bluuebunny/crossref_metadata_2025_split huggingface dataset:
Addition of chlorofluorocarbene to poly(1‐methyl‐1‐phenyl‐1‐sila‐cis‐pent‐3‐ene) and poly(1,1‐dimethyl‐1‐sila‐cis‐pent‐3‐ene): Characterization of chlorofluorocyclopropanated polymer microstructures by 1H‐, 13C‐, 19F‐, and 29Si‐NMR spectroscopy
Authors: Wang Liming , Liao Charles X. , Weber William P. 
Published: April 2003

AbstractChlorofluorocarbene, generated by the sodium iodide catalyzed decomposition of phenyl(dichlorofluoromethyl)mercury, adds to the carbon‐carbon double bonds of poly(1‐methyl‐1‐phenyl‐1‐sila‐cis‐pent‐3‐ene) (I) and poly(1,1‐dimethyl‐1‐sila‐cis‐pent‐3‐ene) (II) to yield poly(3,4‐chlorofluoromethylene‐1‐methyl‐1‐phenyl‐1‐sila‐cis‐pent‐3‐ene) (CIFC‐I) and poly(3,4‐chlorofluoromethylene‐1,1‐dimethyl‐1‐sila‐cis‐pent‐3‐ene) (CIFC‐II). Similarly, two series of random partially chlorofluorocyclopropanated polymers have been prepared. The microstructures of these adduct polymers have been determined by 1H‐, 13C‐, 19F‐, and 29Si‐NMR spectroscopy. The glass transition temperatures (Tg's) depend on the extent of chlorofluoropropanation of these polymers. These copolymers become less thermally stable as the extent of chlorofluorocyclopropanation increases. © 1993 John Wiley & Sons, Inc.
Thermogravimetric study of polyacrylamide with evolved gas analysis
Authors: Van Dyke John D. , Kasperski Kim L. 
Published: April 2003

AbstractDried samples of polyacrylamide in an He atmosphere have been subjected to thermogravimetric analysis in the 30–600°C range, and the evolved gases were monitored by FTIR. Water, ammonia, and small quantities of carbon dioxide are released in the first stages of decomposition (220–340°C), where the polymer chains remain intact and the reaction occurs on the pendant amide groups. In the second stage of decomposition (340–440°C), the majority of the weight loss occurs, and main chain breakdown occurs, releasing carbon dioxide, water, nitrile compounds, and imides. Trapping of the gases in this stage and analysis by GC–FTIR and GC–MS reveals the presence of more than 20 decomposition products, and confirms that a large proportion of these can be assigned to glutarimide and its substituted analogs. Imidization and dehydration reactions on the amide groups, as well as free radical breakdown of the main chains, with inter‐ and intramolecular hydrogen transfer, can account for many of the products of the decomposition. © 1993 John Wiley & Sons, Inc.
New epoxy‐terminated oligoesters: Precursors to totally biodegradable networks
Authors: Storey Robson F. , Hickey Timothy P. 
Published: April 2003

