bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and structural characterization of poly(4‐vinylphenylacetate‐co‐maleic anhydride)
Authors: Jones J. A. , Ottenbrite R. M. 
Published: April 2003

AbstractPoly(4‐vinylphenylacetate‐co‐maleic anhydride) was synthesized by free‐radical initiation to yield a 1:1 copolymer over a 0.2‐0.8 mole fraction range of monomer feed in maleic anhydride. Evidence of 1:1 charge transfer complex between 4‐vinylphenylacetate and maleic anhydride was obtained in the UV region at 355 nm. The 13C NMR chemical shifts and 1H NMR integration data indicate that poly(4‐vinylphenylacetate‐co‐maleic anhydride) has an alternating and stereoregular structure. The molecular weight of poly(4‐vinylphenylacetate‐co‐maleic anhydride) was controlled by using specific solvents and initiator concentrations.
Long‐lived polymer radicals. VIII. Easy formation of long‐lived propagating radicals of vinyl monomers at room temperature
Authors: Sato Tsuneyuki , Yamamoto Tsuyoshi , Ogawa Tetsuo , Otsu Takayuki 
Published: April 2003

AbstractPoly[acryloyl‐L‐valine (ALV)] microspheres containing peroxy ester groups were prepared by radical copolymerization of ALV with a small amount of di‐tert‐butyl peroxyfumarate. When the microspheres were irradiated in the presence of second vinyl monomers, long‐lived propagating radicals of the second monomers were formed in the microspheres by the reaction of microsphere polymer radicals with the monomers. The presence of a minute quantity of ethyl alcohol served to soften the microspheres and made the polymer radicals more mobile in the microspheres. As a result, sharper ESR spectra of the propagating radicals were observed although their lifetimes became shorter. This microsphere method also yielded easily the stable propagating radicals of a‐methylstyrene and 1,1‐diphenylethylene which have no homopolymerizability in usual radical polymerization. When N‐n‐propyldimethacroylamide and N,N′‐dimethyl‐N,N′‐dimethacroylhydrazine, which undergo cyclopolymerization, were used as second monomer, uncyclized polymer radicals were only observed. Some discussions were given on the propagation mechanism of the cyclopolymerization.
Ceric‐ion‐initiated grafting of methyl methacrylate onto (1 → 5)‐α‐D‐ribofuranan and (1 → 5)‐α‐D‐xylofuranan
Authors: Chen Yen‐Yuan , Oshima Ryuichi , Hatanaka Kenichi , Uryu Toshiyuki 
Published: April 2003

AbstractWe report herein studies of grafting of MMA onto (1 → 5)‐α‐D‐ribofuranan and (1 → 5)‐α‐D‐xylofuranan by ceric ion initiation both in water and in dimethyl sulfoxide (DMSO). In aqueous medium, the graft polymer having high grafting (%) can be obtained easily without adding any nitric acid. The degradation of polysaccharide by the acidic ceric ion solution is not serious; 73–82% of its original molecular weight remained after the polymerization. In DMSO, graft polymers having lower grafting (%) and lower molecular weight of grafts were obtained.
Photolysis of polymeric organosilicon systems. III. Synthesis and photochemical behavior of polysiloxanes containing phenyldisilanyl units
Authors: Nate Kazuo , Ishikawa Mitsuo , Imamura Naoya , Murakami Yoshihide 
Published: April 2003

