铈盐引发高吸附量氨基化PGMA高分子微球合成及去除废水中Cr(VI)(英文)

A novel polyglycidylmethacrylate(PGMA) microspheres with high adsorption capacity of Cr(VI) was prepared by cerium(IV) initiated graft polymerization of tentacle-type polymer chains with amino group on polymer microspheres with hydroxyl groups.The micron-sized PGMA microspheres were prepared by a dispersion polym-erization method and subsequently modified by ring-opening reaction to introduce functional hydroxyl groups.The polymer microspheres were characterized by scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FTIR).The results indicated that the polymer microspheres had an average diameter of 5 μm with uniform size distribution.The free amino group content was determined to be 5.13 mmol?g?1 for g-PGMA-NH2 mi-crospheres by potentiometric and conductometric titration methods.The Cr(VI) adsorption results indicated that the graft polymerization of tentacle-type polymer chains on the polymer microspheres could produce adsorbents with high adsorption capacity(500 mg?g?1).The polymer microspheres with grafted tentacle polymer chains have poten-tial application in large-scale removal of Cr(VI) in aqueous solution.     

STUDIES ON SYNTHESIS OF SILICA SOL-ORGANIC POLYMER COMPOSITE EMULSION

An emulsion of polystyrene/poly (butylacrylate-methyl methacrylate acrylic acid) core/shell latex particles (PS/P (BA-MMA-AA)) has been prepared by use of three synthetic methods. The effects of synthetic methods on the distribution of carboxyl groups in latex particles were studied. The results show that the seed emulsion polymerization in which the pre-emulsified monomers were added by dropping method to the second stage is the best technique for obtaining the optimum distribution of carboxyl groups on the surface of the latex particles. Furthermore, by using PS/P (BA-MMA-AA), a type of novel composite emulsion of silica sol-PS/P (BA-MMA-AA) was synthesized with the above method. By observation through transmission EM, the morphology of the latex particles obtained shows that a composite structure has been formed between silica sol particles and organic polymer particles.     

Preparation of an amphoteric flocculant having both high polymer content and low viscosity and its polymerization kinetics

It is not easy for liquid cationic flocculant diallyldimethyl-ammonium chloride(DM) homopolymer to simultaneously exhibit both low viscosity and high polymer content, which limited its application in offshore oilfield.In this paper, sodium allylsulfonate(XS) and sodium formate were used in the aqueous solution polymerization of DM.An amphoteric flocculant(PDMXS) with the properties of high polymer content(about 55 wt%) and low viscosity(efflux time measured by an Apply 4 viscometer was less than 100 s) was prepared.The optimum reaction conditions were identified as follows: the mass ratio of XS/DM was 10 wt%, the concentration of sodium formate was 2000 mg·L~(-1), reaction temperature was 55 ℃, the concentration of KPS was 0.5 wt% and the reaction time was 4 h.The polymerization kinetics was discussed.The results showed that R_p∝ [M]~(1.97)[I]~(0.68)[CTA]~(0.71) and the apparent activation energy was 72.55 kJ·mol~(-1).     

Synthesis and Properties of Micron-size Magneic Polymer Spheres with Epoxy Groups

Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA)spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe_3O_4)nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide(BPO) to form oil in water suspension with the presence of poly(vinyl pyrrolidone) (PVP-K30) as a stabilizer.Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets.Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and propertiesof magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magneticmicrospheres obtained have very small size (about 4-7μm) in diameter with narrow size distribution and super-paramagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure forthe magnetite dispersed in polymer microspheres. FT-IR     

高硅含量有机无机杂化乳液的制备和溶胶-凝胶驱使成膜

A novel polymer/SiO2 hybrid emulsion (PAES) was prepared by directly mixing colloidal silica with polyacrylate emulsion (PAE) modified by a saline coupling agent. The sol-gel-derived thin films were obtained by addition of co-solvents into the PAES. The effects of γ-methacryloxypropyltrimethoxysilane (KH-570) content and co-solvent on the properties of PAES films were investigated. Dynamic laser scattering (DLS) data indicate that the average diameter of PAES (96 nm) is slightly larger than that of PAE (89 nm). Transmission electron microscopy (TEM) photo discloses that colloidal silica particles are dispersed uniformly around polyacrylate particles and some of the colloidal silica particles are adsorbed on the surface of PAE particles. The crosslinking degree data and Fourier transform infrared (FT-IR) spectra confirm that the chemical structure of the PAES is changed to form Si-O-Si-polymer crosslinking networks during the film formation. Atomic force microscope (AFM) photos show the solvent induced sol-gel process of colloidal silica and the Si-based polymer distribution on the film surface of the dried PAES. Thermogravimetric analysis (TGA) curves demonstrate that the PAES films display much better thermal stability than PAE.     

