新型可聚合乳化剂及其在乳液聚合中应用

综述了可聚合乳化剂的分类、性能与应用,比较了可聚合乳化剂与传统乳化剂在乳液聚合中的优缺点,讨论了可聚合乳化剂的溶液性能,指出了可聚合乳化剂的发展趋势。     

A novel copolymer of N-[(tert-butylperoxy)methyl]acrylamide and maleic anhydride for use as a reactive surfactant in emulsion polymerization

A new copolymer of N-[(tert-butylperoxy)methyl]acrylamide (tBPMAAm), containing a primary–tertiary peroxide group and maleic anhydride (MA), was synthesized and employed as a reactive surfactant (inisurf) for the emulsion polymerization of styrene to yield surface-functionalized (peroxidized) reactive latex particles. The copolymerization characteristics were analyzed to determine the monomer reactivity ratios and to provide a way to control the copolymer composition. The ability of tBPMAAm–MA to act as a reactive surfactant during emulsion polymerization was confirmed by the synthesis of monodisperse polystyrene latexes of varying particle size. In addition, peroxide groups were localized on the surface of the particles in a controllable amount (depending on the copolymer concentration), thus, providing the opportunity for further modification of the surface of the particles. This novel copolymer is expected to be a promising and efficient material in the synthesis of functional polymer nanoparticles with well-defined core–shell morphologies.     

聚氨酯预聚体——可聚合乳化剂用于MMA乳液聚合动力学及聚合稳定性研究

将合成的聚氨酯预聚体可聚合乳化剂（APUA）用于甲基丙烯酸甲酯（MMA）乳液聚合体系中，研究了不同引发剂体系和乳化剂对聚合体系的聚合稳定性和动力学影响，并与SDS乳化剂进行了对照。结果显示，用油溶性引发剂（AIBN）和水溶性引发剂（K2S2O8）都能引发该体系的聚合反应，而且聚合速率和转化率都相当高。用AIBN作引发剂时，APUA和SDS两种乳化所对应的动力学曲线不同，但APUA比SDS的聚合速率大得多，其分别类似于微乳液聚合（miniemulsion)和微悬浮聚合（microsuspention)，且聚合过程中会产生一定的凝胶。当乳化剂APUA用量适合时，凝胶量极少，聚合体系是稳定的；而当用K2S2O8作引发剂时，两乳化剂对应动力学曲线相似，聚合过程不产生凝胶。但当引发剂用量较大并以APUA作乳化剂时，在聚合过程中会出现全部粒子突然粗化现象，而以SDS作乳化剂没有出现这一现象。     

Ionic liquid as surfactant in microwave‐assisted emulsion polymerization

The aim of this work is to study the use of an ionic liquid (IL) as surfactant in emulsion polymerization reactions and to evaluate its effect when these reactions are heated under microwave irradiation. The IL 1‐n‐dodecyl‐3‐methylimidazolium chloride was chosen to replace the surfactant dodecyltrimethylammonium bromide (DTAB) in methyl methacrylate emulsion polymerizations. The conversion evolutions and the final average diameter of polymeric particles were quite similar for reactions using the surfactant DTAB or the IL, showing that the IL acted efficiently as surfactant in emulsion polymerizations. Comparing the polymerization reactions performed under microwave irradiation and conventional heating, reaction rate enhancements were obtained for both DTAB and IL. Using a pulsed scheme, under high‐power microwave irradiation, slightly higher reaction rates and molecular weights were obtained in reactions using IL, in comparison with surfactant DTAB, indicating the existence of some specific effects linked to IL–microwaves interaction. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Styrene emulsion polymerization in the presence of a maleate-functional surfactant

Dodecylhemiester of maleic anhydride is a very good anionic stabilizer for the emulsion polymerization of styrene. Rather high solid contents may be produced. Up to about 70% of the surfactant can be grafted onto the surface of the particles. Upon floculation with calcium salt, only 3% of the surfactant is left in the washing water. © 1997 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

J Appl Polym Sci 65: 2289–2296, 1997     

Preparation of soap‐free cationic emulsion using polymerizable surfactant

A kind of polymerizable surfactant, methacryloyloxyethylhexadecyldimethylammonium bromide (DMHB) was used to synthesis soap‐free cationic emulsion with styrene (St), methyl methacrylate (MMA), and methacryloyloxyethyltrimethylammonium chloride (MATMAC) by emulsion polymerization using 2,2′‐azobis(isobutylamidine hydrochloride) (AIBA) as a cationic initiator. The effects of polymerizable surfactant concentration, initiator concentration, and reaction temperature on the conversion of monomer were investigated. The results indicated that the rate of polymerization could be expressed as R_p = k_p[AIBA]^0.42[DMHB]^0.45 and the apparent activation energy (E_a) was 83.42 kJ/mol. The particle size, ζ potential, and apparent charge density of cationic latices were also measured. The average diameter of copolymer particles decreased with increasing DMHB, MATMAC, and AIBA content; the charge properties of the particles were decided by the DMHB, MATMAC, and AIBA content. The polymerization mechanism is discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1111–1116, 2006     

