Emulsion and miniemulsion polymerization of isobornyl acrylate

Isobornyl acrylate, a highly hydrophobic monomer, was batch‐polymerized in both emulsion and miniemulsion recipes. Surfactant levels above and below the critical micelle concentration were used, as were two different initiator types: ionic (potassium persulfate) and nonionic (t‐butyl hydroperoxide) Samples were analyzed for degree of conversion, molecular weight, and particle size. The effects of reaction type (emulsion versus miniemulsion), surfactant level, type of initiator (ionic versus nonionic) of the polymer properties are discussed. Issues of monomer transport across the aqueous phase, and mechanisms of nucleation, especially at very low surfactant concentrations are discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 819–833, 2007     

甲基丙烯酸三氟乙酯和丙烯酸甲酯乳液共聚：乳胶粒子大小及形貌研究

成功地合成了一系列甲基丙烯酸三氟乙酯/丙烯酸甲酯共聚物乳液,固含量约为30%（wt）。研究了乳化剂SDS/OP-10比例、引发剂KPS用量、单体投料比例对乳胶粒子大小及形貌的影响。实验结果表明：阴离子乳化剂十二烷基硫酸钠（SDS）的用量对乳胶粒子的粒径影响较大,粒径从59 nm至100 nm,粒度分布（PDI）变化不大;引发剂用量和单体比例对乳胶粒子影响较小,其中单体比例对乳胶粒子的大小几乎没有影响。     

微波辐射吸油性复合体的制备及性能研究

以甲基丙烯酸丁酯、丙烯酸β－羟乙酯、丙烯酸－２－乙基己酯为单体,ＢＰＯ为引发剂,二甲基丙烯酸二乙醇酯为交联剂,无纺布为基材,在微波辐射下分别合成甲基丙烯酸丁酯与丙烯酸β－羟乙酯的共聚复合吸油体及丙烯酸－２－乙基己酯与丙烯酸β－羟乙酯共聚复合吸油体。并考察了单体配比、引发剂用量、交联剂用量、微波辐射功率诸因素对高吸油性复合体的性能影响,从而制得了性能优异的吸油复合体。     

Emulsion polymerization of pentabromobenzyl acrylate: effect of reaction parameters on the produced flame‐retardant nanoparticles

Flame‐retardant nanoparticles of sizes ranging between 33 ± 6 and 460 ± 50 nm were formed by the emulsion polymerization of the pentabromobenzyl acrylate (PBBA) monomer in the presence of sodium dodecyl sulfate as the surfactant and potassium persulfate as the initiator. The effect of various polymerization parameters, e.g. monomer, crosslinker monomer, initiator and surfactant concentrations, on the size, size distribution and polymerization yield of the poly(pentabromobenzyl acrylate) nanoparticles produced has been elucidated. Poly(pentabromobenzyl acrylate)/polystyrene (PPBBA/PS) nanoblends containing 15% and 70% of PPBBA particles of 33 ± 6 and 460 ± 50 nm diameter were prepared by mixing the particles with a PS solution in methylene chloride, followed by evaporation of the methylene chloride from the mixture. The effect of the size and the content of the PPBBA nanoparticles in the nanoblends on the thermal stability of the PS were also elucidated. Copyright © 2011 Society of Chemical Industry     

Synthesis,characterization, and thermal behavior study of methyl methacrylate polymers containing 4‐carbazole substitutes

A new polymerizable monomer, [4‐(9‐ethyl)carbazolyl]methyl methacrylate ( 2 ), was synthesized by reacting of methacrylic acid and 4‐hydroxymethyl‐9‐ethyl carbazole ( 1 ) by esterification procedure in the presence of N,N′‐dicyclohexylcarbodiimide. The resulting monomer was then polymerized free‐radically to form the poly(methyl methacrylate) containing 4‐(9‐ethyl)carbazolyl pend ent groups. Also, copolymerization of monomer 2 with various acrylic monomers such as methyl methacrylate, ethyl methacrylate, methyl acrylate, ethyl acrylate, and n‐butyl acrylate by azobisisobutyronitrile as a free radical polymerization initiator gave the related copolymers in high yields. The structure of all the resulted compounds was characterized and confirmed by FTIR and ¹H NMR spectroscopic techniques. The average molecular weight of the obtained polymers was determined by gel permeation chromatography using tetrahydrofurane as the solvent. The thermal gravimetric analysis and differential scanning calorimeter instruments were used for studying of thermal properties of polymers. It was found that, with the incorporation of bulky 4‐(9‐ethyl)carbazolyl substitutes in side chains of methyl methacrylate polymers, thermal stability and glass transition temperature of polymers are increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4989–4995, 2006     