AbstractTwo types of novel biodegradable epoxy resins, carrying cycloaliphatic‐epoxy and glycidyl ester end‐groups, have been synthesized from hydroxy‐telechelic oligoesters. The cycloaliphatic‐epoxy end‐groups were based on either methyl cis‐4‐cyclohexene‐2‐(carboxylic acid)‐1‐carboxylate or 3‐cyclohexene‐1‐carboxylic acid. These compounds were reacted with hydroxy‐telechelic poly(ε‐caprolactone‐co‐D,L‐lactide) oligoesters, yielding cycloaliphatic‐olefin‐terminated oligomers. Conversion of the olefin to the epoxide groups was achieved using a phase transfer epoxidation with an inorganic peracid derived from the reaction of phosphoric acid, sodium tungstate, and hydrogen peroxide. Aliquat 336, a quaternary ammonium salt, acted as the phase transfer catalyst. Nearly theoretical conversion of hydroxy to epoxy end‐groups was achieved in only one case, however, alternative variations of this method of synthesis show promise. To prepare glycidyl ester‐terminated prepolymers, hydroxy‐telechelic poly(ε‐caprolactone) oligoesters were reacted with succinic anhydride, in 1,2‐dichloroethane with 1‐methylimidazole as catalyst, resulting in (carboxylic acid)‐terminated oligomers. After conversion of the end‐groups to the potassium carboxylate salt by titration with methanolic KOH, the isolated salt was dried and reacted with epibromohydrin in acetonitrile at reflux, using an 18‐C‐6 crown ether as the phase transfer catalyst, thus preparing the (glycidyl ester)‐telechelic prepolymer. Epoxide equivalent weights differed by 2.7–7.1% from the theoretical values. These cycloaliphatic‐epoxide and glycidyl ester‐terminated prepolymers may be crosslinked with anhydrides or amines, respectively, to produce totally bioabsorbable networks. © 1993 John Wiley & Sons, Inc.
Ultrastructure studies of polystyrene‐based side‐chain liquid‐crystalline copolymers containing charge transfer groups
Authors: Schleeh T. , Imrie C. T. , Rice D. M. , Karasz F. E. , Attard G. S. 
Published: April 2003

AbstractA series of new side‐chain liquid‐crystalline copolymers has been prepared, and the thermal properties of the individual copolymers have been determined. These copolymers are derived from atactic polystyrene and contain both 4‐methoxyazobenzene and 4‐nitroazobenzene mesogens; these are linked through octyl spacers to the polystyrene backbone. All the copolymers exhibit a smectic phase that has been assigned smectic A on the basis of polarizing microscopy and x‐ray diffraction studies. The glass transition temperatures of the polymers exhibit a linear dependence on composition, whereas the clearing temperatures and the associated entropies show significant deviations from such behavior. The smecticisotropic transition temperatures of the copolymers are higher than those of the composition‐weighted averages for the corresponding homopolymers, whereas the entropies of transition are lower than expected. X‐ray diffraction studies of fiber samples revealed that the director of the mesophase is oriented perpendicular to the fiber axis. The liquid‐crystalline polystyrene containing 25 mol % nitro‐substituted mesogen shows an unusual SA‐phase WAXS pattern. The copolymers were investigated further by 13C CP/MAS NMR spectroscopy, and the observed changes in the spectra are analyzed in terms of chemical composition and local electronic environment. The application of the interrupted decoupling technique revealed that the spacer contains a number of gauche defects. These observations lead us to suggest possible microstructural arrangements in the smectic phase. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of polymethylphenylsilane–polystyrene block copolymers
Authors: Demoustier‐Champagne S. , De Mahieu A.‐F. , Devaux J. , Fayt R. , Teyssie Ph. 
Published: April 2003

AbstractBlock copolymers of polymethylphenylsilane (PMPS) and polystyrene (PS) have been successfully prepared by the condensation of α,ω‐dichloro‐polymethylphenylsilane with polystyryl‐lithium. These new materials have been characterized by UV spectroscopy, 29Si‐NMR, and size exclusion chromatography. These block copolymers show a good emulsifying activity to compatibilize blends of the two homopolymers (PMPS and PS). © 1993 John Wiley & Sons, Inc.
Synthesis and properties of fluorinated telechelic macromolecular diols prepared by radical grafting of fluorinated thiols onto hydroxyl‐terminated polybutadienes
Authors: Ameduri Bruno , Boutevin Bernard , Nouiri Mustapha 
Published: April 2003

