bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ion‐free latex films composed of fused polybutadiene and poly (vinyl pyrrolidone) particles as polymer electrolyte materials
Authors: Rutt J. Steven , Matsumoto Morihiko , Ichino Toshihiro , Nishi Shiro 
Published: April 2003

AbstractLatex films composed of fused polybutadiene (PB) and poly (vinyl pyrrolidone) (PVP) particles that contain no ionic, hydroxyl, or amino groups were swelled with lithium salt solutions to yield new polymer electrolyte materials. The latex particle consists of a nonpolar, rubbery core that contains the PB component and a polar, glassy shell that contains the PVP component. The particle core‐shell morphology was retained in the solid state, after the latex dispersion medium was removed and the films dried at high temperatures, due to the high Tg of the PVP shell. The films swelled when immersed in lithium salt solutions, and ionic conductivity of swollen films was greater than 10‐3 S/cm. Swelling and ionic conduction occurred only in the polar PVP component. Extraction of PVP occurred with extended swelling. © 1994 John Wiley & Sons, Inc.
Thermal polycondensation synthesis of biomimetic serine‐containing derivatives of polyaspartate: Potent inhibitors of calcium carbonate and phosphate crystallization
Authors: Donachy Julie E. , Sikes C. Steven 
Published: April 2003

AbstractBiocompatable, degradable polymers that are powerful inhibitors of mineral formation were synthesized by automated solid phase and thermal polycondensation techniques. These polymers are analogues of natural proteins isolated from CaCO3 biomineral and consist primarily of polyaspartic acid and serine or modified serine residues. Phosphorylation of the serine residues greatly enhanced the inhibitory activity of the polymers. Synthesis in the presence of orthophosphoric acid resulted in the decomposition and modification of serine. These modified residues when incorporated into the polyaspartic acid also enhanced inhibitory activity of the polymers. © 1994 John Wiley & Sons, Inc.
Oligomers of a polyester network
Authors: Fawcett Allan H. , Hania Majid , Lo Kwok‐Wing , Patty Alan 
Published: April 2003

AbstractOligomers of glycerol and succinic acid have been prepared by three different methods and characterised by solution 13C‐NMR spectroscopy at 125.8 MHz. The first series of five oligomers was prepared by reacting glycerol with succinic anhydride; only one acid function of each succinic acid residue formed an ester by this means. They were readily distinguished as the shifts of their glycerol residues were dispersed over 16 ppm, and their shifts provided a guide to the assignment of shifts in the more elaborate oligomers. The second set of oligomers was prepared by treating glycerol with a small quantity of succinic acid, ester links being promoted by means of the reagent dicyclohexylcarbodiimide (DCCDI). When we used 2 mol of DCCDI/mol of acid in the presence of an excess of glycerol, no free acid functions remained, and a new set of oligomers was obtained. Furthermore, within this set the proportion of ring molecules was enhanced by repeating the reaction under much more dilute conditions. In this way the shifts of two ring oligomers were recognized in the spectrum. A different set of oligomers again was obtained when the esterification was performed with 1 mol of DCCDI/mol of succininic acid. After the first generation of oligomers had been identified in the mixtures produced by these three experiments, the reactions continued to produce larger oligomers with new fine structure features in the spectra. Glycerol trisuccinate was prepared in a pure form and heated in a vacuum to eliminate succinic acid groups and allow the formation of oligomers with two and three branch points. The structures successively produced by this reaction were readily recognized. In all we were able to recognize the formation of component structures in at least 17 different oligomers. The shifts of the carbons of the glycerol residues are sensitive to the substitution pattern at that residue, to whether the succinic acid residue to which they are linked has reacted a second time, and in some cases the methine shift is sensitive to how the succinic acid residue attached to a neighboring methylene carbon has reacted. © 1994 John Wiley & Sons, Inc.
Role of added Lewis base and alkylaluminum halide on living cationic polymerization of vinyl ether
Authors: Aoshima Sadahito , Onishi Hideshi , Kamiya Masamichi , Shachi Kenji , Kobayashi Eiichi 
Published: April 2003

