-based Pickering emulsion was prepared using NCC as the stabilizer.The presence of NCC particles in the emulsion system resulted in high resistance against creaming.Due to improved stability,the conversion efficiency of styrene was higher in the polymerization process of the styrene-based Pickering emulsion.

A New Kind of Void Soap-free P(MMA-EA-MAA) Latex Particles

Soap-free P(MMA-EA-MAA) particles with narrow size distribution were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and methacrylic acid (MAA), and large voids inside the particles were generated by alkali posttreatment in the presence of 2-butanone. Results indicated that the size of void and the particle volume were related with the amount of 2-butanone. The generation mechanism of voids was proposed.

有机硅树脂乳液的制备方法及应用研究进展

有机硅树脂乳液是将主链含SiOSi的高度交联聚硅氧烷在外加乳化剂或亲水基团的作用下,经过机械分散后形成的聚合物乳液,具有环境友好特性,可用于水性耐高温涂料、防水涂料、水性胶黏剂、日化和纺织品、纸张及皮革整理等。本文详细综述了有机硅树脂乳液的3种常用制备方法,重点介绍了其应用进展,并对未来发展方向进行了展望。

DESIGN AND CONTROL OF SOAP-FREE HYDROPHILIC-HYDROPHOBIC CORE-SHELL LATEX PARTICLES WITH HIGH CARBOXYL CONTENT IN THE CORE OF THE PARTICLES

Soap-flee hydrophilic-hydrophobic core-shell latex particles with high carboxyl content in the core of the particles were synthesized via the seeded emulsion polymerization using methyl methacrylate （MMA）, butyl acrylate （BA）, methacrylic acid （MAA）, styrene （St） and ethylene glycol dimethacrylate （EGDMA） as monomers, and the influences of MMA content used in the core preparation on polymerization, particle size and morphology were investigated by transmission electron microscopy, dynamic light scattering and conductometric titration. The results showed that the seeded emulsion polymerization could be carried out smoothly using ＂starved monomer feeding process＂ when MAA content in the core preparation was equal to or less than 24 wt%, and the encapsulating efficiency of the hydrophilic P（MMA-BA-MAA- EGDMA） core with the hydrophobic PSt shell decreased with the increase in MAA content. When an interlayer of P（MMA- MAA-St） with moderate polarity was inserted between the P（MMA-BA-MAA-EGDMA） core and the PSt shell, well designed soap-free hydrophilic-hydrophobic core-shell latex particles with 24 wt% MAA content in the core preparation were obtained.

A Novel Method for Preparing Approximately Micron-sized Polymethyl Methacrylate Microspheres with Clear Surface

Polymethyl methacrylate (PMMA) microspheres with clear surface and diameter close to 1 祄 were synthesized by newly soap-free emulsion polymerization. The results showed that the presence of ethanol and NaCl made the increase of diameter and distribution, while the presence of toluene could avoid the problem of the increase of distribution, resulting a harvest of PMMA microspheres with a diameter close to 1 祄.

聚硅氧烷的研究进展

聚硅氧烷具有优异的物理、化学性能,在众多的领域中得到广泛应用。文章阐述了聚硅氧烷的合成方法,其中重点介绍了应用较为广泛的阴离子引发的环硅氧烷的本体开环聚合,并对聚硅氧烷的应用情况进行了总结。

全氟丙烯酸酯聚合物乳液研究进展

全氟丙烯酸酯聚合物乳液由于具有优异的表面特性 ,耐候性及环境友好性 ,可望在建筑涂料、纺织工业以及其它重要领域得到广泛的应用。本文综述了全氟丙烯酸酯聚合物的特性及乳液的合成方法与应用 ,介绍了国内外在此领域的研究状况。

无皂乳液聚合的理论研究、制备方法及应用

无皂乳液聚合法可以制备表面洁净的单分散性微球和功能微球 ,并可消除乳化剂对环境的污染。综述了无皂乳液聚合中的反应机理及体系稳定性方面的研究 ,对无皂乳液聚合的制备方法及应用前景作了详尽的介绍。

