Phase behavior of binary and ternary blends of poly(styrene‐co‐methacrylic acid), poly(styrene‐co‐4‐vinylpyridine), and poly(2,6‐dimethyl‐1,4‐phenylene oxide)

Poly(styrene‐co‐methacrylic acid) (PSMA) and poly(styrene‐co‐4‐vinylpyridine) (PS4VP) of different compositions were prepared and characterized. The phase behavior of these copolymers as binary PSMA/PS4VP mixtures or with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as PPO/PSMA or PPO/PS4VP and PPO/PSMA/PS4VP ternary blends was investigated by differential scanning calorimetry (DSC). This study showed that PPO was miscible with PS4VP containing up to 15 mol % 4‐vinylpyridine (4VP) but immiscible with PS4VP‐30 (where the number following the hyphen refers to the percentage 4VP in the polymer) and PSMA‐20 (where the number following the hyphen refers to the percentage methacrylic acid in the polymer) over the entire composition range. To examine the morphology of the immiscible blends, scanning electron microscopy was used. Because of the hydrogen‐bonding specific interactions that occurred between the carboxylic groups of PSMA and the pyridine groups of PS4VP, chloroform solutions of PSMA‐20 and PS4VP‐15 formed interpolymer complexes. The obtained glass‐transition temperatures (T_g's) of the PSMA‐20/PS4VP‐15 complexes were found to be higher than those calculated from the additivity rule. Although, depending on the content of 4VP, the shape of the T_g of the PPO/PS4VP blends changed from concave to S‐shaped in the case of the miscible blends, two T_g were observed with each PPO/PS4VP‐30 and PPO/PS4VP‐40 blend. The thermal stability of the PSMA‐20/PS4VP‐15 interpolymer complexes was studied by thermogravimetry. On the basis of the obtained results, the phase behavior of the ternary PPO/PSMA‐20/PS4VP‐15 blends was investigated by DSC. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The phase behavior and thermal stability of blends of poly(styrene‐co‐methacrylic acid)/poly(styrene‐co‐ 4‐vinylpyridine)

The hydrogen bonding and miscibility behaviors of poly(styrene‐co‐methacrylic acid) (PSMA20) containing 20% of methacrylic acid with copolymers of poly(styrene‐co‐4‐vinylpyridine) (PS4VP) containing 5, 15, 30, 40, and 50%, respectively, of 4‐vinylpyridine were investigated by differential scanning calorimetry, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). It was shown that all the blends have a single glass transition over the entire composition range. The obtained T_gs of PSMA20/PS4VP blends containing an excess amount of PS4VP, above 15% of 4VP in the copolymer, were found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are able to form interpolymer complexes. The FTIR study reveals presence of intermolecular hydrogen‐bonding interaction between vinylpyridine nitrogen atom and the hydroxyl of MMA group and intensifies when the amount of 4VP is increased in PS4VP copolymers. A new band characterizing these interactions at 1724 cm⁻¹ was observed. In addition, the quantitative FTIR study carried out for PSMA20/PS4VP blends was also performed for the methacrylic acid and 4‐vinylpyridine functional groups. The TGA study confirmed that the thermal stability of these blends was clearly improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of thermosensitive copolymer beads containing pyridinium groups and their antibacterial activity

Thermosensitive 4VP‐NIPAAm‐4G copolymer beads containing pyridyl groups were first prepared by suspension copolymerization of 4‐vinylpyridine (4VP), N‐isopropylacrylamide(NIPAAm), and tetraethylene glycol dimethacrylate (4G; crosslinking reagent) in a saturated Na₂SO₄ aqueous solution in the presence of surfactant and MgCO₃ as dispersants. Then the copolymer beads containing pyridinium groups were obtained by the quaternization of the copolymer beads with various alkyl iodides (CH₃I, C₄H₉I, C₈H₁₇I) in N,N‐dimethylformamide. The 4VP‐NIPAAm‐4G (15 : 97 : 3) copolymer bead and the 4VP‐NIPAAm‐4G copolymer beads quaternized with butyl iodide exhibited high thermosensitivity in water, although the 4VP‐NIPAAm‐4G copolymer beads quaternized with methyl iodide or octyl iodide hardly exhibited thermosensitivity. All the quaternized copolymer beads exhibited antibacterial activity against Escherichia coli (E. coli), although the 4VP‐NIPAAm‐4G copolymer bead did not. In particular, the copolymer bead quaternized with butyl iodide exhibited the highest antibacterial activity against E. coli at 30°C. It was also found that the antibacterial activity of the quaternized 4VP‐NIPAAm‐4G copolymer beads was greatly affected by not only chain length of alkyl groups in alkyl iodides, with which the 4VP‐NIPAAm‐4G copolymer beads were quaternized, but also by temperature of the solutions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Influence of triphenylphosphonium pendant groups on the rheological and morphological properties of new quaternized polysulfone

