bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymeric phosphonium salts as a novel class of cationic biocides. III. Immobilization of phosphonium salts by surface photografting and antibacterial activity of the surface‐treated polymer films
Authors: Kanazawa Akihiko , Ikeda Tomiki , Endo Takeshi 
Published: April 2003

AbstractImmobilized polycationic biocides with phosphonium salt on the surface of poly(propylene) film were prepared by surface photografting and surface antibacterial activity of the resulting films against Staphylococcus aureus and Escherichia coli was explored by the viable cell counting method. These films with phosphonium salts were found to exhibit high antibacterial activity against S. aureus and E. coli—particularly against E. coli. Furthermore, morphological changes of the cells of S. aureus and E. coli in contact with the immobilized phosphonium salt were estimated by scanning electron microscopy. It was found that the immobilized biocides exhibited surface bactericidal activity against both strains as evidenced by shrunken and deformed cells of these species in contact with the immobilized biocides. © 1993 John Wiley & Sons, Inc.
One‐phase supported titanium‐based catalysts for polymerization of ethylene. II. Effect of hydrogen
Authors: Salajka Zdenĕk , Kratochvíla Jan , Hudec Pavel , Vĕc̆orek Petr 
Published: April 2003

AbstractThe relation between composition of the one‐phase titanium‐based silica supported catalysts for gas‐phase ethylene polymerization, and the ability of these catalysts to control the molecular weight of polymer using hydrogen has been studied. Halogen containing alkylaluminium compounds and alkoxy groups on titanium promote the chain transfer process. A significant polymerization rate lowering effect is caused by hydrogen. However, catalyst activity fully revives after hydrogen removal from the polymerization system. The proportion of active titanium was found to be 18±4% in the presence of hydrogen, and the value of propagation rate constant (kp) was calculated to be 190±45 L/mol.s. © 1993 John Wiley & Sons, Inc.
Polymerization behavior of 1,2,2,6,6‐pentamethyl‐4‐piperidinyl m‐isopropenyl‐α,α‐dimethylbenzyl carbamate
Authors: Lau Wayne W. Y. , Lee C. S. , Lee S. Y. , Goh S. H. 
Published: April 2003

AbstractCopolymers of 1,2,2,6,6‐pentamethyl‐4‐piperidinyl m‐isopropenyl‐α,α‐dimethylbenzyl carbamate (CB) with styrene (S) and with methyl methacrylate (MMA) were synthesized using AIBN as initiator. S–CB copolymers made from feed ranging from 0.45–0.94 mole fractions S and MMA‐CB copolymers made from feed of 0.34–0.88 mole fractions MMA were used to determine the monomer reactivity ratios r1 and r2. The structure of S–CB copolymers was inferred to be mainly of a random nature and in the MMA–CB copolymerization system there is a stronger tendency to form alternating copolymers. © 1993 John Wiley & Sons, Inc.
Introduction of 2‐methoxycarbonylallyl end group by copolymerization of methyl α‐(phenoxymethyl)acrylate accompanying with addition‐fragmentation reaction
Authors: Yamada Bunichiro , Kobatake Seiya , Satake Masayuki , Otsu Takayuki 
Published: April 2003

AbstractCopolymerizations of methyl α‐(phenoxymethyl)acrylate (MPMA) with methyl acrylate, methyl methacrylate, styrene, and methyl α‐ethylacrylate were carried out. Addition of a polymer radical to MPMA followed by the subsequent fragmentation of poly(MPMA) radical resulted in the 2‐methoxycarbonylallyl end group and phenoxy radical in the course of the copolymerization. The extent of the fragmentation determined by 1H‐NMR spectroscopy depends on reactivity of the MPMA radical toward the reference monomers. An increase in the addition rate of the MPMA radical to the reference monomer brought about suppression of the fragmentation. The addition of the MPMA radical to styrene seems to be sufficiently fast to prevent the fragmentation. Since the rate of the fragmentation relative to the propagation was considerably accelerated by raising the temperature to 110°C, MPMA can be used as a novel chain transfer agent to control molecular weight and end group at a temperature above 100°C. © 1993 John Wiley & Sons, Inc.
Synthesis and properties of novel aromatic polyamides derived from 1,5‐bis(4‐aminophenoxy)naphthalene and aromatic dicarboxylic acids
Authors: Yang Chin‐Ping , Chen Wen‐Tung 
Published: April 2003