AbstractThe radical grafting of CnF2n +1 CH2CH2SH (n = 6,8) onto the double bonds of hydroxyl‐terminated liquid polybutadienes (HTPBD) was studied. Various methods for investigating the amount of grafting (titration of residual thiol and fluorine analysis) were used and compared. The nature and the amount of the initiator, the quantity of thiol, the temperature and the time of the reaction. the solvent, and the microstructure of HTPBD were optimized. The kinetic aspect showed that the thiol disappeared according to a first‐norder law. A method using up to 100% of grafting fluorinated mercaptan was described and standards were set up with fluorine contents of 5–59% to evaluate the physicochemical properties of these thioether group‐containing polymers: solubility, refractive index, intrinsic and dynamic viscosities, and thermal characteristics (glass transition and decomposition temperatures). Finally, the surface properties of these standards showed improvements of surface energy as low as 9 mN m−1 for a totally saturated fluorinated HTPBD. © 1993 John Wiley & Sons, Inc.
New three‐component initiation systems in UV curing: A time‐resolved laser‐spectroscopy investigation
Authors: Fouassier Jean‐Pierre , Ruhlmann Denis , Takimoto Yasuyuki , Harada Masahiko , Kawabata Masami 
Published: April 2003

AbstractAn investigation of the excited state processes in a three‐component initiating system based on a new ketone/amine/onium salt combination has been carried out for the first time. The results obtained through time‐resolved laser spectroscopy and the data gained in radical photopolymerization experiments suggest that the addition of an onium salt to the usual ketone/amine system mostly result in a decrease of the termination reaction of the growing macromolecular chains, thus allowing an increase of the rate of polymerization. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of poly(itaconate ester)s with etheric side chains
Authors: Coltrain Bradley K. , Ferrar Wayne T. , Salva John M. 
Published: April 2003

AbstractThe synthesis and characterization of poly(itaconate ester)s with short poly(ethylene oxide) side chains have been studied. It was found that the monomer syntheses via esterification of itaconic acid resulted in incomplete esterification leaving up to 35 mol % monomers with carboxylic acid functionality. These acid groups were then incorporated into the polymers. This acid incorporation has not previously been reported, nor have the properties of the copolymers been studied. Techniques were developed to effectively remove the acid impurities to generate pure homopolymers. Titration and gas chromatographic techniques were developed to study the amount of acid impurity in the monomers, and titration was also used to characterize the polymers. Size exclusion chromatography and differential scanning calorimetry were used to study both the homopolymers and copolymers. It was found that the location and breadth of the glass transition is a function of acid content. Finally, isomerization of the itaconate monomers to the inactive mesaconate was also found to be a problem during the synthesis. Pure mesaconate and citraconate monomers were synthesized and characterized by 1H‐NMR. © 1993 John Wiley & Sons, Inc.
The synthesis and characterization of amine‐terminated poly(aryl ether ketone)s as a function of side group and molecular weight
Authors: Bennett Greggory S. , Farris Richard J. 
Published: April 2003

AbstractIt is shown that amine‐terminated poly(aryl ether ketone)s based on the reaction of 4,4'‐difluorobenzophenone, and a substituted hydroquinone [either methylhydroquinone (MePK), t‐butylhydroquinone (tBPK), or phenylhydroquinone (PhPK)] of controlled molecular weight and high amine‐termination efficiency can be synthesized by a two‐step reaction technique. Attempts to synthesize analogous materials by a one‐step method were shown to be unsuccessful. The side groups are shown to have a large influence on the aromatic proton chemical shifts and this effect is characterized. The side groups and molecular weight are also shown to influence the thermal transitions of the respective polymers. The tBPK polymer possessed the highest glass transition temperature, while the MePK polymer was found to be the only semi‐crystalline polymer; a unit cell is proposed. The side groups and molecular weight effects are also characterized as a function of thermal stability and mechanical properties. © 1994 John Wiley & Sons, Inc.
Thermotropic copolyamides from triethyleneglycol bis(4‐carboxyphenyl)ether and two kinds of aromatic diamines
Authors: Higashi Fukuji , Zhang Wen Xion , Nakajima Kohji 
Published: April 2003