AbstractIn the living cationic polymerization of isobutyl vinyl ether (IBVE) by the CH3CH (OiBu) OCOCH3 (1)/EtAlCl2 initiating system in the presence of the added base in hexane at +40°C, the stability of the initiating system 1/EtAlCl2, which form initiating species CH3CH⊕ (OiBu) derived from 1, was investigated. In the presence of the Lewis base such as ethyl acetate or 1,4‐dioxane, the active species was stable for 300 min even at +40°C in the absence of IBVE, and the living polymers were quantitatively obtained by adding IBVE. However, the active species was partly consumed by side reactions during the standing time for 60 min in the presence of a less basic additive such as ethyl benzoate, and about 50% of the active species was deactivated in the presence of methyl chloroacetate. Consequently, in the case of a less basic additive such as methyl chloroacetate (which was effective for the fast living polymerization), it can be seen that the careful selection of polymerization conditions was required. The living polymerization rate was dependent on the second order of EtAlCl2 concentration. EtAlCl2 induced the cleavage of 1 into CH3CH⊕ (OiBu) and EtAl⊖Cl2(OCOCH3), and the reactivity of CH3CH⊕ (OiBu) and propagating carbocation may be controlled by EtAl⊖Cl2(OCOCH3) with the aid of other EtAlCl2. Et1.5AlCl1.5 exists as a bimetallic complex of EtAlCl2 and Et2AlCl, and it is expected that the polymers having a bimodal molecular weight distribution will be obtained due to two kinds of counteranions coming from EtAlCl2 and Et2AlCl. However, in the cationic polymerization of IBVE by 1/Et1.5AlCl1.5 in the presence of ethyl acetate, the living polymer exhibiting a unimodal and very narrow molecular weight distribution was obtained. Thereby, it was suggested that the counteranions, EtAl⊖Cl2(OCOCH3) and Et2Al⊖Cl(OCOCH3), exchange rapidly with each other. © 1994 John Wiley & Sons, Inc.
Dimethyltitanocene‐induced surface chemical degradation of synthetic biodegradable polyesters
Authors: Pratt Lawrence M. , Chu C. C. 
Published: April 2003

AbstractThe purpose of this research was to selectively alter the rate of surface degradation of linear aliphatic polyesters without adversely affecting their bulk properties by way of functional group transformation, where the surface ester linkages would be converted to vinyl ether functionalities with dimethyltitanocene. It has been observed that dimethyl titanocene causes surface degradation of poly (glycolic acid) without adversely affecting its bulk properties, such as Mv, bursting strength, and thermal properties The vinvl ether resulting from the conversion of the PGA ester groups was unstable under ambient conditions, and further reacted by polymer chain scissioning, as was observed from measurements of molecular weight. © 1994 John Wiley & Sons, Inc.
Kinetics of propylene polymerization in the initial acceleration stage
Authors: Kim Il , Choi Hong Ki , Kim Jae Ha , Woo Seong Ihl 
Published: April 2003

AbstractThe kinetics of propylene polymerization catalyzed over a superactive and stereospecific catalyst for the initial build‐up period was investigated in slurry‐phase. The catalyst was prepared from Mg(OEt)2/benzoyl chloride/TiCl4 co‐activated with AlEt3 in the absence or presence of external donor. Despite a very fast activation of the prepared catalyst the acceleration stage of polymerization could be identified by the precise estimation of polymerization kinetics for a very short period of time after the commencement of polymerization (ca. 2 min). The initial polymerization rate, (dRp/dt)0 extrapolated to the beginning of the polymerization was second order with respect to monomer concentration. The dependence of initial polymerization rate on the concentration of AlEt3 could be represented by Langmuir adsorption mechanism. The initial rate was maximum at about Al/Ti ratio of 20. The activation energy for the initiation reaction was estimated to be 14.3 kcal/mol for a short‐time polymerization. The addition of a small amount of p‐ethoxy ethyl benzoate (PEEB) as an external donor increased the percentage of isotactic polymer, which was obtained after 120 s of polymerization, to 98% and the initial polymerization rate decreased sharply as [PEEB]/[AlEt3] increased. © 1994 John Wiley & Sons, Inc.
Glycine/Glycolic acid based copolymers
Authors: In 't Veld Peter J A. , Shen Zheng‐Rong , Takens Gijsbert A. J. , Dijkstra Pieter J. , Feijen Jan 
Published: April 2003