A new quaternized polysulfone with triphenylphosphonium pendant groups was synthesized by reacting chloromethylated polysulfone with triphenylphosphine. The molecular restructurations, generated by hydrogen bonding, electrostatic interactions, and association phenomena in ternary quaternized polysulfone/N,N‐dimethylformamide (solvent)/water (nonsolvent) systems, were evaluated by rheological investigations. The polyelectrolyte effect, induced by enhanced dissociation of the ionizable groups and by mixed solvents' quality, modify the rheological functions, that is, dynamic viscosity, elastic shear modulus, and viscous shear modulus, as well as the thermodynamic parameters obtained from the rheological properties, such as apparent activation energy. These results were correlated with the morphological properties of the films obtained from solutions in solvent/nonsolvent mixtures and compared with other quaternized polysulfones, having different hydrophobic characteristics. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation,characterization, and thermal properties of polystyrene‐block‐quaternized poly(4‐vinylpyridine)/Montmorillonite nanocomposites

Polystyrene‐block‐poly(4‐vinylpyridine) (PS‐b‐P4VP) was synthesized by two steps of reversible addition‐fragmentation transfer (RAFT) polymerization of styrene (St) and 4‐vinylpyridine (4VP) successively. After P4VP block was quaternized with CH₃I, PS‐b‐quaternized P4VP/montmorillonite (PS‐b‐QP4VP/MMT) nanocomposites were prepared by cationic exchange reactions of quaternary ammonium ion in the PS‐b‐QP4VP with ions in MMT. The results obtained from X‐ray diffraction (XRD) and transmission electron microscopy (TEM) images demonstrate that the block copolymer/MMT nanocomposites are of intercalated and exfoliated structures, and also a small amount of silicates' layers remained in the original structure; differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results show that the nanocomposites displayed higher glass transition temperature (T_g) and higher thermal stability than that of the corresponding copolymers. The blending of PS‐b‐QP4VP/MMT with commercial PS makes MMT to be further separated, and the MMT was homogeneously dispersed in the polymer matrix. The enhancement of thermal stability of PS/PS‐b‐QP4VP/MMT is about 20°C in comparison with commercial PS. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1950–1958, 2006     

Two‐dimensional regular nanopatterning on block copolymer substrate having lamellar morphology using star‐hyperbranched nanospheres by electrostatic interaction

Hyperbranched polystyrenes (PS) were prepared by living radical photopolymerization of 4‐vinylbenzyl N,N‐diethyldithiocarbamate as an inimer under UV irradiation. The star‐hyperbranched copolymers were derived by grafting from surface N,N‐diethyldithiocarbamate groups of hyperbranched macroinitiator with t‐butyl methacrylate in the presence of N,N‐tetraethylthiuram disulfide. We obtained poly(methacrylic acid) star‐hyperbranched PS nanospheres by hydrolysis of poly(t‐butyl methacrylate)‐grafted chains. We established two‐dimensional (2D) regular nanopatterning by aligning continuously such nanospheres on poly(2‐vinylpyridine) (P2VP) lamellar layers of PS‐block‐P2VP diblock copolymer film. Electrostatic interaction between nanosphere surface having negative charges (? COOCs) and P2VP lamellar layer acted effectively for the 2D nanopattern formation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4206–4210, 2006     

Self-assembly of amphiphilic di and triblock copolymers of styrene and quaternized 5-(N,N-diethylamino) isoprene in selective solvents