带环氧基的超顺磁性高分子微球的制备及其性能表征

Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA)spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4) nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide (BPO) to form oil in water suspension with the presence of poly(vinyl pyrrolidone) (PVP-K30) as a stabilizer.Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets.Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and properties of magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magnetic microspheres obtained have very small size (about 4-7 μm) in diameter with narrow size distribution and superparamagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure for the magnetite dispersed in polymer microspheres. FT-IR spectroscopy indicates extensive oxirane groups existed on the surface of magnetic PSt-DVB-GMA microspheres.     

A comparison of soft magnetic composites designed from different ferromagnetic powders and phenolic resins☆

Soft magnetic composites (SMCs) were prepared from three different ferromagnetic powder particles:iron powder ASC 100.29, spherical FeSi particles and vitroperm (Fe73Cu1Nb3Si16B7) flakes. Two types of hybrid organic–inorganic phenolic resins modified with either silica nanoparticles or boron were used to design a thin insulating layer perfect-ly covering the ferromagnetic particles. Fourier transform infrared (FTIR) spectrometry confirmed an incorporation of silica or boron into the polymer matrix, which manifested itself through an improved thermal stability of the hybrid resins verified by thermogravimetric-differential scanning calorimetry (TG-DSC) analysis. The core-shell particles prepared from the ferromagnetic powder particles and the modified hybrid resins were further compacted to the cylindrical and toroidal shapes for the mechanical, electrical and magnetic testing. A uniform distribution of the resin between the ferromagnetic particles was evidenced by scanning electron microscope (SEM) analysis, which was also reflected in a rather high value of the electrical resistivity. A low porosity and extraordinary high values of mechanical hardness and flexural strength were found in SMC consisting of the iron powder and phenolic resin modified with boron. The coercive fields of the prepared samples were comparable with the commercial SMCs.     

Storage Stability of Alpha-Lipoic Acid-loaded Lipid Nanoparticles

Alpha-lipoic acid-loaded lipid nanoparticles(ALA-LNs) were prepared by high pressure homogenization method.The influences of storage conditions such as time and temperature on the physical and chemical storage stability of ALA-LNs were studied in details.The stability was evaluated by particle size and polydispersity index,morphology of ALA-LNs,and capacity of ALA loading.The dilution and pH stability of ALA-LNs suspensions were also studied.After three months storage,the mean size of ALA-LNs at 4 and 40 ℃ was increased by 2.68% and 3.62% compared with the original size,respectively.ALA-LNs stored at 40 ℃ had ellipsoid shape and the mean size was about 152 nm(SD=23.6).The loading capacity of ALA at 40 ℃ was much higher than those stored at other two temperatures.The good dilution and pH stability were also demonstrated.The sample had good fluidity even at 4 ℃.     

Preparation and Characterization of Two-component Waterborne Poly-urethane Comprised of Water-soluble Acrylic Resin and HDI Biuret

A two-component waterborne polyurethane （2K-WPU） was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU particles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI isocyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction between HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on performance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.     

ZrO2/聚甲基丙烯酸甲酯纳米复合物:制备及其在聚合物阵列中的分散（英文）

ZrO2/PMMA nanocomposite particles are synthesized through an in-situ free radical emulsion polymerization based on the silane coupling agent (Z-6030) modified ZrO2 nanoparticles, and the morphology, size and its distribution of nanocomposite particles are investigated. Scanning electron microscopy (SEM) images demonstrate that the methyl methacrylate (MMA) feeding rate has a significant effect on the particle size and morphology. When the MMA feeding rate decreases from 0.42ml·min-1 to 0.08ml·min-1 , large particles (about 200-550nm) will not form, and the size distribution become narrow (36-54nm). The average nanocomposite particles size increases from 34nm to 55nm, as the MMA/ZrO2 nanoparticles mass ratio increased from 4:1 to 16:1. Regular spherical ZrO2/PMMA nanocomposite particles are synthesized when the emulsifier OP-10 concentration is 2mg·ml-1. The nanocomposite particles could be mixed with VAc-VeoVa10 polymer matrix just by magnetic stirring to prepare the ZrO2 /PMMA/VAc-VeoVa10 hybrid coatings. SEM and atomic force microscopy (AFM) photos reveal that the distribution of the ZrO2 /PMMA nanocomposite particles in the VAc-VeoVa10 polymer matrix is homogenous and stable. Here, the grafted-PMMA polymer on ZrO2 nanoparticles plays as a bridge which effectively connects the ZrO2 nanoparticles and the VAc-VeoVa10 polymer matrix with improved comparability. In consequence, the hybrid coating with good dispersion stability is obtained.     

