Origin of the methylene bonds in poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene] prepared according to Gilch's method: novel applications

Impurities containing methylene bridges between 2‐((2′‐ethylhexyl)oxy)‐5‐methoxy‐benzene molecules are inevitably formed during the synthesis of 1,4‐bis(chloromethyl)‐2‐((2′‐ethylhexyl)oxy)‐5‐methoxy‐benzene, the monomer used in the preparation of poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV), but they can be removed by double recrystallization of the monomer prior to polymerization. When impurities containing methylene bridges participate in a Gilch polymerization, the methylene bonds formed in the main chains are prone to break at 200 °C, that is, at least 150 °C below the major degradation temperature of defect‐free MEH‐PPV. Interestingly, the thermal treatment used to break the methylene bonds present reduces the chain aggregation of MEH‐PPV during film formation and induces its blends with poly(2,3‐diphenyl‐5‐octyl‐p‐phenylene‐vinylene) (DPO‐PPV) to form a morphology similar to that of block copolymers. Both significantly enhance the luminescence properties. Copyright © 2006 Society of Chemical Industry     

Self‐organized MEH‐PPV domains in a TPU matrix and the consequences to the luminescence spectra

Self‐sustained cast films formed from heterogeneous blends of poly(2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene) (MEH‐PPV) conjugated polymer and thermoplastic polyurethane (TPU) were investigated by photoluminescence (PL) and scanning electron microscopy (SEM). A blue shift is observed for the pure electronic transition PL peak (E₀₀) with decreasing MEH‐PPV concentration. The two clear shoulders in the PL spectra at higher energy than the E₀₀ peak appear due to the formation of small conjugation segments of the MEH‐PPV molecules at the interface of the spherical MEH‐PPV domains. This assumption and the origin of the blue shift were confirmed by correlating the average size of the MEH‐PPV domains, observed from SEM images, and the analysis of the PL spectra at low temperatures. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of polystyrene/poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐p‐phenylenevinylene] fluorescent microspheres by miniemulsion polymerization

Fluorescent microspheres have great potential for use as probes in biological diagnostics. In this context, poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐p‐phenylenevinylene] (MEH‐PPV), a conjugated polymer which has high quantum yield, controllable emitting wavelength and facile processing in manufacture, was used as a fluorescent material for the preparation of polystyrene (PS)/MEH‐PPV fluorescent microspheres via miniemulsion polymerization. We demonstrate that the emitting wavelength of the PS/MEH‐PPV fluorescent microspheres can be regulated by changing the amount of azobisisobutyronitrile initiator in the polymerization process. Using acrylic acid comonomer, poly[styrene‐co‐(acrylic acid)]/MEH‐PPV fluorescent microspheres with functional carboxyl groups were also prepared. All the microspheres were characterized using transmission electron microscopy, scanning electron microscopy, fluorescence microscopy and fluorescence spectrophotometry. The functional carboxyl groups were characterized using Fourier transform infrared spectroscopy. This work provides a novel platform for the preparation of conjugated polymer fluorescent microspheres for biological applications. © 2012 Society of Chemical Industry     

Electroluminescence and photovoltaic properties of poly(p‐phenylene vinylene) derivatives with dendritic pendants

A copolymer of dendronized poly(p‐phenylene vinylene) (PPV), poly{2‐[3′,5′‐bis (2′‐ethylhexyloxy) bnenzyloxy]‐1,4‐phenylene vinylene}‐co‐poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylene vinylene] (BE‐co‐MEH–PPV), was synthesized with the Gilch route to improve the electroluminescence and photovoltaic properties of the dendronized PPV homopolymer. The polymer was characterized by ultraviolet–visible absorption spectroscopy, photoluminescence spectroscopy, and electrochemical cyclic voltammetry and compared with the homopolymers poly{2‐[3′, 5′‐bis(2‐ethylhexyloxy) benzyloxy‐1,4‐phenylene vinylene} (BE–PPV) and poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH–PPV). Polymer light‐emitting diodes based on the polymers with the configuration of indium tin oxide (ITO)/poly(3,4‐ethylene dioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS)/polymer/Ca/Al were fabricated. The electroluminescence efficiency of BE‐co‐MEH–PPV reached 1.64 cd/A, which was much higher than that of BE–PPV (0.68 cd/A) and a little higher than that of MEH–PPV (1.59 cd/A). Photovoltaic properties of the polymer were studied with the device configuration of ITO/PEDOT : PSS/polymer : [6,6J‐phenyl‐C₆₁‐butyric acid methyl ester] (PCBM)/Mg/Al. The power conversion efficiency of the device based on the blend of BE‐co‐MEH–PPV and PCBM with a weight ratio of 1 : 3 reached 1.41% under the illumination of air mass 1.5 (AM1.5) (80 mW/cm²), and this was an improvement in comparison with 0.24% for BE–PPV and 1.32% for MEH–PPV under the same experimental conditions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polychromatic light‐emitting conjugated polymer prepared by controlling its structure through active free radical addition