AbstractThe synthesis and photochemical behavior of three types of polysiloxanes containing phenyldisilanyl units as chromophore have been reported. Irradiation of thin liquid films of the polymer (2) prepared from copolymerization of octamethylcyclotetrasiloxane and 1,3,5‐triphenyl‐1,3,5‐tris(trimethylsilyl)cyclostrisiloxane (1) with a 500‐W Xe‐Hg lamp afforded transparent solid films which are insoluble in common organic solvents. Similar irradiation of thin liquid films of polysiloxane (8) containing both phenyldisilanyl units and vinyl groups resulted in formation of crosslinked solid films. When thick films of the polymers 2 and 8 were irradiated with a Xe‐Hg lamp, crosslinking occurred only on the surface of the films, but inside remained as liquid. Irradiation of the films prepared from the polysiloxane involving the phenyldisilanyl units and butenyl groups, however, gave crosslinked solid films, whatever thickness of the films. The mechanism of photochemically induced crosslinking of the copolymers is discussed on the basis of the results obtained from the photolysis of 1,1‐bis(trimethylsiloxy)‐1‐phenyl(trimethyl)disilane as a model compound.
Synthesis of N‐substituted phenoxazine polymers bearing vinyl backbone
Authors: Kamogawa Hiroyoshi , Kobayashi Masahiko , Yoshihara Shigeki 
Published: April 2003

AbstractVinyl monomers bearing N‐substituted phenoxazine or 2,8‐dimethylphenoxazine units were synthesized starting with the corresponding phenoxazines. N‐substituents were 2‐vinylbenzyl‐oxycarbonylethyl group prepared via 2‐carboxyethyl group, 3‐methacrylamido‐, 3‐acrylamido‐, or 3‐(4‐styrenesulfonamido)‐propyl group prepared via 3‐aminopropyl group, vinylbenzyl, or 2‐vinyloxyethyl group attached by the displacements of sodium salts of the phenoxazines to the chlorides, and 2‐methacryloyl‐ or 2‐acryloyl‐oxyethyl group prepared via 2‐hydroxyethyl group. Free‐radical polymerixations of these novel monomers proceeded smoothly, except those with 2‐vinyloxyethyl group, which were susceptible to BF3‐etherate. Changes of the visible absorption spectrum of iodine in THF with addition of the monomers and polymers were considerable, with the appearance of new absorption peaks or shoulders in major cases.
A brief report on novel polyazobenzoxazinones
Authors: Gopal Jayalakshmi , Srinivasan M. 
Published: April 2003

AbstractPolybenzoxazinones were synthesized by solution polycondensation from five different aromatic diacidchlorides and 3,3′‐diaminoazobenzene‐4,4′‐dicarboxylic acid through a polyamic acid precursor which was further cyclodehydrated to polybenzoxazinones. The amic acid and the benzoxazinones were obtained in 85–93% and 56–63% yield, respectively. The polymers were characterized by physical and thermal analysis.
Selective separation of water–ethanol mixture through synthetic polymer membranes having carboxylic acid as a functional group
Authors: Yoshikawa Masakazu , Yukoshi Takashi , Sanui Kohei , Ogata Naoya 
Published: April 2003

AbstractSeparation of water–ethanol mixture through a membrane was carried out by pervaporation using a membrane which provided a hydrogen‐bonding interaction. A membrane obtained from poly(acrylic acid‐co‐acrylonitrile) was effective for a selective separation of water from aqueous ethanol solution by pervaporation technique. Spectroscopic and flux analyses verified that this high selectivity toward water was attributed to the hydrogen‐bonding interaction between water and acrylic acid (carboxylic acid) unit in the membrane. On the other hand, a membrane from poly(acrylic acid‐co‐styrene) preferentially permeated ethanol in the low water feed concentration region.
Segmented poly(ether urethane) films containing ferrocene units in the hard segments
Authors: Gonsalves Kenneth E. , Rausch Marvin D. 
Published: April 2003

AbstractSegmented poly(ether urethanes) were synthesized from polypropylene glycol (PPG) and 4,4′‐methylene‐bis(phenyl‐isocyanate) (MDI), using 1,1′‐bis(β‐aminoethyl)ferrocene (BAF) and 1,1′‐bis(β‐hydroxyethyl)ferrocene (BHF) as chain extenders. These polymers were characterized by infrared and 13C‐NMR spectroscopy. Mass spectrometry was also utilized to determine the linkage of BAF and BHF in these polymers.
Electrical conductivity in vinyl chloride during polymerization
Authors: Uustalu Joan M. 
Published: April 2003