On the fine emulsion polymerization of styrene with non-ionic emulsifier

Summary The fine emulsion polymerizations of styrene initiated by a redox system ammonium peroxodisulfate/sodium thiosulfite stabilized by a non-ionic emulsifier were kinetically investigated. The dependence of the rate of polymerization on conversion or the emulsifier concentration was described by a curve with maximum at medium conversion. The maximum rate of polymerization is proportional to the − 0.45^th and 1.5^th power of initiator and emulsifier concentration, the number of particles to the 0.32^nd and 1.3^rd power of initiator and emulsifier concentration and the molecular weight to the − 0.62^th and −0.97^th power of initiator and emulsifier concentration, respectively. The results show a strong decrease in turbidity at around 20% conversion when emulsion turns into translucent latex. Deviation from the micellar nucleation model was attributed to the solubility of emulsifier in monomer, high level of nonmicellar aggregates, thick interfacial layer and transfer emulsion to microemulsion. The strong decrease of molecular weight with increasing emulsifier concentration is attributed to chain transfer events promoted by the high level of emulsifier at the reaction loci. Received: 16 November 1998/Revised version: 25 May, 10 October 1999/Accepted: 10 October 1999     

Preparation and characterization of maleic anhydride-grafted desulfurization rubber powder by free-radical polymerization

The objective of the article was to enhance the recycling value of solid waste rubber by surface functionalization of desulfurized rubber powder using a one-pot method based on free-radical polymerization theory. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, scanning electron microscopy, and elemental analysis were used to characterize the maleic anhydride-grafted desulfurized rubber powder, and the grafting mechanism was also investigated. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed that maleic anhydride was grafted onto the desulfurized rubber powder. Thermogravimetric analysis indicated that the maleic anhydride-grafted desulfurized rubber powder and desulfurized rubber powder possessed different thermal properties and structure. The results of scanning electron microscopy and elemental analysis illustrated that the surface of the desulfurized rubber powder was covered with a layer of fold-like maleic anhydride polymer. The mechanism of grafting desulfurized rubber powder with maleic anhydride may be achieved by replacing the active α-H on the methylene group of the desulfurized rubber macromolecule chain.     

可聚合表面活性剂 CS-1参与下的苯乙烯浓乳液聚合

合成了一种新型可聚合表面活性剂CS-1并应用于苯乙烯浓乳液聚合。GPC谱图表明聚合过程中同时存在苯乙烯的均聚以及苯乙烯／CS-1的共聚;反应初期苯乙烯／可聚合表面活性剂CS-1的共聚速率快于苯乙烯的均聚速率;均聚苯乙烯的相对分子质量随聚合时间增长有所下降。另外,十二烷基硫酸钠和CS-1体系中转化率数据也表明CS-1参与了苯乙烯的浓乳液聚合。     

Synthesis of polystyrene-clay nanocomposites via emulsion polymerization using a reactive surfactant

Summary Polystyrene-clay nanocomposites were synthesized via emulsion polymerization of styrene in the presence of montmorillonite particles and a reactive cationic surfactant as the emulsifier. The reactive surfactant, vinylbenzyldodecyldimethylammonium chloride (VDAC), was synthesized by the quaternization reaction of vinylbenzyl chloride with dimethyldodecylamine. Partially exfoliated nanocomposites were achieved as revealed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Polystyrene-clay nanocomposites prepared by emulsion polymerization have higher glass transition temperature and dynamic modulus than pure polystyrene. Received: 27 February 2001 /Revised version: 14 February 2002 /Accepted: 14 February 2002     

Emulsion polymerization of styrene with amphiphilic random copolymer as surfactant: Predominant droplet nucleation