BACKGROUND: The HOMO–LUMO energy level width of conjugated polymers can be manipulated by controlling the conjugation length of the polymeric materials in order to adjust their properties in terms of emission of different colors and realize polychromatic displays. In the work reported in this paper azobisisobutyronitrile (AIBN) was used to control the conjugation length of poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)‐co‐(1,4‐phenylene vinylene)] (MEH‐PPV) by free radical addition. In this way a series of MEH‐PPV with various conjugation lengths was obtained. RESULTS: Characterization of MEH‐PPV using ¹H NMR and Fourier transform infrared spectroscopy demonstrated that the cyano groups of AIBN hydrolyzed into carboxyls. The carboxyl free radicals attacked the conjugated double bonds of MEH‐PPV, resulting in a decrease of trans‐vinylenes and in an increase of cis‐vinylenes as well as tert‐methyls on the backbone. Changing the conjugated structure of the polymer caused the peaks of UV and fluorescence spectra to shift to the blue. CONCLUSION: The resulting MEH‐PPV derivatives can emit orange‐red, green and blue light. It is expected that they could be used to prepare PPV‐based materials that could modulate white light emission, by simply blending the PPV derivatives emitting different colors. Copyright © 2008 Society of Chemical Industry     

Optical properties of MEH‐PPV conjugated polymer covered by silica nanoshells

Poly [2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐1,4‐phenylene vinylene] (MEH‐PPV) covered by nanostructured silica shells were synthesized via sol–gel process and investigated after freeze‐drying and heat‐drying in vacuum. The freeze‐dried sample consists of a light pink powder while the heat‐dried sample presents a redder coarse‐grained material. The freeze‐dried sample was analyzed using small angle X‐ray scattering (SAXS). Both samples were analyzed using photoluminescence (PL) and Raman spectroscopy at room temperature. The PL spectra presented relatively large red shifts compared with that of the MEH‐PPV in tetrahydrofuran solution, which was taken as a reference sample. The energy shifts observed in the PL and Raman spectra strongly support an explanation based on denser packing conditions inside the nanostructured silica shells, which can effectively lead the polymer molecules to a higher interchain interaction via aggregate sites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5620–5626, 2006     

Synthesis,photo‐, and electroluminescent properties of the soluble poly[(2,5‐diphenylene‐1,3,4‐oxadiazole)‐ 4,4′‐vinylene]

A novel soluble conjugated polymer, poly[(2,5‐diphenylene‐1,3,4‐oxadiazole)‐4,4′‐vinylene] (O‐PPV), containing an electron‐transporting group on the main chain of PPV, was synthesized according to HORNER mechanism. The oligo‐polymer with M_w = 1000 and T_d = 270°C is soluble in chloroform and tetrahydrofuran. The photoluminescent (PL) properties were investigated using different concentrations of solid‐state O‐PPV/PEO blends absorption and selective excitation measurements. The results show that PL arises from interchain charge‐transfer states in solid‐state O‐PPV. Compared with the analogous single‐layer device constructed with PPV (ITO/PPV/Al), which emits two peaks at λ = 520 nm and 550 nm (shoulder), the electroluminescence (EL) spectrum of the device [ITO/O‐PPV (80 nm)/Al] is a broad peak at λ_max = 509 nm. The quantum efficiency (0.13%) of the device ITO/O‐PPV/Al is much higher than that of the device ITO/PPV/Al, due to the introduction of the electron‐transporting group–oxadiazole units in the main chain of PPV. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3535–3540, 1999     