AbstractVinyl chloride of good polymerization quality showed a measurable electrical conductivity. The ionic strength of redistilled VCM appeared to be independent of temperature in the range from 20 to 50°C, and to decrease at higher temperatures. Conductivity measurements during bulk polymerization of VCM showed that the conductivity decreased with conversion. Other results indicated that electrolytically active species, formed during the polymerization, were trapped in the polymer matrix.
Monomer‐isomerization polymerization. XXII.. Isomerization and polymerization of propenylbenzene with various ziegler–natta catalysts
Authors: Endo Kiyoshi , Otsu Takayuki 
Published: April 2003

AbstractThe isomerization and polymerization of propenylbenzene (PB) with various Ziegler–Natta catalyst systems have been investigated. With the TiCl3–(C2H5)3Al (Al/Ti > 2.0) catalyst at 80°C, PB polymerized to give a polymer exclusively consisting of allylbenzene (AB) unit. During the polymerization, AB, which polymerized readily with the catalyst, was produced through isomerization of PB, indicating that PB underwent monomer‐isomerization polymerization. PB also polymerized with isomerization to AB in the presence of TiCl3−(C2H5)2AlCl−NiCl2 catalyst system, and a copolymer with PB and AB units was obtained. With TiCl3−C2H5AlCl2 catalyst, poly(PB) was formed via ordinary vinylene polymerization without isomerization. From these facts, it was concluded that the structure of the polymers produced from PB widely changed, depending on the catalyst systems used, which determine the rate of isomerization to AB and the polymerization reactivity of the PB and AB isomers formed.
Poly[amino‐p‐(hydroquinone or benzoquinone)]amides and poly(p‐benzoquinono)diimidazoles of aliphatic dicarboxylic acids. V.
Authors: Kehayoglou A. H. , Sideridou‐Karayannidou I. 
Published: April 2003

AbstractPoly(amino‐p‐hydroquinone)amides prepared from 2,3,5,6‐tetraamino‐p‐hydroquinone and adipic, suberic, or sebacic acid dichloride were converted by mild oxidation to the corresponding poly(amino‐p‐benzoquinone)amides. The latter, prepared also directly from 2,3,5,6‐tetraamino‐p‐benzoquinone, were converted by thermal cyclodehydration to the corresponding thermally stable poly(p‐benzoquinono)diimidazoles. The prepared new redox polymers were characterized by elemental analysis, UV and IR spectral study, inherent viscosity, solubility, and thermal analysis (DSC, TGA).
Monomer‐isomerization polymerization. XXIII.. Monomer‐isomerization polymerization of 5‐phenyl‐2‐pentene with ziegler–natta catalysts
Authors: Endo Kiyoshi , Tsujikawa Hajime , Otsu Takayuki 
Published: April 2003

Abstract5‐Phenyl‐2‐pentene (5Ph2P) was found to undergo monomer‐isomerization polymerization with TiCl3–R3Al (R = C2H5 or i‐C4H9, Al/Ti > 2) catalysts to give a polymer consisting of exclusively 5‐phenyl‐1‐pentene (5Ph1P) unit. The geometric and positional isomerizations of 5Ph2P to its terminal and other internal isomers were observed to occur during polymerization. The catalyst activity of alkylaluminum examined to TiCl3 was in the following order: (C2H5)3Al > (i‐C4H9)3Al > (C2H5)2AlCl. The rate of monomer‐isomerization polymerization of 5Ph2P with TiCl3–(C2H5)3Al catalyst was influenced by both the Al/Ti molar ratio and the addition of nickel acetylacetonate [Ni(acac)2], and the maximum rate was observed at Al/Ti = 2.0 and Ni/Ti = 0.4 in molar ratios.
Thermal decomposition mechanisms of sequential bipolyesters based on propeneglycol and hydroxybenzoic/phthalic diacid derivatives
Authors: Giuffrida Mario , Maravigna Pietro , Montaudo Giorgio , Chiellini Emo 
Published: April 2003

