bluuebunny/crossref_metadata_2025 huggingface dataset:
ESCA studies of metal‐containing plasma polymers. II. Plasma polymerization of ferrocene, vinylferrocene, and dimethylaminomethylferrocene
Authors: Munro H. S. , Eaves J. G.
Published: April 2003

The surface aspects of plasma polymers derived from ferrocene, dimethylaminomethylferrocene, and vinylferrocene were studied by electron spectroscopy for chemical applications. From a consideration of the ESCA peak area ratios it is apparent that ferrocene and vinylferrocene maintain a carbon‐to‐iron ratio characteristic of the “monomer”, whereas dimethylaminomethylferrocene plasma polymer is richer in iron than its monomer.
Thermally stable polymers from 1,4,5‐naphthalene–tricarboxylic acid and aromatic tetramines
Authors: Korshak V. V. , Mognonov D. M. , Izyneev A. A. , Doroshenko Yu. E.
Published: April 2003

New thermally stable polymers that contained benzimidazole and benzimidazobenzoisoquinoline fragments in polymer chains were synthesized by one‐stage cyclopolycondensation of aromatic tetramines (3,3′, 4,4′‐tetraminodiphenyl ether, 3,3′,4,4′‐tetraminodiphenyl methane, 3,3′,4,4′‐tetraminodiphenyl sylfone, and 3,3′‐diaminobenzidine) with 1,4,5‐naphthalene tricarboxylic acid 4:5–anhydride in polyphosphoric acid and with 1,4,5‐naphthalene tricarboxylic acid 4:5–anhydride 1‐phenyl ester. All polymers obtained were soluble in concentrated sulfuric acid, 85% phosphoric acid, polyphosphoric acid, methane sylfonic acid. Some were soluble in formic acid. Thermogravimetric analyses indicated that these polymers were stable up to 450–500°C in air. The polymers had good hydrolytic stability.
Solid matrix polymerization and stereoisomeric complexes of poly(methyl methacrylate)
Authors: Yau H. , Stupp S. I.
Published: April 2003

The polymerization of methyl methacrylate within solid matrices of stereoregular poly(methyl methacrylate) has been studied by proton NMR and wide angle X‐ray diffraction. The semi‐crystalline isotactic (i‐) PMMA matrix was synthesized in the laboratory by anionic polymerization initiated by phenylmagnesium bromide, and the syndiotactic (s‐) PMMA matrix was synthesized through a Ziegler–Natta reaction. Matrix polymerization of the monomer was initiated through the redox activation of benzoyl peroxide with N,N‐dimethyl‐p‐toluidine. NMR measurements of triad distributions in matrix‐polymerized chains suggest that the well‐known stereospecific replica polymerization in PMMA (syndiotactic sequences promote isotactic sequences and vice versa) plays only a limited role in the systems studied. Experimental results indicate that chains grown within the i‐PMMA or s‐PMMA solid matrices have greater degrees of configurational disorder. The greater concentration of atactic triads in these chains could be the result of limited free volume or steric effects during polymerization in a highly condensed environment. X‐ray diffraction studies of solution cast blends of isotactic PMMA and PMMA with conventional tacticity reveal some crystallinity with a structure characteristic of the stereocomplex formed by isotactic and syndiotactic PMMA from suitable solvents. Evidence was obtained for the presence of this complex in solidified mixtures of the i‐PMMA solid matrix and liquid monomer. This observation is an example of special intermolecular structures that can form under conditions of in situ growth of chains within a pre‐polymerized matrix.
Effect of stirring on cellulose graft copolymerization. IV. Grafting of styrene by initiator systems involving potassium persulfate
Authors: Graczyk Tomasz , Hornof Vladimir
Published: April 2003

Dissolving pulp and its partially xanthated derivative were grafted with styrene, using either the Fe2+−K2S2O8 redox system of potassium persulfate alone as initiators. The conversion of styrene to both copolymer and homopolymer was found to be influenced by agitator speed. The effect of stirring was much more pronounced with the xanthated substrate in that a welldefined conversion maximum was observed at the same agitation speed for both total polymer and copolymer. Grafting onto dissolving pulp with the redox initiator also showed a maximum, but a maximum total polymer and maximum copolymer were located at different agitator speeds. Grafting of styrene onto dissolving pulp initiated by potassium persulfate was almost independent of stirring in the 0–910 rpm range.
Autooxidation and stabilization of undoped and doped polyacetylenes
Authors: Yang Xun‐Zhuan , Chien James C. W.
Published: April 2003

Autooxidations of polyacetylene have been measured by volumetric, infrared, and isothermal TGA weight uptake techniques. The rate of oxygen uptake is 9 × 10−7 mol (g s)−1 at 70°C and the overall activation energy is about 10 kcal mol−1. The maximum oxygen uptake corresponds to [CHO0.25]x. Above 100°C there is oxidative degradation of the polymer completely to volatile products. The rate constant for the oxidative degradations at 160°C is ca. 1.5 × 10−5s. Autooxidation does not result in formation of significant amounts of crosslinking because there are not carbonaceous residues. TGA under a stream of oxygen showed the degradation to be complete at ca. 420°C leaving no residues. Autooxidation is much slower if the polymer is compressed to higher bulk density. Radical scavengers such as BHT and 4010 are effective stabilizers. Hydroperoxide decomposers, such as DSTDP, does not help in the stabilization; spin trap BPN accelerates the oxidation of polyacetylene. Iodine and AsF5 doped polyacetylenes are oxidatively much more stable than undoped polymers. Perchlorate doped polyacetylenes begin to lose weight as soon as heated above room temperature. Even in an inert atmosphere the polymers often undergo explosive decomposition.
A morphological analogue of japanese lacquer. Grafting of p‐hydroxystyrene onto pullulan by ammonium persulfate initiation in dimethylsulfoxide
Authors: Chen Yen‐Yuan , Oshima Ryuichi , Kumanotani Ju
Published: April 2003