Synthesis and characterization of poly(1,4‐phenylenevinylene) derivatives containing liquid crystalline oxadiazole groups

Two novel poly(1,4‐phenylenevinylene) (PPV) derivatives containing liquid crystalline oxadiazole side chains were prepared by a dehydrochlorination process. The homopolymer poly(2‐methoxy‐5‐((2‐methoxy‐phenyl)‐5‐hexyloxy‐phenyloxy‐1,3,4‐oxadiazole)‐1,4‐phenylenevinylene) (HO–PE₆) is insoluble in common solvents, whereas the copolymer poly(2‐methoxy‐5‐((2‐methoxy‐phenyl)‐5‐hexyloxy‐phenyloxy‐1,3,4‐oxadiazole))‐(2‐methoxy‐5‐(2′‐ethylhexyloxy))‐1,4‐phenylenevinylene) (CO–PE₆) is soluble in common solvents such as chloroform, THF, and p‐xylene. The molecular structure of CO–PE₆ was confirmed by FTIR, ¹H‐NMR, UV–vis spectroscopy, and polarized light microscopy. CO–PE₆ showed a maximum emission at 556 nm in chloroform and at 564 nm in solid film, when excited at 450 nm. The maximum electroluminescence emission of the device indium–tin oxide (ITO)CO–PE₆/Al is at 555 nm. The turn‐on voltage of LEDs based on CO–PE₆ and MEH–PPV is 6.5 and 8.5 V, respectively. The electron mobility of CO–PE₆ is higher than that of MEH–PPV based on the results of current–voltage and electrochemical behavior of both MEH–PPV and CO–PE₆. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 396–403, 2004     

Synthesis and light‐emitting properties of a novel π‐conjugated poly[di(p‐phenyleneethynylene)‐alt‐ (p‐phenylenecyanovinylene)] containing n‐octyloxy side branches

A novel π‐conjugated poly[di(p‐phenyleneethynylene)‐alt‐(p‐phenylenecyanovinylene)] having n‐octyloxy side chains (PPE‐C₈PPE‐PPV) was prepared by polymerization of the monomer DEDB with BCN. Chemical structure of the polymer obtained was confirmed by ¹H NMR, FTIR, and EA. PPE‐C₈PPE‐PPV had a molecular weight enough to fabricate the electroluminescent (EL) device, and showed a good organosolubility, excellent thermal stability, and film‐forming property. In UV absorption and PL spectra in film it showed a maximum at 430 and 543 nm, respectively, which appeared 5 and 41 nm longer wavelengths than that of the solution, respectively. HOMO, LUMO energy levels and band gap were determined to be ?5.70, ?3.29, and 2.41 eV, respectively. Two EL devices with low‐work function cathodes were fabricated with the structures of ITO/PEDOT/PPE‐C₈PPE‐PPV/cathodes (LiF/Al and Mg:Ag/Ag). The both devices exhibited a bright green light emission at 545 nm and the maximum luminescence of 197 cd/cm² (LiF/Al) and 158 cd/cm² (Mg:Ag/Ag). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of the soluble fluorescent poly[2‐decyloxy‐5‐(2′‐(6′‐dodecyloxy)naphthyl)‐1,4‐phenylenevinylene]

A new soluble fluorescent polymer, poly[2‐decyloxy‐5‐(2′‐(6′‐dodecyl‐oxy)naphthyl)‐1,4‐phenylenevinylene] (DDN‐PPV), with no tolane‐bisbenzyl (TBB) structure defects is prepared by the dehydrohalogenation of 1,4‐bis(bromomethyl)‐2‐decyloxy‐5‐(2′‐(6′‐dodecyloxy)naphthyl)benzene (as monomer) in this study. The aforementioned monomer is synthesized via such chemical reactions as alkylation, bromination, and Suzuki coupling reactions. The structure and properties of the DDN‐PPV are examined by ¹H NMR, FTIR, UV/vis, TGA, photoluminescence (PL), and electroluminescence (EL) analyses. The two asymmetric decyloxy and 6′‐dodecyloxynaphthyl substituents on the phenylene ring make the DDN‐PPV soluble in organic solvents and eliminate the TBB structure defects. With the DDN‐PPV acting as a light‐emitting polymer, a device is fabricated with a sequential lamination of ITO/PEDOT/DDN‐PPV/Ca/Ag. The EL spectrum of the device shows a maximum emission at 538 nm. The turn on voltage of the device is about 16.6 V. Its maximum brightness is 14 cd/m² at a voltage of 18.2 V. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2734–2741, 2007     