纳米尺寸聚合物微凝胶的结构表征与调控

通过乳液聚合的方法,以二乙烯基苯为交联剂,用甲基丙烯酸甲酯、甲基丙烯酸-β-羟乙酯、丙烯酸丁酯等丙烯酸酯类单体合成纳米尺寸的聚合物微凝胶粒子。研究了乳化剂体系的选择和用量、交联剂用量以及单体和水的比例等聚合参数对微凝胶乳液体系的影响。并通过纳米粒度仪、动态光散射、静态光散射、透射电镜等手段对聚合物微凝胶粒子的结构形态和性质进行表征。     

Concentrated emulsion polymerization of methyl methacrylate/butyl acrylate initiated by a redox system

Stable concentrated emulsions of methyl methacrylate/butyl acrylate were prepared with sodium dodecyl sulfate and cetyl alcohol as the compound surfactant and poly(vinyl alcohol) as the major reinforcer of the liquid film. With a redox system based on benzoyl peroxide/N,N′‐dimethyl phenylamine introduced into the concentrated emulsions, polymer particles with different shapes and sizes were obtained by initiation of the polymerization at low temperatures. We investigated the kinetic behaviors of concentrated emulsion polymerization and drew linear regression diagrams of its time–conversion curves in a constant rate phase (conversions ranged from 20 to 70%), and the experimental results show that the variation of the concentrations of the compound surfactant and initiator, the categories of reinforcers of the liquid film, the temperatures, and so on were responsible for the polymerization stability and the polymerization rate. Finally, the kinetics equation and activation energy of the initiator were obtained. The particle size and distribution of particle diameters of latex particles were determined by photon correlation spectroscopy. The determination results reveal that concentrations of the compound surfactant, polymerization temperatures, and so on affected the shape and size of the polymer particles greatly. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1695–1701, 2005     

用阴离子Gemini 9 B-6-9 B乳化剂合成苯乙烯-丙烯酸丁酯共聚物纳米乳液

以壬基酚、1,6-二溴己烷、氯磺酸为主要原料合成的阴离子Gemini磺酸盐表面活性剂9 B-6-9 B为乳化剂,苯乙烯(St)、丙烯酸丁酯(BA)为单体,合成了乳胶粒径小于100 nm且分布均匀的苯乙烯-丙烯酸丁酯共聚物纳米乳液,考察了聚合温度、乳化剂用量、引发剂用量、单体配比、单体含量对乳液的影响,探讨了乳胶粒子成核机理。结果表明,随着温度的升高,乳胶粒子的平均粒径减小,转化率与凝胶率增大;随着乳化剂或引发剂用量的增加,乳胶粒子的平均粒径和凝胶率减小,转化率增大;随着软单体比例的增加,乳胶粒子的平均粒径与转化率增大,粒径分布变宽,凝胶率减小;单体用量增大,乳胶粒子的平均粒径与凝胶率增大,转化率降低;乳胶粒子的粒径呈单峰分布,可能是按胶束成核机理形成的。     

EA-MMA共聚乳液合成工艺及优化

以丙烯酸乙酯(EA)和甲基丙烯酸甲酯(MMA)为共聚单体、过硫酸钾(KPS)为引发剂、十二烷基硫酸钠(SDS)和壬基酚聚氧乙烯醚(OP-10)为复合乳化剂,采用乳液聚合法合成出一种稳定的EA-MMA乳液。通过单因素试验法考察了乳化剂浓度、引发剂浓度、反应温度和反应时间等因素对乳液平均粒径和单体转化率的影响,并采用正交试验法进一步优选出制备EA-MMA乳液的最佳工艺条件。结果表明:当w(乳化剂)=2.0%、w(引发剂)=0.60%、反应时间为4 h和反应温度为80℃时,制成的EA-MMA乳液较稳定,并且单体转化率相对最高。     

