Synthesis and characterization of new cationic quaternary ammonium polymerizable surfactants

Two new polymerizable surfactants (surfmers), (11-acryloyloxyundecyl)dimethylethylammonium bromide (ethyl surfmer) and (11-acryloyloxyundecyl)dimethyl(2-hydroxyethyl)ammonium bromide (hydroxyethyl surfmer), were synthesized and characterized. The binary phase diagrams of both surfmer/water systems are described. Both surfmers can form isotropic solutions and lamellar lyotropic liquid crystalline phases. The hydroxyethyl surfmer/water system forms a lamellar phase for weight concentrations of surfmer between 70 and 90% relative to between 75 and 85% for the ethyl surfmer/water system. The differences in the self assembly of these surfmers were attributed to the ability of hydroxyethyl surfmer to form hydrogen bonds (between two head groups and with water), whereas no such interactions can occur with the ethyl surfmer system.     

Reactive surfactants in heterophase polymerization. VIII. Emulsion polymerization of alkyl sulfopropyl maleate polymerizable surfactants (surfmers) with styrene

The copolymerization of styrene with two polymerizable surfactants (surfmers) based on maleic acid (dodecyl sodium sulfopropyl maleate and tetradecyl sodium sulfopropyl maleate) was studied in batch emulsion polymerizations. The surfmer conversion was obtained by serum replacement with water and subsequent analysis of the recovered, unreacted surfmers with two-phase titration. It was found that both surfmers copolymerized well with styrene and their partial conversion was higher than that of styrene. These results are contradictory to what was found before in the literature using ultrafiltration with methanol, and the differences are explained on the basis of oligomer formation: The oligomers formed are detected if the latices are washed with methanol. It was found that at the end of the polymerization (almost complete conversion of both styrene and surfmer) only 45% of the surfmer groups were present on the particle surface, which is in agreement with a high conversion of the surfmer at the beginning of the reaction. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2561–2568, 1997     

Comparative study of classical surfactants and polymerizable surfactants (surfmers) in the reversible addition–fragmentation chain transfer mediated miniemulsion polymerization of styrene and methyl methacrylate

Cationic and anionic amphiphilic monomers (surfmers) were synthesized and used to stabilize particles in miniemulsion polymerization. A comparative study of classical cationic and anionic surfactants and the two surfmers was conducted with respect to the reaction rates and molecular weight distributions of the formed polymers. The reversible addition–fragmentation chain transfer process was used in the miniemulsion polymerization reactions to control the molecular weight distribution. The reaction rates of the surfmer‐stabilized miniemulsion polymerization of styrene and methyl methacrylate were similar (in most cases) to those of the classical‐surfactant‐stabilized miniemulsion polymerizations. The final particle sizes were also similar for polystyrene latexes stabilized by the surfmers and classical surfactants. However, poly(methyl methacrylate) latexes stabilized by the surfmers had larger particle sizes than latexes stabilized by classical surfactants. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 427–442, 2006     

Synthesis and properties of soap-free poly(methyl methacrylate-ethyl acrylate-methacrylic acid) latex particles prepared by seeded emulsion polymerization

In order to obtain functional polymer latex particles with clean surface and with surface carboxyl groups, P(MMA-EA) seed particles with the diameter of 335 nm were first synthesized via soap-free batch emulsion polymerization of methyl methacrylate (MMA) and ethyl acrylate (EA), and then the seeded emulsion copolymerization of MMA, EA and MAA (methacrylic acid) onto the seed particles were performed in the absence of emulsifier. Influences of ingredients and conditions on polymerization, latex particle size (D_p) and its distribution were investigated. Results showed that most of the monomers polymerized onto the seed latex particles in the second step of polymerization by using drop-wise addition method, and D_p increased from 483 nm to 829 nm with the mass ratio of core/shell monomers [C]/[S] decreased from 1:2 to 1:15. It was found that D_p decreased with the increase of MAA and initiator amounts, and the size of the latex particles became uniform with the decrease of MAA amount and with the increase of [C]/[S] value.     

