乳液法制备聚合物纳米粒子的研究进展

综述了乳液法制备聚合物纳米粒子的研究进展,详细介绍了采用新型乳化剂,即高分子表面活性剂与反应性表面活性剂,和以超声波辐照技术为主的新技术制备聚合物纳米粒子方面的研究成果。     

Ab initio emulsion RAFT polymerization of vinylidene chloride mediated by amphiphilic macro‐RAFT agents

An amphiphilic copolymer poly(acrylic acid)‐block‐poly(styrene) (PAA‐b‐PS) with a trithiocarbonate reactive group was used in the ab initio reversible addition‐fragmentation chain transfer (RAFT) emulsion polymerization of vinylidene chloride (VDC). The fast polymerization and high conversion were achieved. The parameters for a good control over the formation of well‐defined PAA‐b‐PS‐b‐PVDC amphiphilic block copolymers and self‐stabilized latexes were identified. To improve the emulsion stability and prevent the desorption of water‐soluble initiating radicals, the acid groups of PAA‐b‐PS were neutralized by NaOH at the later stage of polymerization. The PAA‐b‐PS‐b‐PVDC block copolymer with a high molar mass of 30 kg mol⁻¹ and the stable latex with 30 wt % solid content was obtained. The kinetics of RAFT emulsion copolymerization of VDC in a living manner was first investigated. The as‐prepared PAA‐b‐PS‐b‐PVDC latex particles were further used as seeds in the emulsion polymerization of styrene, enabling the preparation of novel PAA‐b‐PS‐b‐PVDC‐b‐PS tetra‐block copolymers with a molar mass of 76 kg mol⁻¹ and a relatively low molecular weight distribution of 1.6. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40391.     

Block copolymers as polymeric stabilizers in non‐aqueous emulsion polymerization

This review summarizes the background and recent advances of block copolymer stabilized oil‐in‐oil emulsions. For non‐polymerizable emulsions which have promising application possibilities for biomedical and cosmetic formulations, it is shown that tailor‐made block copolymers are by far the most efficient stabilizers with respect to low molecular weight surfactants. The characteristic features of oil‐in‐oil emulsions comprising one polymerizable phase are described. These types of non‐aqueous emulsions are of interest as nanoreactor systems for the polymerization of moisture‐sensitive monomers or catalysts. Furthermore they are the starting point of novel heterophase polymerization processes for the preparation of sterically stabilized polymer particles, as well as of ‘liquid‐filled polymeric materials’. The concept of oil‐in‐oil emulsions is finally extended to those systems where the two phases are polymerizable by distinct polymerization mechanisms. This approach could offer attractive possibilities for the development of special coatings with neither water nor solvent evaporation in their drying or curing step. Copyright © 2011 Society of Chemical Industry     

Heterocoagulation behavior of carbon black with surface encapsulation through emulsion polymerization

Nanocomposite microspheres containing styrene–acrylate resin, wax, and carbon black (CB) with desired CB dispersion were prepared through heterocoagulation. The CB surface was modified using conventional anionic emulsifier and anionic dispersants with different lengths of nonionic chains and reactivities or through polymer encapsulation via emulsion polymerization to regulate the dispersion and concentration of CB in the microspheres. Experimental results showed that anionic dispersants with long nonionic chains effectively dispersed and stabilized CB particles. Polystyrene (PS) was then encapsulated on the CB surface by using a reactive dispersant and a water‐soluble initiator of polymerization. The CB particles exhibited comparable pH stability with other heterocoagulation components. Overall, encapsulation through emulsion polymerization can be used to obtain not only high CB content but also improved CB distribution in the resulting microspheres. High coagulation efficiency can also be achieved using polystyrene‐encapsulated dispersed CB because of its high affinity to emulsifiers and reactive dispersants during dispersion. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43516.     