细乳液聚合法制备PY-17/PE蜡/PS复合乳胶粒子

通过细乳液聚合法制备彩色墨粉用多组分复合乳胶粒子,即通过细乳液聚合法制备聚苯乙烯包覆有机颜料PY-17和聚乙烯蜡的三元复合乳胶粒子。通过透射电子显微镜、激光粒度仪、紫外可见分光光度计和热失重分析仪对制备的复合乳胶粒子形貌、粒度、热学和光学特性进行表征,着重研究了乳化剂种类及用量、颜料用量和聚乙烯蜡用量对复合乳胶粒子粒径和形貌的影响,并对复合乳胶粒子的热学及光学特性进行了表征。结果表明,使用复合乳化剂,颜料PY-17用量不大于单体量8%、聚乙烯蜡用量占单体量不大于10%时,制备的复合乳胶粒子粒径较小,分布窄,包覆较为完整;并且复合乳胶粒子的热学及光学特性发生了一定的改变。     

Colloidal poly(styrene-co-butyl acrylate)/multi-walled carbon nanotubes nanocomposite by heterocoagulation in aqueous media

Colloidal nanocomposite particles were prepared by heterocoagulation of carbon nanotubes (CNTs) dispersion stabilized by cationic hexadecyltrimethylammonium bromide (CTAB) and negatively charged poly(styrene-co-butyl acrylate), P(St-co-BA), latex prepared by conventional emulsion polymerization in aqueous medium with the aid of a flocculant, polyaluminium chloride (PAC), at elevated temperature above the T_g of P(St-co-BA). The hybrid nanocomposite particles were prepared by a simple procedure consisting of mixing two dispersions, particle growth, and stabilization steps. The effects of the surface properties of CNTs, molecular weight of latex polymer, types of flocculants and its optimum concentration were investigated. At a well-controlled condition, the spherical or potato-like particles in the size range of 10-100 μm were achieved. After film formation of the nanocomposite particles, it was able to confirm that CNTs were uniformly distributed without agglomeration in the matrix, resulting in the percolation at a low concentration of CNTs.     

Study on the preparation and properties of styrene–butyl acrylate–silicone copolymer latices

Copolymer latices of styrene–butyl acrylate–silicone were prepared using a semicontinuous addition process and batch and monomer emulsion addition processes. The results showed that a stable latex with narrow particle size dispersion and a high monomer conversion can be obtained only by the semicontinuous addition process. The simultaneous free‐radical and ionic copolymerization mechanisms were discussed. 3‐Methacryloyloxypropyl trimethoxysilane in this work was used as a coupling agent to form a chemical bond between vinyl polymer and polysiloxane. It was found that the copolymerization reaction and the properties of latex and latex film were obviously influenced by silicone content. When the silicone content was less than 25 wt %, copolymerization proceeded readily and a stable latex could be prepared. With increasing silicone content, monomer conversion, latex stability, film hardness, and tensile strength decreased, whereas the water resistance and impact strength increased. Results of Soxhlet extraction, silicon analysis, and dynamic mechanical properties of latex polymer confirmed the occurrence of copolymerization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3194–3200, 2001     

乙烯基硅氧烷共聚改性苯丙乳液的研究

用不饱和的有机硅单体乙烯基三甲氧基硅烷共聚改性苯丙乳液,研究了有机硅用量对乳液粒径、玻璃化转变温度和热稳定性的影响.结果表明:乙烯基三甲氧基硅烷的加入能显著提高乳胶膜的玻璃化转变温度和耐热性能.当有机硅用量为5%时,乳胶膜的玻璃化转变温度从45℃提高到63℃,起始热分解温度从327℃提高到384℃.     

Semi-continuous emulsion copolymerization of vinyl acetate and butyl acrylate in presence of AMPS

The emulsifier-free emulsion polymerization of vinyl acetate (VAc) and butyl acrylate (BA) in the presence of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) was carried out by a semi-continuous process. AMPS was a reactive surfactant in the aqueous emulsion, due to its amphiphilic structure and the unsaturated double bonds. Potassium persulfate (KPS) was used as initiator. The following factors were mainly examined: quantity of AMPS, BA and KPS concentrations, which could significantly affect the particle size and its distribution, conversion, gel content, minimum film-forming temperature, etc. The particle size and its distribution were characterized by dynamic laser particle size analyzer, and morphology of the latex particles was characterized by transmission electron microscopy (TEM). Fourier transform infrared spectroscopy was used to characterize chemical structure of copolymers. The results indicated that AMPS was successfully reacted onto the resulted copolymer of vinyl acetate and butyl acrylate. A hydrophilic sulfonic acid group in the molecular structure of AMPS tended to be distributed in particles surface after polymerization. As a result, an electrostatic repulsion between the particles was produced in order to maintain stability of the system. Thermogravimetric analysis curves suggested that as BA content increased, thermal stability of the polymer increased accordingly. The conversion-time plots with varying AMPS and initiator contents were obtained, which illustrated that the initiator concentration could greatly influence the polymerization rate and the final conversion. The TEM micrographs of the final emulsifier-free latex particles for P(VAc/BA/AMPS) system revealed small particle size in monodisperse polymer latex. The particles of the latex were measured as about 150 nm.     