Mass transfer and radical flux effects in dispersed‐phase polymerization of isooctyl acrylate

The kinetics of dispersed phase polymerization of a highly water‐insoluble monomer (isooctyl acrylate) were explored in emulsion, miniemulsion, and microsuspension polymerization. The effects of monomer water solubility and choice of initiator (oil‐ vs. water‐soluble) strongly impact the final product (particle size and molecular weight distribution). For emulsion polymerization, as the surfactant concentration was increased, there was a transition from homogenous to micellar nucleation near the CMC, then a drop in nucleation rate at high surfactant concentration due to insufficient radical flux to support more nucleation. For miniemulsion polymerization, a slow rate of growth of (droplet) nucleation with surfactant concentration was found, followed (at the CMC) by an increase in the rate of nucleation with added surfactant as the mode of nucleation switched to micellar. The conversion‐time kinetics of microsuspensions could be modeled with a bulk polymerization model. IOA is sufficiently insoluble in the aqueous phase that emulsion polymerization may or may not be reaction limited. The presence of a stabilizer such a PAA, the use of an oil‐soluble initiator such as BPO, and the insolubility of IOA in the aqueous phase all push the polymerization locus toward droplet (microsuspension) nucleation and bulk kinetics.© 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5649–5666, 2006     

Synthesis and characterization of epoxy‐acrylate composite latex

A waterborne epoxy‐acrylate composite latex was synthesized. The effects of the concentration of the initiator, surfactant, and epoxy resin on the particle size, molecular weight, and grafting ratios of the composite latex were investigated. The increase of the concentration of the initiator and epoxy resin led to the decrease of the weight‐average molecular weight. The graft ratios increased with an increase in the initiator level and a decrease in the epoxy resin concentration whereas the variation of the concentration of the surfactant did not have much influence on the graft ratios. The increase in the initiator level caused the aggrandizement of the particle size, and the increase of the concentration of the surfactant and epoxy resin caused a decrease in the latex particle size. Fourier transform IR spectroscopy with attenuated total reflectance indicated that the epoxy resin molecules were enriched in the mold‐facing surface in the film from the composite latex. The differential scanning calorimetry analysis, dynamic mechanical analysis, and Instron test showed that the polymer films cast by the composite latex had lower tensile strength and glass transition than those by the blend latex. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1736–1743, 2002     

Solution properties of anionic hydrophobic association polyacrylamide modified with fluorinated acrylate

The anionic hydrophobic association polyacrylamide (AFPAM) modified with fluorinated acrylate have been synthesized of acrylamide (AM), 2-acrylamide-2-methyl propanesulfonic acid (AMPS) and 2-(perfluorooctyl)ethyl acrylate (FEA) by free radical micellar copolymerization in aqueous solution utilizing sodium dodecyl sulfate(SDS) as the surfactant and potassium persulfate(KPS)/sodium bisulfite(SBS) as the redox initiator. The solution properties of these polymers were investigated. The results show that there are strong hydrophobic associations in the AFPAM aqueous solution. The intrinsic viscosity decreases and Huggins constant increases with the increase of hydrophobic FEA content. The addition of NaCl and CaCl₂ results in an increase of solution viscosity which indicate the good salt-resistant performance. The polymers exhibit good temperature tolerance property, shear-thickening and thixotropy behavior. Additionally, the AFPAM has higher surface activity in salt solution than in water.     

