Preparation of colored latex with polyurea shell by miniemulsion polymerization

Colored latexes with polyurea shell were prepared by applying interfacial polycondensation reaction to the miniemulsion polymerization process. These colored latexes were composed of polystyrene core and polyurea shell, and their particle size was adjusted to <100 nm. Diisocyanate was used as a hydrophobic monomer, and the equivalent mole of diamine was used as a hydrophilic monomer for interfacial polymerization. It was important to control the rate of interfacial polycondensation reaction in order to prepare small particles. Dye preservation property of colored latex loaded with oil-soluble dye was investigated. Polyurea shell formed at the surface of latex particles could restrain the migration of dyes from the latex particles and improve the dye preservation property. The ability to prevent dye migration depended on the composition of the polyurea shell.     

Improvement of the storage stability and photostability of colored latex prepared by miniemulsion polymerization

Polymer particles containing oil-soluble dyes (colored latex) were prepared by miniemulsion polymerization. The dye preservation properties of colored latex loaded with different types of dye were studied; preservation depended on the rate of dye diffusion and thus on the size of the dye molecules and the hardness of the polymer matrix in the latex particles. Hindered amine stabilizers (HAS) were used to improve the photostability of colored latex. The effect of HAS in colored latex was investigated both as an additive and as a comonomer. The photostability of latex particles containing a simple mixture of dye and HAS was improved with increasing HAS content up to 20% in particles. In the case of colored latex particles combined with HAS by a covalent bond, the optimal amount of HAS for photostability improvement was between 8 and 20%.     

Preparation of colored poly(styrene-co-butyl methacrylate) micrometer size beads with narrow size distribution by dispersion polymerization in presence of dyes

The preparation of monodisperse polymer particles formed by a dispersion copolymerization of a system containing styrene, butyl methacrylate, and nonpolymerizable dyes has been studied. Both the polarity of the ethanol–water dispersion medium and the polymerization rate were found to have a significant effect on the particle size. Experimental conditions have been determined that enable the preparation of colored beads having a narrow size distribution. While the benzoyl peroxide initiated polymerization is seriously inhibited by the presence of dyes, polymerization with azobisisobutyronitrile in presence of the black dye Nigrosin affords monodisperse beads in a high yield. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of covalently colored polymer latex based on new polymerizable anthraquinone dyes

Novel polymerizable red and yellow dyes, consisting of anthraquinone chromophore, alkyl spacer, and acryloyl group, were first synthesized and then used as comonomers in the semicontinuous emulsion copolymerization of styrene, butyl acrylate, and methacrylic acid to fabricate polymer latexes. The influences of the dye monomers on the emulsion polymerization process, the latex particle size and its distribution, the molecular weight of the latex polymer, as well as the light fastness of the polymer latex films, were investigated. Results indicated that, despite of the inhibition effect of the polymerizable dyes on polymerization, stable colored polymer latexes could be prepared with high conversion of total monomers, whereas the conversion of the polymerizable dye decreased as increasing the amount of dye. The light fastness of the covalently colored polymer latex films was proved to be much better than that of the noncovalently colored polymer latex films due to the covalent bond of dye and polymer chains.     

Preparation of polystyrene latex particles by γ-rays-induced emulsifier-free emulsion polymerization

Monodisperse polystyrene latex particles were prepared by ⁶⁰Co-γ-ray radiation-induced emulsifier-free emulsion polymerization with the use of surfactant monomer at room temperature. The surfactant monomer 10(9)-hydroxyl-9(10)-allyl ether octadecanoic acid (HAEOA) was synthesized and characterized by FT-IR and ¹H-NMR spectra. TEM was used to characterize the polystyrene latex particles. HAEOA acted as not only a comonomer but also a stabilizer to copolymerize with styrene and stabilize the polystyrene latex particles. Kinetics analysis shows that there is no constant rate stage which seems to indicate a droplet nucleation mechanism.     

