全氟甲基乙烯基醚和其它含氟单体乳液共聚合的竞聚率测定

分别通过气相色谱法测定了全氟甲基乙烯基醚 (PMVE)与偏氟乙烯 (VDF)以及PMVE与四氟乙烯(TFE)二元乳液共聚反应中的气相单体组成和共聚物组成 ,然后用非线性回归法 (RREVM )计算得TFE PMVE及VDF PMVE乳液共聚合反应的表观竞聚率分别为γTFE =3 89和γPMVE =0 0 5以及γVDF =1 0 6和γPMVE =0 11.结合已经测定的TFE VDF二元乳液共聚的表观竞聚率 ,计算了由VDF TFE PMVE三元乳液共聚合反应合成的共聚物组成 ,后者与由1 9F NMR实测的共聚物组成吻合     

Synthesis of highly conductive EDOT copolymer films via oxidative chemical in situ polymerization

Poly(3,4‐ethylenedioxythiophene)s (PEDOT) represent a class of conjugated polymers that can be potentially used as an electrode material for flexible organic electronics due to their superior conductivity and transparency. In this study, we demonstrate that the conductivity of a PEDOT containing copolymer film can be further enhanced by the oxidative chemical in situ copolymerization of a liquid film spun coated from monomer mixture (3,4‐ethylenedioxythiophene (EDOT) and 3‐thienyl ethoxybutanesulfonate (TEBS)), oxidant (iron(III) p‐toluenesulfonate (Fe(OTs)₃)), weak base (imidazole), and solvent (methanol). We investigated that the effect of the processing parameters such as the molar ratios TEBS/EDOT, IM/EDOT, and Fe(OTs)₃/EDOT on the surface morphology, optical property, and the conductivity of the resulting copolymer films. These parameters have been optimized to achieve conductivities for the copolymer films as high as 170 S/cm compared with a conductivity of 30 S/cm for the pure PEDOT film synthesized using the same fabrication method. This conductivity enhancement for the copolymer films was found to be resulted from the fact that the addition of TEBS monomer reduces the copolymerization rate, leading to the formation of much more uniform film surface without defects and copolymers of higher molecular weight which increase the conductivity of the resulting copolymer film. The composition of two monomers in the copolymer film is not related to the variation of conductivity. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1662–1673, 2008     

Composition control of copolymer in semibatch emulsion copolymerization. II. MMA/styrene/BMA three‐component system

In this study, polymers of the MMA/Styrene/BMA three‐component system were synthesized through either soapless semibatch emulsion copolymerization or soapless batch emulsion copolymerization technique. The optimal monomer feed flow rate was determined from the interphase partition laws, monomer reactivity ratios, and three or four times of iterative experimental procedures through semibatch emulsion copolymerization. As a result, the instantaneous composition of polymers could also be effectively controlled to get the desired final products. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3253–3269, 2000     

Some aspects of copolymerization of dienes under the influence of π-allyl complexes of nickel

π-Allyl complexes of nickel induce stereospecific homopolymerization of cyclohexadiene-1,3 and 2,3-dimethylbutadiene with the formation of crystalline polymers. These polymers consist of 1,4-monomer units in cis-configuration for polycyclohexadiene and in trans-configuration for poly-2,3-dimethylbutadiene. Peculiarities of copolymerization of cyclohexadiene-1,3 with butadiene and isoprene and of 2,3-dimethylbutadiene with butadiene under the influence of various π-allyl complexes of nickel are studied. By i.r.- and NMR-spectroscopy and radiochemical methods, the composition of copolymers for the above pairs of monomers are determined and the reactivity ratios are found. Influence of the monomers on the microstructure of the chain in copolymerization is established; the mechanism of this phenomenon is discussed.     

Kinetic and thermodynamic control in the cationic copolymerization of cyclic ethers

Cationic copolymerization of tetrahydrofuran with ethylene oxide in the presence of diols proceeds, at the properly chosen conditions, with complete conversion of both comonomers and leads to telechelic oligodiols. These conditions are based on the simultaneous kinetic and thermodynamic control for two operating mechanisms namely active chain end and activated monomer mechanism. Kinetics of copolymerization and model reactions were studied. The ratios of rate constants of competing reactions, governing the copolymer composition, were determined and it was found, that the microstructure of the copolymer can be controlled at low conversion while at higher conversion the kinetics of the competing parallel reactions is not favourable for the formation of a regular copolymer, in contrast to the previously studied copolymerization of tetrahydrofuran with epichlorohydrin.     

