A novel composite microsphere as a highly efficient absorbent for oils and organic solvents

A novel composite oil‐absorbent microsphere poly(stearyl methacrylate‐co‐butyl acrylate) (PSB)‐SiO₂ was prepared by introducing hydrophobic nano‐silica Aerosil R812 into the suspension polymerization system of stearyl methacrylate and butyl acrylate and was characterized by Fourier transform infrared and scanning electron microscopy energy‐dispersive spectrometer. PSB‐SiO₂ has a loose network structure and exhibits remarkably fast oil absorption speed in relatively high saturated oil absorbency. Besides, PSB‐SiO₂ has good oil retention and reusability. Moreover, the saturated oil absorbencies of PSB‐SiO₂ toward toluene, gasoline, and diesel over water are roughly equivalent to that in pure oil. Owing to its excellent oil absorption performances, PSB‐SiO₂ will find applications in removing oil spills and organic pollutants over water. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and characterization of miniemulsion copolymers of methyl methacrylate (or styrene) and stearyl methacrylate

The copolymers of methyl methacrylate (MMA) (or styrene (ST))/stearyl methacrylate (SMA) obtained from miniemulsion polymerization were prepared and characterized. All the miniemulsions showed satisfactory colloidal stability upon aging due to the effectively retarded Ostwald ripening by the reactive costabilizer SMA. In subsequent miniemulsion copolymerizations, monomer droplet nucleation predominated in the particle formation process, but homogeneous nucleation could not be ruled out even at such high levels of SMA (20–50 wt.%). The contact angle first increased rapidly and then leveled off when the SMA content increased from 20 to 50 wt.% for both the copolymers of MMA/SMA and ST/SMA. At constant level of SMA, the copolymer of MMA/SMA with a less hydrophobic composition showed a larger contact angle compared to the ST/SMA counterpart. The contact angle (103 ± 1°) of the copolymer MMA/SMA (50/50 w/w) was comparable to that (104°) of PSMA. A schematic model was proposed to explain the experimental results.     

Photopolymerization of styrene,p-chlorostyrene,methyl methacrylate,and butyl methacrylate with polymethylphenylsilane as photoinitiator

The rates of photochemical polymerization of styrene (St), p-chlorostyrene (Cl-St), methyl methacrylate (MMA), and butyl methacrylate (BMA) with polymethylphenylsilane (PMPS) as an initiator were measured. Polymethylphenylsilane is photodegrated to form silyl radicals that may initiate polymerization of vinyl monomers. Rate constants k_p and k_t have been determined for these systems. A good correlation (log P = α + βμ) of the resonance stabilization (P) of the chain radicals and the dipole moment (μ) of the monomers is observed for these polymerization systems. This equation may be used to estimate the resonance stabilization (P) of a monomer and the polymerization rate constant (k_p). © 1996 John Wiley & Sons, Inc.     

Dispersion copolymerization of styrene and butyl acrylate in polar solvents

Monodisperse copolymer particles from 1.1 to 2.6 μm in diameter were obtained by unseeded batch dispersion copolymerization of styrene and butyl acrylate in an ethanol–water medium. A two-level factorial design using bottle polymerizations was initially carried out including the following variables: stabilizer concentration, initiator concentration, polarity of the dispersion medium, initial monomer concentration, and temperature. Once the region of experimental conditions in which monodisperse latexes can be prepared was identified, further effort was devoted to analyze the effect of other variables. It was found that the temperature at which nucleation occurs and the evolution of the temperature after the onset of nucleation were critical to obtain monodisperse particles. The particle size increased with increasing initial monomer concentration and ethanol–water weight ratio, and decreasing stabilizer concentration. A minimum quantity of emulsifier was necessary to avoid coalescence of particles and to obtain monodisperse particles. © 1996 John Wiley & Sons, Inc.     

Dispersion copolymerization of styrene and glycidyl methacrylate in polar solvents

Monodispersed copolymer microspheres consisting of styrene and glycidyl methacrylate have been prepared by dispersion polymerization. The effects of various polymerization parameters on the particle size and size distribution were systematically investigated. The initial solubility parameter of the system had a significant effect on the final particle size and size distribution. With decreasing initial solubility parameter, the particle size increased and the size distribution broadened. The particle size decreased with increasing stabilizer concentration, the amount of styrene in the monomer mixture, and decreasing initiator concentration. Received: 30 September 1998 Accepted in revised form: 10 December 1998     

In situ polymerization of methyl methacrylate/multi-walled carbon nanotube composites using cationic stearyl methacrylate copolymers as dispersants

Novel water-soluble amphiphilic copolymers (poly[(stearyl methacrylate)-stat-([2-(methacryloyloxy)ethyl] trimethyl ammonium iodide)]) for dispersing multi-walled carbon nanotubes (MWCNTs) were used to carry out in situ methyl methacrylate (MMA) polymerization. The morphology of the poly(methyl methacrylate)/MWCNT composites and the dispersion of the MWCNTs were analyzed by transmission electron microscopy. The dispersion of multi-walled carbon nanotubes in the composites was excellent for cationic SMA (stearyl methacrylate) copolymers, even at high MWCNT loading (6.0 wt.%). The mechanical properties and electrical and thermal conductivities of the composites were also analyzed. Mechanical properties were improved by MWCNTs; the strain at break values remained stable up to 6.0 wt.% MWCNT loading. Both electrical and thermal conductivities were improved by the addition of MWCNTs.     