Pullulan‐g‐poly(p‐acetoxystyrene) (I) was prepared using ammonium persulfate (APS) as an initiator in dimethylsulfoxide (DMSO) solution. I was deacetylated by hydrazine hydrate to yield pullulan‐g‐poly(p‐hydroxystyrene) (II). The degree of polymerization of the grafted poly(p‐hydroxystyrene) chain (III) was 15–20. Despite the effective grafting (%), this method caused the degradation of pullulan. The number of branch polymer chains per pullulan molecule were evaluated to be 0.9 to 2.5 from number average molecular weights of the permethylated II and III. The glass transition temperature of II was higher than that of III, indicating that the polar hydroxyl groups of pullulan in the graft polymer caused an increase in the rigidity of the grafted polymer chains. Pullulan‐g‐poly(o‐hydroxystyrene) and pullulan‐g‐poly(MMA) were also readily prepared by this method.
Radiolysis of resist polymers. VI. Copolymers of trihalophenylmethacrylate and methyl methacrylate
Authors: Lu P. H. , Babu G. N. , Chien J. C. W.
Published: April 2003

Copolymers of several compositions of methyl methacrylate (MMA), trichlorophenyl methacrylate (TCPMA), and tribromophenyl methacrylate (TBPMA) have been synthesized and characterized. Gamma radiolysis yields are very sensitive to the presence of the halogenated monomers. With less than 10% of the halogenated monomer in the copolymers. Gs values were found to be much greater than that of PMMA. However, the halogenated monomer introduces a tendency toward crosslinking. The results are consistent with the enhancement of chain scission by dissociative electron capture and the tendency of phenyl radical intermediates to cause crosslinking. These structure‐property relationships were found to be valid for all the homopolymers and copolymers investigated in this series.
Block polymer preparation via both anionic and free radical polymerization
Authors: Tung L. H. , Lo G. Y. S. , Griggs J. A.
Published: April 2003

A new method of block polymer preparation using combined anionic and free radical polymerization was investigated. In the method the first monomer was polymerized anionically. The resulting polymeric anions were then reacted with an episulfide to form a polymer with mercaptan end‐groups. This mercapto—polymer was mixed with a second monomer(s) in an inert solvent for the free radical polymerization. Conventional free radical initiation methods were used to initiate the polymerization of the second monomer but because of the high chain transfer constant of the mercaptan groups, a large number of the free radical chains would grow from the first polymer to form a block polymer. Block polymers difficult or impossible to make by direct anionic polymerization can thus be prepared. Several block polymers, including the new thermoplastic elastomers, poly[(styrene‐co‐acrylonitrile)‐b‐butadiene‐b‐(styrene‐co‐acrylonitrile)] and poly(bromostyrene‐b‐butadiene‐b‐bromostyrene) were prepared by this method.
Graft copolymerization onto rubber. V. Graft copolymerization of methyl methacrylate onto rubber using potassium peroxydiphosphate as initiator
Authors: Lenka Subasini , Nayak Padma L. , Das Anil P. , Mishra Surendra N.
Published: April 2003

The graft copolymerization of methyl methacrylate onto natural rubber (NR) is investigated using potassium peroxydiphosphate as the initiator. The rate of grafting is determined by varying monomer concentration, peroxydiphosphate concentration, and temperature. The graft yield increased with an increase in monomer concentration up to 1.4082M/L and thereafter the graft yield decreases. The graft yield increases significantly with an increase of peroxydiphosphate concentration up to 150 X 10‐1M/L and thereafter the graft yield decreases. The grafting reaction is temperature dependent. A suitable kinetic scheme is proposed and the rate equation is evaluated.
The elucidation of the 1H‐ and 13C‐NMR spectra of bis[N,N‐di(2,3‐epoxypropyl)‐4‐aminophenyl]methane (TGMDA) and composite with bis(4‐animophenyl)sulfone (DDS) using two‐dimensional fourier transform techniques
Authors: Herring F. G. , Jagannathan N. R. , Luoma G.
Published: April 2003

The application of Fourier transform (FT) two‐dimensional nuclear magnetic resonance spectroscopy to the study of the composite of bis[N,N‐di(2,3‐epoxypropyl)‐4‐aminophenyl] methane (TGMDA) and the curing agent bis(4‐aminophenyl)sulfone (DDS) is discussed. The combination of 2D‐J resolved and homonuclear (proton) shift correlated experiments permits the complex proton spectrum due to the glycidylamine moiety to be completely elucidated. The potential utility of this in the study of the aging of prepreg is briefly discussed.
Sequential analysis of polyesters by stepwise chemical degradation: Preparation of degradation products
Authors: Rossbach Volker , Windeln Johannes , Schmitz Franz P.
Published: April 2003

Model reactions for the sequential analysis of polyesters, especially those of the poly(ethylene terephthalate) and poly(butylene terephthalate) type, by stepwise chemical degradation were performed. The cyclic degradation products, containing the reagent and an ethylene terephthalate or butylene terephthalate unit, terephthalic acid mono(2‐{o{N‐ 2′‐(imino)ethoxycarbonyl‐}iminobenzoyl‐} oxyalkyl) ester N″‐lactams, were deliberately synthesized.
Thermal and radical polymerization of anthracene acrylates and methacrylates
Authors: Simionescu Cristofor I. , Grigoras Mircea , Bărboiu Virgil
Published: April 2003

The thermal and radical‐induced polymerizations of 9‐anthrylmethyl acrylate (I), 9‐anthrylmethyl methacrylate (II), 1′‐(9‐anthryl)ethyl acrylate (III), and 1′‐(9‐anthryl)ethyl methacrylate (IV) have been studied. It was found that the radical‐induced polymerization takes place for the methacrylates only, while thermal polymerization leads to polymers for both types of monomers and takes place by Diels–Alder cycloaddition in the case of acrylates, and by both normal enchainment and Diels–Alder cycloaddition in the case of methacrylates.
Regiospecifically substituted poly(phenylacetylenes) as potential chemical detectors
Authors: Wentworth Stanley E. , Bergquist Paul R.
Published: April 2003