Modification and Application of Poly(Ethylene Terephethalate) Nonwoven Fiber Using Octadecyl Acrylate and Acrylic Acid as Oil Sorbers

Three series of crosslinked octadecyl acrylate and acrylic acid copolymers were prepared through suspension copolymerization based on acrylic acid content (10, 30, 50%wt. ratio). Divinyl benzene (DVB) was used as a crosslinker with different weight ratios (1, 4 and 10%). Isopropyl alcohol or dioctyl phthalate and methyl benzoate were used as two different reaction solvents in the presence of ABIN as initiator. The prepared crosslinked copolymers were characterized by SEM, TGA and FTIR spectroscopic analyses. The prepared polymers were coated onto poly(ethylene terephethalate) nonwoven fiber (NWPET). The effect of copolymerization feed composition, crosslinker wt% and reaction media or solvent on swelling properties of crosslinked polymers were studied through the oil absorption tests in toluene and 10% of diluted crude oil with toluene. It was noticed that the maximum swelling of crosslinked copolymers was increased from 30 to 100 g/g after grafting of copolymers onto NWPET.     

The Fundamental Basis for Cyclopolymerization. VII. A Cyclopolymerization Study of Certain Allylcycloalkenes

The cyclopolymerization characteristics of 3-allylcyclopentene, 3 allylcyclopentene, 3-allylcyclohexene, and 4-allylohexene were studied and the extent of their cyclopolymerization by cationic initiation were compared with previously reported solvolysis results involving the same intermediate carbonium ion. The results of this study were also compared with previously reported results on 4-vinylcyclohexene and 1, 4-dimethylenecyclohexane. The allylcycloalkenes were also polymerized by metal alkyl coordination catalysts and the extent of cyclization in each case was determined. The polymers derived from these monomers invariably contained polymeric fractions (27 to 99%) which were soluble in non-polar organic solvents. Calculations based on NMR spectral data indicated the cationic polymers were 68 to 95% cyclized. The extent of cyclization was found to parallel the interolefinic separation in the monomer. Coordination polymerization yielded somewhat lower ratios of cyclizations (54 to 80%) in all cases except for 4-allylcyclohexene. 4-Allylcyclohexene gave only 5 to 54% cyclization, 4-Vinylcyclohexene, 3-allylcyclopentene, and 3-allylcyclohexene produced soluble copolymers with maleic anhydride. Elemental analysis indicated the composition of these copolymers to be 2:1 molar in maleic anhydride and diene units. A cyclic copolymerization mechanism suggested the formation of a multicyclic repeating unit. The other monomers gave crosslinked polymers since maleic anhydride could not be incorporated into a six-membered ring.     

Characterization of conducting copolymers of 2,2′-bithiophene and pyrrole by cyclic voltammetry and UV/visible spectroscopy

Several polymers have been prepared by electropolymerization of mixtures of pyrrole (PY) and 2,2′-bithiophene (BT). Cyclic voltammetry on prepared polymer films shows three anodic oxidation peaks, two of which match the oxidation potentials of homopolymeric PY and BT, and a third which is intermediate. UV/visible spectroscopy displays a unique spectrum for each of the reduced and oxidized forms of these polymers. Nernstian plots from UV/visible data exhibit three well-defined redox couples in polymer films produced at 1.3 V. Overall, the data strongly support the formation of a copolymer, consisting of three distinct oxidizable units. Two of these can be attributed to short blocks of either PY or BT, and a third to random and alternate groupings of PY and BT. The polymers produced are electrically conductive, but the conductivity drops rapidly as BT units are introduced into a homopolymer of PY. © 1992 John Wiley & Sons, Inc.     

Monomer reactivity ratios in graft copolymerization

This paper discusses monomer reactivity ratios in various radiation- and redox-initiated graft copolymerizations. The polymers studied were polyethylene, cellulose acetate, poly(vinyl chloride), polytetrafluoroethylene, poly(vinyl alcohol), and poly(methyl methacrylate); the comonomer mixtures were styrene–acrylonitrile, methyl acrylate–styrene, acrylonitrile–methyl acrylate, and vinyl acetate–acrylonitrile. The polymer–comonomer mixture systems were so chosen as to permit study of both homogeneous and heterogeneous systems. The homogeneous systems included systems of low and high viscosity. The heterogeneous systems included both polymers swollen by the comonomer mixture and polymers not swollen by the comonomer mixture. None of the homogeneous grafting systems studied showed deviations from the normal copolymerization behavior under a variety of experimental conditions. Monomer reactivity ratios in graft copolymerization were the same as the values in nongraft copolymerization. The heterogeneous systems in which the polymer was swollen by the comonomer mixture yielded grafted copolymer compositions which were the same as those in nongraft copolymerization. The heterogeneous grafting system polytetrafluoroethylene/styrene–acrylonitrile showed deviations from normal copolymerization behavior at low degrees of grafting when the reaction was only on the polymer surface. The behavior became normal at higher degrees of grafting when the system approaches that in which the polymer is swollen by the comonomers. In all reaction systems, it was found that the use of radiation to initiate the reaction does not in any way affect the copolymerization behavior of the two monomers in a comonomer pair.     