AbstractThermotropic copolyamides were prepared from triethyleneglycol bis(4‐carboxy‐phenyl)ether (PEG3) and two types of diamines, substituted p‐phenylenediamines and 4,4'‐diaminodiphenyls, and depression of melting point and isotropization temperature of the copolymers produced were measured as a function of diamine combination. The depression was not practically observed by the combinations of homologous diamines with several kinds and numbers of substituents, but significant by those of the diamines with different lengths of the mesogenic segments, and by the molar ratios of the diamines employed. The effect was discussed in terms of deviation of interchain hydrogen bonding between amide bonds in the main chain. © 1994 John Wiley & Sons, Inc.
Plasma deposition of thin films from a fluorine‐containing cyclosiloxane
Authors: Favia Pietro , Caporiccio Gerardo , D'Agostino Riccardo 
Published: April 2003

AbstractThin films have been deposited from radio‐frequency glow discharges fed with vapors of a silicon‐ and fluorine‐containing organic compound, namely 2,4,6‐tris[(3,3,3‐trifluoropropyl) (methyl)] cyclotrisiloxane, in mixture with argon.
magnified image2,4,6‐tris[(3,3,3‐trifluoropropyl)(methyl)]cyclotrisiloxaneA triode reactor has been utilized to deposit films by independently changing substrate temperature and bias‐induced ion‐bombardment. Laser interferometry, electron spectroscopy for chemical analysis and Fourier‐transform infrared spectroscopy have been used to monitor film growth rate and composition. Results unambiguously show an activating effect of the ion‐bombardment, which confirm the validity of the ion‐assisted deposition model utilized for the plasma deposition of both teflon‐ and silicone‐like films. In our experiments, low substrate temperature and bias conditions results in films with a “monomer‐like” stoichiometry, while drastic conditions give origin to materials with a completely different composition and a markedly increased hardness. © 1994 John Wiley & Sons, Inc.
Synthesis and properties of polyoxyarylenesiloxanes
Authors: Nye Susan Adams , Swint Sandra A. 
Published: April 2003

AbstractHigh molecular weight polymers containing oligosiloxanes in the backbone were made by the reaction of aromatic diols with α,ω‐diaminosiloxane homologs. The glass transition temperatures dropped by 30–40°C in a homologous series with each siloxane added. The thermal stability also suffered when increasing the number of siloxane groups. The polymers all displayed high % char measurements and one polymer (disiloxane) tested had a V0 rating by UL‐94 testing. The trisiloxane‐containing polymer had a high percent elongation at break (>300%). All the polymers tested were fairly susceptible to hydrolysis. © 1994 John Wiley & Sons, Inc.
Polymerization kinetics and volume relaxation behavior of photopolymerized multifunctional monomers producing highly crosslinked networks
Authors: Anseth Kristi S. , Bowman Christopher N. , Peppas Nikolaos A. 
Published: April 2003

AbstractMultifunctional monomers (trimethylol propane trimethacrylate, trimethylol propane triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol monohydroxy pentaacrylate) were photopolymerized with 2,2‐dimethoxy‐2‐phenylacetophenone as the photoinitiator to produce highly crosslinked networks. The volume shrinkage behavior and the reaction kinetics were studied under various reaction conditions. The volume shrinkage and maximum functional group conversion were dependent on the number of functional groups, type of functional group, and the curing conditions. The maximum functional group conversion was also dependent on the reaction temperature. All the polymerized systems exhibited a strong coupling between the volume relaxation and the reaction kinetics. The kinetic constants were also determined as a function of conversion, and the termination mechanism was found to be reaction diffusion dominated even at low conversions. The importance of these results on the prediction of the reaction behavior for multifunctional monomers producing highly crosslinked polymers is discussed. © 1994 John Wiley & Sons, Inc.
Whiskers. VII. Homo‐ and copolyesters of 6‐hydroxythioxanthone‐2‐carboxylic acid
Authors: Kricheldorf Hans R. , Adebahr Thorsten 
Published: April 2003