Modeling emulsion polymerization stabilized by polymerizable surfactants

A mathematical model for seeded emulsion polymerization stabilized with polymerizable surfactants (surfmers) was developed. The model accounts for the main features of the process and provides information about surfmer conversion as well as surfmer burying inside the polymer particles. The model was validated by comparing its predictions with the experimental results for the effect of particle size, surface properties of the surfmer, and type of initiator on surfmer conversion. The effect of surfmer reactivity on surfmer incorporation to the polymer backbone is also discussed. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 585–595, 2001     

离子型表面活性单体存在下的MMA/BA乳液聚合(Ⅰ)——表面活性单体的合成及其(共)聚合活性

合成了两种离子型表面活性单体(Surfmer)磺化-十二醇-烯丙基甘油-丁二酸酯钠盐(ZC-L)和磺化-十二醇-甲基丙烯酰甘油-丁二酸酯钠盐(ZD-L).着重研究了ZC-L的结构、表面张力行为、均聚及共聚能力.实验结果表明,不同Surfmer用量以及不同固含量下,MMA/BA/Surfmer,MMA/Surfmer及BA/Surfmer共聚乳液的表面张力较高,说明Surfmer已通过共聚结合在乳胶粒上,乳液中残留甚少.对MMA/BA体系,ZC-L的共聚性能比ZD-L好.     

The generation of void morphology inside soap-free P(MMA-EA-MAA) particles prepared by seeded emulsion polymerization

Monodisperse soap-free P(MMA-EA-MAA) latex particles were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and methacrylic acid (MAA), and the particles with void morphology were obtained after undergoing alkali post-treatment. Effects of treatment conditions on particle morphology were investigated. Results showed that the void particles can be obtained under the conditions of the temperature >60 degrees C, initial pH >10.0, treatment time >20 min and 2-butanone amount >2.0 ml. The particle volume and the void size increased to the maximum and then decreased with the increases of initial pH and the treatment time, and these two values increased monotonously with the treatment temperature or 2-butanone amount increased. When the treatment temperature was elevated to 90 degrees C, the treatment time was longer than 180 min, or the 2-butanone amount was more than 8.0 ml, the relatively small voids inside most of the particles combined together to form a large one. The void structure disappeared completely as the initial pH was higher than 12.0. The generation mechanism of the void morphology was discussed.     

Design, synthesis, and miniemulsion polymerization of new phosphonate surfmers and application studies of the resulting nanoparticles as model systems for biomimetic mineralization and cellular uptake

Heterophase polymerizations have gained increasing attention in the past decades, especially as the decoration and functionalization of the particle surface for further applications gets more and more into focus. One promising approach for the functionalization exclusively on the particle surface is the use of surfmers (surfactant and monomer). Herein, we present the synthesis of a new family of surfmers and their use for decorating nanoparticles with phosphonate groups through miniemulsion polymerization. Furthermore the synthesis of a dye-labeled functional surfmer provided an elegant manner to evaluate and get deeper insights about its copolymerization. Additionally, potential applications of the synthesized particles in biological studies as well as their use as template for biomimetic mineralization are presented.     

Microgels containing methacrylic acid: effects of composition on pH-triggered swelling and gelation behaviours

pH-responsive microgels are cross-linked polymer colloids that swell when the pH approaches the pK _a of the particles. In this work, we present a comprehensive investigation of pH-triggered particle swelling and gel formation for a range of microgels containing methacrylic acid (MAA). The microgels investigated have the general composition poly(A/MAA/X), where A and X are the primary co-monomer and cross-linking monomer, respectively. The primary co-monomers were methyl methacrylate (MMA), ethyl acrylate (EA) or butyl methacrylate. The cross-linking monomers were either butanediol diacrylate (BDDA) or ethyleneglycol dimethacrylate (EGDMA). The microgels were studied using scanning electron microscopy, photon correlation spectroscopy (PCS) and dynamic rheology measurements. Gel phase diagrams were also constructed. The particles swelled significantly at pH values greater than approximately 6.0. It was shown that poly(EA/MAA/X) microgels swelled more strongly than poly(MMA/MAA/X) microgels. Furthermore, greater swelling occurred for particles prepared using EGDMA than BDDA. Concentrated dispersions of all the microgels studied exhibited pH-triggered gel formation. It was found that the fluid-to-gel transitions for the majority of the six microgel dispersions investigated could be explained using PCS data. In those cases, gelation was attributed to a colloidal glass transition. Interestingly, the microgels that were considered to have the highest hydrophobic content gelation occurred under conditions where little particle swelling was evident from PCS. The data presented show that gelled poly(EA/MAA/BDDA) and poly(MMA/MAA/EGDMA) microgel dispersions have the strongest elasticities at pH = 7.     