Copolymerization of Maleic Anhydride with Benzofuran,Indole, and Benzothiophene

Abstract

Maieic anhydride (MAn) forms alternating copolymers with benzofuran (BF), indole, and benzothiophene (BT) under the influence of azobisisoburyronitrile. In all three cases the yield and molecular weight were highest when equimolar amounts of both monomers were used. The association constants of charge-transfer complex formation of MAn with the three comonomers have been measured at various temperatures by NMR. The following values were obtained (at 20°C):

MAn-BF ca. 0.01 liter/mole (in cyclohexanone)

MAn-indole 0.28 liter/mole (in chloroform)

MAn-BT 0.30 liter/mole (in chloroform)

The results indicate that the reactivity of the comonomers to form copolymers with MAn is governed by the resonance stabilization of the monomer and to a lesser extent by complex formation. The rate of copolymerization is much higher for the MAn-BF system than for the two other systems. In the former case it is not necessary to invoke charge-complex formation to explain the copolymerization.     

Synthesis of cationic water‐soluble copolymers and hydrogels based on [2‐(methacryloyloxy)ethyl]trimethylammonium chloride and 2‐hydroxyethylacrylate and their complex formation with poly(acrylic acid)

Water‐soluble cationic copolymers and hydrogels were synthesized by radical copolymerization of [2‐(methacryloyloxy)ethyl]trimethylammonium chloride (MADQUAT) and 2‐hydroxyethylacrylate (HEA). The kinetics of copolymerization has been studied and the reactivity ratios were determined. It was found that MADQUAT exhibits higher reactivity in copolymerization. The complexation between linear MADQUAT‐HEA and linear poly(acrylic acid) (PAA) has been studied in aqueous solutions at different pH. It results in the formation of insoluble polyelectrolyte complexes, whose composition and stability to aggregate depends on MADQUAT content in copolymers and pH. The hydrogels were synthesized by three‐dimensional radical copolymerization of MADQUAT and HEA in the presence of a crosslinker. The effects of the feed mixture composition on yield and swelling properties of the hydrogels were studied. The interactions of these hydrogels with linear PAA result in formation of gel–polyelectrolyte complexes and contraction of the samples. It was found that the contraction depends on copolymer composition, PAA molecular weight, and solution pH. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44:845–853, 2006     

Contributions of restructuring and oxidation to the aging of the surface of plasma polymers containing heteroatoms

The properties and composition of plasma polymer surfaces stored in air can change considerably over time, especially as a result of oxidative reactions. When plasma polymers contain an element other than O, it is possible to probe for mechanisms in addition to oxidation that contribute to the aging of the surface. Plasma polymers containing N were fabricated from either 1,3-diaminopropane (DAP),n-heptylamine (nHA), or allylamine (AA), and studied by X-ray photo-electron spectroscopy (XPS) and air/water contact angles (CA). For each of the plasma polymers, a multiexponential increase in the O/C ratio was observed over time using XPS. The N/C ratios remained constant (AA) or decreased somewhat (nHA and DAP). In contrast, the trends in CA values differed, declining for the nHA surfaces, rising for the AA, and changing little for the DAP. Surface roughness, assessed by scanning tunnelling or atomic force microscopy, did not change over time. The diverse adjustments in the polarity of each surface and the similar compositional changes between them are reconcilable if the aging of the plasma polymer surface is a manifestation of the superposition of concurrent oxidative reactions and partial surface reorientation; the former introduce polar groups and the latter transports then from the surface to deeper regions beyond the CA probe depth but within the XPS analysis depth. These processes vary between different plasma polymers. Data for the alkylamine plasma polymers is also compared with that for two plasma polymers fabricated from methanol. The change in composition, but not polarity, of the DAP surface after 4 days of storage demonstrates the importance of using multiple techniques to characterize the aging of plasma polymer surfaces.     

