有机硅氧烷乳液粒子粒径及其分布的测定

本文采用甲基环硅氧烷与乙烯基环硅氧烷共聚合的方法,制得了硅油轧液,利用乙烯基双键使聚合物硬化,以固定乳液颗粒,并用电子显微镜观察研究了液珠的组成及分布情况。发现阴离子硅油乳液颗粒较阳离子乳液的粒子细,且粒径分布窄。在阳离子硅油乳液中添加非离子乳化剂,或采用机械后乳化的方法,能消除大粒径的液珠,使其颗粒变小、变匀,从而大大改善阳离子乳液的稳定性。     

阳离子丙烯酸树脂乳液涂饰剂的合成研究

以丙烯酸二乙氨基乙酯及其它丙烯酸酯类、乙烯基类单体作为共聚单体,以过醋酸-双氧水为引发体系,采用核-壳乳液共聚方法,对阳离子丙烯酸树脂的合成进行了研究,结果表明;引发剂体系和乳化剂体系对乳液的性能、乳胶粒的形态结构、聚合物的性能以及工艺过程的平稳性至关重要。该项研究为阳离子丙烯酸系聚合物在制革业中的广泛应用奠定了基础。     

硅氧烷乳液聚合的研究——Ⅱ.八甲基环四硅氧烷阳离子乳液聚合机理

根据八甲基环四硅氧烷(D_4)在阳离子乳液聚合过程中,聚合物的分子量及数目的变化等特点,提出并证明了D_4在乳液粒子表面进行聚合的机理的假设。     

硅氧烷乳液聚合的研究Ⅲ.八甲基环四硅氧烷在阳离子乳液聚合过程中乳液颗粒的形成

八甲基环四硅氧烷(D_4)在阳离子乳液聚合过程中,首先被乳化成颗粒较大的“过渡粒子”,在这里以D_4的水解开环和加聚反应为主,然后转变为颗粒较小的稳定乳液粒子。聚合物端基≡SiOH的缩合反应主要在乳液粒子中进行。     

水包水型阳离子乳液絮凝剂的合成及其应用

以丙烯酰胺(AM)和丙烯酰氧乙基三甲基氯化铵(DAC)为主要单体在聚乙二醇20000(PEG 20000)溶液中进行自由基共聚合成了固含量高、絮凝效果好且速溶的水包水型阳离子聚丙烯酰胺乳液。在充氮气30 min,60℃下反应5 h,AM和DAC质量百分数分别为20%和0.5%的最优条件下,合成的阳离子絮凝剂(CPF)乳液对生化污水上清液透光率达到95%。红外光谱分析表明,聚合物分子结构中含有AM和DAC链节。     

小粒径无皂阳离子PMMA胶乳粒子的制备与表征

采用溶剂热法,以AIBA为引发剂制得小粒径无皂阳离子PMMA胶乳纳米粒子。讨论了单体用量、引发剂用量和反应温度对胶乳粒径及乳液的粒径分布的影响;用^1H—NMR、TEM、FTIR、GPC、DTA等对聚合物进行了表征。结果表明：采用溶剂热法制得的无皂阳离子胶乳粒子粒径约为35nm,分散均匀;随着温度的升高,粒径逐渐减小;间同、无规、全同立构的相对含量分别为：55．3％、37．8％、6．9％;乳液的抗电解质稳定性好。     

阳离子抗菌聚合物

阳离子抗菌聚合物, 作为一种新型抗菌材料, 具有独特的抗菌机理和高效的抗菌活性, 并且能有效解决细菌耐药性问题, 引起了人们的广泛关注。阳离子抗菌聚合物具有有效的抗菌活性, 其抗菌活性受到亲疏水平衡、分子质量、烷基链长度和阴离子等因素的影响。抗菌活性是评价抗菌剂优劣的重要因素之一, 了解和掌握影响抗菌活性的因素, 对于优化或开发更安全、更高效的阳离子抗菌聚合物具有重大意义。本文总结了通过不同作用方式作用于细菌的多种抗菌策略, 依据影响阳离子抗菌聚合物抗菌活性的因素, 总结包括天然阳离子抗菌聚合物、季铵盐类聚合物、N-卤代胺类聚合物、膦盐和锍盐类聚合物、胍盐类聚合物和抗菌水凝胶的研究进展。最后, 对阳离子抗菌聚合物面临的挑战和未来发展方向进行了讨论。     

