Micron‐sized monodisperse poly(ionic liquid) (PIL) particles, poly([2‐(methacryloyloxy)ethyl]trimethylammonium bis(trifluoromethanesulfonyl)amide), were prepared by dispersion polymerization at 70 °C in methanol with poly(vinylpyrrolidone) as a stabilizer. The obtained particle size could be controlled by addition of ethanol to the methanol medium while maintaining narrow monodispersity. The PIL particles exhibit unique properties; they can be observed by scanning electron microscopy without platinum coating, which is generally used to avoid an electron charge. Moreover, the solubility of the PIL particles can be easily changed by changing the counter anion, similar to the process for ionic liquids. 相似文献
Submicron‐sized monodisperse polystyrene (PS) particles were successfully prepared by dispersion polymerization of styrene in an ionic liquid, N,N‐diethyl‐N‐methyl‐N‐(2‐methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide ([DEME][TFSI]) at 70 °C with poly(vinyl pyrrolidone) (PVP) as a stabilizer. At the optimum PVP and styrene concentrations with regard to preparation of stable polymer particles, the number‐average diameter and coefficient of variation were 350 nm and 5.7%, respectively. The particle size increased with a decrease in the PVP concentration and an increase in the styrene concentration. Moreover, we succeeded in producing PS particles by thermal polymerization in the absence of a radical initiator at 130 °C in [DEME][TFSI] using a conventional reactor (not autoclave) utilizing the advantages of non‐volatility and thermal stability of the ionic liquid.
The phase-transfer behavior of poly(acrylic acid) (PAA) particles from the hydrophobic ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)amide phase to the water phase in the particle state, which we reported previously, was examined in more detail. PAA particles were prepared in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([Bmim][TFSA]) and the organic solvent chloroform and were extracted. The transfer of PAA particles to water in the particle state was also observed in [Bmim][TFSA] systems. In contrast, the transfer phenomenon was not observed in the chloroform system. It was clarified that water/oil interfacial tension γ(wo) is an important parameter in the extraction of PAA in the particle state from the viewpoint of free energy. When the cationic surfactant tetradecyltrimethylammonium bromide, aqueous solution was used as the extraction medium, the PAA particles were extracted in the particle state from chloroform to water, in which γ(wo) became as low as that of the ionic liquid. This suggests that the phase-transfer phenomenon of PAA particles in the particle state was induced by the ionic liquid's unique property of low interfacial tension with water despite its high hydrophobic character. 相似文献
We prepared a ternary composite polymer electrolyte from poly(ethylene carbonate) (PEC), lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and non‐calcined silica nanofibers (SNFs) having 3 average diameters (300, 700, and 1000 nm). The SNF composite electrolytes were obtained as homogeneous, self‐standing membranes. The ionic conductivity of PEC/LiTFSI 100 mol% was increased by the addition of SNFs, and the thinner SNFs with average diameter 300 nm were most effective in improving the conductivity. The conductivity was of the order of 10−4 S/cm at 60°C. The lithium transference number of the SNF300 composite was greater than 0.7. Stress‐strain curves of the composites indicated significant increases in Young's modulus and maximum stress for the PEC electrolytes. The 5% weight‐loss temperature of the composites also improved with the addition of SNF. 相似文献
Composite polymer electrolytes based on poly(ethylene oxide)-polysiloxane/l-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide/organomontmorillonite(PEO-PDMS/1L/OMMT) were prepared and characterized.Addition of both an ionic liquid and OMMT to the polymer base of PEO-PDMS resulted in an increase in ionic conductivity.At room temperature,the ionic conductivity of sample PPB100-OMMT4 was 2.19×10~3 S/cm.The composite polymer electrolyte also exhibited high thermal and electrochemical stability and may potentially be applied in lithium batteries. 相似文献
We report here a successful free-radical dispersion polymerization of vinyl pivalate (VPi) in an ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][TFSI]) using poly(vinyl pyrrolidone) (PVP) as a stabilizer. Morphological analysis by FE-SEM revealed that poly(vinyl pivalate) (PVPi) obtained from dispersion polymerizations were in the form of spherical particles. Micron-sized, PVPi particles with a number-average molecular weight (Mn) of 166,400 g/mol could be obtained using 5% stabilizer (w/w to monomer) at 65 °C for 20 h. The effects of varying concentration of stabilizer, initiator and monomer upon polymer yield, molecular weight, and morphology of PVPi were also investigated. Analogous polymerizations in dimethyl sulfoxide (DMSO) and bulk served as references. In addition, the preparation of poly(vinyl alcohol) (PVA) by saponification of the resultant PVPi was described. 相似文献