Amphiphilic random copolymer consisting of monomeric units of poly (butyl acrylate) and poly (maleic acid salt) was synthesized and characterized. The emulsion polymerization kinetics of styrene stabilized by this copolymer was investigated. The influencing factors, including polymeric surfactant concentration, initiator concentration and polymerization temperature, were systematically studied. The kinetic data show that the polymerization rate (R_P) increased with the increase of the polymeric surfactant concentration ([S]) and polymerization temperature (T). At the higher [S], droplets nucleation and micelle nucleation coexisted in the polymerization system; at the lower [S], only the droplets nucleation process existed. The polymerization did not follow Smith‐Ewart Case II kinetics. Dynamic light scatter and transmission electron microscope were utilized to measure the sizes and shapes of the particles, respectively. It would be speculated that a kind of large heterogeneous particles with multiple‐active‐sites was formed in the polymerization system. The increasing of R_P with increasing initiator concentration ([KPS]) was rapid at a medium [KPS], but the slowly increasing was observed at a lower or higher [KPS]. It was attributed to the barrier effect of the polymeric surfactant around the monomer droplets. The polymerization activation energy was 60.29 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Using anionic polymerizable surfactants in ultrasonically irradiated emulsion polymerization to prepare polymer nanoparticles

An ionic polymerizable surfactant, sodium sulfopropyl‐laurylmaleate (M12), was synthesized and used as an emulsifier, an initiator, and a comonomer in ultrasonically irradiated emulsion polymerization. FTIR spectra and gravimetric method results indicated that copolymers P(Styrene‐M12) and P(Butylacrlate‐M12) were prepared successfully by ultrasonically irradiated emulsion polymerization and the composition of M12 elevated with the increasing concentration of M12 added. TEM photographs of P(St‐M12) showed that the nanoparticles with small diameters (20–45 nm) were prepared. With the increase of M12 concentration, the particle size became smaller and the size distribution became wider. The P(BA‐M12) particles size was also small (<100 nm) but the size distribution was wide due to the high reactivity of BA. Because surfmer M12 was chemically bonded with the latex particles, the stability of the copolymer latex prepared by ultrasonically irradiated emulsion polymerization was much better than that of the homopolymer latex (PSt or PBA) prepared by the same way. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of multi-responsive amphiphilic particles by one-step soapless emulsion polymerization

A novel multi-responsive amphiphilic copolymer (mRAP) particles with tunable emulsifiability was successfully prepared via one-step soapless emulsion polymerization using common monomers, such as methyl methacrylate, methacrylic acid (MAA), butyl acrylate (BA) and N,N-diethylacrylamide (DEAA). The obtained monodisperse spherical mRAP particles were characterized by dynamic light scattering, Fourier transform infrared spectroscopy, scanning electron microscope and transmission electron microscope, which provided the information of particle size, components and anisotropic structure. Its multiple responsivities were investigated under the condition of diversified pH values, salinity and temperature. The results showed that the mRAP particles exhibited good dispersivity based on uniform particle size, as well as tunable emulsifiability and anticipated multiple responsiveness. Furthermore, the tunable emulsifiability of oil–water mixtures could be easily achieved by adjusting the mass ratios of MAA to DEAA. Meanwhile, the obtained multi-responsive polymers relying on simple and effective copolymerization can be used in fundamental research and industrial production.     

Synthesis of a novel polymerizable surfactant and its application in the emulsion polymerization of vinyl acetate,butyl acrylate,Veova 10, and hexafluorobutyl methacrylate

A novel anionic, polymerizable fumaric surfactant (surfmer) was synthesized. The chemical structure of the surfactant was confirmed with ¹H‐NMR, IR, and mass spectrometry. The surfmer was then used with constant addition profiles in the semicontinuous polymerization of vinyl acetate, butyl acrylate, Veova 10, and hexafluorobutyl methacrylate. The particle size, amount of coagulum, and stability against electrolytes and freezing/thawing were evaluated. Films were cast from latices; then, photographs were taken of the films after immersion in water for days, and the water adsorption was assessed. As a reference, an unreactive surfactant (sodium dodecyl sulfate) was also used for the polymerization. Compared with sodium dodecyl sulfate, the surfmer behaved much better with respect to the stability of the latices and the water sensitivity of the films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Nanostructured latex particles synthesized by nitroxide-mediated controlled/living free-radical polymerization in emulsion

Suspensions of diblock and triblock copolymer particles comprising a poly(n-butyl acrylate) first/central block and polystyrene or poly(methyl methacrylate) second/outer blocks were synthesized by nitroxide-mediated controlled/living free-radical emulsion polymerization. Monofunctional and difunctional alkoxyamines based on the nitroxide SG1 were used as initiators. For the sake of simplicity, sequential monomer additions were performed without any removal of unreacted monomer. Self-assembly of the obtained block copolymers was investigated both under the latex form as well as after different thermal treatments. AFM and TEM analyses revealed the occurrence of “onion-like” lamellar microphases directly inside latex particles for high enough copolymer molar masses and irrespective of molar mass distribution. This particular organization evolved towards more classical block copolymer morphologies upon solvent casting and/or thermal annealing of latex films.     

