bluuebunny/crossref_metadata_2025_split huggingface dataset:
Four‐center type photopolymerization in the solid state. III. Polymerization of phenylene diacrylic acid and its derivatives
Authors: Suzuki Fusae , Suzuki Yasuzo , Nakanishi Hachiro , Hasegawa Masaki 
Published: April 2003

AbstractThe solid‐state photopolymerization of phenylene diacrylic acid (PDA) and its derivatives was studied as an application of solid‐state photodimerization of cinnamic acid to photopolymerization of corresponding bifunctional molecule which has two cinnamic units in a single molecule. p‐ and m‐PDA, and their esters and amides were prepared and investigated with respect to their photopolymerizability. Many of them have been found to polymerize into linear high polymers with the cyclobutane rings in the main chain on irradiation by ultraviolet or visible light. The polymerization process, the structure of the polymers, and their general properties were investigated in several ways. All the polymers are very similar to poly‐2,5‐distyrylpyrazine and poly‐1,4‐bis(β‐pyridyl‐2‐vinyl) benzene with respect to their polymerization behavior, polymer structure, and some polymer properties: these polymers are soluble in a limited number of solvents, they have a high melting point and an extremely high crystallinity. On the basis of chemical behavior of poly‐PDA and its phenyl ester the possible steric configurations of these polymers are discussed. It is demonstrated for the PDA series that solid‐state dimerization can be generally extended to solid‐state photopolymerization of the compound having two dimerizable units in a single molecule, although the crystal structure renders polymerization impossible in certain cases.
Polymers from 1,3‐dipole addition reactions. The nitrilimine dipole from tetrazoles
Authors: Stille J. K. , Gotter L. D. 
Published: April 2003

AbstractPolymers containing pyrazole and triazole units in the polymer chain were obtained through the 1,3‐dipolar addition reaction of bisnitrilimines generated from tetrazoles with diynes and dinitrile dipolarophiles. The reaction of 2,2′‐diphenyl‐5,5′‐m‐ and p‐phenyleneditetrazole with the dipolarophiles m‐ and p‐diethynylbenzene, terephthalonitrile, tetrafluoroterephthalonitrile, perfluoroglutarylnitrile, and 4,4′‐dicyanobiphenyl gave a series of thermally stable polymers of high molecular weight. The polypyrazoles were soluble in acid and in some cases in chlorobenzene or 1,2,4‐trichlorobenzene and had intrinsic viscosities as high as 1.67, while the polytriazoles were soluble in 1,2,4‐trichlorobenzene and chlorobenzene, but not in acid, and had viscosities ranging up to 0.40. The thermogravimetric analyses of the finely powdered polymers showed breaks near 500°C in air and nitrogen atmospheres.
Phase diagram and X‐ray diffraction analysis of the acrylic acid–acrylamide system
Authors: Parrish C. F. , Kochanny G. L. , Rinn H. W. 
Published: April 2003

AbstractThe phase diagram of the acrylic acid–acrylamide system as determined by DTA and the supporting x‐ray diffraction data are presented. This diagram shows that the system forms a 1 : 1 addition compound which decomposes above 0°C. There is also one eutectic point at a 67 mole‐% acrylic acid composition.
Anionic graft polymerization of lithiated poly(2,6‐dimethyl‐1,4‐phenylene ether)
Authors: Chalk A. J. , Hoogeboom T. J. 
Published: April 2003

AbstractLithiated poly(2,6‐dimethyl‐1,4‐phenylene ether) has been used as an initiator for the graft polymerization of isoprene, methyl methacrylate, hexamethylcyclotrisiloxane, and phenyl isocyanate with the use of toluene and tetrahydrofuran as solvents. The products were examined by gel‐permeation chromatography for evidence of homopolymerization and graft polymerization. The composition of the graft copolymers was determined by NMR, and for isoprene and hexamethylcyclotrisiloxane, termination by trialkylchlorosilanes enabled chain lengths to be determined by NMR. The use of toluene gave rise to some homopolymerization, but with tetrahydrofuran, only hexamethylcyclotrisiloxane gave homopolymer. In all cases, graft copolymers were formed. With isoprene and methyl methacrylate, soluble graft copolymers were formed in good yield. In the former case approximately 60% 3,4 and 40% 1,4 addition was found. In the latter case 1,1‐diphenylethylene was used to reduce crosslinking, in its absence, methyl methacrylate gave only crosslinked gels in tetrahydrofuran. Hexamethylcyclotrisiloxane added only one molecule per lithium on the polymer, the remainder giving homopolymer. Phenyl isocyanate gave some soluble graft copolymer in toluene, but only crosslinked products were obtained when tetrahydrofuran was used as reaction solvent.
Kinetic study of γ‐radiation‐induced polymerization of ethylene in the presence of acetylene
Authors: Mitsui Hiroshi , Hosoi Fumio , Kagiya Tsutomu 
Published: April 2003