AbstractGlycine/glycolic acid based biodegradable copolymers have been prepared by ring‐opening homopolymerization of morpholine‐2,5‐dione, and ring‐opening copolymerization of morpholine‐2,5‐dione and glycolide. The homopolymerization of morpholine‐2,5‐dione was carried out in the melt at 200°C for 3 min using stannous octoate as an initiator, and continued at lower reaction temperatures (100–160°C) for 2–48 h. The highest yields (60%) and intrinsic viscosities ([η] = 0.50 dL/g; DMSO, 25°C) were obtained after 3 min reaction at 200°C and 17 h at 130°C using a molar ratio of monomer and initiator of 1000. The polymer prepared by homopolymerization of morpholine‐2,5‐dione was composed of alternating glycine and glycolic acid residues, and had a glass transition temperature of 67°C and a melting temperature of 199°C. Random copolymers of glycine and glycolic acid were synthesized by copolymerization of morpholine‐2,5‐dione and glycolide in the melt at 200°C, followed by 17 h reaction at 130°C using stannous octoate as an initiator. The morphology of the copolymers varied from semi‐crystalline to amorphous, depending on the mole fraction of glycolic acid residues incorporated. © 1994 John Wiley & Sons, Inc.
Dispersion polymerization of methyl methacrylate: Mechanism of particle formation
Authors: Shen S. , Sudol E. D. , El‐Aasser M. S. 
Published: April 2003

AbstractThe mechanism for the formation of micron‐size polymer particles in the dispersion polymerization of methyl methacrylate was investigated by applying dynamic light scattering to monitor the evolution of the average particle size in the early stages of the polymerization. In addition, the contributions of physically adsorbed stabilizer and graft copolymer were evaluated by measuring the bound, unbound (adsorbed), and free stabilizer, and by determining the amount of added stabilizer required in seeded dispersion polymerizations. Twenty nanometer particles (termed nuclei) were the smallest particles detected and are considered to be formed by aggregation of growing polymer chains precipitating from solution as they exceed their critical chain length. Aggregation of these nuclei with themselves and their aggregates continues until mature and stable particles are formed. This occurs when sufficient stabilizer occupies the particle surface which includes both the polymeric stabilizer [poly(vinylpyrrolidone)] and its graft copolymer which is created in situ. The effects of process variables are discussed based on this mechanistic picture of the dispersion polymerization process. © 1994 John Wiley & Sons, Inc.
New poly (amide‐imide) syntheses. IX. Preparation and properties of poly(amide‐imide)s derived from 2,7‐bis (4‐aminophenoxy) naphthalene and various bis (trimellitimide)s
Authors: Yang Chin‐Ping , Chen Wen‐Tung 
Published: April 2003