Synthesis and spectroscopic and photoconduction characteristics of coaxial poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)−1,4‐phenylene vinylene] single‐walled carbon nanotube films with ohmic‐like transport attributes

Highly luminescent, core–shell, single‐walled carbon nanotube–poly[2‐methoxy‐5‐(2′‐ethylhexyloxy)?1,4‐phenylene vinylene] (MEH‐PPV) one‐dimensional networks were synthesized by a multicycle unstable micellization method. The current–voltage data indicated that the charge transport within the nanowire network remained Ohmic, with the differential conductance scaling linearly with temperature in the temperature range of about 120 to 300 K. Further analysis based on the comparative study involving photoluminescence and Raman spectroscopic tests pointed to interchain interactions and nanotube–polymer interface as primary factors influencing the electronic characteristics of the processed samples. Likewise, steady‐state photoconduction tests confirmed that the heterointerface played a dominant role behind the increased photoresponse induced by exciton annihilation at a low bias regime. The study helped us identify the underlying physical mechanisms that controlled the optical, electrical, and photoconduction properties of the MEH‐PPV–carbon nanotube heteronetworks. Potentially, this will open a door to the development of next generation, low‐cost, all‐organic nanooptoelectronic devices and systems. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 40029.     

Synergistic extraction of rare earths(III) from chloride medium with mixtures of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate

The synergistic effect of 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazalone‐5 (HPMBP, HA) and di‐(2‐ethylhexyl)‐2‐ethylhexylphosphonate (DEHEHP, B) in the extraction of rare earths (RE) from chloride solutions has been investigated. Under the experimental conditions used, there was no detectable extraction when DEHEHP was used as a single extractant while the amount of RE(III) extracted by HPMBP alone was also low. But mixtures of the two extractants at a certain ratio had very high extractability for all the RE(III). For example, the synergistic enhancement coefficient was calculated to be 9.35 for Y³⁺, and taking Yb³⁺ and Y³⁺ as examples, RE³⁺ is extracted as RE(OH)A₂.B. The stoichiometry, extraction constants and thermodynamic functions such as Gibbs free energy change ΔG (?17.06 kJ mol^?1), enthalpy change ΔH (?35.08 kJ mol^?1) and entropy change ΔS (?60.47 J K^?1 mol^?1) for Y³⁺ at 298 K were determined. The separation factors (SF) for adjacent pairs of rare earths were calculated. Studies show that the binary extraction system not only enhances the extraction efficiency of RE(III) but also improves the selectivity, especially between La(III) and the other rare earth elements. Copyright © 2006 Society of Chemical Industry     

Effect of thermal annealing in atmosphere on photoluminescence of BTEO–PPV films

The photoluminescence (PL) spectra of poly[2,5‐bis‐(tri‐ethoxy)‐1,4‐phenylene vinylene] (BTEO–PPV) films are blue‐shifted with increasing thermal annealing temperature. It is known from the UV–vis absorption spectra that thermal annealing decreases the conjugation length of the polymer. For BTEO–PPV films, unlike with MEH–PPV films, the symmetric triethoxy side groups further block aggregation of the polymer chains. The absorption Fourier transfer infrared spectra showed that thermal annealing in atmosphere destroyed the chain structure of BTEO–PPV film by thermal oxidation to form aldehyde groups, which resulted in low PL efficiency of the annealed films. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Synthesis and Biological Evaluation of Purine 2′‐Fluoro‐2′‐deoxyriboside ProTides as Anti‐influenza Virus Agents

