bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ion conductivity of poly(ethylene oxide)‐based polyurethane networks containing alkali metal salts
Authors: Tada Hiroaki , Fujino Kozo , Kawahara Hideo 
Published: April 2003

AbstractIon conductivity of poly(ethylene oxide) (PEO)‐based polyurethane networks containing alkali metal salts has been investigated. Consequently, it has been revealed that the conductivity is dependent on the following parameters: lattice energy of the alkali metal salt, concentration of alkali metal salt, and the cross‐linking density of the network polymer (which is a function both of the amount of cross‐linking agent and the molecular weight of PEO). Under optimal conditions, the conductivity at ambient temperature corresponded to 2.51 × 10−5 Scm−1, which is greater than that of a typical alkali metal‐PEO system by a factor of about 102 to 103. Moreover, from the standpoint of the application to electrochromic displays (ECD), tensile bond strength between the polymer electrolytes and tungsten trioxide (WO3), which is the most promising electrochromic material, has been evaluated. The bonding strength of the bond of WO3 with the present electrolyte has been found to be much larger than that of the alkali metal‐PEO system.
Functional monomers and polymers. CXLVII. Inclusion compounds of poly(1,3‐butadiyne) in deoxycholic acid and apocholic acid canals: Synthesis and characterization
Authors: Tsutsumi Hiromori , Miyata Mikiji , Takemoto Kiichi 
Published: April 2003

AbstractThe inclusion polymerization of 1,3‐butadiyne was studied at different temperatures using deoxycholic acid and apocholic acid as the host molecules. The polymers that resulted consist of predominantly 1,4‐structure rather than 1,2 or acene structure as confirmed by both IR and Raman spectroscopies. The poly(1,3‐butadiyne)s were found to possess unique optical properties and high electric conductivity as compared with those prepared by the usual polymerization methods.
Polymerization of isobutylene by the adamantane bromide–diethylaluminum chloride catalyst system
Authors: Kuntz Irving , Cheng Doris M. , Dekmezian A. H. , Hsu Chang S. 
Published: April 2003

AbstractIsobutylene has been polymerized in a continuous stirred tank reactor using a catalyst system comprised of 1‐bromoadamantane and diethylaluminum chloride. The polymerization was carried out in hexane solvent at −15 to −27°C and gave 100% conversion to polyisobutylene (PIB) of 1000–3000 Mw. The results of pyrolysis–gas chromatography–mass spectrometry analyses are consistent with a mechanism involving the formation of the adamantyl cabocation and its addition to an isobutylene molecule to initiate polymerization. 13C‐NMR analyses show that the PIB products contain R2CCR2 and R2CCHR olefin types. Information on the nature of these olefins and the route to their formation has been developed.
Esterification reactions on syndiotactic poly(methallylalcohol). IV. Homo‐ and copolymers of N‐protected methallyl‐(L)‐histidinate
Authors: Frey W. , Dernst C. , Klesper E. 
Published: April 2003

AbstractSyndiotactic poly(methylallylalcohol) is fully esterified with Nα‐protected (L)‐histidine by carbodiimide in pyridine to yield the corresponding homopolymers, i.e., Nα‐protected 2‐methylallyl‐(L)‐histidinate monomer units and unreacted 2‐methylallyl alcohol units are obtained, which in a second exhaustive esterification step are reacted with Nα‐(benzyloxycarbonyl)‐(L)‐aspartic acid anhydride. The resulting copolymers consist of Nα‐protected 2‐methylallyl‐(L)‐histidinate and 2‐methylally‐Nα‐(benzyloxycarbonyl)‐(L)‐hydrogen‐α‐aspartate monomer units. They are polyampholytes containing both imidazole and carboxyl groups. The structure, including composition of the copolymers, is determined by 1H‐ and 13C‐NMR, while water solubility and apparent pKaa values are investigated by potentiometry.
A few characterization studies on some poly(methyl aryloxymethacrylates)
Authors: Devarajan R. , Balakrishnan T. , Santappa M. 
Published: April 2003