Preparation of magnetic polystyrene latex via the miniemulsion polymerization technique

Magnetic iron oxide (magnetite, Fe₃O₄) nanoparticles were encapsulated with polystyrene to give a stable water‐based magnetic polymer latex, using the miniemulsion polymerization technique. The resulting magnetic latexes were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), vibrating sample magnetometer measurements (VSM), and ⁵⁷Fe Mössbauer spectroscopy measurements. TEM revealed that all magnetite nanoparticles were embedded in the polymer spheres, leaving no empty polystyrene particles. The distribution of magnetite particles within the polystyrene spheres was inhomogeneous, showing an uneven polar appearance. The DLS measurements indicated a bimodal size distribution for the particles in the latexes. According to our magnetometry and Mössbauer spectroscopy data, the encapsulated magnetite particles conserve their superparamagnetic feature when they are separated in the polymer matrix. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4802–4808, 2004     

高效液相色谱法测定氧化型染发产品中40种染发剂

氧化型染发产品中的多种染发剂具有不同程度的致敏性及其他毒性,建立快速、准确检测多种染发剂的方法,为该类产品监管提供有效的技术手段,十分必要.该研究建立了氧化型染发类产品中40种染发剂的高效液相色谱测定方法.染发产品经含70％乙醇的亚硫酸氢钠水溶液涡旋、超声提取,并经亚硫酸氢钠水溶液稀释后,以0.02 mol/L乙酸铵水...     

Polystyrene/MMT nanocomposites prepared by soap-free emulsion polymerization with high solids content

Polystyrene/montmorillonite (PSt/MMT) nanocomposite latexes have been synthesized by soap-free emulsion polymerization using MMT clay platelets as stabilizer. Small amounts of methacrylic acid were used as auxiliary monomer to promote clay adhesion to the surface of the particles. Overall solids content of the composite latexes in complete absence of coagulation of up to 30.7?wt% are reported under batch conditions. The 3?wt% MMT clay platelets were sufficient to maintain the colloidal stability and increasing MMT clay content resulted in the increase of particle diameter due to the improved viscosity of reaction medium. Transmission electron microscopy results demonstrate the existence of MMT platelets on the particle surface. X-ray diffraction spectroscopy (XRD) results show that an exfoliated structure of PSt/MMT nanocomposites was obtained in this study with the absence of d₀₀₁ diffraction peak of MMT in the XRD region.     

Image formation by dyeing of copolymers bearing photogenerated acid and base groups with dye bath containing acid and basic dyes

Copolymers bearing photoacid generating groups and/or photobase generating groups were dyed after UV irradiation with a dye bath containing both an acid dye and a basic dye. Acetophenone O‐acryloyloxime (AAPO) was used as a monomer bearing acyloxyimino (AOI) group that generates a primary amino group upon irradiation, which is followed by hydrolysis. Phenacylsulfonylstyrene (PSSt) and 1,2,3,4‐tetrahydronaphthylideneamino p‐styrenesulfonate (NISS) were chosen as monomers having β‐keto sulfone (β‐KS) and iminosulfonate (IS) groups, respectively, which yielded acid groups when irradiated. Copolymers of AAPO and methyl methacrylate (MMA) were dyed with only the acid dye, and those of PSSt or NISS were dyed with only the basic dye after irradiation. AAPO‐PSSt‐MMA films became dyeable with the acid dye when irradiated for a short time and with the basic dye with further irradiation. However, AAPO‐NISS‐MMA copolymers showed the reverse dyeing behavior. IR spectra revealed that AOI groups were photochemically decomposed prior to the β‐KS groups for AAPO‐PSSt‐MMA, and AOI and IS groups decomposed simultaneously for AAPO‐NISS‐MMA. These results suggested the possibility of adsorption of different ionic dyes on the films by a change of irradiation time; in fact, color patterns could be obtained in a single staining process using the dye bath. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3043–3051, 2000     

Compartmentalized polymerization with oil-soluble initiators. Kinetic effect of single radical formation