2′‐Fluoro‐2′‐deoxyguanosine has been reported to have potent anti‐influenza virus activity in vitro and in vivo. Herein we describe the synthesis and biological evaluation of 6‐modified 2′‐fluoro‐2′‐deoxyguanosine analogues and their corresponding phosphoramidate ProTides as potential anti‐influenza virus agents. Whereas the parent nucleosides were devoid of antiviral activity in two different cellular assays, the 5′‐O‐naphthyl(methoxy‐L ‐alaninyl) ProTide derivatives of 6‐O‐methyl‐2′‐fluoro‐2′‐deoxyguanosine, 6‐O‐ethyl‐2′‐fluoro‐2′‐deoxyguanosine, and 2′‐deoxy‐2′‐fluoro‐6‐chloroguanosine, and the 5′‐O‐naphthyl(ethoxy‐L ‐alaninyl) ProTide of 6‐O‐ethyl‐2′‐fluoro‐2′‐deoxyguanosine displayed antiviral EC₉₉ values of ～12 μM . The antiviral results are supported by metabolism studies. Rapid conversion into the L ‐alaninyl metabolite and then 6‐modified 2′‐fluoro‐2′‐deoxyguanosine 5′‐monophosphate was observed in enzymatic assays with yeast carboxypeptidase Y or crude cell lysate. Evidence for efficient removal of the 6‐substituent on the guanine part was provided by enzymatic studies with adenosine deaminase, and by molecular modeling of the nucleoside 5′‐monophosphates in the catalytic site of a model of ADAL1, thus indicating the utility of the double prodrug concept.     

Enhancing the electroluminescence properties of novel blue light emitting polymer and MEH‐PPV based white light emitting polymer devices by processing condition optimization

A series of triarylaminooxadiazole‐containing tetraphenylsilane light emitting polymer (PTOA) and poly(2‐methoxy, 5‐(2′‐ethyl‐hexyloxy)‐p‐phenylene‐vinylene) (MEH‐PPV) based white light emitting polymer devices (PLEDs) were fabricated to study blue and orange–red emitter composition and light emitting layer processing effects on white emission electroluminescence properties. Color purity, current turn‐on voltage, brightness, and current efficiency were strongly determined by MEH‐PPV content and the thin film processing condition. The intensity of PTOA blue emission was equal to that of MEH‐PPV orange–red emission when the device was fabricated by a polymer composite film containing 10 wt % of MEH‐PPV. Color purity [Commission Internationale de L'Eclairage (CIE_x,y) coordinates (0.26,0.33)] was nearly white emission under applied 8 V. The brightness and current efficiency of PTOA‐MEH‐PPV composite film based devices increased as MEH‐PPV content increased. Furthermore, white emission blue shifted with increasing spin‐rate of thin film coating and applied voltage. Low turn‐on voltage, high current density, and high brightness were obtained for the device fabricating with light emitting layer coating with high spin‐rate. Moreover, low current efficiency was obtained for the PLED with a thinner light‐emitting layer. A white emission CIE (0.28,0.34) was obtained for PTOA‐MEH‐PPV based white PLED. White PLED brightness and efficiency can be as high as 700 cd/m² and 0.78 cd/A, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Thermal degradation kinetics and lifetime prediction of a luminescent conducting polymer

The thermal stability, degradation kinetics and lifetime‐prediction of a luminescent conducting polymer, poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV), are investigated. The derivative thermogravimetry curves indicate a double‐stage decomposition process in a nitrogen atmosphere, and a multi‐stage decomposition process in an air atmosphere. The apparent activation energy values of MEH‐PPV are higher in nitrogen than in air. Activation energies slightly increase and are then approximately stable in nitrogen for the initial mass loss, while the activation energy changes differently with the percentage mass loss in air. The activation energy decreases for the initial mass loss and increases with mass loss when the mass loss is above 30%; beyond 70% it decreases again. The lifetime of MEH‐PPV decreases dramatically from 10⁶ min to 0.03 min as the temperature increases from 25 °C to 300 °C in air. The lifetime is longer in nitrogen than in air and decreases from 10¹⁴ min to 2.34 min with increasing the temperature from 25 °C to 300 °C in nitrogen. These lifetime parameters indicate that the service/process temperature has a strong influence on the luminescence of MEH‐PPV. The maximum absorption and wavelength at maximum absorption of MEH‐PPV decrease with increasing temperature in the visible region. Copyright © 2003 Society of Chemical Industry     

Effect of interchain interaction on optical properties of poly(p‐phenylene vinylene) derivative containing oxadiazole in backbone

