bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of amphiphilic polyisobutylenes‐b‐polyethylenamines by mannich reaction. II. Study of mannich reaction on model systems
Authors: Jamois Didier , Tessier Martine , Maréchal Ernest 
Published: April 2003

AbstractThe study of the reactions which take place when α‐methyl‐ω‐phenolpolyisobutylene is polycondensed with triethylenetetramine (TETA) and para‐formaldehyde (Mannich condensation) is carried out on model systems including monofunctional [2,4‐di‐tert‐butylphenol (A), dibutylamine (B), and dodecylamine (B′)] and difunctional reactants [4‐tert‐butylphenol (A′) and 1,6‐hexamethylenediamine (B″)]. With the exception of the A + B system which gives only Mannich condensation, all the systems including at least one difunctional reactant are characterized by side reactions which accompany the Mannich condensation. However, when one of the compounds is monofunctional (A + B;′ A′ + B′) only nonpolymeric molecules are formed; their structures were determined by 1H‐ and 13C‐NMR spectroscopy. On the other hand, when both reactants are bifunctional (A′ + B; A′ + TETA) polymers are formed whose monomer units were identified by comparison of their spectra with those of the nonpolymeric molecules. © 1993 John Wiley & Sons, Inc.
Preparation of amphiphilic polyisobutylenes‐b‐polyethylenamines by mannich reaction. III. Synthesis of polyisobutylenes‐b‐polyethylenamines
Authors: Jamois Didier , Tessier Martine , Maréchal Ernest 
Published: April 2003

AbstractCopolymers associating α‐phenololigoisobutylene and triethylenetetramine blocks in the same chain are prepared by reacting aqueous formaldehyde with α‐phenololigoisobutylene and triethylenetetramine. When para‐formaldehyde is used instead of monomeric formaldehyde, the reaction does not take place, contrary to what is observed when low molecular weight models are used instead of oligomers. The ability of these copolymers to disperse sludges in motor oil was evaluated by the “spot‐test” method. When oil does not contain water, the efficiency of the copolymers is comparable to that of commercial compounds. When oil contains water (1% w) the efficiency of the dispersive agent is drastically reduced. We show that this is due to the presence of phenol group. © 1993 John Wiley & Sons, Inc.
Degradable polymer blends. I. Screening of miscible polymers
Authors: Domb Abraham J. 
Published: April 2003

AbstractBlends of biodegradable polymers having properties distinct from the individual polymer components, and that are suitable for use as carriers of pharmaceutically active agents, were prepared from two or more polyanhydrides, polyesters, and mixtures of polyanhydrides and low molecular weight polyesters. The blends have different properties than the original polymers, providing a mean for altering the characteristics of the polymeric matrix without altering the chemical structure of the component polymers. Aliphatic, aromatic, and copolymers of polyanhydrides were miscible in each other and formed less crystalline compositions with a single melting point which was lower than the melting point of the starting polymers. The polyesters: poly(lactide‐glycolide), poly(caprolactone), and poly(hydroxybutyric acid) presented some miscibility in each other. However, the polyanhydrides were immiscible with the polyesters resulting in a complete phase separation both in solution or in melt mixing. Only low molecular weight polyesters (in the range of 2000) of lactide and glycolide, mandelic acid, propylenefumarate, and caprolactone presented some miscibility with polyanhydrides. Similarly, poly(orthoester) and hydroxybutyric acid polymers formed a uniform mixture with the anhydride polymers which had the two melting points of the original polymers. Drug release from polymer blends composed of poly(hydroxybutyric acid) or low molecular weight poly(lactic acid) with poly(sebacic anhydride) (PSA) showed a constant release of drug for periods from 2 weeks to several months as a function of the PSA content in the blend. Increasing the content of PSA, a fast degrading polymer, increases the release rate from the blend. © 1993 John Wiley & Sons, Inc.
Morphology of block copolyurethanes. IV. Effect of synthetic procedure on chain structure
Authors: Wang Tzong‐Liu David , Lyman Donald J. 
Published: April 2003

AbstractAnalysis of products formed in the end‐capping step during the synthesis of two block copolyurethanes being studied as biomedical materials has shown the presence of dimeric soft segments and free diisocyanate. In this standard two‐step synthesis, the presence of these compounds lead to block copolyether‐urethane‐ureas containing sizeable amounts of dimeric hard and soft segments. These standard copolymers are compared in terms of IR spectra, stress‐strain properties, and dynamic mechanical properties to their pure analogs which contain no dimeric segments. © 1993 John Wiley & Sons, Inc.
Fluorine substitutent effects on poly(2,6‐diphenylphenylene ether)
Authors: Yang Hu , Hay Allan S. 
Published: April 2003