The stationary state distribution of radicals in compartmentalized systems initiated by oil-soluble initiators have been calculated for various cases of single radical formation as well as a simultaneous generation of single radicals and pairs of radicals in the particles. The effect of a contribution from radicals produced by initiator dissolved in the aqueous phase has been considered. Desorption and reabsorption of radicals, aqueous phase termination, total rate of radical formation and the water-solubility of the initiator are quantified in terms of dimensionless parameters. The calculations predict that single radicals generated in the particles are kinetically indistinguishable from radicals produced in the aqueous phase over a wide range of variation of the parameters. It is shown that if the rate of generation of single radicals constitutes only about 10 per cent of the overall rate of radical formation in the particles, the former radicals account for the major part of the rate of polymerization. The mechanisms previously proposed to account for the similar kinetic behaviour observed with water-soluble and oil-soluble initiators are discussed. It is concluded that the present calculations support the view that this similarity is mainly due to radicals produced by the water-soluble fraction of the initiator. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2347–2354, 1997     

Radiation-induced polymerization of methyl methacrylate in microemulsion with high monomer content

γ-Ray-induced polymerization of methyl methacrylate was conducted in a microemulsion stabilized by a mixture of sodium of 12-acryloxy-9-octadecenoic acid (AOA) and sodium dodecyl sulfate (SDS) with various weight ratios at room temperature. The experimental data showed that the mixture of AOA and SDS with a weight ratio 2 was an efficient surfactant system for the microemulsion containing 38.6 wt% MMA and 5.5 wt% surfactant. The effects of MMA concentration and dose rate on the polymerization kinetics and particle size are discussed.     

Solar cells sensitized by porphyrin dyes containing a substituted carbazole donor with synergistically extended absorption and suppressed the dye aggregation

To achieve high power conversion efficiency (PCE), three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent (J_sc) and photovoltage (V_oc). On basis of the XW4, a benzothiadiazole (BTD) unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability. As a result, a J_sc of 13.72 mA/cm² has been obtained for XW57, higher than that of XW4. On this basis, XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups, and the superior anti-aggregation character raises the V_oc from 781 mV (XW4) to 844 mV. When both the BTD unit and the bulky groups are introduced to the acceptor and donor units, respectively, the resulting sensitizer XW59 exhibits a highest PCE value of 7.34% with synergistically enhanced J_sc of 13.19 mA/cm² and V_oc of 793 mV. These results provide further insight into developing high performance dye-sensitized solar cells     

Preparation and characterization of microcapsules containing particulate phosphorescent agent with suspension polymerization

Microcapsules containing particulate phosphorescent agent (strontium aluminate) were prepared by the suspension polymerization method and characterized about a few items such as the mean diameters, the content, the inner structure and the afterglow luminance property. Furthermore, the fundamental experiments were conducted to investigate how the dispersing feature of particulate phosphorescent agent affects the afterglow luminance property. In the experiment, the concentration of oil soluble surfactant, the crosslinking agent species, the added weight of the phosphorescent agent and the pre‐bulk polymerization time were mainly changed stepwise. Afterglow luminance of particulate phosphorescent agent gradually decreased with the afterglow time and considerably decreased because of soaking them in water. Decline of afterglow luminance because of soaking in water could be prevented by microencapsulation. Afterglow luminance of the multicore type microcapsules was found to be higher than that of the core–shell type microcapsules. The content of particulate phosphorescent agent could be increased by performing pre‐bulk polymerization and increasing the concentration of the oil soluble surfactant. Copyright © 2016 John Wiley & Sons, Ltd.     

Properties and characterization of novel cationic polyacrylate latex containing fluorine and silicon prepared with soap-free emulsion polymerization

The novel cationic polyacrylate latex containing fluorine silicon was successfully prepared via soap-free emulsion polymerization of butyl acrylate, methyl methacrylate, vinyltriethoxysilane and hexafluorobutylmethacrylate in water phase, which were initiated with water soluble azo initiator and emulsified with the mixed surfactants polymerizable emulsifier and OP-10. The films of the resultant latex were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA) determinator, respectively. In comparison with the conventional polyacrylate latex, the thermal stability and water resistance of novel latex film are improved. The conditions of preparing the novel cationic acrylate latexes were optimized. The optimum conditions of preparing the novel latex are as follows: the amount of emulsifiers and the initiator are 6.0% and0.3%, respectively; both the amount of VETS and amount of HFMA are 6.0%. In this case, the conversion is high and the polymerization stability is good.     