Abstract6‐Hydroxythioxanthone‐2‐carboxylic acid (HTCA) was prepared from commercial dimethylnitroterephthalate via 2‐(4'‐hydroxythiophenyl) terephthalic acid. HTCA was acetylated and polycondensed in an inert reaction medium at 350 or 400°C. An insoluble and infusible, highly crystalline polyester was obtained, which did not form whisker‐like crystals. Furthermore, copolyesters with 4‐hydroxybenzoic acid (4‐HBA) were synthesized and whiskers were obtained at a molar ratio of 1 : 9 (in favor of 4‐HBA). A meltable, nematic copolyester was prepared by cocondensation of silylated 6‐acetoxythioxanthone‐2‐carboxylic acid and silylated 4‐acetoxybenzoic acid in bulk. © 1994 John Wiley & Sons, Inc.
NMR study of PMR‐15 prepolymerization steps
Authors: Milhourat‐Hammadi A. , Chayrigues H. , Merienne C. , Gaudemer A. 
Published: April 2003

AbstractVariations in PMR‐15 composites properties could be due to differences in their chemical compositions occurring during the curing cycle. Variations in the composition of the PMR‐15 resin were studied for four different curing cycles, to determine the influences of parameters such as the heating rate or the presence of a temperature stage. The resin mixture was sampled at the same four different temperature points in each cycle and analyzed mainly by 1H‐ and 13C‐NMR. Quantitative analysis of the different chemical species were realized by deconvolution of NMR spectra. At a given temperature, the resin contains the same molecules but in proportions which depend on the curing conditions and which reflect differences in the chemical reactivity of the monomeric species. We have precisely defined the temperature ranges at which each of the key reactions (amidization, imidization, exoendo isomerization) occurs. An imine condensation product of NE and MDA has been identified and shown to be present in the resin mixture even at low temperature. As a result of this study, two possible causes of resin alteration during ageing can be put forward: the presence of nonimidized BTDE moieties and the endo‐exo isomerization reaction which will result in deformation and, possibly, microcracking, if reticulation of the end‐capped nadimides is not total. © 1994 John Wiley & Sons, Inc.
Synthesis of functional polymers bearing cyclic carbonate groups from (2‐oxo‐1,3‐dioxolan‐4‐yl) methyl vinyl ether
Authors: Nishikubo Tadatomi , Kameyama Atsushi , Sasano Mikio 
Published: April 2003

Abstract(2‐Oxo‐1,3‐dioxolan‐4‐yl) methyl vinyl ether (OVE) was synthesized with high yield by addition reaction of glycidyl vinyl ether with carbon dioxide using tetrabutylammonium bromide (TBAB) as a catalyst. OVE was also prepared by reaction with β‐butyrolactone or sodium hydrogencarbonate in the presence of TBAB as the catalyst. Poly [(2‐oxo‐1,3‐dioxolan‐4‐yl) methyl vinyl ether] [P(OVE)] was obtained with high yield by cationic polymerization of OVE catalyzed using boron trifluoride diethyl ether complex in dichloromethane. Polymers bearing pendant 5‐membered cyclic carbonate groups were also prepared by radical copolymerization of OVE with some electron‐accepting monomers. Furthermore, addition reaction of P(OVE) with alkyl amines yielded the corresponding polymer having pendant 2‐hydroxyethyl carbamate residue with high conversions. © 1994 John Wiley & Sons, Inc.
Syntheses and properties of aromatic polyamides and polyimides based onN‐phenyl‐3,3‐bis[4‐(p‐aminophenoxy) phenyl] phthalimidine
Authors: Yang Chin‐Ping , Lin Jiun‐Hung 
Published: April 2003

