bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polymerization of methyl 12‐acryloxystearate, N,N‐dimethyl 12‐acryloxystearamide, and methyl 14‐acryloxyeicosanoate
Authors: Sowa J. R. , Marvel C. S. 
Published: May 2003

AbstractSeveral homopolymers and copolymers of the title compounds have been prepared by radical initiation with potassium persulfate or diethyl azobisisobutyrate. The copolymers exhibit a combination of the properties of the homopolymers of the monomers. The homopolymers are adhesive, very slightly elastic, and show cold flow. Several of the copolymers show possible promise for use as adhesives.
Colored electrically conducting polymers from furan, pyrrole, and thiophene
Authors: Armour M. , Davies A. G. , Upadhyay J. , Wassermann A. 
Published: May 2003

AbstractFuran, pyrrole, and thiophene were polymerized under catalysis by trichloro‐ and trifluoroacetic acid to produce colored polymers which were characterized by various methods, including electronic and proton magnetic resonance spectra and electrical conductances of deeply colored trichloroacetic acid adducts. The predominant repeat units of these polymers are of the same type as those of deeply colored cyclopentadiene polymers, except that a CH2 group is replaced by O, NH, or S.
Grafting in reaction of polyethylene and poly(maleic anhydride)
Authors: Gabara Włodzimierz , Porejko Stanisław 
Published: May 2003

AbstractPolyethylene has been grafted in a reaction with poly(maleic anhydride) in the presence of radical initiators. The role of oxygen, the comparison of the effectiveness of benzoyl peroxide and AIBN, and the kinetics of the reaction suggest that side chains are formed via a combination of the macroradicals of both polymers.
Grafting of maleic anhydride on polyethylene. I. Mechanism of grafting in a heterogeneous medium in the presence of radical initiators
Authors: Gabara Włodzimierz , Porejko Stanisław 
Published: May 2003

AbstractPolyethylene has been grafted with maleic anhydride, as proved by the infrared spectra and the properties of the grafted films. The influence of oxygen and a comparison of the effectiveness of benzoyl peroxide and AIBN showed that polyethylene macroradicals are formed through the decomposition of hydroperoxide and peroxide groups. Side chains of poly(maleic anhydride) are formed by a combination of polyethylene macroradicals with those of poly(maleic anhydride). This mechanism of reaction was confirmed by the influence of the amount of film, the initiator and monomer concentrations, and temperature on the percentage of grafting.
Grafting of maleic anhydride on polyethylene. II. Mechanism of grafting in a homogeneous medium in the presence of radical initiators
Authors: Porejko Stanisław , Gabara Włodzimierz , Kulesza Janina 
Published: May 2003

AbstractGrafting of maleic anhydride on polyethylene is found to take place also in a homogeneous medium. The course of reaction in nitrogen and in air and the influence of temperature of initiator and polymer concentrations suggest that grafting is due to the chain transfer reaction to polyethylene.
Synthesis and polymerization of N‐[1‐(1‐substituted‐2‐oxopropyl)]acrylamides and ‐methacrylamides. copolymerization of these monomers with styrene and substituent effects
Authors: Iwakura Yoshio , Toda Fujio , Suzuki Hideaki 
Published: May 2003

AbstractThe synthesis and polymerization of N‐[1‐(1‐substituted‐2‐oxopropyl)]acrylamides and ‐methacrylamides are described. Seven new monomers were prepared by two kinds of synthetic procedure. The polymerization of these monomers was carried out. Monomer reactivity ratios in the polymerization of these monomers with styrene were determined and the Alfrey‐Price Q and e values calculated. The effects of substituents on the reactivities in copolymerization were observed, and an interpretation of the results is given.
Mechanism of the tertiary amine‐catalyzed dicyandiamide cure of epoxy resins
Authors: Saunders T. F. , Levy M. F. , Serino J. F. 
Published: May 2003

AbstractInfrared and NMR data on tertiary amine‐catalyzed, dicyandiamide—epoxy resin (and model compound) systems have been utilized to elucidate the mechanism of the curing process. The early exothermic curing reaction is shown to be ring opening of the resin epoxy groups by dicyandiamide imino and amino anionic species, giving rise to N‐alkyl cyanoguanidines; a minor amount of polyether formation also occurs at this time. After the exothermic reaction is essentially complete at <90°C., a slow, high temperature (110–200°C.) addition of hydroxyl hydrogen across the nitrile triple bond occurs, giving rise to an imino ether which then rearranges to the guanyl urea.
Oxidative degradation of polystyrene
Authors: Beachell Harold C. , Smiley Leonard H. 
Published: May 2003