抗菌阳离子聚合物的研究进展

两亲性阳离子聚合物在抗细菌感染，尤其是抵抗细菌耐药、突破细菌生物膜障碍中发挥着重要作用。为了进一步增加阳离子聚合物与细菌等病原体的相互作用，在提高杀菌效率的同时提高生物相容性，研究者们设计与制备了一系列具有优良性能的阳离子聚合物。本文综述了近年来新型阳离子聚合物的设计、制备及其在抗病原体方面的应用，讨论了不同阳离子聚合物的作用机理与特点，并对该领域所面临的挑战进行了展望。     

聚合物互通多孔材料的乳液模板法制备及其功能化研究*

本文对近年来利用乳液模板制备聚合物互通多孔材料的研究进行了综述,主要介绍以高内相乳液模板制备互通多孔聚合物整体柱和利用双重乳液 (或称多重乳液) 制备多孔或多空聚合物微球的进展;分析目前多孔聚合物材料研究中存在的问题及其研究动态;讨论合成多孔聚合物材料的性能缺陷及其表面功能化改性的相关研究;并对聚合物互通多孔材料潜在的应用和研究前景进行了展望。     

有机硅改性丙烯酸酯乳液的流变性

聚合物乳液;流变性能;反应性乳液;有机硅改性丙烯酸酯乳液的流变性     

Sol-gel reaction in acrylic polymer emulsions: the effect of particle surface charge

Acrylic polymer-silica hybrid emulsions were synthesized from both anionic and cationic polymer emulsions by simple post-addition of tetraethoxysilane as a silica precursor. Solvent resistance of the films from the hybrid emulsions and the zeta-potential of the hybrid emulsions suggested the different forms of silica components in each hybrid emulsion. Thermal gravimetric analysis, 29Si NMR measurements, and transmission electron microscope observations revealed that the hybrid emulsion from the anionic polymer emulsion was a mixture of anionic polymer particles and homogeneously dissolved silicate oligomer-polymer. On the contrary, the hybrid emulsion from cationic polymer emulsion consisted of polymer core-silica shell particles. The electrostatic interaction between the cationic polymer particle surface and the silicate would be responsible for the accumulation of the silicate onto the particle surface, leading to the silica shell layer formation. The sol-gel condensation reaction of silicate in the acidic emulsion phase was revealed to be controllable by the surface charge of the coexisting particles.     

Preparation of microspheres by an emulsification-complexation method

Microspheres were prepared by complexation of a cationic polymer, polyquaternium-24, and an anionic surfactant, sodium lauryl sulfate (SLS). The cationic polymer solution was emulsified in dimethylsiloxane to give water in silicone emulsion (W/Si), and it was used as a template for the formation of microspheres. The emulsion was dispersed into the SLS solution. In this process, two kinds of droplets, silicone dropletes and microspheres composed of the cationic polymer and SLS, were formed, evidenced by X-ray energy dispersive spectra. The mean diameter of the microspheres was reduced from 105.7 to 64.8 mum as the stirring rate for W/Si preparation increased from 300 to 1000 rpm. It is believed that water droplets in W/Si emulsion, when exposed to SLS solution, could be solidified by the complexation of the cationic polymer and the anionic surfactant.     

The synthesis,interfacial, and colloidal properties of waterborne cationic methacrylic co-polymers

Two cationic polymers with similar composition were prepared by two different polymerization methods. By monitoring the evolution of the molar mass and chemical composition during the reactions together with charge density measurements and calculations, it was concluded that the cationic polymer synthesized by emulsion polymerization had a less uniform compositional distribution than the cationic polymer prepared by solution polymerization. Contributing to the heterogeneity was the hydrolysis of one monomer (dimethylamino ethylmethacrylate (DMAEMA)) during the synthesis. As a result, the polymer prepared by emulsion polymerization had a more blocky structure and was more surface active as supported by static and dynamic surface tensions data. Fluorescence experiments showed that both polymers formed aggregates at very low concentrations of approximately 0.01 wt%. The aggregates of the polymer prepared by emulsion polymerization were compact, whereas the solution polymerization-based polymer aggregates exhibited a rather expanded geometry.     

可聚合表面活性剂的研究进展

在乳液聚合中，表面活性剂发挥着非常关键的作用，但同时它们也存在不足的方面，一个比较有前景的方法就是使用可聚合表面活性剂。可聚合表面活性剂以牢固的共价键键合到聚合物粒子上，有效避免了表面活性剂的解析及其在膜中的迁移。本文综述了近年来可聚合表面活性剂的进展，主要讨论了阴离子、非离子、阳离子可聚合表面活性剂的特征和性质及其在乳液聚合中的应用。     

Immobilization of cationic polymer particles having active ester groups onto solid surfaces

Monodispersed cationic polymer particles with sulfonium groups and active ester groups at their surfaces were prepared by emulsifier-free emulsion copolymerization of styrene (ST) with a water-soluble active ester monomer, methacryloyloxyphenyldimethylsulfonium methylsulfate (MAPDS). The cationic polymer particle monolayers were fabricated on unmodified and aminated glass plates by electrostatic interactions and chemical reactions, respectively. The polymer particles were immobilized onto unmodified glass plates at relatively regular intervals in the absence of electrolytes, and the morphology of particle monolayers on the glass plates was changed with solid content of latex, electrolyte and cationic surfactant concentration. The polymer particles were immobilized onto aminated glass plate as aggregates by controlling the pH of latex and electrolyte concentration. Remaining active ester groups of the particle monolayers were confirmed to react easily with primary amino compounds.     