Self-association of highly asymmetric block copolymers of styrene and quaternized 5-(N,N-diethylamino)isoprene was studied. After quaternization with dimethyl sulfate, the di and triblock copolymers consisted of a long block of polystyrene (PS) with a short poly[5-(N,N,N-diethylmethylammonium)isoprene][methyl sulfate](PAI) block at one or both chain ends, respectively. The aggregates were prepared by first dissolving the copolymers in an organic solvent and then adding water to induce the segregation of the PS chains. Pure DMF, THF or dioxane was used as the organic solvent, as well as DMF/THF mixtures. The critical water content (cwc) and the morphologies were studied as a function of the common solvent, initial copolymer concentration and architecture (di or triblock) by static light scattering and by Transmission Electron Microscopy (TEM), respectively. It was found that both, the cwc and the morphologies of the aggregates are most strongly affected by the nature of the common solvent. Some unexpected behaviors were found for the triblock copolymer. Morphologies of a triblock copolymer in various mixtures of DMF and THF, quenched at determined water contents, were investigated in order to study the degree of morphological control that can be achieved solely as function of the organic solvent composition. Multiple morphologies have been found including equilibrium morphologies and kinetically trapped ones. Finally, the stability of primary micelles prepared in DMF was studied by DLS, upon dilution with DMF and water, and a possible mechanism for the destabilization of the aggregates is proposed.     

Synthesis of poly(aryl ether sulfone)‐graft‐polystyrene and poly(aryl ether sulfone)‐graft‐[polystyrene‐block‐poly(methyl methacrylate)] through atom transfer radical polymerization

A new graft copolymers poly(aryl ether sulfone)‐graft‐polystyrene (PSF‐g‐PS) and poly(aryl ether sulfone)‐graft‐[polystyrene‐block‐poly(methyl methacrylate)] (PSF‐g‐(PS‐b‐PMMA)) were successfully prepared via atom transfer radical polymerisation (ATRP) catalyzed by FeCl₂/isophthalic acid in N,N‐dimethyl formamide. The products were characterized by GPC, DSC, IR, TGA and NMR. The characterization data indicated that the graft copolymerization was accomplished via conventional ATRP mechanism. The effect of chloride content of the macroinitiator on the graft copolymerization was investigated. Only one glass transition temperature (T_g) was detected by DSC for the graft copolymer PSF‐g‐PS and two glass transition temperatures were observed in the DSC curve of PSF‐g‐(PS‐b‐PMMA). The presence of PSF in PSF‐b‐PS or PSF‐g‐(PS‐b‐PMMA) was found to improve thermal stabilities. © 2002 Society of Chemical Industry     

Surface and interface properties of functionalized polysulfones: Cell‐material interaction and antimicrobial activity

Quaternized polysulfones with different ionic chlorine content tested for biomedical applications were obtained by quaternization reaction of chloromethylated polysulfones with N,N‐dimethylethanolamine. The relationship between the different physical and chemical characteristics of these polymers and their biocompatible and antimicrobial properties was established for maximizing the selectivity and performance of these materials for biomedical applications. Therefore, topographic reorganization of the polysulfonic films induced by the type of nonsolvent in casting solutions of polymer significantly influences films morphology, depending on the charge density of polyelectrolytes, the hydrophilic/hydrophobic characteristics, as well as on the history of the formed films. Furthermore, the study of the adhesion of red blood cells and cohesion of platelets on the surface of quaternized polysulfone films, as well as analysis of antibacterial activity, using Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923 microorganisms, contribute to extending the possible applications of quaternized polysulfones as semipermeable membranes in biomedical domains. POLYM. ENG. SCI., 55:2184–2194, 2015. © 2015 Society of Plastics Engineers     

Studies on blends of LLDPE and polar polymers compatibilized by a random copolymer

Compatibilization of blends of linear low‐density polyethylene (LLDPE)–poly(methyl methacrylate) (PMMA) and LLDPE–copolymer of methyl methacrylate (MMA) and 4‐vinylpyridine (poly(MMA‐co‐4VP) with poly(ethylene‐co‐methacrylic acid) (EMAA) have been studied. Mechanical properties of the LLDPE–PMMA blends increase upon addition of EMAA. In order to further improve interfacial adhesion of LLDPE and PMMA, 4‐vinyl pyridine units are introduced into PMMA chains, or poly(MMA‐co‐4VP) is used as the polar polymer. In LLDPE–poly(MMA‐co‐4VP)–EMAA blends, interaction of MAA in EMAA with 4VP of poly(MMA‐co‐4VP) causes a band shift in the infrared (IR) spectra. Chemical shifts of N_1s binding energy in X‐ray photoelectronic spectroscopy (XPS) experiments indicate a transfer of proton from MAA to 4VP. Scanning electron microscopy (SEM) pictures show that the morphology of the blends were improved upon addition of EMAA. Nonradiative energy transfer (NRET) fluorescence results attest that there exists interdiffusion of chromophore‐labeled LLDPE chains and chromophore‐labeled poly(MMA‐co‐4VP) chains in the interface. Based on experimental results, the mechanism of compatibilization is studied in detail. Compatibilization is realized through the interaction between MAA in EMAA with 4VP in poly(MMA‐co‐4VP). © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 967–973, 1999     