Viscoelastic behaviour of butyl acrylate/styrene/2-hydroxyethyl methacrylate/acrylic acid latices thickened with associative thickeners

The rheological behaviour of butyl acrylate/styrene/acrylic acid latices thickened with a hydrophobically modified ethoxylated polyurethane (HEUR) or hydrophobically modified alkali-soluble polyacrylate emulsion (HASE) was investigated. While the pseudoplastic character of frequency dependence of complex viscosity was similar for both thickeners, viscoelastic behaviour, expressed as the ratio of loss and storage moduli, significantly differed, indicating that the HEUR molecules, unlike swollen HASE particles, create a viscoelastic space structure. The increase in hydrophilicity of the particle surface, achieved by incorporation of 2-hydroxyethyl methacrylate (HEMA) monomer into the latex copolymer reduced the viscoelasticity of latices thickened with HEUR, but not of those thickened with HASE. This confirms that adsorption of hydrophobic end-groups on particle surface is important for thickening of latices with HEUR and that a physical network of latex particles interconnected by the thickener macromolecules is formed. To cite this article: O. Quadrat et al., C. R. Chimie 6 (2003).     

Preparation of organic/inorganic hybrid nanomaterials using aggregates of poly(stearyl methacrylate)-b-poly(3-(trimethoxysilyl) propyl methacrylate) as precursor

A novel brush-type amphiphilic copolymer of PSMA-b-PTMSPMA was synthesized via ATRP technique. As-synthesized polymer was characterized by GPC and ¹H NMR. It was of interest that the resultant polymer could self-assemble into micelles with different morphologies and sizes in selective solvents by adjusting the copolymer concentrations. These aggregates could be prepared into novel stable organic/inorganic hybrid nanomaterials by the gelation process. The size and structure of these aggregates and the corresponding hybrid nanomaterials were observed by TEM.     

Volumetric properties of cyclohexane with ethyl acrylate, butyl acrylate, methyl methacrylate, and styrene at 298.15 K

Densities of the binary systems of cyclohexane with ethyl acrylate (EA), butyl acrylate (BA), methyl methacrylate (MMA), and styrene have been measured as a function of the composition, at 298.15 K and atmospheric pressure, using an Anton Paar DMA 5000 oscillating U-tube densitometer. The calculated excess volumes were correlated with the Redlich–Kister equation and with a series of Legendre polynomials. The excess volumes are positive for the systems reported here.     

Synthesis of ether-linked fluorocarbon surfactants and their aggregational properties in organic solvents

A series of single- and double-tailed hydrocarbon-fluorocarbon (HF) surfactants were prepared to evaluate the effect of molecular structure on aggregate formation in organic solvents. The molecules were designed with ether linkages to permit facile syntheses of both sets of molecules. Solvent foaming studies were used to rapidly assess the surface-active properties of the surfactants, while dynamic light scattering provided quantitative critical micelle concentrations (CMC) and hydrodynamic radius (R(h)) measurements of the aggregates in solution. The single-tailed surfactants did not produce any foaming action in a number of hydrocarbon solvents, nor was any micellar formation observed up to 100 mM concentrations. Double-tailed surfactants, on the other hand, gave low CMC values in dodecane but with R(h) values that indicated a tight micelle structure. Bilayer formation was expected but not observed for these molecules, which is believed to be due to their unusual structural geometry, imparted by the glycerol backbone. No thermotropic liquid crystalline (LC) behavior was observed for any of the single- or double-tailed molecules. These data contrast with the known behavior of perfluorinated alkanes and other fluorinated surfactants, suggesting that the ether linkage plays an important role in the self-organizing behavior of these molecules.     

Preparation and control of surface properties of monodisperse micrometer size beads by dispersion copolymerization of styrene and butyl methacrylate in polar media

The dispersion copolymerization of styrene and butyl methacrylate in ethanol-water medium to afford micrometer-size monodisperse beads has been investigated. Hydroxypropyl cel-lulose, poly (acrylic acid), and poly (vinylpyrrolidone) have been used as steric stabilizers, benzoyl peroxide and azobisisobutyronitrile as initiators. A novel steric stabilizing system consisting of a mixture of poly (acrylic acid) and hydroxypropyl cellulose has also been shown to lead to monodisperse beads for which the surface charge can be controlled by the relative ratio of steric stabilizers. The effect of several variables, such as the solvency of the medium, the concentration of co-monomers, the reaction temperature, and the type of steric stabilizer and initiator used on the bead size and size distribution are discussed. © 1995 John Wiley & Sons, Inc.     