AbstractNuclear magnetic resonance, infrared, and ultraviolet spectroscopy were used to elucidate the structure of oxidized polystyrene. To identify the nuclear magnetic resonance peaks of the degraded polystyrene, deuterated polystyrenes were synthesized and degraded. The primary structure present in the degraded polystyrene was found to be an aromatic carbonyl group. It was shown that this structure was formed regardless of the presence of ultraviolet light and was also present when polystyrene was degraded in carbon tetrachloride solution. When polystyrene was degraded in carbon tetrachloride solution, stable polymeric peroxides were formed in a concentration of 4 peroxide groups for every 1000 styrene units.
Influence of addition of olefins on the alternating copolymerization of carbon monoxide and ethylenimine by azobisisobutyronitrile or by γ‐ray irradiation
Authors: Kagiya Tsutomu , Maruta Isao , Ichida Taizo , Narisawa Shizuo , Fukui Kenichi 
Published: May 2003

AbstractThe alternating copolymerization of carbon monoxide and ethylenimine to give poly‐β‐alanine could be initiated by γ‐irradiation but hardly by α,α'‐azobisisobutyronitrile (AIBN). It was found that in the case of the addition of olefin, this system could be copolymerized even by AIBN and that, in the γ‐ray copolymerization of carbon monoxide and ethylenimine, the addition of olefin brought about an increase in the copolymer yield. No difference was observed between the nature of copolymers obtained by AIBN and those obtained by γ‐irradiation, except in the system carbon monoxide–ethylenimine–ethylene. An increase in the amount of reacted olefin gave rise to an increase in copolymer yield. The melting points of the copolymers were in the range 295–335°C. The infrared spectra, x‐ray diffraction diagrams, and NMR spectra of the copolymers were almost identical with that of poly‐β‐alanine obtained by the hydrogen‐migration polymerization of acrylamide. Paper chromatographic analysis of the hydrolysis product of the copolymer showed the existence of β‐alanine, ethylamine, and δ‐aminovaleric acid homolog in the products. From these results, it was concluded that terpolymerization of carbon monoxide, ethylenimine, and olefin took place in the presence of AIBN or γ‐irradiation which gave a crystalline solid copolymer containing the units of nylon 3 and nylon 5. A mechanism of this copolymerization was proposed on the basis of these results.
Preparation of polymeric amines from poly(schiff bases)
Authors: Dyer Elizabeth , Anderson C. Clement 
Published: May 2003

AbstractA study was made of the preparation of aromatic polymeric amines in order to test their thermal stability. The most useful method was the hydrogenation of polymeric Schiff bases by the dimethylamine—borane reagent or the borane—tetrahydrofuran reagent. The Schiff bases were prepared by the solution polymerization of terephthalaldehyde with various aromatic diamines, including 4,4′‐methylenedianiline, benzidine, and p‐phenylenediamine, and for comparison, 1,6‐hexanediamine. The Schiff bases and the polyamines from the aromatic diamines were found to be dimers or trimers, not high polymers: the polymers from the aliphatic diamine had a degree of polymerization of about 14. Thermogravimetric analyses of the aromatic polyamines under nitrogen showed that the initial temperatures of marked degradation were 350–400°C.
Polymer reactions. VI. Inhibited autoxidation of polypropylene
Authors: Chien J. C. W. , Boss C. R. 
Published: May 2003

AbstractThe autoxidation of polypropylene inhibited by 2,6‐di‐tert‐butyl‐p‐cresol (AH) and dilauryl thiodipropionate (S) was studied by the combined methods of electron spin resonance, oxygen absorption, and chemical analysis. With AH alone, there is a critical concentration of about 6 X 10‐3 mole/l. below which there is no inhibition. This critical concentration agrees with that determined for inhibited squalane autoxidation and that calculated from known rate constants. Above the critical concentration there is a well‐defined induction period during which the ROO· concentration is estimated to be 10‐8 mole/l. [ROOH] decreased rapidly as did [A·] and [AH]; the latter are kinetically related. The rate constant for the reaction between A· and ROO· is estimated to be 7 X 107 l./mole‐sec. at 130°C. At the end of the induction period, [ROOH], [ROO·], and –d[O2]/dt increased rapidly until steady‐state values were attained for all of them. With S alone, there are only retarded oxidation but no well‐defined induction periods. [ROOH] is greatly reduced by S. In all systems where the oxidation rates were appreciably suppressed there was formed a very stable paramagnetic species, S·, which was inert toward AH and I2 but reactive toward triethyl phosphite. Because of its similarity with spin centers in carbon black, S· is postulated to be a delocalized polysulfide spin center. With both S and AH present, the combined effect of stabilization is synergistic. The observed time‐dependent variations of [ROOH], [ROO·], and [A·] follow familiar mechanisms. Mathematical relationships describing each of these three systems are included.
Organic photoconductors. VIII. Photoconductors obtained from the reaction products of poly(9‐vinyl anthracene)
Authors: Morimoto Kazuhisa , Ishida Eisuke , Inami Akira 
Published: May 2003