两亲嵌段共聚物基高内相乳液模板的制备与应用研究进展

多孔聚合物材料具有孔隙率高、加工性能好、质量轻的特点,在化学工程、生物医学工程及环境工程等领域具有广阔的应用前景。高内相乳液模板法为多孔聚合物材料提供了一种简单高效的制备途径,且以此方法制备的多孔材料形状及结构可控,因而引起了人们的广泛关注。本文聚焦于两亲嵌段共聚物稳定的高内相乳液及其所制备多孔聚合物的最新研究进展。同时,介绍了该类型多孔聚合物材料在吸附分离、生物医学、能量存储及催化材料等领域的应用。最后,对该领域的未来发展进行了展望。     

Lamotrigine‐loaded polyacrylate nanoparticles synthesized through emulsion polymerization

A series of copolymeric nanoparticles of the partially water‐soluble monomer ethyl methacrylate and the water‐soluble monomer 2‐hydroxyl ethyl methacrylate were synthesized from emulsions containing sodium dodecyl sulfate via free‐radical polymerization. Lamotrigine, as a model drug, was loaded in nanoparticles during in situ polymerization. A stable and transparent poly(ethyl methacrylate‐co‐hydroxyl ethyl methacrylate) nanolatex was produced for all compositions and characterized for particle size by dynamic light scattering and transmission electron microscopy. Particles were found to be smaller than 50 nm in size. Structural characterization of copolymers was done by infrared spectrometry, gel permeation chromatography, and NMR spectroscopy. Drug encapsulation efficiency was determined by ultraviolet (UV)–visible spectrometry and was found to be 26–62% for copolymers with different compositions. UV data suggest molecular‐level dispersion of the drug in the nanoparticles. In vitro drug‐release studies showed the controlled release of lamotrigine. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of acrylate polymers by a novel emulsion polymerization for adhesive applications

Pressure‐sensitive adhesives (PSAs) are viscoelastic–elastomeric materials that can adhere strongly to solid surfaces with light contact pressure and a short contact time. Polyacrylates produced by solution polymerization are used widely because of their good adhesive properties. A novel emulsion polymerization was established to improve the low physical properties of PSA on the basis of conventional poly(n‐butyl acrylate) (PBA) by emulsion polymerization. PBA latex was synthesized by the emulsion polymerization of 50 wt % n‐butyl acrylate mixed with 15 wt % ethyl acetate (EA) with Emal‐10P and Emulgen‐920 as anionic and nonionic surfactants, respectively, at 70°C. Potassium persulfate (KPS) or a combination of KPS and dicumyl peroxide (DCP) was used as the initiator. The KPS/DCP system gave a very high‐molecular‐weight PBA of a narrow molecular weight distribution with a weight‐average molecular weight/number‐average molecular weight value of 1.01–1.03 in 15 min. The PSA tape was prepared by the casting of the PSA latex onto a corona poly(ethylene terephthalate) film as an adherent to obtain a 50‐μm‐dry‐thickness film. The PSA tape produced from PBA by the novel emulsion polymerization showed better adhesive properties, such as 180° peel adhesion, shear holding power, and rolling ball tack tests according to JIS and ASTM standards, than PSA tape produced from solution polymerization. The occlusion of a small amount of EA in emulsion particles before polymerization was found to give higher properties than those of PBA prepared by the addition of EA to the PBA latex after polymerization. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:413–421, 2006     

催化乳液合成可溶性超支化聚合物的IFIRP法研究

描述了可进行催化乳液聚合合成可溶性超支化聚合物的一种新的聚合物合成过程——引发剂残片嵌入自由基聚合（IFIRP,Initiator-Fragment Incorporation Radical Polymerization）。分别以高浓度的偶氮二异丁酸甲酯（MAIB）和α-甲基苯乙烯（α-MS）为引发剂及阻聚剂,在十二烷基磺酸钠（SDS）和水及苯形成的乳液中,通过IFIRP过程,在70～80℃条件下将单体二异丁烯酸乙二酯（EGDMA）聚合反应3 h即可得到可溶性的超支化聚二异丁烯酸乙二酯纳米粒子聚合物。研究发现,当EGDMA、MAIB和α-MS浓度分别为1.0、2.0和2.0 mol/L时,到80℃为止未见到凝聚现象发生,生成可溶性聚合物的产率为44%左右,相对分子质量分布在1.2～1.5之间。分析结果表明共聚物的成分为（质量分数）：α-MS为57%,MAIB为24%,含双键的EGDMA为5%,不含双键的EGDMA为14%。     