Synthesis of highly branched polymers via three-dimensional radical polymerization in the presence of oxygen

It is shown that branched and highly branched vinyl polymers can be prepared by three-dimensional radical polymerization in the presence of dissolved oxygen, as exemplified by the oxidative copolymerization of styrene and divinylbenzene. The conditions of synthesis of highly branched polymers with a high yield??the ratio between monovinyl and divinyl comonomers and the rate of oxygen bubbling??are determined. The kinetics of formation of branched polystyrenes and the features of their molecular-mass distribution are studied. Elemental-analysis data show that the polymeric product contains 22?C24 wt % oxygen, which, according to the IR data, enters into the composition of carbonyl, hydroxyl, and peroxide groups. The thermal decomposition of polymeric products is investigated via the TGA-DSC method. The main exothermal peak at ??145°C is associated with the decomposition of peroxide groups, which is accompanied by the evolution of formaldehyde.     

Property changes of powdery polyacrylonitrile synthesized by aqueous suspension polymerization during heat-treatment process under air atmosphere

High molecular weight powdery polyacrylonitrile (PAN) polymers were prepared by aqueous suspension polymerization employing itaconic acid (IA) as comonomer and alpha,alpha(')-azobisisobutyronitrile (AIBN) as initiator at 60 degrees C. PAN polymers obtained with different monomer ratios were characterized by EA, DSC, FTIR and XRD. It is investigated that the oxygen element content in PAN polymers increased with the increase of required IA amounts in the feed and heat-treatment temperatures. DSC curves of PAN copolymers exhibited the triplet character, owing to the exothermic cyclization and oxidative reactions during heat-treatment process. Introduction of IA in the feed relaxed exothermic reactions of PAN polymers under air atmosphere. Structure and crystallinity changes were affected by required IA amounts in the feed and enhancement of heat-treatment temperatures. The characteristic functional groups (including C[triple bond]N, C=O, CH(2)) presented in FTIR spectra of PAN polymers indicated copolymerization reaction of AN and IA. Existence of some organic groups (C-O, C=C and/or C=N) indicated formation of ladderlike structure during heat-treatment process. PAN homopolymer had the better crystallinity (mainly peak intensity and peak area around 2theta = 17 degrees) than most RT-PAN copolymers. When heat-treatment temperature is around 210 degrees C, peak intensity, peak area, L(c) and CI of HT-PAN polymers corresponding to samples 1# and 2# got maxima, while crystallinity became weak at higher heat-treatment temperatures.     

In situ UV-visible spectroelectrochemical evidences for conducting copolymer formation between diphenylamine and m-methoxyaniline

Electrochemical copolymerization of diphenylamine (DPA) with m-methoxy aniline (MA) was carried out in 4 M H(2)SO(4) by cyclic voltammetry (CV). Cyclic voltammograms (CVs) of the copolymer films were recorded in monomer-free background electrolyte. In situ sepectroelectrochemical studies were carried out on an optically transparent electrode (Indium tin oxide (ITO) coated glass) in 4 M H(2)SO(4) for different feed ratios of the comonomers. Constant potential and potential sweep methods were employed for performing polymerization. UV-visible absorption spectra were collected continuously and concurrently during the copolymerization in both the cases. The results from constant potential electropolymerisation indicated the formation of an intermediate with an absorption peak at 576 nm. Derivative cyclic voltabsorptogram (DCVA) was deduced from the results of cyclic spectrovoltammetry. The DCVA derived at 576 nm confirms the intermediates formed during the electrochemical copolymerization. The compositional changes of the two monomers in the copolymers with changes in feed composition of two monomers as predicted from in situ spectro electrochemical studies are evident from elemental analysis. A plausible copolymerization mechanism is suggested.     

Alternating copolymers of electron‐rich arylamine and electron‐deficient 2,1,3‐benzothiadiazole: Synthesis,characterization and photovoltaic properties

A series of alternating copolymers of electron‐rich arylamine and electron‐deficient 2,1,3‐benzothiadiazole (BT), PV‐BT, DP‐BT, and TP‐BT, were synthesized by Heck coupling reaction. UV–vis absorption and fluorescence spectra show that the copolymerization of electron‐rich diphenylamine (DP), triphenylamine (TP), MEH‐PV (PV), and electron‐deficient BT results in low‐bandgap conjugated polymers. Within the three copolymers of PV‐BT, DP‐BT, and TP‐BT, TP‐BT possesses the highest hole mobility of 4.68 × 10^{? 5} cm²/V, as determined from the space charge limited current (SCLC) model. The bulk heterojunction‐typed polymer solar cells (PSCs) were fabricated with the blend of the copolymers and PCBM as the photosensitive layer. The power conversion efficiencies (PCE) of the PSCs based on PV‐BT, DP‐BT, and TP‐BT reached 0.26%, 0.39%, and 0.52%, respectively, under the illumination of AM 1.5, 100 mW/cm². The results indicate that TP‐BT is a promising photovoltaic polymer for PSCs. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3861–3871, 2007     