AbstractN‐Phenyl‐3,3‐Bis[4‐(p‐aminophenoxy)phenyl] phthalimidine (II) was used as a monomer with various aromatic dicarboxylic acids and tetracarboxylic dianhydrides to synthesize polyamides and polyimides, respectively. The diamineIIwas derived by a nucleophilic substitution ofN‐phenyl‐3,3‐bis(4‐hydroxyphenyl) phthalimidine withp‐chloronitrobenzene in the presence of K2CO3and then hydro‐reduced. PolyamidesIVa‐ghaving inherent viscosities of 0.55–1.64 dL/g were prepared by the direct polycondensation of the diamineIIwith various aromatic diacids using triphenyl phosphite and pyridine as condensing agents. All the aromatic polyamides were amorphous and readily soluble in various polar solvents such asN,N‐dimethylacetamide (DMAc),N,N‐dimethylformamide, dimethylsulfoxide, andN‐methyl‐2‐pyrrolidone (NMP). Transparent and flexible films of these polymers could be cast from the DMAc solutions. These aromatic polyamides had glass transition temperatures in the range of 293–319°C and 10% weight loss occurred up to 480°C. The polyimides were synthesized from diamine II and various aromatic dianhydrides via the two‐stage procedure that included ring‐opening polyaddition in DMAc to give poly(amic acid)s, followed by thermal or chemical conversion to polyimides. Most of the aromatic polyimides obtained by chemical cyclization were found to be soluble in NMP,m‐cresol, ando‐chlorophenol. These polyimides showed almost no weight loss up to 500°C in air or nitrogen atmosphere. © 1994 John Wiley & Sons, Inc.
Polyisobutylene‐containing block polymers by sequential monomer addition. X. Synthesis of poly(α‐methylstyrene‐b‐isobutylene‐b‐α‐methylstyrene) thermoplastic elastomers
Authors: Tsunogae Yasuo , Kennedy J. P. 
Published: April 2003

AbstractPreparatory to triblock synthesis experiments, the cationic polymerization of α‐methylstyrene (αMeSt) was investigated using the 2‐chloro‐2,4,4‐trimethylpentane (TMPCI)/TiCl4 initiating system in the presence of triethylamine (Et3N) as electron donor (ED) and CH3Cl/n‐hexane mixed solvent in the −80 to −40°C range. Conversions are influenced by temperature, [TiCl4], [Et3N], and [αMeSt]. The polymerization of αMeSt is living at −80°C: Both termination and chain transfer to monomer are frozen out, however, initiation is slow relative to propagation. Highly syndiotactic (>94%) Pα Mest was obtained. At−60deg;C initiator efficiency is ca. 100%, but termination becomes evident. Et3N may act both as Ed and as proton scavenger. Novel poly(α‐methystyrene‐b‐isobutylene‐b‐α‐methylstyrene) (PαMeSt‐PIB‐PαMeSt) triblocks have been synthesized by adding αMeSt to biliving polyisobutylene carbocations (⊕PIB⊕) in the −80 to −40°C range. The effects of temperature, solvent polarity, and [Et3N] on the block copolymerization have been investigated. At −80°C, the rate of crossover from ⊕PIB⊕ to αMeSt is lower than that of propagation of PαMeSt⊕, so that the triblock is contaminated by PIB and PIB‐b‐PαMeSt. At −60°C, crossover occurs preferentially. The rate of propagation relative to that of crossover is also reduced by lowering the solvent polarity and increasing the [Et3N]. High crossover efficiency and blocking efficiency can be obtained under optimum blocking conditions. The triblocks are novel thermoplastic elastomers (TPEs). © 1994 John Wiley & Sons, Inc.
Electrically conductive composite prepared by template polymerization of pyrrole into a complexed polymer
Authors: Mohammadi A. , Paul D. W. , Inganäs O. , Nilsson J. O. , Lundström I. 
Published: April 2003

AbstractElectrically conducting polymer composite films have been synthesized by the exposure of poly(4‐vinylpyridine) complexed with cupric ions to pyrrole and water vapor. To immobilize a stoichiometric amount of the oxidant inside the polymer matrix, the ratio of poly(4‐vinylpyridine)/cupric ion = 1.8 was chosen. Polypyrrole was formed in this tailored structure by a template polymerization process. Opaque polymer composite films with electrical conductivity up to 60 (Ω cm)−1 have been obtained by this method, However, slightly colored transparent composite thin films with a conductivity as high as 50 (Ω cm)−1 were also produced. The electrically conducting polymer composite films and the metal‐polymer complex have been characterized by XPS and IR spectroscopy, elemental analysis, EDX, and scanning electron microscopy. The polymerization process was also followed by use of a quartz crystal microbalance. © 1994 John Wiley & Sons, Inc.