AbstractThe effects of acetylene on the γ‐radiation‐induced polymerization of ethylene were studied from the viewpoint of kinetics. The experiments were carried out under a pressure of 150–400 kg/cm2; the temperature was 30°C; the dose rates were 2.7 × 104 and 1.1 × 105 rad/hr; the acetylene content was 0–2.21%. Both the polymer yield and the molecular weight increased acceleratively with the reaction pressure in the polymerization containing 0.18% acetylene. The yield increased almost proportionally with the dose rate, and the molecular weight was found to be almost independent of the dose rate in the polymerization containing 2.21% acetylene. The polymerization rate and the molecular weight increased with reaction time, but the increment decreased with increasing acetylene content. The degree of increase in the molecular weight also decreased with increasing time. These results were analyzed by using a graphical evaluation method for kinetics, and the effects of acetylene on each elementary step in the polymerization discussed.
Condensation of benzyl chloride catalyzed by group II metals
Authors: Spanier Edward J. , Caropreso Frank E. 
Published: April 2003

AbstractThe polymerization of benzyl chloride in the presence of various group II metal salts has been investigated. The extent of reaction and the relative activities of various salts were determined by measurement of the evolved HCl as a function of time. Formation, in situ, of an active catalyst is proposed.
Effect of viscosity on termination rate constant in radical polymerization at low conversion
Authors: Ito Katsukiyo 
Published: April 2003

AbstractBy using the expression, kt = A1Ds for the chain termination rate constant (where A1 is a constant and Ds is the diffusion constant of radical chain end), a familiar chain termination rate constant, kt = A2/ηs (where A2 is a constant and ηs is solvent viscosity) was examined with variation of conversion x. It was found that the proportionality of chain termination rate constant and solution viscosity is a valid relation at conversion 0 but is approximate at conversion xc ≥ x > 0. Here xc denotes a critical conversion under the average distance around spherical polymers formed in polymerization solution is zero. At conversions above xc, the inverse relation between chain termination rate constant and solution viscosity is not correct.
Radiation‐induced polymerization of 1,1,2‐trichlorobutadiene in the solid state
Authors: Ito Katsukiyo , Matsuda Tatsuo 
Published: April 2003

AbstractChanges in the polymerization and in the structure of the polymer formed during the course of polymerization of 1,1,2‐trichlorobutadiene in the solid state were studied. We observed that the rate of polymerization and the molecular weight of the polymers formed increasing conversion. The content of 1,4 units in the polymer also increases with increasing conversion.
Grafting with acrylonitrile with the redox system cellulose xanthogenate–hydrogen peroxide
Authors: Dimov Kyril , Pavlov Pavel 
Published: April 2003

AbstractThe possibility of obtaining modified cellulose products by reacting cellulose xanthogenate in solutions containing oxidizers and acrylonitrile was studied. The ability of the cellulose xanthogenate–hydrogen peroxide redox system to initiate graft copolymerization of acrylonitrile on the cellulose was demonstrated. The influence of various factors on the processes was investigated. An attempt was made to clarify the nature of the reactions involved.
Three‐component catalysts containing aldehydes for stereospecific polymerization of propylene
Authors: Watt W. R. , Fisher C. D. 
Published: April 2003

AbstractAldehydes, when added to mixtures of ethylaluminum dichloride and titanium trichloride under pressure of propylene, have been found to promote either propylation of benzene or stereospecific polymerization of propylene. Selectivity between the two reaction paths is influenced by the molecular structure of the aldehyde. Most aldehydes promote propylation of benzene to cumene and higher isopropyl benzenes. Propylation occurs with or without titanium trichloride present. Substituted aromatic aldehydes with three or more alkyl substituents promote stereospecific polymerization of propylene. Both reactions are dependent upon the ethylaluminum dichloride/aldehyde molar ratio.
Chain‐transfer constant of fluoroalcohols
Authors: Kar Indrajit , Mandal B. M. , Palit S. R. 
Published: April 2003

AbstractChain transfer constants of some fluoroalcohols [HCF2(CF2)n−1CH2OH, n = 2, 4, 6] in the catalyzed polymerization of vinyl acetate, styrene, acrylonitrile, and methyl methacrylate at 60°C have been evaluated by a method based on degree of polymerization. Since fluoroalcohols are normally nonsolvents for polymers, a homogeneous reaction phase is maintained by carrying out the polymerization in benzene (except in case of acrylonitrile, where no solvent was used). The transfer constants vary, depending on the reactivity as well as the polarity of the radicals, in the following order: vinyl acetate > styrene > methyl methacrylate > acrylonitrile. Of the three fluoroalcohols studied, the transfer constants increase with the increasing value of n. The results have been interpreted in terms of polar structure contribution in the transition state of the transfer reactions.
Photopolymerization of vinyl monomers in the presence of chlorosilane compounds
Authors: Minoura Yuji , Toshima Hiroyuki 
Published: April 2003