Abstract9‐Vinyl anthracene has been polymerized by three methods in cationic systems to obtain organic photoconductors. Cationic polymerization catalysts used were titanium tetrachloride and aluminum chloride anhydride. According to the degree of conversion from poly(9‐vinyl anthracene) to poly(9,10‐dimethylene anthracene) the photosensitivity increased.
Kinetics of polymerization of gaseous formaldehyde
Authors: Boyles James G. , Toby Sidney 
Published: May 2003

AbstractThe polymerization of gaseous monomeric formaldehyde has been studied. The effects of the following variables have been investigated: temperature, initial monomer pressure, surface‐to‐volume ratio of reaction vessel, thickness of polymer deposit, and partial pressure of added oxygen. A three‐step mechanism is proposed which successfully accounts for the results of experiments in which monomer is allowed to deposit on the bare wall of the reaction vessel. When a sufficient amount of polymer has been laid down, the termination reaction becomes negligible and a limiting two‐step mechanism holds. The present results combined with literature values from work done on the depolymerization reaction give the activation energy of the propagation and termination reactions to be 14.2 ± 0.6 and 7.8 ± 0.9 kcal./mole, respectively. Although the reaction is heterogeneous, the activation energies are independent of surface‐to‐volume ratios within the experimental error. The nature of the polymer active sites is considered and these are thought to be hydroxyl groups. The results of work done with added oxygen show a small inhibitory effect.
Dielectric properties of vinylidene chloride–vinyl chloride copolymers
Authors: Kakutani Haruko , Asahina Mitsuo 
Published: May 2003

AbstractThe dielectric properties of vinylidene chloride—vinyl chloride copolymers prepared at conversions of less than 5% were studied. The magnitude of dielectric α absorption (absorption at high temperature) is not a linear function of the composition on account of the effect of the copolymer's crystallinity. On the other hand, a nearly linear relationship was observed between the dielectric glass transition temperature (Tg) of low‐conversion polymer and its composition, while the relationship in a high‐conversion copolymer system, observed by Boyer and Narita et al., is sigmoid. The differences in the temperature—composition relationship between low‐conversion and high‐conversion copolymer systems are illustrated in terms of the distribution of molecular composition. The dielectric β absorption observed in the copolymer whose vinyl chloride molar fraction is more than 0.5 was interpreted as the local motion of vinyl chloride sequences, and the vinyl chloride sequence of 2 or 3 units is sufficient to participate in the β absorption of the copolymer.
Photopolymerization initiated by triphenylphosphine
Authors: Mao T. J. , Eldred R. J. 
Published: May 2003

AbstractThe triphenylphosphine‐initiated photopolymerization of acrylic monomers was studied. Only those monomers containing an α,β‐unsaturated carbonyl group could be photoinitiated by triphenylphosphine, styrene being unaffected at the level of initiator employed. Kinetic studies with methyl methacrylate showed that the propagation was free radical in nature. Analysis of the resulting polymer indicated that it contained one phosphorus atom per chain. Ultraviolet spectral data suggested the formation of complexes between the triphenylphosphine and each monomer for which it is initiator. A relationship between the complex and the polymerization was shown to exist. A mechanism is proposed, involving a light‐activated dipole interaction between the carbonyl oxygen and the phosphorus atom with the ultimate formation of a methacrylate type of free radical.
Studies on the charge‐transfer complex and polymerization. Part XIII. Dilution and solvent effects in radical terpolymerization
Authors: Iwatsuki Shouji , Yamashita Yuya 
Published: May 2003