AbstractA series of fluoro‐substituted poly(2,6‐diphenylphenylene ether)s (P3O) with systematically varied structures were prepared. The properties of the polymers change significantly with the variations in the polymer structures. By increasing the number of fluorine substituents on P3O polymer, the melting points and the tendency to crystallize for these polymers decrease significantly. Random copolymers from fluoro‐substituted 2,6‐diphenylphenols and 2,6‐diphenylphenol were also prepared. The influence of copolymer structure on the transition temperatures and crystallinity of the resulting copolymers is described. © 1993 John Wiley & Sons, Inc.
Equilibrium constants and the prediction of miscibility windows for polymer blends containing poly(tetrafluoroethylene‐alt‐vinyl alcohol)
Authors: Coleman Michael M. , Yang Xiaoming , Zhang Hongxi , Painter Paul C. , Scherer Kirby V. 
Published: April 2003

AbstractTheoretical calculations of miscibility windows for binary polymer blends in which one component is an essentially alternating copolymer of tetrafluoroethylene and vinyl alcohol (FVOH) are reported. FVOH has an inherently low solubility parameter [≈ 6.2 (cal. cm−3)0.5] that is outside the range commonly encountered in miscible polymer blends and thus represents a stringent test of the predictive capabilities of an association model we have used in previous work. The application of this model requires that we determine dimensionless equilibrium constants describing the self‐association of a model compound 3,4‐pentafluorobutan‐2‐ol (PFB) at 25°C from infrared spectroscopic data. Analogous equilibrium constants for FVOH were scaled from those of PFB by taking into account differences in the molar volume of the model and the specific repeat of the copolymer (see M. M. Coleman, J. F. Graf, and P. C. Painter: Specific Interactions and the Miscibility of Polymer Blends, Technomic, Lancaster, PA, 1991). Equilibrium constants describing the inter‐association of FVOH with ester type carbonyl groups were obtained from spectroscopic studies of miscible blends with poly(ethyl methacrylate). These equilibrium constant values were then used to calculate theoretical miscibility windows for the complete range of blends of FVOH with polymethacrylates, ethylene‐co‐methyl acrylate, styrene‐co‐methyl acrylate, and ethylene‐co‐vinyl acetate copolymers. Experimental results performed in our laboratories confirm the general validity of the predicted miscibility windows. © 1993 John Wiley & Sons, Inc.
Postcondensation and oxidation processes in molten polyamide 6
Authors: Marechal Ph. , Legras R. , Dekoninck J. M. 
Published: April 2003

AbstractPolyamide samples were heated under vacuum or mixed in a Brabender plastograph. UV absorbance, chain end concentration, and molecular weight were studied. Postcondensation was observed for polyamide heated under vacuum. For polyamide samples mixed in the plastograph, atmosphere, shear rate, and temperature changed. Melt viscosity and intrinsic viscosity are in good correlation in a log‐log plot. Oxidation effect on molecular weight and amine chain end concentration could be well related to UV absorbance. The oxygen diffusion into the molten polyamide is a critical parameter. The oxygen concentration in the polyamide mixed under air is ca. 20 times higher than when mixed under nitrogen. The introduction of preoxidized material in the molten polyamide or mixing in the presence of oxygen have similar effects. Postcondensation and oxidation strongly influence the melt behavior of polyamides. © 1993 John Wiley & Sons, Inc.
Soluble copolyimides with high modulus and low moisture absorption
Authors: Shiang William R. , Woo Edmund P. 
Published: April 2003

AbstractA series of transparent copolyimides were prepared from PMDA‐ODPA‐TFDB via chemical imidization of the corresponding poly(amic acid)s. Copolyimides containing less than 70% PMDA were completely soluble in DMAc and other amide solvents and gave ductile films with unexpectedly high tensile moduli (up to 8.9 GPa). Water absorption, after boiling in water for 72 h, were less than 1 % for the copolymer with 67% PMDA and less than 0.5% for copolymers with less PMDA. Thermooxidative stability was comparable to a commercial polyimide film up to 325°C. A copolyimide containing 34% PMDA had the best overall properties based on the above tests. Additional evaluations revealed a coefficient of linear expansion of about 6 X 10−6/°C, an essentially frequency independent dielectric constant of 2.8, a dissipation factor of about 0.004–0.01 over the range of 1–1000 kHz, and complete retention of tensile properties after exposure to a humid environment for 16 weeks. A model compound study suggests the probable presence of short blocks in these copolymers. © 1993 John Wiley & Sons, Inc.
Kinetics and mechanisms of emulsion polymerization initiated by oil‐soluble initiators. IV. Kinetic modeling of unseeded emulsion polymerization of styrene initiated by 2,2′‐azobisisobutyronitrile
Authors: Nomura M. , Ikoma J. , Fujita K. 
Published: April 2003