AbstractA new bis(phenoxy)naphthalene‐containing diamine, 1,5‐bis(4‐aminophenoxy)naphthalene, was synthesized in two steps from the condensation of 1,5‐dihydroxy‐naphthalene with p‐chloronitrobenzene in the presence of potassium carbonate, giving 1,5‐bis(4‐nitrophenoxy)naphthalene, followed by hydrazine hydrate/PdC reduction. A series of polyamides and copolyamides were synthesized by the direct polycondensation of the diamine with various aromatic dicarboxylic acids or with mixed dicarboxylic acids in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. The polymers having inherent viscosity of 0.81–1.25 dL/g were obtained in quantitative yield. Most of the polymers were generally soluble in aprotic solvent such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, etc. The polymers derived from rigid dicarboxylic acids such as terephthalic acid, naphthalene dicarboxylic acid, and 4,4′‐biphenyldicarboxylic acid exhibited crystalline patterns. Glass transition temperatures of polymers were in the range of 230–360°C, and 10% weight loss temperatures in nitrogen and air were above 492 and 470°C, respectively. © 1993 John Wiley & Sons, Inc.
Design of monomers for nonshrinking polymerizations, and synthesis of some N, S‐analogs of spiroorthocarbonates
Authors: Millich F. , Eick J. D. , Jeang L. , Byerley T. J. 
Published: April 2003

AbstractThe design of spiroorthocarbonate monomers (SOCs) and related structures is discussed with the aim of maximizing monomer polymerizability in the absence of undesirable byproducts. The successful syntheses of N,S‐analogs of aryl‐ and alkaryl‐SOCs are reported; these are monomers of structure
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where P and Q are O and OC(CH3)2−, mp 156–158°C; and P and Q are OCH2 and OCH2, mp 148–150°C. As is indicated by infrared spectra, the polymerization of both monomers is initiated by boron trifluoride etherate. © 1993 John Wiley & Sons, Inc.
Interaction between Na+ and polymer in aqueous solution of sodium salts of poly(2‐hydroxyethyl methacrylate‐co‐methacrylic acid) studied by 23Na‐NMR
Authors: Song Jin Deog , Jhon Mu Shik 
Published: April 2003

AbstractThe interaction between Na+ and polymer was studied by 23Na‐NMR for the aqueous solution of P(HEMA‐co‐MAANa), sodium salt of poly(2‐hydroxyethyl methacrylate‐co‐methacrylic acid), as a function of the polymer concentration, charge density of the polymer chain, and temperature. The NMR line width of 23Na‐NMR in 1% (w/v) aqueous solution of the P(HEMA‐co‐MAANa) narrowed with increasing temperature due to the rapid exchange of Na+ between free and polymer‐bound states with a rate of exchange exceeding the quadrupolar relaxation rate in the latter state. At high concentrations of the polymer above 1.0% (w/v) at 298 K, the 23Na‐NMR relaxation fits for a single Lorentzian due to the rapid exchange between two Na+ states. However, it follows a biexponential decay of magnetization in dilute solutions of polymer. The biexponential decay character of relaxation increased with the increase of the fraction of the MAANa monomer unit on the polymer chain. This feature of 23Na‐NMR relaxation was used to deduce the correlation time (τc), the degree of binding (pB), and the quadrupole coupling constants (X) of the polymer‐bound counterion. The χ and τc values show that the mobilities of the polymer chain are correlated with the motion of Na+ in aqueous solution of the polymer and there is a small degree of the specific binding between COO− and Na+. No evidence in support of the intramolecular conformational change by the charge density variation in P(HEMA‐co‐MAANa) was obtained. © 1993 John Wiley & Sons, Inc.
Preparation and properties of poly(alkyl vinyl ether‐2‐ethyl‐2‐oxazoline) diblock copolymers
Authors: Liu Q. , Konas M. , Davis R. M. , Riffle J. S. 
Published: April 2003

AbstractA method for the synthesis of well‐defined poly(alkyl vinyl ether–2‐ethyl‐2‐oxazoline) diblock copolymers with hydrolytically stable block linkages has been developed. Monofunctional poly(alkyl vinyl ether) oligomers with nearly Poisson molecular weight distributions were prepared via a living cationic polymerization method using chloroethyl vinyl ether together with HI/ZnI2 as the initiating system and lithium borohydride as the termination reagent. Using the resultant chloroethyl ether functional oligomers in combination with sodium iodide as macroinitiators, 2‐ethyl‐2‐oxazoline was polymerized in chlorobenzene/NMP to afford diblock copolymers. A series of poly(methyl vinyl ether–2‐ethyl‐2‐oxazoline) diblock materials were found to have polydispersities of ≈ 1.3–1.4 and are microphase separated as indicated by two Tg's in their DSC thermograms. These copolymers are presently being used as model materials to study fundamental parameters important for steric stabilization of dispersions in polar media. © 1993 John Wiley & Sons, Inc.
Synthesis, characterization, and chiroptical property of optically active poly(urea‐urethane)s
Authors: Chen Yun , Tseng Hsien‐Hsiung 
Published: April 2003