The synthesis of a series of regiospecifically substituted polyphenylacetylenes via sealed tube thermal polymerization has been accomplished. Measurement of their conductivities alone and in the presence of SO2, NH3, H2O, or dimethyl methylphosphonate vapors shows them to be extremely weakly conductive, contrary to previous reports. Higher conduction in these prior materials is thus attributed to the presence of ionic impurities arising from their method of synthesis. These results cast doubt on the suitability of such materials alone as chemical sensors but suggest that intentional incorporation of ionic species might be effective.
Study of the microstructure of tetrahydrofuran‐3,3 dimethyloxetane copolymers by 13C‐NMR spectroscopy.
Authors: Guzmàn J. , Riande E. , Rico M. , Santoro J.
Published: April 2003

The microstructure of tetrahydrofuran (A)‐3,3 dimethyloxetane (B) copolymers was studied by 13C‐{1H}‐NMR spectroscopy. Only the methyl carbons corresponding to the 3,3 dimethyloxetane unit appear as a singlet, whereas the other carbons present a more complicated spectral pattern than it would be expected if ϵ effects were negligible. The assignment of the resonance signals allowed the determination of the values of the probabilities of the different triads, which were in good agreement with those obtained from the reactivity ratios.
Organic solid photochromism by photoreduction mechanism: Polar aprotic viologen copolymers
Authors: Kamogawa Hiroyoshi , Amemiya Suguru
Published: April 2003

Copolymers of vinyl viologens such as N‐vinylbenzyl‐N′‐yalkyl and N‐(γ‐methyacryloyloxy)propyl‐N′‐propyl‐4,4′‐bipyridinium dihalides and polar aprotic comonomers such as N‐vinyl‐2‐pyrrolidone (VP) and N,N‐dimethylacrylamide (DMA) were prepared by the copolymerizations of vinyl viologens with DMA and the chemical modifications of VP copolymers containing reactive halogens. Copolymers containing various viologen anions such as Br−, BF, SO, and I− were also prepared by the anion exchange of copolymers containing Cl−. The photocolor developments of these aprotic copolymers in the film state were completely reversible and faster than for the corresponding copolymers with protic comonomers such as acrylamide and 2‐hydroxyethyl acrylate, all with characteristic absorption spectra attributable to single radical cations.
Photopolymerization initiated by carbonyl compounds. VII. Solvent effects on biacetyl photoinitiation
Authors: Encinas M. V. , Garrido J. , Lissi E. A.
Published: April 2003

Biacetyl is solvated by methanol or water giving an α‐substituted alkanone. Irradiation of the solvated species at 300 nm in the presence of vinyl acetate or vinyl pyrrolidone, produces a significant amount of polymer. The photoprocesses leading to active free radicals are considered to be a type I photocleavage of the α‐substituted alkanone.
Characterization of surface endgroups in polystrene latexes
Authors: Jayasuriya R. M. , El‐Aasser M. S. , Vanderhoff J. W. , Yue H. J.
Published: April 2003

The stability against electrolytes for all‐sulfate, all‐carboxyl, and all‐hydroxyl, polystyrene model latexes followed the order, sulfate > carboxyl > hydroxyl when determined from an IR light scattering technique. Two types of hydroxyl endgroups were identified by 13C‐NMR (chemical shift correlations, and model compound comparisons), for the polystyrene model latexes. One type was due to termination of growing chain with an oligomer with a single monomer unit, and the other due to termination of growing chains. The surface hydroxyl groups of an all‐hydroxyl latex were derivatized with hexafluoroacetone, and quantified using 19F‐NMR techniques. Good agreement with the indirect conductometric titration values were obtained.
Polymerization of styrene miniemulsions
Authors: Choi Y. T. , El‐Aasser M. S. , Sudol E. D. , Vanderhoff J. W.
Published: April 2003

Polymerization of styrene miniemulsions, prepared using a mixed emulsifier system comprising sodium lauryl sulfate and cetyl alcohol, was carried out using both water‐soluble (potassium persulfate) and oil‐soluble [2,2′‐azobis‐(2‐methyl butyronitrile)] initiators. The effects of variation of initiator concentration, polymerization temperature, and added inhibitor on the kinetics and particle‐size distributions were investigated to obtain more quantitative evidence concerning the locus of polymerization in miniemulsion systems. Experimental results for the kinetics and particle‐size distributions clearly showed that monomer droplets became the main source of polymer particle formation. This was attributed to the fact that stable emulsions with droplet diameters in the range of 0.05 to 0.15 μm were produced using this mixed‐emulsifier system. In this size range, droplet initiation could effectively compete with other mechanisms due to their large surface area. Their size was indeed similar to the corresponding latex particle size obtained after polymerization.
Radical copolymerization of γ‐methylene‐Δα,β‐butenolide derivative: Ethyl(E)‐5‐oxo‐2,5‐dihydrofuran‐2‐ylidene‐acetate
Authors: Nagai Katsutoshi , Akiyama Kazuhiko , Kuramoto Noriyuki
Published: April 2003

Radical polymerications including co‐ and terpolymerizations of a γ‐methylene‐Δα,β‐butenolide derivative, ethyl (E)‐5‐oxo‐2,5‐dihydrofuran‐2‐ylideneacetate(EODY) was investigated. The monomer had no homopolymerizability but copolymerized with styrene (ST) and 1,3‐cyclohexadiene to yield alternating copolymers. From IR and 1H‐NMR spectra of the copolymers, the 1,4‐addition was confirmed to exclusively occur for the conjugated double bond of EODY. Terpolymerization for the system involving an acceptor monomer such as maleic anhydride, α‐chloromaleic anhydride, or 7,7,8,8‐tetracyanoquinodimethane in addition to ST and EODY gave the terpolymer containing about 50 mol% of ST, in spite of a high fraction of ST in the feed. It was inferred that such an apparent behavior of EODY as an acceptor monomer could be due to a resonance‐stabilization of the propagating radical having EODY as a terminal unit, which is also responsible for the poor yields of the copolymers and terpolymers.
Soluble magnesium and titanium catalyst components for ethylene polymerization
Authors: Yano Takefumi , Ikai Shigeru , Washio Katsutoshi
Published: April 2003