无皂乳液聚合法合成含氟聚合物的研究进展

含氟聚合物由于其优异的物理和化学性能以及广阔的应用前景而受到关注,近年来成为研究的热点。基于含氟聚合物无皂乳液的最新研究进展,综述了含氟聚合物无皂乳液的制备方法,其中主要包括可聚合乳化剂共聚法、加入助溶剂法、水溶性单体共聚法、添加无机粉末法、加入两亲性聚合物法和采用两亲性结构RAFT试剂聚合法。系统地归纳了含氟聚合物无皂乳液在功能微球、表面施胶剂、皮革涂饰材料、织物整理剂和涂料粘合剂等方面的应用,并展望了其今后的发展方向。

反相乳液聚合的新进展

对反相乳液聚合做了概括介绍。总结了近年来在反相乳液聚合方面的研究结果，探索了反相乳液聚合的发展动态。

苯胺的乳液聚合及应用

聚苯胺是目前最有商业应用前景的导电功能塑料之一。然而由电化学和化学氧化聚合制备的聚苯胺因不溶解不熔融而难以加工,从而严重地阻碍了聚苯胺的进一步广泛应用。近年来许多研究小组致力于苯胺的乳液聚合研究,大量的最新研究结果表明:乳液聚合是提高聚苯胺加工性能而又不丧失其导电性能的有效途径。系统论述了聚苯胺的4种典型而重要的乳液聚合和微乳液聚合方法,着重强调了聚苯胺纳米颗粒、纳米管等的乳液制备及新性能,分析了乳液聚合聚苯胺的工业应用前景,指出了未来的研究开发方向。

无皂乳液聚合技术及应用研究进展

无皂乳液聚合可用于制备单分散有或无功能性微球。介绍了无皂乳液聚合技术的最新进展及其应用。

钻井液降滤失剂PAAS的制备及性能

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)和对苯乙烯磺酸钠(SSS)为聚合单体,采用反相乳液聚合法制备了一种水基钻井液降滤失剂PAAS,通过正交实验确定了最佳合成条件,采用FTIR及EA(元素分析)对其结构进行了表征,采用TG-DTG对其耐温性进行了分析。通过钻井液流变性、滤失性及抑制性实验对降滤失剂PAAS应用性能进行了考察,并对其降滤失机理进行了推测。结果表明:PAAS具备良好的高温稳定性,各类功能基团在温度升至225℃时均未发生明显的热分解现象;钻井液流变性实验、老化实验及失水实验表明:w(PAAS)=1.5%(以体系总质量计,下同)时,钻井液流变性良好,动塑比(YP/PV)=0.30 Pa/(m Pa·s),高温160℃老化前后失水量分别为8.4 mL和10.2 mL。功能基团含量渐变实验、SEM和横向弛豫时间(T_2)结果表明:该降滤失剂主要通过吸附作用改善钻井液体系抗滤失性能。

改性聚丙烯酰胺纳米微球的合成及其在调剖堵水上的应用

以亲水性丙烯酰胺(AM)为单体,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,氢氧化钠(NaOH)/亚硫酸氢钠(NaHSO_3)为引发剂,失水山梨醇单油酸酯(Span80)/失水山梨醇单油酸酯聚氧乙烯醚(Tween80)/烷基酚聚氧乙烯醚(Tx-10)为乳化体系,在白油中进行反相乳液聚合,制备了改性聚丙烯酰胺微球(PAM)。采用红外光谱、粒径分析和动态流变仪等方式对该微球进行了表征。结果表明聚丙烯酰胺微球已聚合且性能良好,在水中溶胀5 d后,粒径增大至1μm,乳液能迅速分散在水中,且黏度低、耐剪切,可以被顺利注入到地层深部。将此微球在长庆油田进行现场应用,结果显示试验井均出现不同程度的增油,说明此微球在调剖堵水方面具有良好的效果。