Influence of DMF on the polymerization of tert‐butyl acrylate initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator

BACKGROUND: In a number of studies it has been shown that 2,2,6,6‐tetramethylpiperidinooxy (TEMPO)‐mediated polymerization of acrylates is not facile. Therefore, the object of the study reported here was to prepare poly[styrene‐block‐(tert‐butyl acrylate)] (PS‐b‐PtBA) block copolymers using 4‐oxo‐TEMPO‐capped polystyrene macroinitiator as an initiator, in the presence of small amounts of N,N‐dimethylformamide (DMF). The kinetic analysis and the effect of DMF on the reaction mechanism are also discussed. RESULTS: PS‐b‐PtBA block copolymer was prepared through polymerization of tert‐butyl acrylate (tBA) initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator at 135 °C. The polymerization rate of tBA could be increased by adding a small amount of DMF, and the number average molecular weight of the PtBA block in PS‐b‐PtBA reached 10 000 g mol^?1 with narrow polydispersity. The activation rate constant k_act?tBA of alkoxyamine increased and the recombination rate constant k_rec?tBA decreased with increasing DMF concentration. CONCLUSION: DMF was shown to be a rate‐enhancing additive for the polymerization of tBA using a 4‐oxo‐TEMPO‐capped polystyrene macroinitiator. From the kinetic analysis, it was concluded that the improvement of polymerization with the addition of DMF was due to an increase in k_act?tBA and a decrease in k_rec?tBA. Copyright © 2008 Society of Chemical Industry     

Rheological and morphological characteristics of multicomponent polysulfone/poly(vinyl alcohol) systems

A series of blends obtained from polysulfone (PSF) or chloromethylated polysulfone (CMPSF) and poly(vinyl alcohol) (PVA) in N‐methyl‐2‐pyrrolidone were investigated by means of attenuated total reflection Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), rheology and atomic force microscopy (AFM). Mechanisms through which specific interactions developed via hydrogen bonding in ternary systems affect the blend properties were established from FTIR spectra. The results confirm the presence of hydrogen bonding in PSF/PVA and CMPSF/PVA blends at 0.5 and 0.75 weight fractions of PVA, respectively. Consequently, the type of interactions and structural peculiarity of polymers in the blends as well as the composition of polymer mixtures modify the rheological functions, evidencing the orientation or mobility of chain segments in the shear field. The results derived from rheological measurements are consistent with those above, evidencing significant changes for blends with a greater amount of PVA (i.e. 50/50 and 25/75 (w/w) PSF/PVA and CMPSF/PVA blends, respectively). These blends represent the optimum compositions and possess specific properties, confirmed by the glass transition temperatures. Additionally, the specific microarchitecture of the blends, determined using AFM, represents excellent scaffolds as porous membranes for biomedical applications. © 2014 Society of Chemical Industry     

Synthesis and characterization of polystyrene/poly(4‐vinylpyridine) triblock copolymers by reversible addition–fragmentation chain transfer polymerization and their self‐assembled aggregates in water

Reversible addition–fragmentation chain transfer polymerization (RAFT) was developed for the controlled preparation of polystyrene (PS)/poly(4‐vinylpyridine) (P4VP) triblock copolymers. First, PS and P4VP homopolymers were prepared using dibenzyl trithiocarbonate as the chain transfer agent (CTA). Then, PS‐b‐P4VP‐b‐PS and P4VP‐b‐PS‐b‐P4VP triblock copolymers were synthesized using as macro‐CTA the obtained homopolymers PS and P4VP, respectively. The synthesized polymers had relatively narrower molecular weight distributions (M_w/M_n < 1.25), and the polymerization was controlled/living. Furthermore, the polymerization rate appeared to be lower when styrene was polymerized using P4VP as the macro‐CTA, compared with polymerizing 4‐vinylpyridine using PS as the macro‐CTA. This was attributed to the different transfer constants of the P4VP and PS macro‐CTAs to the styrene and the 4‐vinylpyridine, respectively. The aggregates of the triblock copolymers with different compositions and chain architectures in water also were investigated, and the results are presented. Reducing the P4VP block length and keeping the PS block constant favored the formation of rod aggregates. Moreover, the chain architecture in which the P4VP block was in the middle of the copolymer chain was rather favorable to the rod assembly because of the entropic penalty associated with the looping of the middle‐block P4VP to form the aggregate corona and tailing of the end‐block PS into the core of the aggregates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1017–1025, 2003     