AbstractHigh polydispersity values obtained for the molecular weights, as determined by light scattering, osmometry, and GPC, of polymers prepared by different methods from the monomers recently synthesised indicate the presence of large quantities of low molecular weight species besides the high molecular weight species besides the high molecular weight species. Intrinsic viscosity data were used to evaluate Mark–Houwink constants K and “a” for this new series of monomers. DSC analyses show that the polymers have low Tg. X‐ray diffraction studies made on the fibers show a high percentage of crystallinity in poly(methyl α‐phenoxymethacrylate).
Methanol transport in PMMA: The effect of mechanical deformation
Authors: Harmon Julie P. , Lee Sanboh , Li J. C. M. 
Published: April 2003

AbstractThe effect of cold work on the transport of liquid methanol in crosslinked PMMA disks has been determined at temperatures from 35–56°C. Deformed samples absorb at fast rates with kinetics that approach those of Fickian diffusion. Undeformed samples sorb at lower rates and the kinetics tend toward those of Case II transport. Shape recovery accompanied swelling in deformed samples. Samples saturated with methanol were desorbed in cyclohexanol. Resorption of desorbed samples showed fast rates for both deformed and undeformed samples and matched those of the absorption cycle in deformed samples. An analogy is made between the microstructure due to cold work and due to swelling.
Modification of olefin polymerization catalysts. I. Mechanism of the interaction between AIEt3 and silyl ethers
Authors: Vähäsarja Eila , Pakkanen Tuula T. , Pakkanen Tapani A. , Iiskola Eero , Sormunen Pekka 
Published: April 2003

AbstractThe interaction between AlEt3 and silyl ethers, PhnSi(OMe)4‐n (n = 0–3), was followed by 13C‐ and 29Si‐NMR techniques in conditions close to those typical for an olefin polymerization reaction with supported Ziegler–Natta catalysts (A1Et3:silyl ether ratios from 1 to 10, temperature range 25–75°C). A1Et3 and silyl ethers form instantaneously at ambient temperature a donor‐acceptor complex, which is stable at a 1:1 molar ratio. In the presence of excess A1Et3 the complex decomposes via a mechanism consisting, in the case of PhSi(OMe)3, of five consecutive steps: alternating complexation and ether reductions with the formation of alkylated silyl ethers, Ph(Et)nSi(OMe)3‐n (n = 1,2), and dialkyl‐aluminum alkoxides, (Et2A1OMe3)n (n = 2,3). The rate of decomposition was enhanced by the increasing number of methoxy groups present in the silyl ether, heating, or a high A1Et3:silyl ether ratio. The decomposition was not inhibited by the presence of 1‐hexene.
Electrophilic substitution of organosilicon compounds. II. Synthesis of allyl‐terminated polyisobutylenes by quantitative allylation of tert‐chloro‐polyisobutylenes with allyltrimethylsilane
Authors: Wilczek Lech , Kennedy Joseph P. 
Published: April 2003

AbstractEssentially quantitative allylation of linear and three‐arm star tert‐chloro capped polyisobutylenes [tCl–PIB–Clt and PIB(Clt)3] has been achieved by the use of allyltrimethylsilane (AllylSiMe3) and Friedel–Crafts acids. Quantitative allylation occurs under suitable conditions, e.g., slight molar excess of TiCl4 and AllySiMe3 polar media, −70°C. These conditions have been developed from quantitative model allylation experiments using 2,4,4‐trimethyl‐2‐chloropentane. Essentially quantitative allylation occurs with long‐chain or “once fired” tert‐chloro‐end groups. Complete allylation can also be effected in a “one‐pot two‐step” synthesis, i.e., by first preparing the tert‐chloro‐ended PIB by the inifer method and without isolating the product, completing the synthesis by allylation in the same reactor. Extensive but not quantitative allylation can also be obtained in situ, i. e., during polymerization, by the use of the AllylSiMe3/cumyl chloride/BCI3/isobutylene combination. While allylation proceeds with great ease under the mildest conditions, e.g., −70°C, vinylation with vinyltrimethylsilane could not be achieved even under more forcing conditions.
Macromonomers from vinyl and cyclic monomers prepared by initiation with stable carbenium salts
Authors: Velichkova R. S. , Toncheva V. D. , Panayotov I. M. 
Published: April 2003