Influence of dispersion conditions and nature of the emulsifier on the dispersity and stability of artificial polymer suspensions based on polyetherimide

New methods for producing artificial polyetherimide suspensions in the presence of domestic cationic surfactants, their mixtures, and mixtures of cationic and organosilicon surfactants were proposed. The effect of the polymer concentration in the initial solution and conditions of emulsion dispersion on the stability and particle size of the final polymer suspensions is shown. The colloidal chemical properties of the obtained polymer suspensions are considered. Conclusions about the influence of the nature and concentration of surfactants on the stability of the obtained suspensions are drawn. When using a mixture of cationic and organosilicon surfactants, polymer suspensions stable during production and storage are formed, which is explained by the formation of structural mechanical and electrostatic stability barriers in the surface layers of the particles.

     

聚合物纳米微粒静电组装行为及其表征

使用2,2′-偶氮二异丁基脒二盐酸盐自由基引发剂,改变甲基丙烯酰氧乙基十六烷基二甲基溴化铵阳离子功能单体的量与苯乙烯进行乳液聚合获得不同粒径的阳离子乳胶粒,使用十二烷基硫酸钠为乳化剂和过硫酸钾为引发剂制备阴离子聚合物乳胶粒.采用基于静电相互作用的异凝聚法将以上2种带有相反电荷的乳胶粒组装,获得了表面粗糙程度不同的复合微粒.对异凝聚过程中复合液透光率和微粒大小及分布进行跟踪测试,并用透射电子显微镜表征了阳离子微粒、阴离子微粒以及复合微粒的形态和大小.结果表明,在一定范围内可以通过控制阴离子乳胶粒与阳离子乳胶粒的复合比例改变单个复合微粒表面阳离子小微粒的数目.     

Kinetics of the batch cationic emulsion polymerization of styrene: A comparative study with the anionic case

An in‐depth study on the kinetics of the cationic emulsion polymerization of styrene in a batch reactor is presented. This study is focused on the effect of the amount of the cationic surfactant dodecyltrimethylammonium bromide (DTAB), using two different cationic initiators: 2,2′‐azobisisobutyramidine dihydrochloride (AIBA), 2,2′‐azobis (N,N′‐dimethyleneisobutyramidine) dihydrochloride (ADIBA), on kinetics and colloidal features such as conversion, number of particles, number average of radicals per particle, mean particle diameter, and particle size distribution (PSD) of the polystyrene latices obtained by emulsion polymerization in a batch reactor. Furthermore, the results of the cationic emulsion polymerization were compared with its homologous anionic case. Using DTAB as cationic surfactant an expected increase in the total rate of polymerization was observed when the DTAB concentration increased. However, the total number of particles increased much more than in the anionic system. On the other hand, a dependence on the particle size of the rate of polymerization per particle together with the average number of radicals per particle was found. These differences between cationic and anionic emulsion polymerizations were explained taking into account the limited particle coagulation observed with cationic surfactants, and the high rate of radical formation of cationic initiators. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4461–4478, 2006     

Study on controlling particle growth in seeded emulsion polymerization with regulated coagulation based on the electrostatic interactions

30wt% solid content, anionic seed copolymer latex P(methyl acrylate-co-methyl methacrylate) was prepared by conventional emulsion polymerization, and then the seeded emulsion polymerization was carried out accompanied with the electrostatic coagulation during the reaction in the presence of counter-ion species, such as cationic monomer and initiator. In this article, effects of cationic monomer (dimethyl aminoethyl methacrylate, DM) content, secondary monomer to seed polymer weight ratio, M/P and amount of emulsifier (polyoxyethylene nonylphenylether with 23 units of ethylene oxide, PEO23) were investigated on the effective particle growth and the stability of final latex. With 10wt% DM in monomer, M/P ratio at 2.0 were recommended. An optimal policy for handling the emulsifier content without the nucleation of secondary particles while achieving the controlled coagulative growth was proposed from the observations of polymer yield and particle size during the polymerization.