AbstractIn the terpolymerization of 2‐chloroethyl vinyl ether—maleic anhydride—acrylonitrile and p‐dioxene—maleic anhydride—acrylonitrile systems the compositions of the terpolymers obtained from feed of the same mole fraction were found to be changed beyond the limit of error for the given amounts and kinds of solvent. This change was considered to be divided into two parts. The first part, discussed quantitatively, was due to a dilution effect on the equilibrium complex formation between donor and acceptor monomer, and the second, as tentatively proposed, was due to a solvent effect on the reactivity of the complex.
Cyclopolycondensations
Authors: Kurihara Masaru , Yoda Naoya 
Published: May 2003

AbstractFully aromatic polyquinazolinediones of high molecular weight were prepared by the cyclopolycondensation reaction of 4,4′‐diamino‐3,3′‐biphenyldicarboxylic acid with aromatic diisocyanates. The poly(phosphoric acid) solution polymerization techniques yielded tractable poly(urea acid), which was converted to polyquinazolinediones by thermal cyclodehydration at 300–400°C. under reduced pressure. The polyquinazolinediones thus obtained have excellent thermal stability both in nitrogen and in air. The poly(urea acid) is soluble in dimethyl sulfoxide, and films can be cast from the polymer solution of poly(urea acid) (ηinh = 0.8 to 1.8). The films are made tough by being heated in nitrogen or under reduced pressure at 300–400°C. The polymerization mechanism of the cyclopolycondensation reaction was studied, and it was established that the polymerization proceeded through the formation of tractable poly(urea acid), Structure (I), of high molecular weight, followed by cyclodehydration, yielding poly(1,2‐dihydro‐2‐imino‐4H‐3,1‐benzoxazin‐4‐one), Structure (II). On subsequently being heated this undergoes intramolecular rearrangement along the polymer chain, giving the thermodynamically stable polyquinazolinedione, Structure (III).
Analysis of the negative peaks in gel permeation chromatography
Authors: Alliet David 
Published: May 2003

AbstractThe negative peak usually encountered in gel permeation chromatography has been resolved into three distinct peaks through selection of appropriate columns. The three peaks are associated with water, nitrogen, and oxygen. Separation of these simple molecules was found to follow the fundamental theory of gel permeation chromatography, that is, separation according to straight‐chain length.
Multicenter nature of titanium‐based Ziegler–Natta catalysts: Comparison of ethylene and propylene polymerization reactions
Authors: Kissin Yury V. 
Published: May 2003

AbstractThis article discusses the similarities and differences between active centers in propylene and ethylene polymerization reactions over the same Ti‐based catalysts. These correlations were examined by comparing the polymerization kinetics of both monomers over two different Ti‐based catalyst systems, δ‐TiCl3‐AlEt3 and TiCl4/DBP/MgCl2‐AlEt3/PhSi(OEt)3, by comparing the molecular weight distributions of respective polymers, in consecutive ethylene/propylene and propylene/ethylene homopolymerization reactions, and by examining the IR spectra of “impact‐resistant” polypropylene (a mixture of isotactic polypropylene and an ethylene/propylene copolymer). The results of these experiments indicated that Ti‐based catalysts contain two families of active centers. The centers of the first family, which are relatively unstable kinetically, are capable of polymerizing and copolymerizing all olefins. This family includes from four to six populations of centers that differ in their stereospecificity, average molecular weights of polymer molecules they produce, and in the values of reactivity ratios in olefin copolymerization reactions. The centers of the second family (two populations of centers) efficiently polymerize only ethylene. They do not homopolymerize α‐olefins and, if used in ethylene/α‐olefin copolymerization reactions, incorporate α‐olefin molecules very poorly. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1745–1758, 2003
Radical‐initiated polymerization of β‐methyl‐α‐methylene‐γ‐butyrolactone
Authors: Pittman Charles U. , Lee Hookun 
Published: May 2003