Synthesis of a complex additive based on stearyl methacrylate and vinyl acetate for environmentally clean diesel fuel

An additive based on stearyl methacrylate–vinyl acetate copolymer was synthesized by the method of controlled atom transfer radical polymerization. The additive simultaneously improves the low-temperature properties of hydrotreated diesel fuels and enhances their resistance to thermal oxidation to meet the European quality standards. Comparative analysis of the effect exerted on the characteristics of environmentally clean diesel fuel by the synthesized additive and Dodiflow commercial depressor additive was made, and the negative effect of the latter on the thermo oxidative stability of diesel fuel was revealed of the fuel to thermal oxidation was revealed.     

Synthesis and properties of new functionalized guanidinium based ionic liquids as non-toxic versatile organic materials

Functionalized guanidinium ionic liquids as a new class of versatile organic materials have been developed. Guanidinium salts containing olefinic functionalities have been prepared and completely characterized. In order to illustrate the versatility of olefinic units, they were brominated and some bromine-containing ionic liquids have been obtained. Relevant physico-chemical properties of the new synthesized salts were evaluated including their melting points, glass transition temperatures, miscibilities, densities, surface tensions and contact angles with glass and Teflon surfaces. Additionally toxicity studies were performed using the human colon carcinoma CaCo-2 cell line. Several new functionalized guanidinium based ILs showed high densities, low contact angles with Teflon, low surface tensions as well as a non-toxic behaviour.     

离子型共价有机框架材料的制备及对染料吸附性能的研究

茜素红(Alizarin Red,AR)作为蒽醌类染料中的重要组成,由于其具有优异的特性,在染料和酸碱指示剂等方面被广泛使用。但是AR具有毒性高、结构复杂以及化学需氧量(COD)值大等原因,使其成为了主要污染物之一,去除水体中的茜素红染料污染物已经成为了目前亟待解决的问题。共价有机框架材料作为一种新型的多孔有机材料,由于其具有比表面积大,孔径均一和可设计的独特优势,已经广泛应用吸附和分离等方面。因此,以三醛基间苯三酚和溴化乙锭为构筑单元,通过水热的方法合成一种二维离子型共价有机框架材料(TpEB-COF)。对制备的TpEB-COF进行相关表征,包括X射线衍射仪(XRD),扫描电镜(SEM)和能量色散谱仪(EDS)等。然后将制备的TpEB-COF作为固体吸附剂,将其应用对水中AR的吸附,研究了不同吸附时间和不同pH值对吸附过程的影响。实验结果证明制备的离子型共价有机框架材料具有良好的晶型结构。同时,对实验数据分析表明,离子型共价有机框架材料对于茜素红的吸附符合准二级动力学方程和Langmuir吸附模型,吸附效率为82.8%,最大吸附量为828 mg g-1。本研究不仅为共价有机框架材料的设计和合成奠定坚实的基础,而且拓展了离子型共价有机框架材料的应用范围,促进共价有机框架材料的发展。     

Synthesis and application of inorganic/organic composite materials

A new type of inorganic-organic composite has been developed using organic monomeric or polymerizable silanes (with appropriate organic groupings like double bonds or epoxides) as monomers or in situ prepared or separately added nano-scale ceramic or metal particles. Due to the small size of the particulate phase, these composites are still highly transparent but show properties at least partially to be attributed to the inorganic phase. The introduction of special functions into these materials has been used for the fabrication of interesting functions like non-linear optical properties, low surface free energy coatings, controlled release properties or special mechanical properties (scratch resistance).     

Synthesis and characterization of tricyanovinyl-capped oligothiophenes as low-band-gap organic materials

Tricyanovinyl-capped oligothiophenes of up to six rings have been synthesized and characterized. The substituted oligomers display dramatic reductions in both their optical and electrochemical band gaps in comparison to unsubstituted oligomers. The solvatochromic behavior of the terthiophene-substituted molecule was investigated in a variety of solvents. Stable oxidations and reductions were exhibited by the sexithiophene-substituted molecule on the CV time scale. [structure: see text]     

Synthesis of a novel centipede-like copolymer of styrene and methyl methacrylate

A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(PS-PS-PMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATRP) . The synthetic approach involves the coupling reaction of polystyrene(PS) backbone bearing 1,1-diphenylethene(DPE) pendant groups,produced by ATRP and Wittig reaction,with living polystyryllithium(PSLi) ,and subsequent polymerization of the resulting 1,1-diphenylmethyl anions with methy methacrylate. The centipede-like copolymer was characterized by 1H NMR,IR,SEC,SLS,and DSC measurements.     

Synthesis and properties of highly lipophilic phosphazene bases

Twelve novel phosphazene bases (X-C₆H₄-NN-C₆H₄-NPR₃) with an unusual combination of properties – high lipophilicity of both neutral and charged forms, lack of localized charges in the cations, and strong spectral changes upon protonation/deprotonation – were synthesized using the Staudinger reaction and characterized by UV–Vis spectra, pK_a values and lipophilicities (logP values). The bases could potentially be useful as working agents in optical sensors and acid-base indicators for lipophilic membranes.     

Synthesis of copolymers of decyl methacrylate with o-allylphenol and their investigation as viscosity improving additives for petroleum oils

Russian Journal of Applied Chemistry - The synthesis of copolymers of decyl methacrylate with o-allylphenol was performed. The influence of various factors on the results of the process was...