Entry in emulsion polymerization using a mixture of sodium polystyrene sulfonate and sodium dodecyl sulfate as the surfactant

A mixture of sodium polystyrene sulfonate (NaPSS) and anionic surfactant, sodium dodecyl sulfate (SDS), was used as the emulsifier in the emulsion polymerization of styrene at 60 °C. The latexes prepared were stable, bearing the better resistance to the addition of electrolyte, and have the larger values in particle size and the higher polymerization rates than those counterparts prepared using SDS only. The NaPSS was prepared by a series of process: a concentrated cyclohexane solution of an anionically polymerized polystyrene (PS) was sulfonated with sulfuric acid at 80 °C, and then neutralized and purified through dialysis. The data of average polymer number per particle (n_p) were found useful in investigating the surfactant content effect on the entry of radicals into particles, where the latex particle size plays an important role.     

Preparation of planar and oblate particles from emulsion polymerization using polymerizable comb-like branched emulsifiers

This paper presents a method for preparation of planar polymeric microstructures by emulsion polymerization using polymerizable branched emulsifier. Planar, oblate and spherical particles can be prepared by changing the volume and functionality of the hydrophobic tail of the comb-like polymerizable emulsifier, together with altering the monomers. Emulsifiers with bulky tails favored the formation of planar microstructure. The polymerizable emulsifiers were immobilized on the latex particles. Hindered desorption of the emulsifier from the latex improved the latexes' stability and facilitate the formation of planar and oblate particles. The polymerization conversion also depends on the molecular characteristics of the emulsifiers and monomers.     

可聚合表面活性剂在磁性纳米材料制备中的应用(英文)

以马来酸酐和正十八醇为原料合成了可聚合表面活性剂马来酸单十八酯,并用其改性Fe3O4纳米磁粉.用改性纳米磁粉制备了苯乙烯基可聚合磁流体,并通过本体聚合获得了磁性纳米复合材料.透射电镜分析结果表明,直径约7 nm的Fe3O4纳米颗粒在磁流体和复合材料中分散均匀,无明显团聚现象;红外光谱分析结果表明,磁粉表面包覆的马来酸单十八酯和苯乙烯基质发生了共聚.差示扫描量热、热重及凝胶渗透色谱分析结果表明,与相间条件聚合的聚苯乙烯(PS)相比,复合材料的玻璃化转变温度和去除磁粉后的相对分子质量明显降低,但热稳定性比相同条件下聚合的PS有明显提高,这说明可聚合表面活性剂和活性PS链之间形成了共价键,从而增强了Fe3O4纳米颗粒与基质的相互作用.     

Radical polymerization of N-substituted citraconimides as polymerizable 1,1,2-trisubstituted ethylenes

Summary The radical polymerization behavior of N-substituted citraconimides, 1, 1, 2-trisubstituted ethylenic monomers, was investigated. N-Alkylcitraconimides were found to homopolymerize in bulk at 60°C to give polymers with molecular weight of 680010000, except methyl and ethyl derivatives. Polymerization of N-phenylcitraconimides in benzene at 60°C or in bulk at 120°C gave polymers with relatively low molecular weight from 700 to 2000. From thermogravimetric analysis, the initial and maximum decomposition temperatures for poly(N-isopropyl-citraconimide) were 309 and 365°C, respectively, and these were lower than those for poly(N-isopropylmaleimide) by about 40°C.     

乳化剂浓度对苯乙烯乳液聚合成核机理的影响

以苯乙烯（St）为单体、十二烷基硫酸钠（SDS）为乳化剂、过硫酸钾（KPS）为引发剂,重点研究了该乳液聚合体系中乳化剂浓度（[S]）对胶束成核和沉淀成核的影响规律。结果表明,当SDS浓度高于CMC时（[S]≥ 8mmol/L）,体系的成核以胶束成核为主;当[S]=2mmol/L时,体系的成核以沉淀成核为主;当2mmol/L<[S]< 8mmol/L时,体系同时以沉淀成核和胶束成核两种方式成核,且胶束成核所占的比例随着SDS浓度的增加而增大。研究了聚合反应过程中SDS浓度对单位体积水中乳胶粒个数（Np）的影响规律：当[S]≥8mmol/L时,Np∝[S]0.9;当[S]<8mmol/L时,Np∝[S]0.8。