Influences of the polymerization ingredients on the porous morphology of soap‐free poly(methyl methacrylate/ethyl acrylate/methacrylic acid) seeded latex particles

Monodispersed soap‐free poly(methyl methacrylate/ethyl acrylate/methacrylic acid) latex particles were synthesized by the seeded emulsion polymerization of methyl methacrylate, ethyl acrylate, and methacrylic acid (MAA), and particles with a porous morphology were obtained after an alkali posttreatment. The effects of the unsaturated acid and crosslinking agent on the properties and morphology of the latex particles were investigated. The results showed that the particle size decreased and its distribution widened when the concentration of MAA was greater than 10.0 mol % or the concentration of ethylene glycol dimethacrylate (EGDMA) was greater than 1.5%. When more than 4.0 mol % MAA was used, a porous structure could be detected clearly under a transmission electron microscope, and the particle volume and pore size first gradually increased to a maximum and then decreased rapidly with an increase in the MAA concentration. The porous morphology disappeared completely as the MAA concentration reached 16.0 mol %. A multihollow morphology was generated when the EGDMA concentration exceeded 1.0%, and the particle volume decreased monotonously with the concentration of EGDMA increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1934–1939, 2006     

Synthesis and properties of copolymer microemulsions of siloxane and acrylate with a high solid content

Copolymer microemulsions of methyl methacrylate, butyl acrylate, and vinyltriisopropoxysilane with high monomer/surfactant ratios were prepared through a seeded semicontinuous polymerization in the presence of a redox initiator, ammonium persulfate/sodium hydrosulfate. The mean diameter of the particles decreased with an increase in the amount of the surfactant, the monomer concentration, and the vinyltriisopropoxysilane/monomer ratio, but it increased with an increase in the concentration of the initiator. When the initiator concentration was 0.23% (ammonium persulfate/sodium hydrosulfate = 1.5 : 1), the concentration of the composite surfactant was 0.9 wt %, and the reaction temperature was 50°C; the solid content of the microemulsion could be up to 43% with a small particle size (mean diameter) of 39.8 nm. The chemical, freeze–thaw, and mechanical stability of the latexes was tested as well as the thermal stability of the films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 851–857, 2007     

Intrinsic viscosity, surface activity, and flocculation of cationic polyacrylamide modified with fluorinated acrylate

A novel cationic polyacrylamide modified with fluorinated acrylate had been synthesized of acrylamide (AM), methacryloxyethyl trimethylammonium chloride (DMC), and 2-(perfluorooctyl)ethyl acrylate (FEA) by free radical micellar copolymerization in aqueous solution utilizing cetyl trimethylammonium bromide (CTAB) as the surfactant and potassium persulfate (KPS)/sodium bisulfite (SBS) as the redox initiator. Some factors affecting synthesis, such as the amount of FEA, CTAB, and KPS, were described. Surface activity and flocculation of the polymer were studied. The results showed that with the incorporation of FEA, the intrinsic viscosity decreased until the modified polymer was not able to dissolve in water; and with the increase of CTAB and KPS, the intrinsic viscosity decreased firstly then increased slowly. The polymer exhibited good surface activity in both water and salt solution. Its flocculation properties were evaluated with kaolin suspensions using a standard jar test. The results demonstrated the superiority of the copolymer over the no-modified cationic polyacrylamide as a flocculant.     

Synthesis of poly(butyl acrylate)‐poly(methyl methacrylate) core–shell nanomaterials of anti‐crease‐whitening properties

Core–shell nanomaterials of poly(butyl acrylate)‐poly(methyl methacrylate) were synthesized using a differential microemulsion polymerization method for being used as polyacrylate‐based optical materials, which meet the requirement of anti‐crease‐whitening and proper mechanical strength. The effects of reaction temperature and surfactant amount on the particle sizes, as well as the effect of reaction temperature on the conversion and solid content were investigated to reveal the dependence of the application properties on the reaction conditions. The spherical morphology of core–shell nanoparticles was also studied via transmission electron microscopy. The resulting polymers with a core–shell monomer ratio of butyl acrylate/methyl methacrylate at 32/10 (vol/vol) demonstrated the optimal balanced properties in the anti‐crease‐whitening and mechanical property, confirmed by the visible light transmittance measurement and the dynamic analysis of the viscoelastic properties of the synthesized core–shell nanomaterials. The smaller the particle size, the better the transparency of the resulting polymer films. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39991.     