AbstractFive new optically active poly(urea‐urethane)s were synthesized by solution polyaddition of (1S,2S)‐(+)‐2‐amino‐3‐methoxy‐1‐phenyl‐1‐propanol (4) with diisocyanates (diphenylmethane‐4,4′‐diisocyanate, toluene‐2,4‐diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, m‐xylylene diisocyanate) at 80°C for 60 h. In some cases, the reaction mixture transformed into a gel when cooled to room temperature. The reduced viscosities are between 0.14 and 0.63 dL/g depending on the solvents and diisocyanates. Thermal behaviors of these polymers were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The Tg and crystallization temperature (Tc) were in the range of 80–200°C and 220–238°C, respectively. Thermal decomposition started at about 275°C, and the residual weights at 400°C were 15–60% depending on the polymers. The conformation of the polymers in film state was studied by circular dichroism (CD) spectra, by comparison with the corresponding model compounds which were synthesized from 4 and phenyl isocyanate or propyl isocyanate. Polymers derived from aromatic diisocyanates formed as ordered conformation in the film state, while those from aliphatic diisocyanates did not. After packing as chiral stationary phases of high‐performance liquid chromatography (HPLC), the polymers showed selective resolution to trans‐stilbene oxide and trans‐1,2‐cyclopentanedicarboxanilide. © 1993 John Wiley & Sons, Inc.
The effect of ionic electrolytes on hydrolytic degradation of biodegradable polymers: Mechanical and thermodynamic properties and molecular modeling
Authors: Pratt Lawrence , Chu Caryn , Auer Jeff , Chu Alfred , Kim Jennifer , Zollweg John A. , Chu C. C. 
Published: April 2003

AbstractThe purpose of this study was to examine the effect of electrolytes on the hydrolytic degradation of synthetic biodegradable polymers and fibers. Both Polyglycolic acid (PGA) and poly(glycolide–lactide) copolymer (PGL) were used for the study. Four different electrolytes were used: NaCl, LiCl, MgCl2, and ZnCl2. The electrolyte effect was evaluated in terms of the change in tensile properties, water uptake, and surface morphology of the polymers and fibers. It was found that the NaCl and MgCl2 solutions significantly retarded the hydrolytic degradation of both PGA and PGL as evidenced in the prolonged retention of tensile breaking strength of these fibers when compared to deionized water control. Increasing the concentration of the electrolyte retarded the hydrolytic degradation rate further. These mechanical property data agreed well with the rate and amount of water uptake of PGA and could be correlated with the chemical potential difference of water between the electrolyte solution and pure water. The effect of electrolyte was further analyzed by theoretical calculation. Semiemperical molecular orbital calculations indicated that hard cations like Mg, Li, and Zn strongly coordinated to the polar sites of the polymer chain segments (CO) and severely disrupted their solvation spheres. Such a disruption was reflected in the smaller amount and slower rate of water uptake by PGA, and thus a slower rate of hydrolytic degradation as evident in the retention of tensile breaking strength. © 1993 John Wiley & Sons, Inc.
Fully aromatic thermotropic liquid crystalline polyesters of substituted 4,4′‐biphenols. IV. Homopolyesters with terephthalic acid and copolyesters with terephthalic acid and 4‐hydroxybenzoic acid
Authors: Bhowmik Pradip K. , Lenz Robert W. 
Published: April 2003

AbstractA series of fully aromatic thermotropic polyesters based on mono‐, di‐, and tetra‐substituted biphenols was prepared by the melt polycondensation method and examined for their thermotropic behavior by a variety of experimental techniques. The homopolyesters obtained from substituted biphenols containing either one phenyl or two phenyl groups as substituent(s) and TA formed nematic melts, but the homopolymers of the substituted biphenols containing either four sec‐butyl groups or two tert‐butyl groups with TA had melting transitions, Tm, above 400°C. Thus, it was not possible to determine whether they formed nematic melts. On copolymerization with 30 mol % HBA most of the resulting copolyesters had much lower Tm values, compared to those of respective homopolyesters, and the copolymers of the biphenol monomer containing the tert‐butyl groups formed a nematic melt at an observable temperature. However, the copolymer of the biphenol with sec‐butyl groups still had a Tm above 400°C. © 1993 John Wiley & Sons, Inc.
Ethylene–vinyl acetate semi‐batch emulsion copolymerization: Use of factorial experiments for improved process understanding
Authors: Scott P. J. , Penlidis A. , Rempel G. L. 
Published: April 2003