The catalyst system comprised of a heptane solution of magnesiumoctoate‐H2O‐Tetrabutoxytitanium/diethylaluminumchloride was highly active for ethylene polymerization at a high temperature. High productivity for the catalyst system at a low temperature was achieved by the aging of the catalyst components. The effect of different orders of addition of the catalyst components on productivity was investigated to assume the role of each components in the formation of active species.
In‐situ poling and synthesis of NLO chromophore‐bearing polyurethanes for second harmonic generation
Authors: Kitipichai P. , La Peruta R. , Korenowski G. M. , Wnek G. E.
Published: April 2003

The preparation of six diol and one triol monomers bearing donor–acceptor chromophores is described. The monomers contain the N,N′‐bis(2‐hydroxyethyl)aniline unit with various acceptor groups attached in some cases via azo or olefin linkages, at the para position. Acceptors studied include nitro, tricyanovinyl, cyclobutene‐1,2‐dione, and imidazolidine‐2,4‐dione. Poled polymer films were prepared by thermal polymerization of these with 2,4‐toluenediisocyanate (TDI) in the presence of an electric field generated by a corona tip. The resulting thin (ca. 1 μm), glassy polymer films were shown to exhibit reasonably good second harmonic generation efficiencies. Preliminary results show that the polymers with higher Tg's have the best temporal stability. The polymer derived from the diol bearing an imidazolidine‐2,4‐dione acceptor shows only a ca. 30% decrease in its second harmonic generation (SHG) signal over 200 days at room temperature, even though it is not crosslinked. We attribute this to hydrogen bonding interactions from the urethane and imidazolidine‐2,4‐dione groups. A crosslinked film derived from the triol and TDI has an exceedingly stable SHG response at room temperature, and no decrease in the SHG response is observed at 100°C for a few hours. © 1993 John Wiley & Sons, Inc.
Synthesis of polymers bearing pendant norbornadiene moieties by addition reaction of poly(glycidyl methacrylate‐co‐methyl methacrylate)s with 2,5‐norbornadiene‐2‐carboxylic acids
Authors: Nishikubo Tadatomi , Kawashima Tatsuo , Watanabe Sadayuki
Published: April 2003

Polymers bearing photoresponsive norbornadiene (NBD) moieties were synthesized by the addition reaction of poly(glycidyl methacrylate‐co‐methyl methacrylate)s containing pendant epoxide groups with 3‐phenyl‐2,5‐norbornadiene‐2‐carboxylic acid (PNBC), 3‐[(phenyl)carbamoyl]‐2,5‐norbornadiene‐2‐carboxylic acid 3‐[(4‐acetylphenyl) carbamoyl]‐2,5‐norbornadiene‐2‐carboxylic acid (APCND), and 3‐[(4‐methoxyphenyl)carbamoyl]‐2,5‐norbornadiene‐2‐carboxylic acid using tetrabutylammonium bromide as a catalyst in DMF. The polymers bearing pendant PNBC or APCND moieties have higher photochemical reactivity in the film state than the polymers bearing pendant PCND or MPCND moieties. Although the pendant quadricyclane (QC) group produced by the photoirradiation of the PNBC moiety in these polymers has excellent storage stability in the film state, without catalyst at room temperature, the QC group in the polymer film with the catalyst reverts gradually to the NBD moiety at room temperature. © 1993 John Wiley & Sons, Inc.
Hexene‐1 polymerization by homogeneous zirconocene and heterogeneous‐supported TiCl3 catalysts
Authors: Chien James C. W. , Gong Ben Min
Published: April 2003

MgCl2‐supported TiCl3 catalysts, with and/or without electron donor modifier (internal Bi or external Be), were compared with rac‐ethylenebis(indenyl)zirconium dichloride (1) activated with either MAO or the cation forming agent, triphenyl carbenium tetrakis(pentafluorophenyl)borate (2), with triethylalumium (TEA). The activities of the heterogeneous catalysts depend on the presence or absence of the Lewis base, were relatively insensitive to the temperature of polymerization, and produce poly(hexene) with molecular weights up to 106. The 1/MAO catalyst has about five times higher activity at 50°C but is almost inactive at −30°C; the overall activation energy is 12.4 kcal mol−1. In contrast, the activity for hexene polymerization by the 1/2/TEA catalyst is actually slightly greater at lower temperature. The MW's of poly(hexene) obtained with the zirconocenium catalysts are only in the tens of thousands because of rapid β‐hydride elimination by the electrophilic cationic Zr center. © 1993 John Wiley & Sons, Inc.
One‐pot synthesis of nylon 6–clay hybrid
Authors: Kojima Yoshitsugu , Usuki Arimitsu , Kawasumi Masaya , Okada Akane , Kurauchi Toshio , Kamigaito Osami
Published: April 2003

Nylon 6–clay hybrid is a molecular composite of nylon 6 and uniformly dispersed silicate layers of montmorillonite. One‐pot synthesis of the hybrid was carried out by the following procedures. Montmorillonite was dispersed in water, and then ε‐caprolactam, acid (phosphoric acid, hydrochloric acid, benzenesulfonic acid, isophthalic acid, trichloroacetic acid, or acetic acid), and 6‐aminocaproic acid were added to the dispersion. The mixtures were reacted at 260°C for 6 h, yielding the nylon 6–clay hybrids (1potNCHs). X‐ray diffraction revealed that the silicate layers of 1potNCH by phosphoric acid were uniformly dispersed in the nylon 6 matrix. The 1potNCH had excellent mechanical properties. The strength and the modulus of the hybrid increased compared with previously reported nylon 6–clay hybrid (NCH) synthesized by montmorillonite intercalated with 12‐aminolauric acid. The heat distortion temperature (HDT) of the 1potNCH was 160°C, which was 8°C higher than that of NCH. In other 1potNCHs, montmorillonite had a smaller effect on the increase of those properties, and interlayer spacing of montmorillonite was observed at ca. 20 Å. © 1993 John Wiley & Sons, Inc.
Propenyl ethers. III. Study of the photoinitiated cationic polymerization of propenyl ether monomers
Authors: Crivello J. V. , Jo K. D.
Published: April 2003