AbstractSome bipolyesters consisting of 1,2‐propene glycol residue (P) and symmetric aromatic diacid residue constituted by two p‐oxybenzoyl groups coupled by a terephthaloyl (HTH), phthaloyl (HOH) and isophthaloyl (HIH) group, and a nonsymmetric diacid residue constituted by a p‐oxybenzoyl and a terephthaloyl group (HT), have been investigated by direct pyrolysis–mass spectrometry. The results show that intramolecular exchange reactions occurring at the pyrolysis stage cause a reorganization of the copolymer sequences. Sequential bipolyesters I–IV are ideal materials for the investigation of the extent of thermal reorganization induced in the bipolymer sequences by the pyrolytic process.
Addition reactions of pendant epoxide group in poly(glycidyl methacrylate) with various active esters
Authors: Nishikubo Tadatomi , Iizawa Takashi , Saita Seiji 
Published: April 2003

AbstractAddition reactions of pendant epoxide groups in poly(glycidyl methacrylate) (PGMA) with various active esters such as 1‐benzotriazolyl benzoate, S‐(2‐benzoxazolyl) thiobenzoate, S‐(2‐benzothiazolyl) thiobenzoate, 4‐nitrophenyl benzoate (4NPB), and S‐phenyl thiobenzoate (PTB) were carried out using quaternary salts as catalysts. The reactions of PGMA with those active esters proceeded in diglyme at 100°C for 24 h quantitatively without the formation of 2‐hydroxyl pendant groups in the polymer when 10 mol % of tetraethylammonium bromide was used as a catalyst. Furthermore, it was found that the respective quaternary salts have higher catalytic activity than tertiary amines in the reaction of PGMA with the active esters, and the reaction of PGMA with 4NPB gave the corresponding polymer with the highest conversion by addition of tetrabutylammonium bromide as a catalyst, while tetraethylammonium chloride showed the highest activity for the reaction of PGMA with PTB. In addition, the rate of reaction of PGMA with 4NPB was proportional to third order kinetics of the epoxide concentration, the ester concentration and the catalyst concentration as follows: −d[Epoxide]/dt = −[Ester]/dt = k3[Epoxide] [Ester] [Catalyst].
Direct polycondensation of hydroxybenzoic acids with thionyl chloride in pyridine
Authors: Higashi Fukuji , Mashimo Toshio 
Published: April 2003

AbstractThe reaction promoted by thionyl chloride and pyridine could selectively activate carboxyl groups of hydroxybenzoic acids to give polyesters of high inherent viscosities up to 3.8. Favorable conditions were studied in terms of the temperatures for the initial reaction with the acids and subsequent aging at room temperature. Copolymers of several combinations of hydroxybenzoic acids with high molecular weights were obtained in quantitative yield by carrying out the polycondensation at 80°C for 3 h. The reaction could also produce high molecular polyesters in a simpler process without the initial activation of dicarboxylic acids by adding a mixture of these monomers to the condensing agent, and a tough film‐ and fiberforming polymer was obtained from 4,4′‐dihydroxyphenylsulfone of low nucleophilicity whose polymer of high molecular weight is difficult to obtain. The process was also successfully applied to the direct copolycondensations of hydroxybenzoic acids, aromatic dicarboxylic acids, and bisphenols to produce polyesters of ηinh up to 5.6.
Kinetics of polymerization of vinyl monomers initiated by lead tetraacetate
Authors: Balakrishnan T. , Kasilingam E. K. 
Published: April 2003

AbstractA systematic study of the thermal polymerization of α‐chloroacrylic acid and α‐bromoacrylic acid in aqueous nitric acid was carried out. The effect of variation of monomer concentration lead tetraacetate concentration, hydrogen ion concentration, ionic strength, and temperature on the rate of monomer disappearance was carried out. Based on the experimental observations, suitable reaction schemes were proposed for the polymerization of the above monomers. The rate constants and the thermodynamic parameters were evaluated.
Characterization of large water‐soluble macromolecules by size exclusion chromatography
Authors: Lundy Charles E. , Hester Roger D. 
Published: April 2003