AbstractEleven bis(phenoxy) naphthalene‐containing poly(amide‐imide)s IIIa–k were synthesized by the direct polycondensation of 2,7‐bis (4‐aminophenoxy) naphthalene (DAPON) with various aromatic bis (trimellitimide)s IIa–k in N‐methyl‐2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Poly (amide‐imide)s IIIa–k having inherent viscosities of 0.70–1.12 dL/g were obtained in quantitative yields. The polymers containing p‐phenylene or bis(phenoxy) benzene units exhibited crystalline x‐ray diffraction patterns. Most of the polymers were readily soluble in various solvents such as NMP, N, N‐dimethylacetamide, dimethyl sulfoxide, m‐cresol, o‐chlorophenol, and pyridine, and gave transparent, and flexible films cast from DMAc solutions. Cast films showed obvious yield points in the stress‐strain curves and had strength at break up to 87 MPa, elongation to break up to 11%, and initial modulus up to 2.10 GPa. These poly(amide‐imide)s had glass transition temperatures in the range of 255–321°C, and the 10% weight loss temperatures were recorded in the range of 529–586°C in nitrogen. The properties of poly(amideimide)s IIIa–k were compared with those of the corresponding isomeric poly (amide‐imide)s III′ prepared from 2,7‐bis(4‐trimellitimidophenoxy) naphthalene and aromatic diamines. © 1994 John Wiley & Sons, Inc.
Anionic polymerization of propylene oxide: Isomerization of allyl ether to propenyl ether end groups
Authors: Yu Ga‐Er , Heatley Frank , Booth Colin , Blease Trevor G. 
Published: April 2003

AbstractThe isomerization of allyl ether to propenyl ether end group in anionically‐polymerized poly (propylene oxide) was monitored by 1H NMR spectroscopy. It was confirmed that the reaction followed a simple second‐order rate law: −d[allyl]dt = k2[allyl] [O−]. Values of k2 determined over the 90–130°C temperature range, indicated an activation energy of 116 kJ mol−1. © 1994 John Wiley & Sons, Inc.
Copolymerization of methacrylonitrile with p‐methylstyrene
Authors: Chen Junjie , Goh S. H. , Lee S. Y. , Siow K. S. 
Published: April 2003

AbstractMethacrylonitrile was copolymerized with p‐methylstyrene in methyl ethyl ketone at 80°C initiated by azobisisobutyronitrile. Monomer reactivity ratios of methacrylonitrile and p‐methylstyrene were found to be 0.205 and 0.377, respectively, using the Kelen‐Tüdos method. Triad fractions and monomer sequence lengths of three copolymers were determined from 13C‐NMR spectra and were found to be in good agreement with those calculated from reactivity ratios. © 1994 John Wiley & Sons, Inc.
Photocrosslinked hydrogels based on copolymers of poly(ethylene glycol) and lysine
Authors: Vyavahare Narendra , Kohn Joachim 
Published: April 2003

AbstractA group of new, water‐soluble poly(ether‐urethane)s, derived from poly(ethylene glycol) and the amino acid L‐lysine, provide pendent carboxylic acid groups along the polymer backbone at regular intervals. The carboxylic acid groups were utilized for the attachment of acrylate and methacrylate pendent chains (hydroxyethyl acrylate, hydroxyethyl methacrylate, aminoethyl methacrylate, and aminoethyl methacrylamide), leading to functionalized polymers. The pendent chains were attached via ester and/or amide bonds having different degrees of hydrolytic stability. The attachment reactions proceeded with high yields (up to 95%). The functionalized polymers were subsequently photopolymerized (UV irradiation) to obtain crosslinked hydrogels. Crosslinked membranes with the highest degree of mechanical strength were obtained when the crosslinking reaction was performed in dioxane with benzoin methyl ether (0.1 wt %) as the initiator. the crystallinity, thermomechanical properties, and hydrolytic stability of the crosslinked membranes were studied. All membranes were transparent and highly swellable (equilibrium water content: 64–88%). The tensile strength in the swollen state ranged from 0.15 to 1.09 MPa. Under physiological conditions (phosphate buffered water, 0.1M, pH 7.4, 37°C) the hydrolytic stability of the hydrogels varied depending on the bonds used in the attachment of the acrylate pendent chains: Hydrogels with hydroxyethyl acrylate pendent chains dissolved within 30 days, while hydrogels containing aminoethyl methacrylamide pendent chains remained unchanged throughout a 30 day period. Using high molecular weight FITC‐dextrans as model compounds, complete release from the swollen hydrogels required between 60 and 150 h. Overall, the evaluation of poly(ethylene glycol)‐lysine derived, photocrosslinked hydrogels indicated that these materials provide a range of potentially useful properties. © 1994 John Wiley & Sons, Inc.
Reaction of diphenyldiacetylene by annealing under elevated pressure
Authors: Kojima Yoshitsugu , Tsuji Masao , Matsuoka Takaaki , Takahashi Hideroh 
Published: April 2003