The effects of photoinitiator structure and variations in the experimental parameters on the rate and extent of the photoinitiated cationic polymerization of propenyl ether monomers were studied. It was found that the photoinitiators can be divided into two classes: those which exhibit an induction period and those which do not. It was demonstrated that in those propenyl ether polymerizations using iodonium salts and certain sulfonium salts which do not have an induction period, a free radical chain‐induced decomposition of the onium salt takes place. The reactivity of a particular onium salt photoinitiator was shown to be related to its reduction potential. It was also shown that the structure of the monomer plays a major role in the free radical induced decomposition reaction. © 1993 John Wiley & Sons, Inc.
Stereospecific polymerization of butene‐1 with supported titanium catalyst
Authors: Diao Jianbo , Wu Qing , Lin Shangan
Published: April 2003

Butene‐1 was polymerized with a highly‐active supported titanium catalyst which was developed in this laboratory. The influences of various conditions (e.g., catalyst composition, temperature, external ester, H2, triethylaluminum, and catalyst concentration) on the catalytic activity, decay of polymerization rate, molecular weight, and isotacticity of the products were studied in detail. The structural properties of the PB‐1 were characterized by WAXD, DSC, and 13C‐NMR. It was found that the catalyst TiCl4, Ti(OBu)4/MgCl2/ethyl benzoate (EB)/Ph2SiCl2–AlEt3 shows high activity, i.e., 3.2 × 104 g PB/g Ti h. Isotacticity of the product was increased by adding p‐CH3C6H4COOEt into the catalytic system. Molecular weight of the product can be easily controlled by H2. The decay of polymerization rate with time fulfills the equation: Rt − Rs = (Ro − Rs)e−βt. © 1993 John Wiley & Sons, Inc.
Thermally polymerizable bisaryloxy‐bisimido‐bisphthalonitriles containing dimethylsilane, hexafluoroisopropylidene, ether, and keto groups: Synthesis, characterization, and NMR study
Authors: Kumar Devendra , Razdan Uday , Gupta Alka D.
Published: April 2003

A proton‐NMR study of the condensation reaction (step 1) of 4‐(3′‐aminophenoxy)phthalonitrile (4‐3′APPN) (I) in an aprotic solvent with various aromatic dianhydrides demonstrated the formation of the corresponding bisamic acid within 5–10 min. There was no effect of the electron affinity of the used aromatic dianhydrides on the time of the condensation reaction and also no charge‐transfer complex formation was indicated. Proton‐NMR study of the synthesized bisaryloxy‐bisimido‐bisphthalonitriles at 250.1 MHz has revealed general findings for their NMR characterization. The coupling constant (J) value for the ortho‐coupled protons of the phthalonitrile ring of the 4–3′‐APPN portion is 8.8 ± 0.05 Hz and that for the ortho‐coupled protons of the aminophenoxy ring of 4–3′‐APPN is 8.1 ± 0.05 Hz. The coupling constant (J) values for ortho‐coupled protons of the dianhydride portion range from 8.1 to 7.5 Hz. Various thermally polymerizable bisaryloxybisimido‐bisphthalonitriles (BBBP) (X, XI, XII, and XIII) containing dimethylsilane, hexafluoroisopropylidene, ether, and keto groups, suitable for the development of thermooxidative stable, void‐free composites, were synthesized by two methods. In method 1,4–3′‐APPN (I) in N,N‐dimethylacetamide (DMAC) was condensed (step 1) with bis(3,4‐dicarboxyphenyl)dimethylsilane dianhydride (SIDA) (II), 4, 4′‐hexafluoroisopropylidenediphthalic anhydride (6FDA) (III), bis(3,4‐dicarboxyphenyl)ether dianhydride (ODPA) (IV), and 3,4,3′,4′‐benzophenonetetracarboxylic dianhydride (BTDA) (V), respectively, to give the corresponding bisamic acids. Thermal cyclodehydration of the intermediate bisamic acid at 160°C gave the bisphthalonitriles. In method 2, the second step of thermal cyclodehydration was performed in situ in refluxing toluene. The characterization of the synthesized bisaryloxy‐bisimido‐bisphthalonitriles (BBBP) was performed using FT‐IR, 1H‐NMR, 13C‐NMR, mass spectroscopy, and elemental analysis. A preliminary study indicated that thermal‐polymerization of these bisphthalonitriles (BBBP) gave tough, thermosetting polymers, useful for high‐temperature applications. © 1993 John Wiley & Sons, Inc.
Hydrosilylation of allyl carbamates by poly(methylhydrosiloxane) and related side‐reactions
Authors: Yu Jian Ming , Teyssie Dominique , Boileau Sylvie
Published: April 2003

Hydrosilylation of allyl carbamates by poly(methylhydrosiloxane) (PMHS) catalyzed by platinum‐ or rhodium‐based complexes was investigated. About 10% of the carbamate molecules decompose during the hydrosilylation reaction through the cleavage of the carbamate bond. A redistribution process also takes place among the polysiloxane chains resulting in the formation of branched polymers but no crosslinking occurs. A mechanism for this side‐reaction is proposed. © 1993 John Wiley & Sons, Inc.
Novel preparation of electrically conducting poly (vinyl chloride) by photo‐dehydrochlorination from poly (vinyl chloride)/polypyrrole composite film
Authors: Ogura Kotaro , Yano Jun , Kisaka Kotaro , Goto Hideo
Published: April 2003