Abstractβ‐Methyl‐α‐methylene‐γ‐butyrolactone (MMBL) was synthesized and then was polymerized in an N,N‐dimethylformamide (DMF) solution with 2,2‐azobisisobutyronitrile (AIBN) initiation. The homopolymer of MMBL was soluble in DMF and acetonitrile. MMBL was homopolymerized without competing depolymerization from 50 to 70 °C. The rate of polymerization (Rp) for MMBL followed the kinetic expression Rp = [AIBN]0.54[MMBL]1.04. The overall activation energy was calculated to be 86.9 kJ/mol, kp/kt1/2 was equal to 0.050 (where kp is the rate constant for propagation and kt is the rate constant for termination), and the rate of initiation was 2.17 × 10−8 mol L−1 s−1. The free energy of activation, the activation enthalpy, and the activation entropy were 106.0, 84.1, and 0.0658 kJ mol−1, respectively, for homopolymerization. The initiation efficiency was approximately 1. Styrene and MMBL were copolymerized in DMF solutions at 60 °C with AIBN as the initiator. The reactivity ratios (r1 = 0.22 and r2 = 0.73) for this copolymerization were calculated with the Kelen–Tudos method. The general reactivity parameter Q and the polarity parameter e for MMBL were calculated to be 1.54 and 0.55, respectively. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1759–1777, 2003
Synthesis of functional graft copolymers by solution copolymerization and their evaluation as dispersants in nonaqueous phase dispersion polymerization
Authors: Fujioka Masahiro , Ma Guang‐Hui , Du Yong‐Zhong , Ogino Kenji , Nagai Masatoshi , Omi Shinzo 
Published: May 2003

AbstractThe poly(HEMA‐co‐MMA‐g‐PMMA) graft copolymer was prepared with a poly(methyl methacrylate) (PMMA) macromonomer, 2‐hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA), and its application as a dispersant for the nonaqueous phase dispersion polymerization of polystyrene (PST) was investigated. Monodisperse PST particles were obtained with two‐dimensionally tailored graft copolymers, with the number of grafted chains controlled and the polar component (HEMA) in the backbone chains balanced. As for the reactor, a stirred vessel with moderate agitation yielded uniform polymer particles, whereas sealed glass ampules with an overturning motion yielded broader size distributions. Increasing the polarity of the solvent in the continuous phase yielded smaller polymer particles with a gradual deterioration of monodispersity. Uniform polymer particles with a coefficient of variation of less than 6% were obtained up to 30 wt % solid contents. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1788–1798, 2003
Synthesis and nonlinear optical properties of methacrylate polymers based on 2‐[4‐(N‐methyl,N‐hydroxyethylamino)phenylazo]‐phenyl‐6‐nitrobenzoxazole chromophore
Authors: Persico Paola , Centore Roberto , Sirigu Augusto , Casalboni Mauro , Quatela Alessia , Sarcinelli Felice 
Published: May 2003

AbstractMethacrylate polymers containing different molar contents of nonlinear optical (NLO) active molecular segments based on 2‐[4‐(N‐methyl,N‐hydroxyethylamino)phenylazo]‐phenyl‐6‐nitrobenzoxazole chromophores were synthesized, and their phase behavior and second‐order NLO properties were investigated. Polymers containing 6–17 mol % chromophore segments allowed the preparation of amorphous and optically clear thin films. Some mesomorphic structuration was exhibited by a polymer with 33 mol % chromophoric units. However, this feature did not prevent the possibility of investigating the NLO properties. Nonlinear resonance‐enhanced d33 coefficients were determined by second harmonic generation experiments on spin‐coated, corona‐poled thin films at λ = 1064 nm. Values ranging from 40 to 60 pm/V were measured with increasing chromophore molar contents. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1841–1847, 2003
Effect of the reaction parameters on the particle size in the dispersion polymerization of 2‐hydroxyethyl and glycidyl methacrylate in the presence of a ferrofluid
Authors: Horák Daniel , Semenyuk Nataliya , Lednický František 
Published: May 2003

AbstractThe precipitation of Fe3O4 from an aqueous solution with ammonium hydroxide produced nanoparticles that were coated with a layer of oleic acid [or, in some cases, poly(ethylene oxide) or poly(vinylpyrrolidone)] before their dispersion into the organic phase. The encapsulation of magnetite nanoparticles in poly(2‐hydroxyethyl methacrylate) or poly(2‐hydroxyethyl methacrylate‐co‐glycidyl methacrylate) microparticles was achieved by dispersion polymerization in toluene/2‐methylpropan‐1‐ol. Magnetic poly(glycidyl methacrylate) microparticles were obtained in the presence of poly(ethylene oxide) at the magnetite/monomer interface. The particles containing up to 20 wt % iron maintained their discrete nature and did not aggregate. The effect of the reaction medium polarity, the concentrations of the monomer, initiator, and stabilizer, and the temperature on the particle size, particle size distribution, and iron and oxirane group contents was studied. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1848–1863, 2003