Polystyrene latex particles bearing primary amine groups via soap‐free emulsion polymerization

Polystyrene latexes were prepared in the presence of an amino‐containing functional comonomer, N‐(3‐aminopropyl)methacrylamide hydrochloride (APMH), via soap‐free batch emulsion polymerization initiated by the cationic initiator 2,2′‐azobis(2‐amidinopropane) dihydrochloride. These latexes were characterized by studying the influence of the ionic comonomers on the polymerization kinetics, particle size, surface charge density and colloidal properties. The synthesized latexes were monodisperse with a final size between 100 and 600 nm depending on the APMH concentration. The initial polymerization rate and the particle number increased in accordance with the Smith–Ewart theory for soap‐free styrene emulsion polymerization with a hydrophilic functional comonomer. The final functionalization rate of the particles has been particularly studied with the intention of fitting the prepared latexes to be used in the immobilization of biological molecules for biological sample preparation and diagnostic applications. © 2020 Society of Chemical Industry     

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     

Preparation of emulsifier‐free polystyrene by conventional emulsion polymerization with a hydrolysable emulsifier

An alkali‐hydrolyzable surfactant, (1‐tetradecyloxycarbonyl)trimethylammonium chloride, was used as an emulsifier for emulsion polymerization of styrene inwater. The polymerization yielded a high molecular‐weight polymer almost quantitatively. Addition of a small amount of NaOH to the resulting latex solution precipitated the polymer immediately. Analysis of the centrifuged solid indicated almost perfection of both recovery of the polymer and removal of surface‐active species from it. Minimization of ionic species in the polymer solid was confirmed by a high contact angle of the polymer film with water. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

氯乙烯-丙烯腈共聚物乳液合成技术及其表征

介绍了氯乙烯-丙烯腈共聚物的乳液聚合方法,研究了合成过程中乳化剂、引发剂的加入方式及工艺条件对共聚物性能的影响,并对共聚物进行了表征。结果表明:乳化剂的最佳投加方式为(以乳化剂/VCM表示):先投加0.02,反应开始后流加0.02;引发剂的最佳投加方式为(以引发剂/VCM表示):先投加0.012,反应开始后流加0.012。该共聚物具有优良的阻燃性能。     

Core–shell emulsion polymerization of styrene and butyl acrylate in the presence of polymerizable emulsifier

A series of core–shell polymeric particles of styrene butyl acrylate were successfully prepared in the presence of polymerizable emulsifier. The compositions of the emulsions obtained were confirmed by Fourier transformed infrared spectrometry. Latexes and emulsion films were characterized by transmission electron microscopy and scanning electron microscopy, respectively. The thermostability of emulsion films was characterized by thermogravimetric analysis. The results showed that the existence of polymerizable emulsifier could enhance the solid content of the emulsion and the monomer conversion. The optimum mass ratio of polymerizable emulsifier to traditional emulsifier was 1:1, and the polymerizable emulsifier can participate in the emulsion polymerization perfectly. An emulsion with reverse core–shell particles exhibited better hydrophobic properties and thermostability than one with traditional core–shell particles. The film formed by the emulsion with reverse core–shell particles had lower water absorption, and it could be used in the fields of coatings, surface sizing agents, and spinning. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43091.     

激光在线监测无皂乳液聚合

当激光束通过乳液时其吸光度与乳液浊度有关，而浊度又与乳液粒子直径、浓度相关，在无皂乳液聚合过程中，由于体系的稳定性较差，若加料速度不适当，很容易在聚合初期出现乳液浊度陡增甚至凝胶。本研究利用氦氖激光器分别对苯乙烯、丙烯酸酯、醋酸乙烯酯等单体的无皂乳液聚合实施监测，即通过吸光度变化来控制加料速度，使乳液吸光度保持平缓变化，也就是在聚合初期使乳液粒子浓度保持在适当水平，从而避免因小粒子溶胀聚并产生凝胶，制得了具有良好稳定性的无皂聚合乳液。     

Molecularly imprinted polymer beads prepared by pickering emulsion polymerization for steroid recognition