Polypyrrole (PPy) was deposited electrochemically on a platinum plate from a nitric acid solution of pyrrole. The PVC/PPy composite film was finally obtained by casting poly(vinyl chloride) (PVC) onto the PPy electrode from a tetrahydrofuran solution of PVC. The prepared composite film was irradiated at 90°C with a low‐pressure mercury lamp in the stream of hydrogen gas saturated with steam, and the PVC film was dehydrochlorinated, leading to the formation of conjugated polyene. The electrical conductivity (σ) of the PVC film in the irradiated composite film was reveled: σ=2.51 × 10−5S cm−1. By iodine doping, σ was further enhanced up to 5.04 X 10−3 S cm−1. The tensile strength of the irradiated composite film became larger than that of the original PVC film; i.e., the stress at break was: 461 (composite film); 401 kg cm−2 (PVC). These results were brought about by the doping of radical species to the conjugated polyene. The anion, NO−3, doped during the electrodeposition of PPy was photodecomposed to generate radical NO2 and this species was doped to the polyene, resulting in the formation of electrically conductive PVC and mechanically improved composite film. © 1994 John Wiley & Sons, Inc.
Syntheses of new poly (arylene vinylene) analogues: Poly (4,7‐benzofuran vinylene) and poly (4,7‐benzothiophene vinylene)
Authors: Sarker Ananda , Lahti Paul M. , Karasz Frank E.
Published: April 2003

The reaction of bis(4,7‐tetrahydrothiopheniomethyl) benzofuran dibromide with aqueous tetramethylammonium hydroxide leads to a water‐soluble polyelectrolyte which can be film cast and thermolytically eliminated to give poly(4,7‐benzofuran vinylene) (PBFV). Subjection of bis(4,7‐tetrahydrothiopheniomethyl) benzothiophene dibromide to the same reaction sequence gives poly(4,7‐benzothiophene vinylene) (PBTV). UV‐VIS studies show that PBFV has a band gap of 2.76 eV, while PBTV has a band gap of 2.92 eV. These polymers are members of a new class of conjugated poly (arylene vinylene)s, in which heterocyclic pseudoaromatic rings are fused onto a poly(1,4‐phenylene vinylene) backbone. © 1994 John Wiley & Sons, Inc.
Polyimides with alicyclic diamines. II. Hydrogen abstraction and photocrosslinking reactions of benzophenone‐type polyimides
Authors: Jin Qiu , Yamashita Takashi , Horie Kazuyuki
Published: April 2003

Photosensitive polyimides with alicyclic diamines and benzophenone moiety were prepared by reactions of 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) with diamines in aprotic solvents, followed by thermal or chemical imidizations. Among them the polyimide from BTDA and bis(4‐amino‐3‐methylcyclohexyl) methane (DMDHM) can be dissolved in several organic solvents such as dichloromethane, tetrachloroethane, and N‐methyl‐2‐pyrrolidone (NMP). In order to compare properties of the polyimides with alicyclic diamines with those of corresponding aromatic polyimides, the UV absorption spectra and fluorescence spectra of these polyimides and their model compounds were investigated. No occurrence of charge transfer at photoexcited states was ascertained for the polyimides with alicyclic diamines. The hydrogen abstraction and crosslinking during photoirradiation have been studied to learn the influence of the elimination of charge transfer process in these photosensitive polyimides. The quantum yield of hydrogen abstraction for the model compound of alicyclic polyimides is 0.56 in THF measured with HPLC. The quantum yield for the photocrosslinking reaction of the solvent‐soluble polyimide with alicyclic diamine, PI(BTDA/DMDHM), was determined to be 0.004 in air from gel permeation chromatography (GPC) measurement, which is four times higher than that for photosensitive polyimides with aromatic diamines. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of styrenic polymers with pendant pyrazole groups. II
Authors: Ameduri Bruno , Boutevin Bernard , Malek Fouad
Published: April 2003

The synthesis of styrenic monomers that have pyrazolic or bipyrazolic pendant groups is described. Their homopolymerization and their copolymerization with maleic anhydride (MA) and N‐(3‐acetoxy propyl) maleimide is reported. The monomers were prepared from the Williamson reaction between 2‐pyridine carbinol, hydroxy monopyrazole, hydroxy bipyrazole, and chloromethyl styrene. The homopolymerizations of such styrenic monomers were tried under different conditions, which led to low molecular weight polymers with a high polydispersity. However, alternating copolymers were obtained using maleic anhydride or N‐(3‐acetoxy propyl) maleimide as comonomers, as shown by 1H‐NMR, elemental analysis, and reactivity ratios r1 and r2. Furthermore, the hydrolysis of the acetate function of different copolymers was performed quantitatively. Unlike the acetoxy copolymers, such products do not have any glass transition temperature. Thermogravimetric investigations have shown that these copolymers exhibit good thermostability. © 1994 John Wiley & Sons, Inc.
Preparation, characterization, and mesophase formation of esters of ethylcellulose and methylcellulose
Authors: Guo J.‐X. , Gray D. G.
Published: April 2003

A range of mixed ether‐esters of cellulose was prepared from partially substituted ethylcellulose and methylcellulose. The 13C‐NMR analysis of ethylcellulose with a DS of 2.5 indicated that the hydroxyl groups at carbon six of anhydroglucose units were completely substituted. Acetylation of the ethylcellulose under different conditions yielded (acetyl) (ethyl) cellulose (AEC) samples with acetyl degree of substitution ranging from 0 to 0.5. Fully substituted (propionyl) (ethyl) cellulose (PEC) and (acetyl) (methyl) cellulose (AMC) were also prepared. Chiral nematic liquid crystals were formed in these mixed ester/ethers of cellulose in concentrated solutions of acidic solvents. The critical concentration for the phase separation of the cellulosic solutions depended on the nature of the substituent, the degree of substitution, and the solvent at a given temperature. Methylcellulose solutions in trifluoroacetic acid and dichloroacetic acid form chiral nematic liquid crystals with a left‐handed helicoidal structure. The acetylated methyl cellulose samples did not show the reversal of handedness with increasing acetyl content that was previously observed for the corresponding ethylcellulose samples. © 1994 John Wiley & Sons, Inc.
Synthesis of polyesters having quaternary ammonium groups in the side chains and preparation of their blends with poly(vinyl alcohol)
Authors: Wang Chonghui , Nakamura Shigeo
Published: April 2003