Sequential living cationic polymerization of octadecyl vinyl ether (ODVE) and methyl vinyl ether (MVE) was used for the preparation of amphiphilic ABA‐type block copolymers. The polymerization of ODVE was initiated with the trimethyl silyl iodide/1,1,3,3‐tetramethoxy propane/ZnI2 system at 0°C in toluene. The living bifunctional polyODVE thus obtained was used as initiator for the polymerization of MVE. Below the LCST of polyMVE (37°C), the copolymers are amphiphiles. Above the LCST of polyMVE, the polyMVE‐blocks become hydrophobic and the amphiphilic nature of the block copolymer is lost. This was demonstrated by using the block copolymers as emulsifiers for water/decane mixtures. The emulsions were stable for several hours at room temperature, while the emulsion stability decreased to about 30 seconds at 40°C. PolyMVE‐α,ω‐bis‐methacrylates were obtained by end‐capping of living bifunctional polyMVE with 2‐hydroxyethyl methacrylate (HEMA). Copolymerization of these bis‐macromers with HEMA leads to segmented networks. The networks showed a reversible swelling/deswelling behavior in water as a function of temperature. This is caused by a change of the hydrophilicity of the polyMVE segments in the networks. Hexa(chloromethyl)melamine, combined with zinc chloride was found to be an efficient hexafunctional initiator for the living cationic polymerization of vinyl ethers. This simple initiating system opens new ways for the synthesis of endgroup‐functionalized star‐shaped poly(vinyl ethers). 相似文献
Nanostructured amino acid containing poly(amide-imide) (PAI) was synthesized from the direct polycondensation reaction of 2–(3,5–diaminophenyl)–benzimidazole and N,N′–(pyromellitoyl)–bis–phenylalanine diacid under green condition by using tetrabutylammonium bromide as molten ionic liquid. Field emission scanning electron microscopy images show that the average diameter of polymeric nanoparticles with spherical shape was around 20–35 nm. In the next step, these polymeric nanoparticles were used as nano-fillers for reinforcement of poly(vinyl alcohol) (PVA) for the first time. Bionanocomposite of PVA and various compositions of PAI nanoparticles were produced through ultrasound-assisted technique. Fourier transform infrared spectroscopy, x-ray diffraction, field emission scanning electron microscopy, and thermogravimetric analysis were utilized to characterize the obtained hybrid materials, morphology, and properties. Results of thermal properties indicated that the thermal stability is enhanced. The improvement of thermal properties was attributed to the homogeneous and good dispersion of PAI nanoparticles in the PVA matrix and the strong hydrogen bonding between O–H groups of PVA and the carbonyl of amide and imide groups of the used PAI nanoparticles. 相似文献
Photoconductive poly(4-butyltriphenylamine) particles were prepared by a chemical oxidative dispersion polymerization. The
utilization of statistical copolymer of methyl methacrylate with 2-hydroxyethyl methacrylate (30:70) as a dispersant afforded
particles with the narrowest distribution when the other experimental conditions such as the rate of monomer feed, and the
dispersant concentration were appropriately selected. Porous particles were obtained at 40 °C using poly(vinyl pyrrolidone)
as a dispersant. 相似文献
This study has concerned the development of polymer composite electrolytes based on poly(vinyl butyral) (PVB) reinforced with calcinated Li/titania (CLT) for use as an electrolyte in electrochemical devices. The primary aim of this work was to verify our concept of applying CLT-based fillers in a form of nano-backbone to enhance the performance of a solid electrolyte system. To introduce the network of CLT into the PVB matrix, gelatin was used as a sacrificial polymer matrix for the implementation of in situ sol–gel reactions. The gelatin/Li/titania nanofiber films with various lithium perchlorate (LiClO4) and titanium isopropoxide proportions were initially fabricated via electrospinning, and ionic conductivities of electrospun nanofibers were then examined at 25 °C. In this regard, the highest ionic conductivity of 2.55 × 10−6 S/cm was achieved when 10 wt% and 7.5 wt% loadings of LiClO4 and titania precursor were used, respectively. The nanofiber film was then calcined at 400 °C to remove gelatin, and the obtained CLT film was then re-dispersed in solvated PVB-lithium bis(trifluoromethanesulfonyl)imide (PVB-LiTFSI) solution before casting to obtain reinforced composite solid electrolyte film. The reinforced composite PVB polymer electrolyte film shows high ionic conductivity of 2.22 × 10−4 S/cm with a wider electrochemical stability window in comparison to the one without nanofillers.