Preparation and Characterization of Polymer Core Shell Latex Particles

Stable core‐shell latex was synthesized by semicontinuous seeded emulsion polymerization with core monomers consisting of styrene (St), butyl acrylate (BA), and shell monomers consisting of methyl methacrylate (MMA), eutyl acrylate (EA), and methacrylic acid (MAA). The effects of compound emulsifier amount, mass ratio of anionic/nonionic emulsifier, and initiator amount on latex performance were investigated. By particle size analysis and transmission electron microscopy (TEM) observation, results suggest that final latex particles have clearly core shell structures.     

分散共聚法制备窄分布P(St-co-nBA)微球

用分散共聚法制得窄分布苯乙烯(St)和丙烯酸正丁酯(nBA)的共聚物微球.采用1H-NMR、DSC、FTIR、SEM、LS等对共聚物的结构、形态、性能进行表征,考察了初始单体配比、温度、稳定剂浓度、分散介质极性、引发剂对微球粒径、粒径分布及转化率的影响.实验结果表明,初始单体比nBA/St增大,微球粒径增大,分布变宽,...     

A study of poly(butadiene/methacrylic acid) dispersions: from pH-responsive behaviour to the effects of added Ca2+

This study investigates the effects of added Ca(2+) on the properties of poly(Bd/MAA) dispersions (1,3-butadiene and methacrylic acid) and considers the effect of particle composition on the pK(a). Four latex dispersions are considered in detail. These include poly(Bd/6MAA) and poly(Bd/20MAA) which contain, 6 and 20 wt% MAA, respectively, based on the total monomer mass used for dispersion preparation. Two model systems are also used for comparison. These are poly(Bd) and poly(EA/33MAA/BDDA) (EA and BDDA are ethyl acrylate and butanediol diacrylate). The latter is a well-studied model pH-responsive microgel. The apparent pK(a) of the poly(Bd/MAA) dispersions was determined from potentiometric titrations and found to increase with Bd content. The pH-dependence of the particle size was studied using photon correlation spectroscopy. Electrophoretic mobility measurements were also used. The hydrodynamic diameters and mobilities exhibited major changes as the pH approached the pK(a) for the particles. The critical coagulation concentrations were also measured. The results indicate that Ca(2+) caused pronounced dispersion instability at low pH. Moreover, Ca(2+) prevents swelling of the poly(Bd/MAA) particles at high pH. It was found that efficient ionic binding of all of the RCOO(-) groups within the poly(Bd/20MAA) particles occurred when the mole ratio of RCOO(-) to Ca(2+) was less than or equal to 2.0. Consideration of all the data leads to the suggestion that poly(Bd/MAA) particles have a core-shell structure. It is suggested that the particle core contains mostly poly(Bd) and that the shell is comprised of lightly crosslinked poly(Bd-co-MAA) copolymer.     

Incorporation of a new alkenyl‐based nonionic surfmer into acrylic latexes

The mechanisms by which a new nonionic alkenyl‐based surfmer (Maxemul 5011?) was involved in acrylic emulsion polymerization were investigated. No proof of homopolymerization or of chain transfer to surfmer was obtained under the conditions studied. The effect of the initiator type, feeding time of the surfmer, particle size of the seed, and surfmer concentration, on kinetics and surfmer incorporation showed that the surfmer reacted mainly by copolymerization with the monomers in the outer shell of the polymer particles. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4202–4211, 2004     