Triethyl‐2,3‐propanediolammonium chloride (TPC) was prepared and used for the preparation of polyester and copolyesters having quaternary ammonium groups in the side chains. The polycondensation of isophthaloyl dichloride with TPC and other dihydroxy compounds was performed by the organic phase/organic phase interfacial polycondensation method using N,N‐dimethylacetamide/n‐heptane or trimethyl phosphate/n‐heptane as reaction media in the presence of tetramethyl ethylenediamine. Blend films were prepared from these polyesters and poly(vinyl alcohol) by casting from aqueous or aqueous NaOH solution. The electrical conductivity of the blend films is remarkably affected by the moisture content and in the order of 10−5 ∼ 10−8 S/cm in the presence of moisture. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of poly(ethylene oxide‐co‐ethylene sulfone)s and their precursors: Poly(ethylene oxide‐co‐ethylene sulfide)s
Authors: Zhang Tianhong , Litt Morton H. , Rogers Charles E.
Published: April 2003

Three poly(ethylene oxide‐co‐ethylene sulfide)s with oxygen to sulfur ratios of 2/1, 2/2, and 1/2 were prepared by phase‐transfer catalyzed polycondensations of (1) sodium sulfide and 1,2‐bis (2‐chloroethoxy)ethane, (2) 1,2‐ethanedithiol and 1,2‐bis(2‐chloroethoxy)ethane, and (3) 1,2‐ethanedithiol and 2‐chloroethyl ether, respectively. A buffered solution with pH between the pKa of the monothiol (RSH) and the pKa2 of the dithiol (HS–R–SH), or H2S, was needed to obtain high molecular weight polymers, which suggests that nucleophiles transfer and react as monoanions rather than dianions. These poly(ethylene oxide‐co‐ethylene sulfide)s were oxidized completely to poly(ethylene oxide‐co‐ethylene sulfone)s using 3‐chloroperoxybenzoic acid as oxidant. Both the final polymers and the precursors have regular sequenced structures and are semicrystalline. As expected, their glass transition temperatures and melting points increase and solubilities decrease with the decrease of ether oxygen to sulfur ratio. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of poly(ester‐sulfone)s
Authors: Zhang Tianhong , Litt Morton H. , Rogers Charles E.
Published: April 2003

Aliphatic and aromatic‐aliphatic poly(ester‐sulfone)s were synthesized by the transesterifications of diphenyl adipate and diphenyl phthalates (ortho, meta, para) with two sulfonecontaining diols, 1,3‐bis (3‐hydroxypropylsulfonyl) propane (Diol‐333) and 1,4‐bis(3‐hydroxypropylsulfonyl) butane (Diol‐343). Based on DSC and WAXD studies, the aliphatic homopoly(ester‐sulfone)s are semicrystalline at room temperature and liquid crystalline at elevated temperature, while their copolymers with alkanediols are liquid crystalline. The liquid crystalline phase formation in aliphatic poly(ester‐sulfone)s is attributed to the strong dipole‐dipole interactions between sulfone groups. The aromatic‐aliphatic poly(estersulfone)s from diphenyl phthalate (ortho) and isophthalate (meta) are amorphous. They are soluble in trifluoroacetic acid and m‐cresol at room temperature, and DMF, DMAC, and DMSO at elevated temperature. The aromatic‐aliphatic poly(ester‐sulfone)s from diphenyl terephthalate are semicrystalline and are soluble only in trifluoroacetic acid. For a given diol, the glass transition temperatures of aromatic‐aliphatic poly(ester‐sulfone)s increase from phthalate to isophthalate to terephthalate. This is because the flexibility of the benzene ring in the polymer backbone decreases from ortho to meta to para substitution. As a comparison, polyesters without sulfone groups were synthesized from two alkanediols, 1,9‐nonanediol and 1,10‐decanediol, and the diphenyl esters. The poly(ester‐sulfone)s have glass transition temperatures 60–80°C higher than the corresponding polyesters without sulfone groups, due to the strong dipolar interactions between sulfone groups. © 1994 John Wiley & Sons, Inc.
Synthesis of graft polymers from an ozonized ethylene vinyl acetate copolymer (EVA). I. Study of the radical polymerization of styrene initiated by an ozonized EVA
Authors: Fargere Thierry , Abdennadher Mohamed , Delmas Michel , Boutevin Bernard
Published: April 2003

Polymers can be ozonized with an ozone/oxygen mixture to create peroxides and hydroperoxides on the polymer chain. These heat‐sensitive functional groups can be used to initiate radical polymerization of vinyl monomers and give graft copolymers. The properties of these copolymers are well described in literature; however, we notice that available data concerning decomposition rate constants are inconsistent. Decomposition rate measurements, time of assay of free radicals and stability of the ozonized polymers do not give the same results. In this work, we studied the kinetics of the styrene polymerization initiated by an ozonized ethylene vinyl acetate copolymer. Consequently, the f·kd product can be calculated (f is the efficiency and kd the decomposition rate constant). The ozonized copolymer is not similar to usual radical initiators. The initial viscosity of the solution has an important effect on the calculation of the kinetic values. Activation energy and Arrhenius coefficient are different than the one obtained for the usual initiators. © 1994 John Wiley & Sons, Inc.
Quantitative theory of iniferter polymerization. I. Kinetics
Authors: Kuchanov S. I.
Published: April 2003

On the basis of a rather general scheme of elementary reactions of radical polymerization conducted in the presence of iniferters, kinetic equations have been derived describing this process over the whole range of monomer conversion. Proceeding from thorough analysis of these equations, different regimes of polymerization have been found that differ in values of order with respect to the iniferter and monomer of the initial rate of polymerization. Conditions for kinetic parameters have been formulated whose fulfillment predetermines that radical polymerization occurs according to the iniferter mechanism. © 1994 John Wiley & Sons. Inc.
Synthesis of hydroxyl‐containing polyimides derived from 4,6‐diamino‐resorcinol dihydrochloride and aromatic tetracarboxylic dianhydrides
Authors: Moy T. M. , Mcgrath J. E.
Published: April 2003