We have investigated the optical properties of poly [2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylene vinylene] containing oxadiazole in backbone (MEH‐OPPV) in dilute tetrahydrofuran solution and solid solution films. There is a large dihedral angle between the two adjacent monomer units in MEH‐OPPV, which restrains interchain interactions and destroys the conjugation of the polymer to result in blue shifted absorption and emission spectra. The red shifted photoluminescence (PL) peak is continuously changed in the solid solution films with increasing the concentration of MEH‐OPPV. Comparison with the dilute solution, an obvious shoulder peak at 465 nm is found in the UV–vis absorption and PL excitation (PLE) spectra of the MEH‐OPPV film. The intensity of the PLE shoulder at 465 nm is increased with the concentration of MEH‐OPPV in the solid solution films, which is connected with the aggregation of the MEH‐OPPV chains. The interchain interactions are restrained and the π‐stack aggregates of the polymer chains can not form in the MEH‐OPPV due to the large dihedral angle, and then the interchain species are effectively suppressed in the MEH‐OPPV films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of 3‐aminopropyltriethoxysilane on properties of poly(butyl acrylate‐co‐maleic anhydride)/silica hybrid materials

The transparent poly(butyl acrylate‐co‐maleic anhydride)/silica [P(BA‐co‐MAn)/SiO₂] has been successfully prepared from butyl acrylate‐maleic anhydride copolymer P(BA‐co‐MAn) and tetraethoxysilane (TEOS) in the presence of 3‐aminopropyltriethoxysilane (APTES) by an in situ sol–gel process. Triethoxysilyl group can be readily incorporated into P(BA‐co‐MAn) as pendant side chains by the aminolysis of maleic anhydride unit of copolymer with APTES, and then organic polymer/silica hybrid materials with covalent bonds between two phases can be formed via the hydrolytic polycondensation of triethoxysilyl group‐functionalized polymer with TEOS. It was found that the amount of APTES could dramatically affect the gel time of sol–gel system, the sol fraction of resultant hybrid materials, and the thermal properties of hybrid materials obtained. The decomposition temperature of hybrid materials and the final residual weight of thermogravimetry of hybrid both increase with the increasing of APTES. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that the morphology of hybrid materials prepared in the presence of APTES was a co‐continual phase structure. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 419–424, 1999     

Etherification rates of 2‐methyl‐2‐butene and 2‐methyl‐1‐butene with ethanol for environmentally clean gasoline production

Etherification of C₅ reactive olefins available in light fluidized catalytic cracking (FCC) gasoline is an attractive way to decrease the olefins and to increase the octane number. The reactivities of 2‐methyl‐1‐butene (2M1B) and 2‐methyl‐2‐butene (2M2B) in the etherification reaction with ethanol catalysed by a strongly acidic macroreticular resin catalyst were investigated in a temperature range of 333–360 K using a liquid phase differential flow reactor. In the presence of excess alcohol, the apparent reaction orders of etherification reactions of isoamylenes were found to be 0.93 and 0.69 with respect to 2M1B and 2M2B concentrations, respectively. 2M1B was shown to be more reactive than 2M2B and its activation energy is also lower in the etherification reaction. It was also shown that diffusion resistances, especially in the macropores of the catalyst, may play an important role on the observed rates. © 1999 Society of Chemical Industry     

Synthesis and characterization of p‐perfluoro{1‐[2‐(2‐fluorosulfonyl‐ethoxy)propoxy]}ethylated poly(α‐methyl styrene)

p‐Perfluoro{1‐[2‐(2‐fluorosulfonyl‐ethoxy)propoxy]}ethylated poly(α‐ methyl styrene) 3 was synthesized via electron transfer of perfluoro‐di{2‐[2‐(2‐fluorosulfonyl‐ethoxy)propoxy]}propionyl peroxide 2 and poly(α‐methyl styrene) 1 at different reactant molar ratios (2 : 1). The modified polymer 3 was characterized by various techniques. The ring p‐substitution was proved by FTIR and ¹⁹FNMR. The desulfonation appeared at above 124°C was found by TGA. The molecular weight determined by GPC increased with the increase of reactant molar ratio, and the polydispersity values indicated there was no degradation of the parent polymer chain in the reaction. Followed by hydrolysis and acidification, the modified polymer 3 could be further quantitatively converted into its sulfonic form 4. Ion exchange capacity of novel polyelectrolyte 4 can be controlled by changing reactant molar ratio (2 : 1). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3615–3618, 2006