AbstractThe initiation of polymerization of α‐methylstyrene and p‐methoxystyrene with 9‐anthranylmethyl salts proceeds by hydride transfer from the monomer to the initiator. As a result, macromonomers with a double bond as head group are formed. These products polymerize and copolymerize by radical and ionic mechanism leading to graft and block copolymers. Styrene and α‐caprolactone polymerize with the same initiator by cationation of the monomer. In this case each macromonomer contains one photoreactive anthranylmethyl group which may photodimerize. As a result copolymers of the type AA or AB are produced.
Plasma fluorination of polystyrene
Authors: Strobel Mark , Thomas Patrick A. , Lyons Christopher S. 
Published: April 2003

AbstractESCA and contact‐angle measurements were used to characterize the surfaces of polystyrene films exposed to SF6, CF4, and C2F6 plasmas. SF6 plasmas cause loss of aromaticity in the polystyrene surface region via saturation of the phenyl ring and/or carbon‐bond breakage and subsequent fluorination. C2F6 plasmas graft CFx radicals directly to the polystyrene surface without necessarily destroying the aromaticity of the polymer. CF4 plasmas appear to be intermediate in character between SF6 and C2F6 plasmas.
Polymerization of vinyl monomers by a new oligoperoxide: Oligo(adipoyl‐5‐peroxy‐2,5‐dimethyl n‐hexyl peroxide)
Authors: Hazer Baki 
Published: April 2003

AbstractA new polymeric initiator, oligo(adipoyl‐5‐peroxy‐2,5‐dimethyl n‐hexyl peroxide), was synthesized by interfacial condensation of adipoyl chloride with 2,5‐dimethyl‐2,5‐dihydroperoxy hexane. This can be used as an initiator to prepare block copolymers by free radical mechanism in a procedure involving several steps, since the colorless, viscous liquid, oligoperoxide, has 8–10 peroxide groups per molecule. The thermal decomposition of this oligoperoxide in benzene solution at 98°C was first order and its half life was 9.75 h. The results of the polymerization kinetics show that this oligoperoxide lies in between of 2,5‐dimethyl‐2,5‐dihydroperoxyhexane and benzoyl peroxide for empirical polymerization rates of styrene and methyl methacrylate at 80°C.
Synthesis and solid state 13C‐NMR studies of some cellulose derivatives
Authors: Pawlowski W. P. , Sankar S. S. , Gilbert R. D. , Fornes R. E. 
Published: April 2003

AbstractSeveral cellulose derivatives were synthesized and characterized by IR and 1H‐NMR spectroscopy. The positions of substitution in these derivatives were confirmed using solid state 13C‐NMR spectroscopy techniques.
Polyanhydrides. I. Preparation of high molecular weight polyanhydrides
Authors: Domb A. J. , Langer R. 
Published: April 2003

AbstractPolyanhydrides composed of the following diacids–sebacic acid, bis(p‐carboxyphenoxy)propane, bis(p‐carboxyphenoxy)hexane, isophthalic acid, 1,4‐phenylene dipropionic acid, and dodecanedioic acid–were synthesized by a melt polycondensation process. Polymers of molecular weight up to 137,010 (weight average) and intrinsic viscosity of 0.92 dL/g were achieved. These high molecular weight polymers were reached by using pure isolated mixed anhydrides of diacids and acetic acid, under optimized reaction conditions (temperature of 180°C for 90 min under vacuum of 10‐4 mm Hg). Polymers of higher molecular weights were synthesized in shorter times by using heterogenic coordination catalysts: cadmium acetate, ZnEt2‐H2O (1:1), barium oxide, calcium oxide, and calcium carbonate. By using these catalysts molecular weights of up to 245,000 were reached in 30 min of reaction. Films made of high molecular weight bis(p‐carboxyphenoxy)propane–sebacic acid copolymers showed tensile strengths of 40–160 kg/cm2; the strength increased as a function of the bis(p‐carboxyphenoxy)propane content and molecular weight.
Synthesis and characterization of N‐phenylated aromatic polyureas from N,N′ ‐dichloroformyl‐p‐dianilinobenzene and N,N′ ‐bistrimethylsilyl‐diamines
Authors: Oishi Yoshiyuki , Padmanaban Munirathina , Kakimoto Masa‐Aki , Imai Yoshio 
Published: April 2003