AbstractTo explain the kinetic features of particle formation and growth in unseeded emulsion polymerization initiated by oil‐soluble initiators, a mathematical kinetic model is proposed, based on the assumption that when initiator radicals or monomer radicals in the water phase enter monomer‐solubilized emulsifier micelles, initiate polymerization, and propagate to a chain length which is long enough not to desorb from the micelles, the micelles are regarded to be transformed into polymer particles. It is demonstrated by comparing the experimental results obtained in the emulsion polymerization of styrene initiated by the oil‐soluble initiator, 2,2'‐azobisisobutyronitrile, with sodium lauryl sulfate as emulsifier that the proposed kinetic model satisfactorily explains the kinetic features such as the effects of initial emulsifier, initiator, and monomer concentrations on both the number of polymer particles produced and the monomer conversion versus time histories. © 1993 John Wiley & Sons, Inc.
Synthesis and polymerization of 2‐alkylanilines
Authors: Bodalia R. , Stern R. , Batich C. , Duran R. 
Published: April 2003

Abstract2‐Alkylanilines with alkyl groups in the range of 4–15 carbon atoms were synthesized via a known method as well as via a more general path which should allow the introduction of a larger variety of substituted alkyl groups into the ortho position of aniline, e.g., alkenyl or OH, NH2, COOH, and phenyl functionality. Polymerization was found to be achievable according to a method previously described for unsubstituted aniline, i.e., chemically with Cu(ClO4)2 · 6H2O in acetonitrile. Intrinsic viscosities of the obtained poly(2‐alkylaniline)s lay between 0.10 and 0.26 dL/g (97% H2SO4 at 30°C). The dc conductivity of the HCl salts decreased with increasing length of the alkyl side chains from 1 S/cm (polyaniline) over 3 X 10−4 S/cm [poly(2‐butylaniline)] to 1 X 10−6 S/cm poly(tridecylaniline). Further characterization of the polymers were performed by means of UV/VIS/NIR‐and‐IR spectroscopy, in dilute solutions or as KBr pellets, respectively, and by solubility tests. © 1993 John Wiley & Sons, Inc.
Influence of the seed polymer on the chromatographic properties of size monodisperse polymeric separation media prepared by a multi‐step swelling and polymerization method
Authors: Hosoya Ken , Fréchet Jean M. J. 
Published: April 2003

AbstractMonodisperse polymer particle‐based separation media were prepared by a multi‐step swelling and polymerization method with two pairs of monomers and two porogenic solvents. Their chromatographic properties were compared to those of beads prepared by a corresponding suspension polymerization method without the use of seed polymer to ascertain the influence of the seed polymer on their porous structures. A large change in porous structure was observed when the swollen particle consisting of monomers and porogenic solvents contained at least one good solvent for the polystyrene seed polymer, allowing it to remain in the polymerizing medium. In contrast, when the polystyrene seed particle was excluded from the swollen oil droplets, due to its poor solubility in the monomers and the porogenic solvents, there was no difference in the chromatographic properties such as pore volume, pore size, pore size distribution, or retention selectivity between the multi‐step swelling and polymerization method and the suspension polymerization method. Since the only difference between the multi‐step swelling and polymerization method and the suspension method is the use of the seed polymer, it appears that a very small amount (< 1% v/v) of seed polymers in the enlarged swollen droplets plays an important role as a porogen and affects the porous structure as well as the chromatographic properties of the monodisperse polymer particle‐based separation media. © 1993 John Wiley & Sons, Inc.
Syntheses and properties of aromatic polyamides and polyimides derived from 9,9‐bis[4‐(p‐aminophenoxy)phenyl]fluorene
Authors: Yang Chin‐Ping , Lin Jiun‐Hung 
Published: April 2003