新型支化有机硅与甲基丙烯酸甲酯共聚乳液稳定性的研究

用甲基丙烯酰氧基丙基三(三甲基硅氧基)硅烷(TR IS)与甲基丙烯酸甲酯进行了乳液共聚合,研究乳化剂的用量和配比、反应时间、单体的配比等对乳液稳定性,凝胶率,转化率的影响,用透射电镜测试了乳液的粒径。结果表明用有机硅改性表面活性剂,十二烷基硫酸钠(SDS)和1-丙烯基-2-羟基烷机磺酸钠(COPS-1)为复配乳化剂,在适宜条件下,可使有机硅共聚乳液胶粒达到纳米级分散,得到高硅含量的稳定乳液。     

Preparation of highly conductive reduced graphite oxide/poly(styrene-co-butyl acrylate) composites via miniemulsion polymerization

Polymer/reduced graphite oxide (rGO) composite nanoparticles with a high electrical conductivity were synthesized using the miniemulsion polymerization technique. The rGO was modified with a reactive surfactant, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), to facilitate monomer intercalation into the rGO nanogalleries. The AMPS-modified rGO was emulsified in the presence of styrene (St) and butyl acrylate (BA) monomers, and the stable miniemulsion was polymerized to form poly(St-co-BA)/rGO composite latex nanoparticles. The transition in the composite nanoparticles from an electrical insulator to an electrical conductor occurred at an rGO content of 10 wt% (relative to the monolayer content), yielding an electrical conductivity of 0.49 S/cm. The electrical conductivity of the composite nanoparticles reached 2.22 S/cm at 20 wt% rGO, yielding a much better conductivity than other polymer composites prepared using a GO filler. Importantly, the miniemulsion polymerization method for fabricating poly(St-co-BA)/rGO composite nanoparticles is easy, green, low-cost, and scalable, providing a universal route to the rational design and engineering of highly conductive polymer composites.     

高固含量有机硅改性丙烯酸酯微胶乳的合成及性能

用自制的由阴离子乳化剂十二烷基硫酸钠(SDS)、非离子乳化剂辛基酚聚氧乙烯醚(OP-10)、反应型乳化剂WH-100以及非离子表面润湿剂所组成的混合乳化剂体系,通过半连续单体滴加法合成了平均粒径为59·8nm、粒径分布窄、总固物质量分数达40%的有机硅改性丙烯酸酯微胶乳,并对微胶乳及胶膜的性能进行了研究。结果表明,与间歇预乳化法制备的乳液相比,有机硅改性丙烯酸酯微胶乳的钙离子稳定性较差,其胶膜的吸水率较小,凝胶含量相当;随着乙烯基三乙氧基硅烷(A151)用量的增加,对转化率的影响不明显,微胶乳的钙离子稳定性、胶膜的吸水率下降,乳胶粒子的粒径变大,A151的质量分数宜为4%;随着功能单体甲基丙烯酸-2-羟乙酯(HEMA)用量的增加,微胶乳的钙离子稳定性先提高后降低,而胶膜的吸水率先降低后增大,HEMA的质量分数不宜超过3%。     

有机硅氧烷改性丙烯酸酯微乳液的合成与表征

采用种子乳液聚合法,以阴离子乳化剂DF-2和非离子乳化剂OP-10作为复合乳化剂,以FeSO4、K2S2O8和甲醛合次亚硫酸氢钠(SFS)作为氧化-还原引发剂,在65℃合成了有机硅改性丙烯酸酯聚合物微乳液。实验采用单体滴加工艺,用COULTERLS粒度仪和傅里叶变换红外光谱仪分别测定了共聚乳液的粒径分布和产物的结构,研究了加料方式、配方组成及操作方式对聚合稳定性、乳液的粒径分布以及产物性能的影响。结果表明,采用单体滴加工艺能得到平均粒径为50～80nm的单峰窄分布微乳液,并有效地将有机硅氧烷引入到共聚物大分子中。     

Preparation of Raspberry-Like Adsorbed Silica Nanoparticles via Miniemulsion Polymerization Using a Glycerol-Functionalized Silica Sol

A series of polymer/SiO₂ organic-inorganic composite microspheres were successfully prepared through miniemulsion polymerization. A TEM study indicated that the composite microspheres had raspberry-like morphology and silica particles were successfully deposited onto the surfaces of organic polymer microspheres. The average particle size and the silica content of composite microspheres could range from 180 nm to 240 nm and 15 ～ 35 wt%, respectively. The influence of reaction conditions such as the amount of emulsifier, the sonification frequency and sonification time, the amount of silica sol, butyl acrylate (BA) on the particle size, silica content and morphology of composite microspheres have been studied.