Synthesis,viscosity behavior,and interactions with a surfactant of some amphiphilic copolymers of diallyldimethylammonium chloride and diallyldodecyl‐ or diallyloctadecyl‐ammonium chloride

The compatibilization of an immiscible polymer system polystyrene/poly(4-vinylpyridine) has been induced by the introduction of carboxylic acid groups within the polystyrene chains. Poly(styrene-co-cinnamic acid), PSCA, copolymers were used to prepare blends and complexes with poly(4-vinylpyridine), P4VP, and in a second time with poly(styrene-co-4-vinylpyridine), PS4VP, copolymer in order to reduce the density of the interacting groups. The miscibility of the systems has been ascertained by DSC, which revealed that both blends and complexes exhibit a single glass transition temperature indicating their single phase nature. The T_gs of the complexes of PS4VP with PSCA15, containing 15 mol % of cinnamic acid content, were higher than those of the corresponding blends indicating that stronger interpolymer interactions were developed in the complexes. Furthermore, the application of the Kwei equation suggested that P4VP interacts more strongly with PSCA15 than does PS4VP. FTIR spectra revealed the development of hydrogen bonding within the PS4VP/PSCA system and both hydrogen bonding and ionic interaction in the P4VP/PSCA blends whereas the same interactions were expected in both systems. This observation confirmed the stronger ability of P4VP to interact with PSCA copolymer. The viscosimetric study showed both positive and negative deviations of the reduced viscosity of the blends from the additivity law confirming the presence of specific interactions within the blend solutions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis,properties, and functions of thermosensitive copolymers having pyridyl and/or pyridinium groups

Thermosensitive copolymers with pyridyl and/or pyridinium groups were prepared by copolymerization of 4-vinylpyridine (4VP) and N-isopropylacrylamide (NIPAAm) followed by the reaction of 4VP–NIPAAm copolymers with benzyl chloride.The copolymer 4VP–NIPAAm was soluble in dilute HCl below 32 °C, but the quaternized 4VP–NIPAAm copolymer was soluble even in aqueous solutions of pH 6.5 below 28 °C. The thermosensitivity of both 4VP–NIPAAm and the quaternized 4VP–NIPAAm copolymer was observed. The quaternized 4VP–NIPAAm copolymer could adsorb food dyes dissolved in water and the copolymer–dye complexes became water-insoluble. The quaternized 4VP–NIPAAm copolymer also exhibited high antibacterial activity against bacteria such as Escherichia coli.     

Surface characterization of quaternized polysulfone films and biocompatibility studies

A novel quaternized polysulfone with N‐dimethyloctylammonium groups was investigated with respect to its surface properties, hydrophobicity, interactions with blood, and morphology. The history of the films formed from N,N‐dimethylformamide/methanol and N,N‐dimethylformamide/water solutions and the compositions of the solvent/nonsolvent mixtures influenced the surface morphology. Thus, atomic force microscopy investigations of the films showed pores and nodules of different sizes and intensities, which depended on the content of methanol or water in the solvent mixtures. Hydrophilicity modification, evidenced by the apolar components and the electron‐acceptor and electron‐donor parameters of the polar components of the surface tension parameters, was correlated with atomic force microscopy data. Surface wettability trends were analyzed on the basis of the free energy of hydration between the prepared films and water and the work of adhesion. The adhesion of red blood cells to the modified polysulfone showed the influence of the hydrophobic properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A super thin polytetrafluoroethylene/sulfonated poly(ether ether ketone) membrane with 91% energy efficiency and high stability for vanadium redox flow battery