Abstract9,9‐Bis[4‐(p‐aminophenoxy)phenyl]fluorene (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 of 9,9‐bis(4‐hydroxyphenyl)fluorene withp‐chloronitrobenzene in the presence of K2CO3and then hydro‐reduced. PolyamidesIVa‐ghaving inherent viscosities of 0.73–1.39 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,N,N‐dimethylformamide, dimethylsulfoxide, andN‐methyl‐2‐pyrrolidone. 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 283–309°C and 10% weight loss occurred up to 460°C. The polyimides were synthesized from diamineIIand various aromatic dianhydrides via the two‐stage procedure that included ring‐opening poly‐addition in DMAc to give poly(amic acid)s, followed by thermal or chemical conversion to polyimides. The poly(amic acid)s had inherent viscosities of 0.62–1.78 dL/g, depending on the dianhydrides. Most of the aromatic polyimides obtained by chemical cyclization were found to be soluble in NMP. These polyimides showed almost no weight loss up to 500°C in air or nitrogen atmosphere. © 1993 John Wiley & Sons, Inc.
Interpenetrating polymer networks based on poly(chloroprene) and poly(carbonate‐urethane)
Authors: Xue Yongpeng , Frisch H. L. 
Published: April 2003

AbstractSimultaneous interpenetrating polymer networks (SIN's) of poly(chloroprene) (CR) and poly(carbonate‐urethane) (PCU) were prepared and characterized. The effect of composition on the phase morphology of full IPN's of CR/PCU has been studied by DSC and SEM. A single phase morphology of IPN's has achieved when the content of CR component is below 50 wt %. The microphase separation of the component networks in the IPN's occurred in samples whose weight percentage of the CR component was 50% and higher. © 1993 John Wiley & Sons, Inc.
Poly(aryl ether amide)s
Authors: Lucas M. , Brock P. , Hedrick J. L. 
Published: April 2003

AbstractA general method for the preparation of poly(aryl ether amide)s has been developed where the generation of an aryl ether linkage is the polymer‐forming reaction. The amide linkage was found to be sufficiently electron‐withdrawing to activate halo‐substituents towards nucleophilic aromatic substitution analogous to conventional activating groups (i.e., sulfone, ketone, etc.). Model reactions demonstrated that the amide‐activated displacement occurred with high selectivity in near quantitative yield and was judged suitable as a polymer‐forming reaction. Appropriately fluoro‐substituted amides were prepared and subjected to displacement polymerization with bisphenoxides in a N‐methyl‐2‐pyrrolidone (NMP)/N‐cyclohexyl‐2‐pyrrolidone (CHP) solvent mixture. High molecular weight polymers with glass transition temperatures in the 200–225°C range were obtained. © 1993 John Wiley & Sons, Inc.
Synthesis of substituted poly(1‐vinylpyrene)s and investigation of their fluorescent properties
Authors: Katritzky Alan R. , Zhu Dong‐Wei , Schanze Kirk S. 
Published: April 2003

AbstractA series of functionalized linear poly(1‐vinylpyrene) (PVP) polymers bearing substituents such as NO2, CHO, NH2, Br, and CHC(CN)2, were prepared by chemical modification of PVP in solution. The degree of substitution in PVPCHC(CN)2 was varied from 40% to nearly 100% by control of the reaction conditions. The other polymers were partially functionalized. The UV‐visible and fluorescence spectroscopy of the polymers were studied in solution. The influence of solvent polarity, excitation energy, and degree of substitution on the fluorescence of the polymers were examined. © 1993 John Wiley & Sons, In
The synthesis, characterization, and weathering behavior of polycarbonates derived from bis(P‐hydroxyphenyl) dimethylsilane (BPSI)
Authors: Factor A. , Engen P. T. 
Published: April 2003

AbstractPolycarbonates and copolycarbonates based on BPSi and BPA were easily made using the standard interfacial technique. Molecular weight and NMR data indicate that up to 4 mol % of the BPSi decomposes during polymerization via a base‐catalyzed rearrangement of BPSi to arylsiloxanes. Oxygen index studies show an increased flame resistance with increasing BPSi monomer content. DSC measurements show a decrease in glass transition with BPSi monomer concentration while TGA shows an increase in char residue with BPSi monomer content. In addition, TGA indicates no change in either thermal or thermooxidative stability with the relative BPSi/BPA concentrations. Outdoor weathering of BPSi PC and BPA PC films indicates that BPSi PC is ca. 5 times more weathering resistant than BPA PC. This latter result can be attributed to a combination of BPSi PC's lower UV absorptivity, higher water repellency, and lower likelihood for side chain photooxidation. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of novel epoxy monomers and liquid crystal thermosets
Authors: Mallon Joseph J. , Adams Paul M. 
Published: April 2003