Reactivity Ratios and Sequence Distribution Characterization by Quantitative 13C NMR for RAFT Synthesis of Styrene‐Acrylonitrile Copolymers

The kinetics and reactivity ratios of styrene‐acrylonitrile (SA) copolymerization have been studied extensively in bulk and in a variety of solution media using conventional free radical polymerizations (FRPs). Due to the significant difference in the two reactivity ratios for this monomer pair, at certain feed ratios the copolymers display composition drift with conversion due to monomer depletion. In this study, the kinetics of SA copolymerization using Reversible Addition‐Fragmentation Chain Transfer (RAFT) has been studied in bulk at 80 °C. The reactivity ratios for the terminal model were calculated from the comonomer sequence distributions for the RAFT process at low conversion for nine different compositions and found to be in the same range as those reported for conventional FRP of SA. The changes in the composition and sequence distribution with conversion were studied for three feed compositions. The copolymers show compositional drift with conversion, except at the azeotropic composition, and match the predictions from the reactivity ratios obtained at low conversion. From quantitative ¹³C NMR the triad distributions of these copolymers were estimated and found to match the predicted triad distributions as conversion increased. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 919–927     

Efficient Hybrid Photovoltaic Devices Based on in-situ Electrochemical Copolymerization of 3-Methylthiophene and Bithiophene into Pores of Nanocrystalline TiO2

Novel organic and inorganic hybrid photovoltaic devices were thbricated by in-situ electrochemical copolymerization of 3-methylthiophene（3MT） and bithiophene（BT） into the pores of nanostructured TiO2 sintered on fluorine-doped tin oxide（FTO） substrate. The photoactive layer was investigated by Fourier transform infrared（FTIR） spectroscopy, ultraviolet-visable（UV-Vis） spectrometer, scanning electron microscope（SEM） and cyclic voltammo- gram characterization. Device efficiency based on different molar feed ratios of 3MT and BT during electrochemical polymerization, and the effect of in-situ copolymer state（doped by electrolyte and de-doped） were measured and compared. Under the solar illumination of 100 mW/cm2（AM 1.5）, an optimized device efficiency of 0.938% was obtained when the molar ratio of 3MT to BT was 500：1, polymerization time was 500 s and the system was in doped copolymer state, respectively. The mechanism of overall photovoltaic parameter improvement was discussed.     

Copolymerization of tetraoxane with styrene catalyzed by BF3·O(C2H5)2

The copolymerization of tetraoxane with styrene catalyzed by BF₃·O(C₂H₅)₂ was studied at 30°C. to determine whether a cyclic monomer can copolymerize with a vinyl monomer. The formation of the copolymer was confirmed by elementary analysis of both benzene-soluble and benzene-insoluble fractions of the polymer obtained. It was found by gas chromatography that a fairly large amount of 4-phenyl-1,3-dioxane and a small amount of trioxane were formed in the present system, in addition to polymers. Roughly a third of the total amount of the monomers reacted was consumed in the formation of methanol-insoluble polymer, a third for 4-phenyl-1,3-dioxane, and another third for trioxane and unknown products which could not be indentified. The formation of these cyclic compounds during the copolymerization may be explained in terms of a back-biting (or intramolecular transacetalization) reaction. The cationic reactivity of tetraoxane was found to be similar to that of styrene on the basis of both the consumption rate of each monomer in the copolymerizing system and the composition of the methanol-insoluble polymer obtained.     

Linear polymers of acrylic monomers containing an acetylenic moiety

1-Acryloxy-2-butyne and 1-methacryloxy-2-butyne were synthesized and polymerized by means of anionic initiators to soluble linear polymers containing acetylenic bonds in the pendant side chains. In contrast, insoluble, crosslinked polymers were formed when cationic and radical initiators were used. The unpolymerized acetylenic bonds in the resulting linear polymers were shown to be present by infrared spectroscopic methods and by the following post-reactions of these bonds: (1) the thermal- and radical-initiated crosslinking of the linear polymers through the acetylenic bonds; (2) the post-bromination of the acetylenic bonds; and (3) the reaction of decaborane with the acetylenic bonds. The anionic copolymerization of both monomers with a number of selected monomers was performed and the copolymer reactivity ratios for several of the comonomer pairs were determined. Dibromination of the linear polymers affords self-extinguishing polymers with apparently good hydrolytic stability. Decarbonation of the linear polymers yields soluble polymers which do not soften up to 300°C. The linear polymers and copolymers, as well as their partially brominated and partially decaboronated products, may be classified as “self-reactive” polymers which yield thermosetting polymers.