In order to further decrease the cost and enhance the durability of sulfonated poly(ether ether ketone) membrane for vanadium redox flow battery, a super thin (40 μm) polytetrafluoroethylene (PTFE)/SPEEK (PS) membrane is prepared. The physico‐chemical properties and single cell performance of PS membranes prepared with different casting solvents including NMP (N‐methyl‐2‐pyrrolidone), DMF (N,N′‐dimethylformamide), and DMAc (N,N′‐dimethylacetamide) have been investigated. Results show that the energy efficiency of VRB with PS/DMF can reach up to 91.2% at the current density of 40 mA cm^?2, which is 11.1% and 6.4% higher than that of the commercial Nafion 212 and pristine SPEEK membrane, respectively. In addition, charge–discharge test over 150 times proves that the PS/DMF membrane possesses high stability and thus it is suitable for VRB application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43593.     

The transport properties of CO2 and CH4 for chemically modified polysulfones

The sorption and transport properties of pure CO₂ and CH₄ for a series of polysulfones were measured. The effects of molecular structure of polysulfones on transport properties were studied using chemically modified polysulfones, including TMSPSF (bisphenol‐A trimethylsilylated polysulfone), BPSF (bromobisphenol‐A polysulfone), and BTMSPSF (bromobisphenol‐A trimethylsilylated polysulfone). The effects of operating pressure on the sorption and permeation properties of polysulfones were examined. The permeation properties for a mixture of CO₂ and CH₄ were also measured and these results were compared with those obtained from the experiments of pure gases. The sorbed concentrations and permeability coefficients are well fitted to a conventional dual‐mode model. The permeability coefficients of each gas of a binary mixture are lower than those of pure gases, which shows the competition effect between each component. The permeability coefficients of polysulfones rank in the following order, TMSPSF > BTMSPSF > bisphenol‐A polysulfone (PSF) > BPSF. The effect of the substituents on chain packing was related to the gas‐permeation properties. Fractional free volume (FFV) calculations and X‐ray diffraction were used to judge chain packing. In comparison with PSF, the higher values of permeability coefficients for TMSPSF and BTMSPSF are due to higher FFV and d spacing. The lower permeability coefficients for BPSF is attributed to the strong induced dipole interchain interaction. Addition of bromo substituents to TMSPSF is also found to decrease the permeability coefficients for BTMSPSF, suggesting that the potential increase in FFV due to packing–disrupting bulky trimethylsilyl groups is overridden by the increase in cohesive energy density. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 391–400, 2000     

Morphology of ultrafine polysulfone fibers prepared by electrospinning

Ultrafine fibers of bisphenol‐A polysulfone (PSF) were prepared by electrospinning of PSF solutions in mixtures of N,N‐dimethylacetamide (DMAC) and acetone at high voltages. The morphology of the electrospun PSF fibers was investigated by scanning electron microscopy. Results showed that the concentration of polymer solutions and the acetone amount in the mixed solvents influenced the morphology and the diameter of the electrospun fibers. The processing parameters, including the applied voltage, the flow rate, and the distance between capillary and collection screen, were also important for control of the morphology of electrospun PSF fibers. It was suggested that uniform ultrafine PSF fibers with diameter of 300–400 nm could be obtained by electrospinning of a 20 % (wt/v) PSF/DMAC/acetone (DMAC:acetone = 9:1) solution at 10–20 kV voltages when the flow rate was 0.66 ml h^?1 and capillary–screen distance was 10 cm. Copyright © 2004 Society of Chemical Industry     

Tunable morphology and photoluminescence of poly(styrene‐block‐4‐vinylpyridine)–cadmium sulfide nanocomposites

Poly(styrene‐block‐4‐vinylpyridine) (PS4VP)–CdS nanocomposites containing different concentrations of CdS were synthesized by an in situ method. Scanning electron microscopy and transmission electron microscopy results indicate that the morphologies of PS4VP–Cd(II) and PS4VP–CdS were controlled by the Cd(II) concentration and the solvent, respectively. The effects of the CdS concentration on the crystal style of CdS in PS4VP–CdS and the photoluminescence (PL) properties of the PS4VP–CdS were also examined. By a comparison of the PL spectra of PS4VP–CdS in solutions, films, and powders, the PL mechanism of PS4VP–CdS was also delivered. The PS4VP–CdS nanocomposite shows potential for application in water‐soluble fluorescence probes. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013