High Tg polyimides containing pendant phenolic hydroxyl groups were synthesized in high molecular weight via one‐step solution polymerization of the dihydrochloride salt of 4,6‐diaminoresorcinol with various commercially available dianhydrides. Polymerization proceeds via initial dissociation of diaminoresorcinol dihydrochloride to hydrogen chloride gas and diaminoresorcinol, followed by rapid dissolution of diaminoresorcinol and polymerization with the dianhydride monomer to afford soluble, fully‐cyclized polyimide. The resulting poly(hydroxy‐imide)s, which contain two phenolic hydroxyl groups per repeat unit, were soluble in amide solvents and dilute aqueous bases, displayed reasonably high glass transition temperatures and a high degree of water uptake. © 1994 John Wiley & Sons, Inc.
Study on chain transfer to acetic anhydride of THF polymerization
Authors: Li Fang‐Xing , Wang Hong‐Jun , Li Chun‐Gang , Ma Ke‐Qin
Published: April 2003

In the presence of acetic anhydride, the catalyst containing protons makes the polymerization complex.1,2 Thus, whether the living center, during the polymerization process of THF, transfers to the acetic anhydride is a difficult problem to answer. In this article, CH3COSbCl6 is used as the catalyst to avoid the interference of the protons. It is found that acetic anhydride is an effective chain transfer agent, by the experiment at different temperatures for two systems in the presence or absence of acetic anhydride, and by the comparison of kinetic behavior. In the system without acetic anhydride at the temperature of 7, 15, and 22°C, the propagation rate constants of THF, kp are 7.90, 14.23, and 23.35 10−3L/Mol.S, respectively. In the presence of acetic anhydride, kp are 1.51, 2.85, and 4.98 10−3L/Mol.S; and ktr are 2.04, 3.59, and 6.49 10−4L/Mol.S, respectively. © 1994 John Wiley & Sons, Inc.
Novel polystyryl resins for size exclusion chromatography
Authors: Li W.‐H. , Stöver H. D. H. , Hamielec A. E.
Published: April 2003

New size exclusion chromatography (SEC) resins based on a crosslinker having independent vinyl groups have been produced and compared with SEC resins based on divinylbenzene‐55 (DVB). 1,2‐Bis(p‐vinylphenyl)ethane (p,p‐BVPE) and its meta‐isomers were suspension‐copolymerized with p‐methylstyrene in the presence of different porogens to give particles of about 5 μm average diameter. The porous particles were slurry‐packed into stainless steel columns for SEC evaluation. Calibration curves were obtained using narrow disperse polystyrene standards with molecular weights ranging from 580 to 3,040,000. The calibration curves for the new BVPE resins covered wider useful molecular weight ranges than those for comparable divinylbenzene resins. Particle size, surface morphology and the properties of pores were studied using a Coulter Multisizer II, scanning electron microscopy, nitrogen adsorption, and mercury porosimetry. © 1994 John Wiley & Sons, Inc.
Polymer‐supported Ziegler–Natta catalysts. II. Ethylene homo‐ and copolymerization with TiCl4/MgR2/poly(ethylene‐co‐acrylic acid) catalyst
Authors: Sun L. , Hsu C. C. , Bacon D. W.
Published: April 2003

A novel polymer‐supported titanium‐based catalyst shows high activity and nondecaying kinetic profiles for ethylene polymerization. The presence of 1‐hexene comonomer drastically increases the catalyst activity, exhibiting a similarity to the MgCl2‐supported catalysts. However, the nondecaying kinetic profiles of copolymerization distinguish this catalyst from the latter. Infrared analysis indicates that the transition metals were immobilized on the polymer support via functional groups. The effects of polymerization conditions on catalyst activity have been assessed. Characterization of the resulting polymer product by means of 13C‐NMR, DSC, and SEM demonstrates a branch‐free structure with high melting point, high crystallinity, and high molecular weight for the ethylene homopolymer. The reactivity ratios of ethylene‐1‐hexene copolymerization are evaluated from 13C‐NMR analysis data. © 1994 John Wiley & Sons, Inc.
Electrically conductive pseudo IPNs of linear poly(carbonate‐urethane) and crosslinked polychloroprene
Authors: Chen Z. J. , Xue Yongpeng , Frisch H. L.
Published: April 2003

A number of pseudo IPNs of poly(carbonate‐urethane) (PCU) and crosslinked polychloroprene (CR) have been synthesized and characterized. The single phase morphology of these novel pseudo IPNs has been confirmed by DSC measurements and electron microscopy. The room temperature electrical conductives of homopolymers and pseudo IPNs have been investigated for both undoped and iodine‐doped samples. © 1994 John Wiley & Sons, Inc.
Synthesis and radical crosslinking reaction of poly (vinylcyclopropanone acetal)s
Authors: Sanda Fumio , Takata Toshikazu , Endo Takeshi
Published: April 2003

Synthesis and radical crosslinking reaction of poly (vinylcyclopropanone acetal)s (4), volume change on the crosslinking, and thermal analysis of 4 and the crosslinked polymers were carried out. 4was prepared by the reaction of 1,1‐dichloro‐2‐vinylcyclopropane with sodium dialkoxides. Radical crosslinking of 4a was carried out in the presence of AIBN, BPO, or DTBP at 60, 80, or 120°C, respectively. 4a afforded no dichloromethane‐insoluble part in the crosslinking in chlorobenzene but afforded in 37% yield in bulk at 120°C. On the other hand, 4b afforded dichloromethane‐insoluble part in 33% yield in the crosslinking in chlorobenzene at 120°C. Volume shrinkage of 4a and 4b on crosslinking at 120°C was 4.11 and 3.55%, respectively. Glass transition temperatures of the crosslinked polymers obtained from 4a and 4b were 28 and 163°C, respectively, which were 32 ∼ 49°C higher than those before crosslinking. © 1994 John Wiley & Sons, Inc.