AbstractNovelN‐phenylated aromatic polyureas having inherent viscosities of 0.13–0.35 dL/g were synthesized by the solution polycondensation of N,N′‐dichloroformyl‐p‐dianilinobenzene with N,N′‐bistrimethylsilyl derivatives of bis(4‐aminophenyl)ether, piperazine, and p‐dianilinobenzene in sulfolane. Except the polyurea containing piperazine unit, the other polyureas were amorphous and readily soluble in a variety of organic solvents such as tetrahydrofuran. The polyurea derived from p‐dianilinobenzene, which has no vulnerable hydrogen on the urea linkage, did not melt below 350°C and was stable up to 450°C in air.
Copper carboxylate formation in the thermal oxidative degradation of atactic polypropylene on copper oxide films
Authors: Webb John D. , Czanderna A. W. , Pitts J. R. 
Published: April 2003

AbstractThe thermal oxidation of atactic polypropylene on CuO0.67 surfaces in air was studied using IR reflection‐absorption spectroscopy. Degradative losses of primary, secondary, and tertiary alkyl hydrogens were observed. At 60 and 73°C, carboxylic acids are the primary degradation products, while at 85 and 100°C, copper carboxylate formation predominates and CuO0.67 is decomposed. The distinct change in the oxidative mechanisms between 73 and 85°C apparently is related to an irreversible thermal transition in the atactic polypropylene films, which may favor carboxylate production by increasing the permeability of the films to oxygen and water vapor.
Radiation‐induced copolymerization of trioxane: Reactivities of some cyclic ether comonomers
Authors: Sagu M. L. , Bhattacharyya K. K. 
Published: April 2003

AbstractCopolymerization of trioxane solid state induced by gamma radiation with oxycyclic comonomers such as penta acetyl glucose, tetrahydrofuran, styrene oxide, and 1,3 dioxolane has been reported. The relative yields, properties of the copolymers, and the reactivities of the comonomers are discussed. A mechanism for the reactivity is presented.
Epitaxial polymerization of 1,3‐butadiyne by chemical vapor deposition
Authors: Nakada Mikitoshi , Kobayashi Norihisa , Ohno Hiroyuki , Tsuchida Eishun , Matsuda Hiro , Nakanishi Hachiro , Kato Masao 
Published: April 2003

Abstract1,3‐Butadiyne was epitaxially polymerized on the graphite basal plane by chemical vapor deposition to form a homogeneous thin film. The film thickness varied from 100 to 3000 Å depending on the polymerization condition. The films on the graphite showed a variety of interference colors such as blue, purple, or gold depending on the film thickness. Raman spectra revealed that the polymerized film was mainly composed of CCbonds. Electron diffraction pattern and the ESCA spectrum of the film were quite similar to those of graphite, suggesting that butadiyne was polymerized in an epitaxial manner.
Synthesis, separation, and resolution of cis‐ and trans‐3‐ethylproline
Authors: Tiba Omar , Overberger C. G. 
Published: April 2003