高效液相色谱法同时测定氧化型染发产品中33种染发剂

建立了高效液相色谱同时测定氧化型染发产品中33种禁限用染发剂含量的分析方法。采用Waters Atlantis^® T3 MV Kit色谱柱（250 mm×4.6 mm，5 μm），以磷酸盐缓冲液-乙腈为流动相，梯度洗脱，流速为1.0 mL/min，柱温为25℃；采用二极管阵列检测器（DAD），检测波长为235及280 nm，进样量为5 μL。结果表明，各成分在线性范围内线性关系良好，相关系数均高于0.999，各成分精密度实验相对标准偏差（RSDs）均小于2%；四氨基嘧啶硫酸盐和2，4-二氨基苯氧基乙醇盐酸盐在12 h内稳定性实验RSDs小于5%，其余31种成分在24 h内稳定性实验RSDs均小于5%；各成分在3个浓度水平下的加标回收率为77.6%~116.3%。该方法简便、快速、准确，适用于氧化型染发产品中多种染发剂的检测。     

Compartmentalized polymerization initiated by oil-soluble initiators. Calculation of average number of radicals per particle

Expressions for calculating the stationary state distribution of radicals in compartmentalized systems with a constant number of reaction loci containing an oil-soluble initiator are given. Besides pairwise formation of radicals in the particles, desorption and reabsorption, water phase termination, solubility of the initiator in the aqueous phase, and the possibility of formation of a single radical species are taken into consideration. The calculation is based on a probabilistic analysis leading to a third-order recurrence relation solved using confluent, hypergeometric Kummer functions. Some calculated curves illustrating the de-pendence of the average number of radicals per particle on various relevant parameters are included. © 1995 John Wiley & Sons, Inc.     

On the main locus of radical formation in emulsion polymerization initiated by oil-soluble initiators

The effect of the monomer/water ratio on the rate of polymerization per polymer particle in both seeded emulsion polymerizations and miniemulsion polymerizations was used in an attempt to elucidate the main locus of radical formation in emulsion polymerization initiated by an oil-soluble initiator (AIBN). It was found that, for the rest of conditions constant, the polymerization rate per polymer particle increased when the monomer/water ratio increased, namely when the amount of initiator dissolved in the aqueous phase per polymer particle decreased. This is an evidence against a dominant aqueous phase formation of radicals. On the other hand, these results are consistent with a mechanism in which the radicals are mainly produced in the oil-phase with significant aqueous phase termination.     

Preparation of high selective molecularly imprinted polymers for tetracycline by precipitation polymerization

High selective molecularly imprinted polymers(MIPs) for tetracycline have been prepared by precipitation polymerization. Effects of monomer and solvent,the ratio of monomer and template and the characterization of the polymer were investigated by frontal chromatography and selectivity experiment.The results clearly indicated that the polymer,which had the highest molecular recognition abilities for tetracycline antibiotics,had been received.     

Photosensitized polymerization of methyl methacrylate with acriflavine dye

The kinetics of photopolymerization by ultraviolet-light with acriflavine as the sensitizer was studied in nonaqueous medium. The reducing agent used was alcohol. The rates of the photopolymerization were determined dilatometrically. The order of the reaction with respect to the sensitizer concentration was 0.14 while that with respect to the reducing agent concentration was 0.8 × 10^?1. These results are interpreted in terms of a kinetic scheme which involves a competitive ground-state deactivation of the dye triplet and photoreduction. A low initiator efficiency of the primary radicals (cage recombination) and bimolecular termination processes are assumed.