AbstractA good working knowledge of the mechanism and an appreciation of the effects the process variables have on the properties of interest are required for optimization and control of polymerization processes. Despite the importance of ethylene‐vinyl acetate emulsion copolymers, limited kinetic information is available. Results from a series of factorial experiments are presented here which examine the emulsion polymerization of ethylene with vinyl acetate. Copolymers of up to 32 wt % ethylene have been produced at an ethylene pressure of 500 psig and a temperature of 20°C. The effects of the process variables on the rate of polymerization, copolymer composition, particle size and number, molecular weight averages, and gel content are discussed. The kinetic results obtained suggest process improvements for the production of homogeneous copolymer. Mechanistically, the locus of polymerization has been verified as the polymer particles and little water phase polymerization was observed. © 1993 John Wiley & Sons, Inc.
Polyimides with alicyclic diamines. I. Syntheses and thermal properties
Authors: Jin Qiu , Yamashita Takashi , Horie Kazuyuki , Yokota Rikio , Mita Itaru 
Published: April 2003

AbstractThe polyaddition reactions of alicyclic diamines such as 1,4‐diaminocyclohexane (1,4‐CHDA) or 4,4′‐diaminodicyclohexylmethane (DCHM) and configurational isomers of 1,4‐CHDA or DCHM with tetracarboxylic aromatic anhydrides in aprotic solvents were carried out to prepare high molecular weight poly(amic acid)s. Through the thermal imidization of poly(amic acid)s, several flexible polyimide films were prepared. Because of the stiffness of the alicyclic moieties in diamines, the resulting polyimides exhibit high glass transition temperatures (220–340°C) almost similar to those for corresponding aromatic polyimides which have phenylene groups in place of cyclohexyl groups, and show good thermal stability. The partial crystallization was observed for polyimides with trans‐cyclohexyl moiety during the heating in differential scanning calorimetry and ascertained by wide‐angle x‐ray diffraction. Thus, the inhibition of the occurrence of charge transfer in polyimides is accomplished by introducing alicyclic diamines in place of aromatic diamines without reducing their thermal stability. © 1993 John Wiley & Sons, Inc.
Synthesis of a stable, foamable, gold‐containing organic carboxylate polymer
Authors: Khan Md. Nazrul I. , Fackler John P. , Chum Steve P. , Paquet Andrew 
Published: April 2003

AbstractThe functionalized polyethylene acrylic acid copolymers Primacor 1430 (P1430, containing 9.5% acrylic acid) and Primacor 5980 (P5980, containing 20% acrylic acid) have been used to synthesize gold/polymer dispersions and gold/polymer ionomers, respectively. When [Ph3PAu]+ is bonded directly to the carboxylate, work‐up of the polymer leads to decarboxyation and metallic gold formation. However, ionic bonding of [(Ph3P)2Au]+, and related bis phosphine cations produce workable, foamable polymers. Analysis shows samples from these reactions to contain between 4–15 wt % of Au depending on the type of gold complex used and the reaction conditions. The gold/polymer (ionomer) sample with about 12% Au has been worked to mold sheets of foam. © 1993 John Wiley & Sons, Inc.
Sulfur‐containing polyacrylates. IV. The effect of Sand Olinkages on the photo‐ and thermally induced polymerization of dimethacrylates
Authors: Andrzejewska E. , Andrzejewski M. 
Published: April 2003

AbstractThe photo‐and thermally induced polymerization of four analogous dimethacrylates2,2′‐thiobisethanol dimethacrylate, 2,2′‐oxybisethanol dimethacrylate, pentanediol‐1,5‐dimethacrylate, and butanediol‐1,4‐dimethacrylatewas studied to determine the influence ofSandOlinkages on the polymerization course. Generally, the presence of the heteroatom in the monomer molecule results in higher reaction rates and yields but the extent of this influence highly depends on the polymerization conditions and the type of heteroatom. The effect of the thioether bond exceeds the effect of the ether bond at lower (40°C) temperature in the presence of oxygen but the reverse situation takes place at higher (75°C) temperature and/or in an inert atmosphere when photofragmentating and thermal initiators are used. The results are discussed mainly in terms of propensity of sulfides and ethers to act as hydrogen donors and chain‐transfer agents. © 1993 John Wiley & Sons, Inc.
On the formation and properties of a high‐temperature resin from a bisphthalonitrile
Authors: Burchill P. J. 
Published: April 2003