AbstractThe synthesis, separation, and optical resolution of cis‐ and trans‐3‐ethylproline are described. Two different approaches were employed: (1) The Michael addition reaction of 2‐pentenal with diethyl‐N‐carbobenzyloxyaminomalonate gave the intermediate 3‐ethyl‐5‐hydroxy‐N‐benzyloxypyrrolidine. Hydrogenolysis of this intermediate followed by acid hydrolysis gave a mixture of cis‐ and trans‐3‐ethylproline. Separation of the isomers was accomplished by selective saponification of N‐(p‐toluenesulfonyl)‐cis‐ and trans‐3‐ethylproline methyl esters using 0.25N methanolic sodium hydroxide. (2) The Michael condensation of diethyl acetamidomalonate with 2‐pentenoic acid ethyl ether produced the intermediate 5,5‐bis(ethoxycarbonyl)‐4‐ethylpyrrolidine. Partial saponification followed by decarboxylation afforded a mixture of cis‐ and trans‐isomers of ethyl‐3‐ethylpyroglutamate. The diastereoisomers were separated using low temperature fractional crystallization. Reduction of these isomers and tosylation in situ afforded the corresponding N‐(p‐toluenesulfonyl)‐cis‐ and trans‐3‐ethylprolinols. Chromic acid oxidation gave N‐(p‐toluenesulfonyl)‐cis‐ and trans‐3‐ethylproline. Reaction of these tosylates with 30% hydrogen bromide in acetic acid gave cis‐ and trans‐3‐ethylproline. Both optically active isomers of D(+)‐and L(‐)‐trans‐3‐ethylproline were successfully resolved using (+)‐dibenzoyl‐D‐tartaric acid and (‐)‐dibenzoyl‐L‐tartaric acid as resolving agents. The absolute configurations of the optically active isomers were determined by circular dichroism spectroscopy.
Characterization of organometallic polymers by 13C‐ and 119Sn‐NMR: Configurational/compositional triads in poly(tri‐n‐butyltin methacrylate/methyl methacrylate)
Authors: Manders William F. , Bellama Jon M. , Johannesen Rolf B. , Parks Edwin J. , Brinckman Frederick E. 
Published: April 2003

AbstractThe 1:1 and 2:1 formulations of the free radical initiated copolymers of methyl methacrylate (MMA) and tri‐n‐butyltin methacrylate (TBTM), and the homopolymer, poly(TBTM), are characterized by 13C‐ and 119C‐NMR structural analyses were performed on the tributyltin‐free hydrolyzate, a copolymer of MMA and methacrcylic acid (MAA). Configurational sequencing at the triad level is performed using the α‐methyl region of the 13C‐NMR spectrum. The probability of isotactic (meso) dyad placement at 80°C in the homopolymer (0.19) is determined to be significantly less than the probabilities observed for the copolymers (0.23–0.24). Random compositional sequencing is established for the copolymers through a comparison of the carbonyl regions of the 13C‐NMR spectra of the hydrolyzates with the carbonyl regions in published spectra of structurally characterized copolymers of MMA and MAA. The 119Sn chemical shift and the tin‐carbon J coupling for the polymers are dependent on the solvent employed. This dependence is attributed to electron donor or acceptor interactions between the solvent and the strong SnO dipole. The tin‐containing copolymers exhibit multiple 119Sn resonances, which appear related to compositional sequencing.
Surface modification. I. Graft polymerization of acrylamide onto low‐density polyethylene by Ce4+‐induced initiation
Authors: Batich Christopher , Yahiaoui Ali 
Published: April 2003

AbstractPolyacrylamide was grafted onto a hydroxylated LDPE (low‐density polyethylene) surface yielding a highly hydrophilic and stable new surface. LDPE was first oxidized by chromic acid and then reduced with diborane to form a hydroxyl‐rich surface. Polymerization was then initiated by Ce4+/HNO3 solution. X‐ray photoelectron spectroscopy and Fourier transform‐IR/attenuated total reflection were used for elemental analysis and identification of the functional groups introduced.
Application of two‐dimensional NMR techniques for the elucidation of the proton spectrum of the epoxy monomer, diglycidyl ether of bisphenol A
Authors: Jagannathan N. R. , Herring F. G. 
Published: April 2003

AbstractThe application of two‐dimensional Fourier transform NMR spectroscopy to the study of the epoxy resin diglycidyl ether of bisphenol A is discussed. The combination of the homonuclear shift‐correlated and J‐resolved experiments permits the complete elucidation of the proton spectrum of the glycidyl ether moiety.
Polystyrene and polystyrene‐butadiene latexes stabilized by poly(N‐isopropylacrylamide)
Authors: Pelton R. H. 
Published: April 2003