AbstractReaction of diphenyldiacetylene (1,4‐diphenylbutadiyne) by annealing under elevated pressure (0.1–500 MPa) was carried out. Diphenyldiacetylene reacted at 210°C with appearance of gas, and this temperature was independent of the pressure. The measurement of high pressure differential thermal analysis (DTA) revealed that the reaction temperature under elevated pressure was below 24–42°C of the exothermic peak temperature. This implied that exothermic reaction occurred under elevated pressure. Elementary analysis, gel permeation chromatography (GPC), FTIR, Raman scattering, and high resolution 13CNMR experiments were performed to characterize the structure of the product. It was indicated that the product was a mixture of derivative of condensed polycyclic aromatic compound with phenyl group and diphenyldiacetylene oligomer. The fraction of the derivatives increased with increasing pressure, and pressure accelerated the dehydrogenation of the derivatives. The number‐averaged molecular weight (Mn) of the diphenyldiacetylene oligomer was 470–610 and the weight‐averaged molecular weight (Mw) was 1700–2300. It was considered that the oligomer had a polyacene‐based structure. © 1994 John Wiley & Sons, Inc.
Cationic polymerization of diglycidyl ether of bisphenol A
Authors: Matĕjka L. , Chabanne P. , Tighzert L. , Pascault J. P. 
Published: April 2003

AbstractThe cationic nonlinear polymerization of diglycidyl ether of Bisphenol A (DGEBA) in the presence of a diluent γ‐butyrolactone (BL) was initiated by the BF3‐4‐methoxyaniline (MA) complex. The reaction was studied by size exclusion chromatography, DSC, and dynamic mechanical analysis. Reaction mechanism involves a fast formation of adducts of DGEBA with MA released from the initiator. Formation of spiro orthoesters (S) by reaction of BL with DGEBA and homopolymerization of DGEBA as well as copolymerization with S follow. Gelation occurs at 60°C within a few minutes at conversion of epoxy groups (ξE)c= 0.20–0.45. The networks cured under optimum conditions show high glass transition temperature,Tα= 178°C. The mechanism‐structure‐property relations are discussed. © 1994 John Wiley & Sons, Inc.
Dye distribution in fluorescent‐labeled latex prepared by emulsion polymerization
Authors: Sosnowski Stanislaw , Feng Jianrong , Winnik Mitchell A. 
Published: April 2003

AbstractEmulsion polymerizations were used for preparing fluorescent‐labeled polymers. The labeled polymers were analyzed by gel permeation chromatography (GPC) using both fluorescence (FL) and refractive index (RI) as detectors. The uniformity of polymer labeling was measured by the ratio between FL and RI signals, calculated by a computer software, on the basis of each GPC chromatogram. It was found that in emulsion polymerizations, the semicontinuous process can produce a more homogenous dye distribution in the host polymer molecules than the batch method. Uniform labeling of a polymer with various dyes can be achieved by the semi‐continuous process. However, experimental conditions for polymerization, such as initiator concentration and the presence of surfactant or chain transfer agent, may influence the uniformity of dye distribution. © 1994 John Wiley & Sons, Inc.
Amphiphilic graft copolymers with poly(oxyethylene) side chains: Synthesis via activated ester intermediates—properties
Authors: Berlinova Iliyana V. , Amzil Aissa , Tsvetkova Svetlana , Panayotov Ivan M. 
Published: April 2003