Influence of ingredients in water-based polyurethane–acrylic hybrid latexes on latex properties

Polyurethane–acrylic (PU–AC) hybrid latexes were prepared. Main monomers for PU preparation were isophorone diisocyanate, DMPA (dimethylol propanic acid) and polypropylene oxides (PPO) of different molecular weights. Acrylic monomers included butyl acrylate, methyl methacrylate and a crosslinker, trihydroxymethyl propane triacrylates (TMPTA). Several important ingredients in PU–AC latex preparation, such as surfactants, initiator, DMPA and PU/AC ratio, etc., were varied, and their effects on latex properties studied. Compared with surfactant free latexes, a sharp increase in particle size was observed in latexes done with 0.1% of surfactant regardless of the nature of the surfactants used (anionic, nonionic and anionic with long chain of amphiphilic alkylphenyl polyethoxylate). Further increase in surfactant content, however, led to latexes with smaller particle size and narrower particle size distribution when compared between latexes prepared using a same surfactant. When amount of the oil soluble initiator, azobisisobutyronitrile, was increased, AC monomers conversion was increased. It is interesting to observe that PPO with long propylene oxides brought about larger particle size combined with broader size distribution and less charge on particle surface; whereas lower DMPA levels led to latexes also of larger size combined with broader size distribution but more charges on particle surface. AC monomer crosslinker, TMPTA, contributed to reduce particle size, narrower size distribution and lower particle surface charges. By increasing AC amount in PU–AC latex, latex particle size significantly increased accompanied by a remarkable increase in particle surface charges. Mechanisms of particle formation and of DMPA stabilization were discussed in order to understand the experimental results.     

丙烯酸酯与丙烯酰胺共聚物表面活性剂的合成

研究了烷基酚聚氧乙烯醚丙烯酸酯活性大单体的合成。以ＤＭＦ为溶剂,过氧化物为引发剂,烷基酚聚氧乙烯醚丙烯酸酯（ＡＥ）、丙烯酰胺（ＡＭ）和丙烯酸异辛酯（ＭＧ）共聚,得到了三元共聚物（ＡＥＡＭＭＧ）高分子表面活性剂,探讨了单体组成、引发剂和溶剂用量、反应温度对共聚物表面活性和粘度的影响。结果表明,ＡＥＡＭＭＧ共聚物表面高,增粘能力强,１％共聚物水溶液的表面张力低达３２．４ｍＮ／ｍ,油水界面张力小于１ｍＮ     

Interpenetrating polymer networks from caster oil-based-polyurethanes and poly(ethyl acrylate). VII

Liquid prepolyurethanes were synthesized from castor oil and toluene-2, 4-diisocyanate (TDI) under different experimental conditions and varying NCO/OH ratios. All these prepolyurethanes were subsequently reacted with ethyl acrylate/ethylene glycol dimethacrylate mixtures by radical polymerization using benzoyl peroxide as initiator to obtain interpenetrating polymer networks (IPNs) by transfer molding. The novel polyurethane/poly(ethyl acrylate) IPNs are found to be tough films. These IPNs are characterized in terms of their resistance to chemical reagents, thermal behavior (DSC, TGA), mechanical behavior including tensile strength, Young's modulus, and elongation. The dielectric properties, namely electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε″), and loss tangent (tan δ) were computed. The mechanothermal behavior was analyzed by dynamic mechanical spectroscopy. The morphological behavior was studied by scanning electron microscopy.     

Kinetics of the emulsion copolymerization of MMA/BA in the presence of sodium montmorillonite

The kinetics of the emulsion copolymerization of methyl methacrylate/butyl acrylate (MMA/BA = 50/50) in the presence of sodium montmorillonite (Na-MMT) was investigated. Sodium laurylsulfate was used as surfactant at different concentrations and potassium persulfate as initiator. Two series of experiments were carried out at 30% and 10% solids content and varying the amount of surfactant and sodium montmorillonite. The effect of surfactant and sodium montmorillonite content on the stability of the final latices was assessed. The effect on particle nucleation, polymerization kinetics and molar mass distribution was also discussed, and compared with the predictions of the Smith–Ewart theory.