AbstractFour new epoxy monomers have been synthesized and characterized as part of a program to prepare novel liquid crystal thermoset (LCT) materials. Three of the new epoxy monomers contained a biphenyl mesogen and were not liquid crystalline (LC). The remaining epoxy monomer, which contained a 1,4‐dibenzoyloxybenzene mesogen, was synthesized in an overall yield of 30% and displayed a broad (83°C) nematic liquid crystalline phase. The new liquid crystalline epoxy monomer was cured at 120°C and postcured at 175°C with a stoichiometric amount of 1,4‐phenylenediamine. The thermal transitions of the resulting LCT were studied by differential scanning calorimetry (DSC), polarized light optical microscopy (POM), thermomechanical analysis (TMA), and wide angle x‐ray diffraction (WAXD) as a function of cure time and temperature. A process characterization diagram was constructed which shows that LCTs based on this new LC monomer can be processed in the liquid crystalline phase over a broad range of times and temperatures. Qualitative agreement with previous epoxy LCT results was found, as LCT's with smectic phases and without clearing temperatures were observed at long cure times (high crosslink densities), whereas nematic phases with clearing temperatures predominated in networks at short cure times (low crosslink densities). © 1993 John Wiley & Sons, Inc.
Crosslinked polystyrene with improved mechanical properties
Authors: Sundell Mats J. , Pajunen Esko O. , Hormi Osmo O. E. , Nåsman Jan H. 
Published: April 2003

AbstractThe synthesis of some divinyl monomers—bis(vinylphenyl)ethane (2), bis(vinylbenzyloxy)hexane (3a), and bis(vinylbenzyloxy)dodecane (3b) is reported. Copolymers of the new monomers and styrene were evaluated as an alternative to divinylbenzene‐crosslinked polymers for use as matrices and absorbents. The mechanical properties and the amount of residual double bonds in the copolymers were compared. It was found that the new copolymers, unlike the divinylbenzene‐crosslinked polymers, retained their mechanical strength even at high crosslinking degrees. Stress at break values of 79, 68, and 18 N/mm2 were found for the polymers crosslinked with 20 mol % of 3a, 2, and divinylbenzene; 5, 25 and 45% of the divinyl units in these polymers were left as pendant double bonds. Porous styrene–2 copolymers were synthesized and shown to have lower surface areas than the corresponding divinylbenzene‐crosslinked polymers. The pore size distribution showed that this was due to the absence of the smallest pores which are found in the divinylbenzene‐crosslinked polymers in between heavily crosslinked nodules. © 1993 John Wiley & Sons, Inc.
Synthesis and polymerization of oligo(oxyethylene) macromonomer bearing sodium sulfonate
Authors: Zhang Sheng‐Shui , Liu Qing‐Guo , Yang Lei‐Ling 
Published: April 2003

AbstractOligo(oxyethylene) macromonomers bearing sodium sulfonate group have been synthesized through four reactions: (1) ring‐opening polymerization of oxirane, (2) etherification of monomethoxyl oligo(oxyethylene) and epichlorohydrin, (3) sulfonation of cycloxyl compound, and (4) end‐capping of sodium oligo(oxyethylene) sulfonate by methacrylic group. A desired length of oligo(oxyethylene) in the macromonomers can easily be achieved by controlling the ratio of reactants in the ring‐opening step. The structures of the products of each reaction were identified by IR, 1H‐NMR, and GPC. Polymers of the monomers were also characterized by GPC and DSC. © 1993 John Wiley & Sons, Inc.
Influence of HCL on polypyrrole films prepared chemically from ferric chloride
Authors: Ayad Mohamad M. 
Published: April 2003

AbstractSmooth, adherent films of the electrically conducting polypyrrole formed on surfaces in contact with unstirred aqueous solutions containing the pyrrole monomer and the oxidant, FeCl3. Contradictory reports in the literature concerning the influence of HCl on the growth rate and electrical conductivity of polypyrrole grown in this manner prompted this study of the growth rate and conductivity of films. With no intentional addition of HCl, the growth rate of the films, measured using a quartz crystal microbalance, was fit to a simple second‐order model in which the rate was limited by the bulk depletion of reactants. The conductivity of the films was found to be about 1 S cm−1. Both the growth rate and the electrical conductivity initially increased with the deliberate addition of HCl to the solution. The conductivity was found to peak at a value about 20 S cm−1 at an initial HCl concentration of 0.3 M. At initial HCl concentration of 2M or more, films could not be grown. © 1994 John Wiley & Sons, Inc.