Pickering emulsion polymerization was used to synthesize molecularly imprinted polymer beads for the selective recognition of 17‐β‐estradiol under aqueous conditions. Scanning electron microscopy analysis indicated that the imprinted polymer beads had a small diameter with a narrow size distribution (18.9 ± 2.3 μm). The reduction in particle size achieved in this study was attributed to the altered polarity of the stabilizing nanoparticles used in the Pickering emulsion. The imprinted polymer beads could be used directly in water and showed a high binding affinity for the template molecule, 17‐β‐estradiol, and its structural analogs. These water‐compatible polymer beads could be used as affinity adsorbents for the extraction and analysis of low‐abundance steroid compounds in aqueous samples. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39606.     

Novel hydrophilic N-halamine polymer with enhanced antibacterial activity synthesized by inverse emulsion polymerization

N-halamine-based antibacterial agents have high efficiency and rechargeable antibacterial properties. However, their applications are limited due to their complex synthetic process and fuzzy antibacterial mechanism. In this study, a novel N-halamine antibacterial polymer was synthesized by inverse emulsion polymerization and characterized by Fourier transform infrared, nuclear magnetic resonance, scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. Due to the difficulty of purification, most of the subjects studied previously were hydrophobic polymers, while little research on hydrophilic polymers. In this experiment, this difficulty was overcome by controlling the dosage of sodium hypochlorite and methods of dialysis. Because of the complex cell structure of Gram-negative bacteria, it is difficult for N-halamines to release the oxidizing chlorine into the cell. However, the hydrophilic N-halamines can solve this problem, which showed a stronger antibacterial effect on Gram-negative Escherichia coli synthesized in this study. In addition, the particle size and hydrophilic property of the polymer were changed by changing the amount of initiator, and the differences in their antibacterial properties were studied. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47419.     

丙烯酰胺共聚物乳液增稠剂的合成及性能研究

以丙烯酰胺(AM)和2-丙烯酰胺基-2-甲基丙磺酸钠(SAMPS)为聚合单体,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,采用反相乳液聚合法,合成了微交联型丙烯酰胺共聚物乳液。当n(AM)∶n(SAMPS)=3∶2,MBA为单体总质量的0.08%,过硫酸铵为单体总质量的0.03%,异丙醇为单体总质量的0.3%,亚硫酸氢钠为单体总质量的0.06%时,合成产物具有优良的增稠性能和耐电解质性能。测试结果表明,质量分数1%的聚合物水溶液黏度大于1.0×105mPa.s,质量分数1.2%的聚合物水溶液在质量分数0.1%氯化镁和氯化钠存在时的黏度保持率分别为32.76%和24.66%。另外该聚合物乳液的残留丙烯酰胺(2 mg/kg,反相时间(15 s。     

Core‐shell latex synthesized by emulsion polymerization using an alkali‐soluble resin as sole surfactant

A series of alkali‐soluble resins were prepared from esterification reaction of styrene‐maleic anhydride copolymer (SMA) and four fatty alcohols having different alkyl chains. The critical aggregates concentration of the prepared hemiester was lower than SMA, indicating that modification of SMA resin with long alkyl chains could improve their emulsification efficiency. The detailed experiments of emulsion polymerization of methyl methacrylate and butyl acrylate using these hemiesters as sole surfactants showed that SMA‐C12‐75, SMA‐C14‐70, and SMA‐C16‐65 were good surfactants. In the end, we successfully prepared stable latexes using above three good surfactants with relatively low surfactant concentration and high solid content. Characterization of latexes by Zetasizer and transmission electron microscopy revealed that particles of these latexes have core‐shell nanostructure with average particle size below 60 nm. Compared with SMA, the improvement of emulsification efficiency of its hemiesters may come from the better hydrophilic‐lipophilic balance and steric stabilization after incorporation of long alkyl chain. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

乳液聚合方法研究进展

乳液聚合方法具有各方面的优点和广泛的应用范围,因此,受到人们的广泛关注。本文介绍了乳液聚合的优缺点,并着重介绍了一些新的乳液聚合方法及其原理、特点、应用以及中外最新的一些研究成果。     

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