表面活性单体存在下的MMA／BA乳液共聚合（Ⅱ）：聚合动力？…

研究了表面活性单体「磺化－十二醇－烯丙基甘油－丁二酸酯钠盐（ＺＣ－Ｌ）」的用量对ＭＭＡ／ＢＡ／ＺＣ－Ｌ乳液聚合速率和粒径的影响,用Ｃｏｒｌｔｉｒ ＬＳ２３０型激光粒径分析仪测定聚合过程中乳液的粒径和粒径分布变化,并与ＭＭＡ／ＢＡ无皂乳液聚合及十二烷基苯磺酸钠存在下的ＭＭＡ／ＢＡ乳液聚合作了比较。「ＺＣ－Ｌ」〈ＣＭＣ时,成核机理为均相成核机理,乳胶粒需依靠粒子间的凝聚来提高表面电荷密度而稳定;「ＺＣ     

表面活性单体存在下的MMA/BA乳液共聚合(Ⅱ)聚合动力学及机理

研究了表面活性单体[磺化-十二醇-烯丙基甘油-丁二酸酯钠盐(ZC-L)]的用量对MMA/BA/ZC-L乳液聚合速率和粒径的影响,用CoulterLS230型激光粒径分析仪测定聚合过程中乳液的粒径和粒径分布变化,并与MMA/BA无皂乳液聚合及十二烷基苯磺酸钠存在下的MMA/BA乳液聚合作了比较.[ZC-L]CMC时,成核机理包括均相成核和胶束成核机理,生成的粒子因吸收体系中的表面活性单体而稳定存在.     

A Study on the Vinyl Acetate-co-Butyl Acrylate Latexes in the Presence of N-Methylol Acrylamide and Mixed Type Emulsifiers

Summary: The properties of copolymer latexes depend on the copolymer composition, polymer morphology, initiator, polymerization medium and colloidal characteristics of copolymer particles. Poly(vinyl acetate-co-butyl acrylate) latexes with N-metylol acrylamide were prepared by applying semicontinuous emulsion polymerization. The systems studied were (a) the mixture of anionic sodium lauryl sulfate ether (SELES) with nonionic 30 moles ethoxylated nonyl phenol (NP 30) (50:50), (b) the mixture of anionic sodium lauryl sulfate ether (SELES) with nonionic 30 moles ethoxylated nonyl phenol (NP 30) (70:30), and (c) anionic sodium lauryl sulfate ether (SELES) (100%). The effects of the emulsifier and emulsifier composition on the physicochemical properties of obtained vinyl acetate-co-butyl acrylate latex properties in the presence of N-methylol acrylamide initiated by ammonium persulfate were investigated.     

Microgel particles containing methacrylic acid: pH-triggered swelling behaviour and potential for biomaterial application

pH-responsive microgels are crosslinked polymer particles that swell when the pH approaches the pK(a) of the ionic monomer incorporated within the particles. In recent work from our group it was demonstrated that the mechanical properties of degenerated intervertebral discs (IVDs) could be restored to normal values by injection of poly(EA/MAA/BDDA) (ethylacrylate, methacrylic acid and butanediol diacrylate) microgel dispersions [J.M. Saunders, T. Tong, C.L. Le Maitre, T.J. Freemont, B.R. Saunders, Soft Matter 3 (2007) 486]. In this work we report the pH dependent swelling and rheological properties of poly(MMA/MAA/EGDMA) (methylmethacrylate and ethyleneglycol dimethacrylate) microgel dispersions. This system was investigated because it contains monomers that are already used as biomaterials. The poly(MMA/MAA/EGDMA) particles exhibit pH-triggered volume swelling ratios of up to ca. 250. The swelling onset for these particles occurs at pH values greater than ca. 6.0. A pK(a) for these particles of ca. 6.7 is consistent with titration and swelling data. Fluid-to-gel phase diagrams for concentrated poly(MMA/MAA/EGDMA) dispersions were determined as a function of polymer volume fraction and pH using tube-inversion measurements. The rheological properties for the gelled microgel dispersions were investigated using dynamic rheology measurements. The elastic modulus data for the poly(MMA/MAA/EGDMA) gelled dispersions were compared to data for poly(EA/MAA/BDDA) microgels. A similar pH-dependence for the elastic modulus was apparent. The maximum elastic modulus was achieved at a pH of about 7.0. The elastic modulus is an exponentially increasing function of polymer volume fraction at pH 7.0. Preliminary cell challenge experimental data are reported that indicate that gelled poly(MMA/MAA/EGDMA) microgel dispersions are biocompatible with cells from human intervertebral discs. However, the duration over which these experiments could be performed was limited by gradual redispersion of the gelled microgel dispersions. Based on the results presented it is suggested that poly(MMA/MAA/EGDMA) microgel would be a good candidate as a biomaterial for structural support of soft connective tissues.     