AbstractA method for characterizing very large, water‐soluble polymers by size exclusion chromotography (SEC) has been developed. Sephacryl S1000 packing material, a precision syringe pump, and an eluent pressure detector have been utilized to produce highly accurate chromatograms of polymers having molecular hydrodynamic diameters up to 250 nm. Previous SEC analysis has been limited to polymers having hydrodynamic diameters of less than 120 nm.
Polymerization of 1‐(trimethylsilyl)‐1‐propyne homologs containing two silicon atoms by tantalum‐ and niobium‐based catalysts
Authors: Isobe Eiji , Masuda Toshio , Higashimura Toshinobu , Yamamoto Akira 
Published: April 2003

AbstractPolymerization of new 1‐(trimethylsilyl)‐1‐propyne homologs containing two silicon atoms [CH3CCSi(CH3)2CH2Si(CH3)3 and CH3CCSi(CH3)2CH2CH2Si(CH3)3] was investigated by use of Ta and Nb catalysts. CH3CCSi(CH3)2CH2Si(CH3)3 was polymerized quantitatively by TaCl5 alone to provide a polymer having molecular weight over 106. CH3CCSi(CH3)2CH2CH2Si(CH3)3 was polymerized in good yield by an equimolar mixture of TaCl5 with an appropriate organometallic cocatalyst such as Ph4Sn to give a polymer with molecular weight of ca. 4 X 105. Nb catalysts were less active toward these monomers than the corresponding Ta catalysts. These two kinds of polymers had alternating double bonds along the main chain according to IR and 13C‐NMR spectra. Both polymers were white solids completely soluble in low‐polarity solvents like toluene, and solution casting afforded uniform, tough films. These polymers were thermally fairly stable, and their softening points were above 350°C. Films of these polymers showed smaller oxygen permeability coefficients [P = 4 × 10−9 – 8 × 10−9 cm3(STP) · cm/(cm2·sec·cmHg)] but larger separation factors [(P/P) = 3.4 – 3.6] than a poly[1‐(trimethylsilyl)‐1‐propyne] film.
Thermooxidatively stable articulated benzobisoxazole and benzobisthiazole polymers
Authors: Evers Robert C. , Moore George J. 
Published: April 2003

AbstractArticulated all‐para polymers with 2,6‐benzobisoxazole and 2,6‐benzobisthiazole units in the backbone weree synthesized by copolycondensation in polyphosphoric acid of 4,6‐diamino‐1,3‐benzenediol dihydrochloride and 2,5‐diamino‐1,4‐benzenedithiol dihydrochloride, respectively, with terephthalic acid and reactive 3,3′‐biphenyl or 4,4′‐(2,2′‐bipyridyl) monomers. Inherent viscosities of up to 13.18 dL/g (CH3SO3H, 25°C, 0.2 g/dL) were achieved. The average length of the rodlike all‐para segments between the relatively flexible biphenyl or bipyridyl units was controlled by the stoichiometry of the copolycondensation reactions. Dependent upon the solids content of the polymerization mixture and the mole proportion of the flexible units in the polymer backbone, copolycondensation proceeded in the liquid‐crystalline state to give polymerization mixtures which exhibited lower bulk viscosities than comparable copolycondensation reactions that remained in the isotropic state. Films which exhibited optical birefringence under crossed polars could be cast from methanesulfonic acid solutions of the polymers. Thermooxidative stability of the articulated polymers was evaluated by isothermal aging in air at 371°C. Stability for the polymers was found to decrease slightly with increased content of the flexible biphenyl structure in the polymer backbone. The biphenyl structure was found to be more thermooxidatively stable than the bipyridyl structure.
Photolysis of aromatic diisocyanate‐based polyurethanes in solution
Authors: Hoyle Charles E. , Kim Kyu‐Jun 
Published: April 2003