AbstractLatexes stabilized by poly(N‐isopropylacrylamide) (polyNIPAM) were prepared by polymerizing NIPAM in the presence of polystyrene and polystyrene‐butadiene latex or by styrene emulsion polymerization in the presence of NIPAM. In 0.01 M CaCl2 polyNIPAM stabilized latexes exhibited critical flocculation temperatures in the range 32–35°C, which is approximately equal to the lower critical solution temperature of polyNIPAM in water. Partial substitution of NIPAM with some acrylamide (AM) gave higher flocculation temperatures. Coagulation studies with cleaned latex indicated that the polyNIPAM or polyNIPAM‐co‐AM polymer chains were anchored to the latex particle surfaces.
Studies on graft copolymerization onto cellulose derivatives. XXVII. Photo‐induced graft copolymerization onto nitrocellulose
Authors: Takahashi Akira , Sugahara Yasusato 
Published: April 2003

AbstractPhoto‐induced graft copolymerization was investigated using nitrocellulose having a different nitrogen content, especially by a noncatalytic method. The effects of a sample nitrogen content, reaction temperature, and monomer, sample, solvent and photosensitizer concentrations on the degree of grafting, the grafting efficiency, and the apparent number of grafted chains were examined. Methyl methacrylate (MMA) and methyl acrylate (MA) easily polymerized, but acrylamide (AAm), vinyl acetate (VAc), and styrene (St) scarcely polymerized. The apparent activation energies were 4.1–11.5 kcal/mol, indicating the small value in the high nitrogen content sample. The degree of grafting and the apparent number of grafted chains increased with increasing monomer and sample concentrations. In every case, the grafting efficiency was at a high level, above 90%. The polymerization did not occur without the sample in the same condition. Furthermore, a part of nitro groups split off by the irradiation of light. With respect to these results, the mechanisms of the photo graft copolymerization was discussed.
Study on thermal behavior of thermooxidized poly(vinyl formal)
Authors: Aoki Hiroyuki , Suzuki Tsutomu 
Published: April 2003

AbstractThe thermal behavior of thermooxidized poly(vinyl formal) has been investigated by means of thermogravimetry, derivative thermogravimetry, and differential thermal analysis. As a result, it has been clarified (1) that thermal decomposition is composed of three weight loss processes, (2) that, when investigating the ratic of percentage of weight remaining in each process, the behavior differs for each both before and after the thermooxidizing time of 2–4 h; the second weight loss process caused by formation of crosslinking structure prevails in the initial stage of thermooxidation while the first weight loss process caused by decomposition of various types of thermooxidation products such as unsaturated bonds and crosslinking prevails as the thermooxidation proceeds, and (3) that the volume of carbonaceous residue produced as the thermooxidation advances increases about 4 times. When kinetic parameters have been evaluated by applying the Coasts and Redfern method to each weight loss process, on the other hand, it is concluded (1) that each order of reaction is first and (2) that the value of activation energy in the third process of carbonization and burning reaction is substantially lowered as the process of the thermooxidation advances.
Ethylene–chlorotrifluoroethylene copolymers. II. Effects of structure on resistance to thermal stress cracking
Authors: Reimschuesel H. K. , Marti J. , Murthy N. S. 
Published: April 2003

AbstractCopolymers of ethylene and chlorotrifluoroethylene that contain small amounts of units derived from perfluorohexylethylene show improved resistance of thermal stress cracking. This is a consequence of effects of these units on structural parameters of both the crystalline and amorphous phases. Those of the crystalline phase entail growth and organization of lamellae, whereas those of the amorphous phase are related to conformation and packing of polymer chains. The crystalline phase consists exclusively of alternately arranged units of ethylene and chlorotrifluoroethylene. The amorphous phase is characterized by chain segments composed of randomly distributed units derived from ethylene, chlorotrifluoroethylene, pairs of these two units, and units derived from perfluorohexylethylene.