AbstractWhen 4,4'‐bis (3,4‐dicyanophenoxy) biphenyl is heated with small amounts of aromatic amine or amidine salts, a highly crosslinked polytriazine is obtained. This polymer has been shown to be the same as that reported when bisphthalonitriles are heated with amines. Salts promote this reaction more readily and the glass transition temperature of the polymer after post‐cure at 315°C is generally 30°C higher than when free bases are used. The fracture properties and elasticity of the salt‐cured polymer have been measured at temperatures up to 250°C. As a model system, the self reaction of phthalonitrile promoted by amines and their salts has been studied. In both cases, poly[4‐(2‐cyanophenyl)‐1,3,5‐triazine‐2,6‐diyl‐1,2‐phenylene] is produced, and more efficiently using the salts. A reaction mechanism for this polymerization has been proposed. © 1994 John Wiley & Sons, Inc.
Fluorination of polymers by sulfur hexafluoride gas under electric discharge
Authors: Das Partha Sarathi , Adhikari Basudam , Maiti Sukumar 
Published: April 2003

AbstractFluorination of low‐density polyethylene, polyacetylene, and poly(vinyl alcohol) was carried out using SF6 gas under electric discharge. The polymers were partially fluorinated and the extent of fluorination was more in the case of poly (vinyl alcohol) than the other two polymers. The fluorinated polymers were characterized by elemental analysis (Fluorine), IR, and x‐ray diffraction. Optical transparency of the films was also measured. The fluorinated polymers show better solvent resistance and decreased transparency than the virgin polymer. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of polyesters from hindered biphenols and hydroquinones
Authors: Kim Whan‐Gi , Hay Allan S. 
Published: April 2003

AbstractPolyesters have been synthesized by polycondensation of terephthaloyl dichloride or isophthaloyl dichloride with hindered biphenols and hydroquinones which contain bulky substituents (methyl and phenyl) on the arylene ring. Polymers derived from isophthaloyl dichloride have better solubility and lower glass transition temperatures than the corresponding polymers obtained from terephthaloyl dichloride. © 1994 John Wiley & Sons, Inc.
The effect of supporting electrolyte on the electrochemical synthesis, morphology, and conductivity of polyaniline
Authors: Duić L J. , Mandić Z. , Kovačiček F. 
Published: April 2003

AbstractElectrochemical synthesis of polyaniline (PANI) was carried out under cyclovoltammetric conditions using H2SO4, HCl, HNO3, and HClO4 as supporting electrolytes. The observed different rate of PANI deposit growth depending on the acid in the solution has been explained on the grounds of a different degree of specific adsorption for particular anion. It has been found that morphology of the deposit depends greatly upon the anion present in the solution. Thus, PANI synthesized from the solution of oxyacids results in a dense sponge‐like structure while PANI from the hydrochloric acid solution results in a spaghetti‐like structure. The structure of the deposit influences the conductivity, being higher for a dense deposit from oxyacid solutions and three orders of magnitude lower in case of a deposit from hydrochloric acid solution. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of 1,3,4,‐thiadiazole‐containing polyethers from 2,5‐bis (4‐fluorophenyl)‐1,3,4‐thiadiazole and various aromatic diols
Authors: Saegusa Yasuo , Iwasaki Takeshi , Nakamura Shigeo 
Published: April 2003

AbstractSeven 1,3,4‐thiadiazole‐containing polyethers with reduced viscosities of 0.27–1.44 dL/g were synthesized by the high‐temperature solution polycondensation of novel activated difluoride, 2,5‐bis (4‐fluorophenyl)‐1,3,4‐thiadiazole, with aromatic diols possessing a variety of ring structures. The expected chemical structures were confirmed by IR and 1H‐NMR spectroscopy and elemental analysis. Of all the polymers, three polyethers were highly crystalline and soluble only in limited solvents such as concentrated sulfuric acid. The other polyethers were amorphous and dissolved easily in a variety of organic solvents including N‐methyl‐2‐pyrrolidone (NMP), phenols, and chlorinated hydrocarbons. Colorless to slightly yellow‐colored, transparent, and tough films could be cast from the NMP solutions of the amorphous polyethers. The mechanical properties of the films were excellent, and their tensile strength, elongation at break, and tensile moduli were in the ranges of 48–72 MPa, 5–7%, and 1.3–1.9 GPa, respectively. The amorphous polyethers had high glass transition temperatures of 204–299°C. All the polyethers were highly thermally and thermooxidatively stable and exhibited no weight loss up to 400°C, with 10% weight loss being recorded at 464–513°C in air. © 1994 John Wiley & Sons, Inc.