AbstractFluorescence analysis has been employed as an analytical technique to elucidate the photolysis mechanism of several aromatic diisocyanate‐based polyurethanes in solution. Based on a comparison with model arylmonocarbamates and arylbiscarbamates, the photo‐Fries rearrangement and cleavage‐type products found for the small‐model arylcarbamates were also identified for the photolyzed polyurethanes in solution. Viscosity and absorbance change results for photolysis of both air and nitrogen‐saturated polyurethane solutions are consistent with a general two‐step mechanism for the photolysis of aromatic diisocyanate‐based polyurethanes.
Radiation‐induced graft polymerization of acrylamide I. Preparation conditions and gel determination for polyethylene‐grafted films
Authors: Hegazy El‐Sayed A. , Dessouki Ahmed M. , El‐Boohy Hussain A. 
Published: April 2003

AbstractRadiation‐induced graft polymerization of acrylamide (AAm) onto low‐density polyethylene(LDPE) film has been investigated. The appropriate reaction conditions at which the graft polymerization was carried out successfully were selected. It was observed that the grafting process was enhanced remarkably by using distilled water as diluent. In this grafting system ammonium ferrous sulphate (Mohr's salt) was used as inhibitor to minimize the homopolymerization of AAm and the suitable concentration of such inhibitor was found to be 3 wt %. The dependence of the grafting rate on the monomer concentration was calculated to be 2.9 order, regardless of the irradiation atmosphere (N2 gas or under vacuum). When the radiation grafting process was carried out under vacuum, higher degrees of grafting were obtained as compared to those in nitrogen gas or in air atmosphere. Network structure was formed in the graft copolymer and the gel formation was determined in the p‐xylene‐extracted grafted films. Results showed good evidence that the grafting process takes place by the front mechanism.
Organosilane polymers: Synthesis and photochemical and photophysical behavior of poly[dimethyl‐co‐methyl(1‐naphthyl)silylene]
Authors: Todesco R. V. , Basheer R. 
Published: April 2003

AbstractA meltable, partially crystalline silane copolymer, PSN, containing dimethylsilylene and methyl(1‐naphthyl) silylene units was synthesized and characterized. The polymer has a high molecular weight, is appreciably soluble in common solvents and is photoactive. The emission properties of PSN, under stationary and nonstationary conditions, were studied in dilute THF solution. PSN is the first organosilane polymer showing an intense intramolecular excimer emission in addition to monomer and intramolecular charge transfer (CT) fluorescence. It is shown that the ratio of excimer to monomer fluorescence can be used to monitor the UV induced degradation of the polymer.
Synthesis and characterization of the novel type of polymerizable bisphthalonitrile monomers
Authors: Achar B. N. , Fohlen G. M. , Parker J. A. 
Published: April 2003

AbstractThree new bisphthalonitrile derivatives are prepared by the nucleophilic displacement of the nitrosubstituent from 4‐nitrophthalonitrile with 9,9‐bis(4‐hydroxyphenyl)fluorene; 9,9‐bis(3,5‐dimethyl‐4‐hydroxyphenyl)fluorene, and phenolphthalein in the presence of potassium carbonate. The reaction has been carried out in dimethylsulfoxide solvent. These monomers are characterized by elemental analysis, FT‐IR, 1H NMR, TGA, DSC, and mass spectral studies. A tentative mechanism for the fragmentation of the compounds is given to explain the mass spectral data. The compounds are expected to be useful to prepare thermally stable thermosetting phthalocyanine polymers.
Crystallization and melting behavior of isotactic polybutene‐1 at high pressures
Authors: Kishore K. , Vasanthakumari R. , Ramesh T. G. 
Published: April 2003

AbstractAn equation has been developed for the study of the kinetics of polymer crystallization at high pressures using differential scanning calorimetry (DSC) in the dynamic mode of operation. The activation energy for the crystallization of isotactic polybutene‐1 (PB‐1) has been determined to be ca. 20 kcals/mol; this has been attributed to the transport of chain segments to the site of crystallization. The melting behavior of form‐I PB‐1 crystals has been studied by using a high‐pressure differential thermal analyzer (DTA) setup and high‐pressure DSC. The melting temperature Tm does not show any significant change with pressure in the low‐pressure region up to 1.2 kbar; beyond this point a large increase in Tm with pressure was observed. This unusual low‐pressure behavior of PB‐1 has been attributed to formation of intermediate form I′, which has a lower melting point than form I.