Effect of sulfonated 3-pentadecyl phenyl acrylate as surfmer in the emulsion polymerization of styrene: synthesis and polymer properties

In this work, the evaluation of a newly developed anionic polymerizable surfactant (surfmer), viz., sulfonated 3-pentadecyl phenyl acrylate, in the emulsion polymerization of styrene and its effect on the polymer properties is reported. The results were compared with the commercially available non-reactive anionic surfactant sodium lauryl sulfate. The surfmer has a low critical micellar concentration value of 40.11 mg/L (8.7?×?10^?5?mol/L) in comparison to 2,400 mg/L (8.28?×?10^?3?mol/L) for sodium dodecyl sulfate. Nanosized polystyrene dispersions with varying concentration of this surfmer were prepared and characterized for conversion, particle size, and size distribution at a fixed monomer/water ratio of 0.1. The particle radii decreased from 560 nm for the surfactant-free dispersions to 45 nm for the dispersion with 2.3 mol% surfmer. Increasing surfmer content above this concentration did not further affect the particle size but increased the width of the particle size distribution. Transmission electron microscopy results along with particle size data show that with increasing surfmer content the particle size distribution broadens, and film formation is facilitated. The microstructure analysis of the copolymers using infrared and ¹H-NMR spectroscopy confirms that the surfmer is chemically attached to the polymer chains. The effect of the ionic sulfonate groups and the alkyl chains of the surfmer moieties on the polymer properties have been studied through measurement of dilute solution viscosity and thermal and viscoelastic properties. These results indicate that the behavior of surfmer-containing polymers resembles that of plasticized ionomers.     

OPTICAL PROPERTIES OF IPN-LIKE NETWORKS. II. POLYETHYLENE/POLY-(BUTYLMETHACRYLATE-CO-METHYLMETH-ACRYLATE) COPOLYMER SYSTEMS

IPN-like systems, made of Poly[butylmethacrylate(BMA)-co-methylmethacrylate (MMA)] copolymers and Low Density Polyethylene (PE) networks, were synthesized by a procedure described in previous papers.

The initial PE/copolymer molar ratio was kept constantly equal to one for all the samples. Different molar BMA/MMA copolymer ratios (50/50, 60/40, 80/20, 90/10 100/0) and a molar percentage of 1.0% of the copolymer crosslinker, 1,4-Butandioldimethacrylate (BDDM), were used.

The samples obtained were analyzed by DSC, WAXS, swelling in CCl₄, and dynamic-mechanical tests. PE crystallinity was lowered by the network formation and slightly increased, whereas, the overall network density decreased, with enhancing the BMA content.

Optical investigations were performed in a temperature range between room temperature (R.T.) and 180°C, using MMA as comonomer of BMA, instead of Styrene (S), as well as a different crosslinker (BDDM instead of DVB).

All the IPN's showed the matching-mismatching optical transition of R.I., with temperatures corresponding to a transparency condition. The larger the BMA content, in the initial reactant MMA-BMA comonomeric mixture, the higher such temperatures. An analytical expression was found relating this temperature to the copolymer composition.     

丙烯酸酯共聚物无皂水溶胶稳定性的研究

用溶液聚合法合成了四种AA含量不同的丙烯酸酯共聚物(MMA/BA/HEMA/AA)，通过中和AA使共聚物带有—COO~-能起自乳化作用分散于水中而成为无皂水溶胶．TEM观察表明水溶胶粒子呈球状，单分散性好，粒径随AA含量增加而变小，在30～90 nm范围．用电导滴定法测定水溶胶粒子中—COOH和—COO~-的分布，表明绝大部分—COO~-处于粒子表面，并且随AA含量增加，粒子表面的—COO~-增多，Zeta电位增大，这是导致水溶胶的抗电解质稳定性(以C.C.C.值反映)和贮存稳定性(以表现粘度反映)随AA含量增加而提高的主要原因。