AbstractAmphiphilic graft copolymers were synthesized via activated ester substitution of derivatives of fumaric acid with amino‐functionalized methoxypoly (oxyethylene)s (MPEO‐NH2) of different molecular weights. The monomeric activated esters, isopropyl pentachlorophenyl fumarate (PCPFA) and isopropyl succinimido fumarate (SIFA), were copolymerized with styrene (St) or N‐vinyl pyrrolidone (VP) at equimolar ratio. The polymeric‐activated esters proved to be good precursors for grafting of definite amounts of MPEO‐NH2. The aminolysis of the succinimide esters and VP‐containing copolymers proceeded with gel formation due to extensive hydrogen bonding. The hydrodynamic behavior, the emulsifying ability, the thermal properties, and crystallinity of the graft copolymers were studied as a function of their molecular characteristics. The length of the PEO grafts and the degree of grafting are the factors which affect the melting parameters and the crystallinity of the side chains. © 1994 John Wiley & Sons, Inc.
Phase‐transfer catalytic activity of soluble polystyrenes containing crown ether moieties and hydroxyl groups adjacent to the macrorings
Authors: Gotoh Yoshitaka , Kohno Yutaka , Fukuda Wakichi , Tomoi Masao 
Published: April 2003

AbstractSoluble polystyrenes with crown ether structures and hydroxyl groups adjacent to the macrorings were prepared by the reaction of epoxide‐containing polystyrenes with monoaza‐15‐crown‐5 or monoaza‐18‐crown‐6. Rate of formation of the polymer‐bound alkali cation‐crown alkoxide ion pair from the soluble polystyrenes and aqueous NaOH or KOH depended on the loading of crown ether and hydroxyl units and on the size of the macroring. The elimination of HCl from less reactive 2‐chloroethylbenzene with aqueous NaOH or KOH in the presence of the soluble polystyrene catalysts under two‐phase conditions was limited mainly by the intrinsic reaction rate. The elimination of HBr from more reactive 2‐bromoethylbenzene in the presence of the less (11%) ring‐substituted polymer catalyst with 18‐crown unit was limited by the alkoxide formation rate. © 1994 John Wiley & Sons, Inc.
Synthesis of saccharide‐conjugated polyamides by quasi‐living anionic polymerization of a bicyclic lactam
Authors: Hashimoto Kazuhiko , Sugata Tohru , Imanishi Shin‐Ichiro , Okada Masahiko 
Published: April 2003

AbstractSeveral well‐defined graft copolymers (7) having a water‐soluble natural polysaccharide (dextran) stock and hydrophilic polyamide branches of different molecular weights were synthesized by using a quasi‐living anionic polymerization of a bicyclic lactam 1, namely by the reaction of the acyllactam group in the quasi‐living polyamide 2 with the hydroxyl and amino groups in the dextran derivative (6), of which the reducing end was converted to an amino group. An oligosaccharide‐terminated polyamide 3 was also prepared efficiently by similar coupling reaction of the corresponding quasi‐living polyamide 2, with the maltose derivative (5) having an amino group. © 1994 John Wiley & Sons, Inc.
New fluorinated polysiloxanes containing an ester function in the spacer. I. Synthesis and characterization
Authors: Beyou Emmanuel , Babin Pierre , Bennetau Bernard , Dunogues Jacques , Teyssie Dominique , Boileau Sylvie 
Published: April 2003

AbstractUnsaturated perfluoroalkyl esters derived from undecylenic acid: CH2CH(CH2)8COOCH2CH2RF (with RFC6F13, 2a and RFC8F17, 2b) and C8F17(CH2)10COOCH2CHCH2, 2c were prepared with excellent yields. Their hydrosilylation by methylhydrodimethylsiloxane copolymers of various SiH contents gives new fluorinated polysiloxanes which were examined by 1H‐ and 13C‐NMR, GPC, differential scanning calorimetry, and optical polarizing microscopy. Polymers derived from compounds 2a and 2b exhibit mesomorphic structures. © 1994 John Wiley & Sons, Inc.