AbstractThe photopolymerization of vinyl monomers (methyl methacrylate and styrene) was investigated in the presence of chlorosilane compounds. It was found that these additives acted as photosensitizers. In the case of the photopolymerization of methyl methacrylate, the rate of polymerization was found to be proportional to the concentration of methyl methacrylate and to the square root of the chlorosilane concentration. The chain‐transfer constants of these photosensitizers, SiCl4, CH3SiCl3, (CH3)2SiCl2, (CH3)3‐SiCl, and (CH3)4Si, with ultraviolet irradiation were 25.6 × 10−3, 18.4 × 10−3, 17.5 × 10−3, 14.4 × 10−3 and 0.5 × 10−3, respectively, for methyl methacrylate.
Room‐temperature polycondensation of β‐amino acid derivatives VI. Synthesis of various N‐(hydroxyethyl) nylons
Authors: Ogata Naoya , Sanui Kohei 
Published: April 2003

AbstractVarious N‐(hydroxyethyl)amino acid esters having a methyl substituent or phenyl group between amine and ester groups have been synthesized and their polycondensation behavior was investigated. These substituted amino acid esters gave amorphous polyamides which were soluble in alcohol. A model reaction between N‐(hydroxyethyl)‐amine and carboxylic acid ester was carried out in order to elucidate the role of hydroxyethyl group on the polycondensation. It was found that the amidation reaction took place rapidly at room temperature when the alkyl group of the carboxylic acid was small. N‐(Hydroxyethyl) polyamides were obtained from N,N′‐(bishydroxyethyl)‐dicamines and dicarboxylic acid esters. The reaction mechanism of the room‐temperature polycondensation reaction is discussed.
Anionic polymerization of o‐ and p‐methoxystyrene
Authors: Geerts J. , Van Beylen M. , Smets G. 
Published: April 2003

AbstractThe butyllithium‐initiated polymerization of o‐ and p‐methoxystyrene was studied in toluene at 20°C by dilatometry. Initiation of o‐methoxystyrene was found to be instantaneous as evidenced by the absence of any induction period. The propagation rate proceeds by an internal first order with respect to the monomer concentration while the order with respect to the living chain ends varies from 0.67 to 0.51 over a concentration range from 4.5 × 10−4 to 1.8 × 10−2 mole/1. The rate may thus be expressed by the equation,

where [M] and [PLi] denote concentration of monomer and poly‐o‐methoxystyryllithium, respectively, and n varies from 0.67 to 0.51. It is assumed that the propagation proceeds exclusively via the monomeric form of the ion‐pairs in analogy with the polymerization of styrene. The variable order results from the relatively high value of the dissociation equilibrium constant of dimeric into the monomeric ion‐pairs K that was evaluated graphically to be 10−3 instead of 10−6 for styrene. The propagation rate constant kp was found to be equal to about 50 l./mole‐min; the propagation activation energy is equal to 12 kcal/mole. No appreciable termination was found in the polymerization of o‐methoxystyrene. On the contrary, no quantitative data could be obtained for the polymerization of p‐methyoxystyrene due to a slow initiation and a relatively fast termination reaction with formation of a precipitate of highly branched or crosslinked polymer. It is assumed that this precipitate results from a secondary ring metallation reaction.
Thermal degradation of polymers with phenylene units in the chain. II. Sulfur‐containing polyarylenes
Authors: Ehlers G. F. L. , Fisch K. R. , Powell W. R. 
Published: April 2003

AbstractPoly(p‐phenylene sulfide), a poly(arylene sulfone), and a poly(arylene sulfonate) were subjected to thermal degradation in vacuo, at temperatures between 250 and 620°C. The volatile and solid degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. The major decomposition product of poly‐(phenylene sulfide) is a condensate, which consists of di‐ and trimeric chain fragments, dibenzothiophene, and possibly thianthrene. The residual polymer loses two thirds of its sulfur as hydrogen sulfide, however, one third is retained even at 620°C. The most characteristic decomposition reaction of the polysulfone and of the polysulfonate is the almost complete removal of the sulfur as sulfur dioxide. The elimination of sulfur dioxide is practically complete at 450°C for the polysulfone and at 350°C for the polysulfonate.
Thermal degradation of polymers with phenylene units in the chain. III. Polyarylates
Authors: Ehlers G. F. L. , Fisch K. R. , Powell W. R. 
Published: April 2003

AbstractThe thermal decomposition of three aromatic polyesters was studied in vacuo. The degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. Breakdown mechanisms are proposed. Primary cleavage of the ester linkages appears to take place either between the carbonyl and the oxygen or between the oxygen and the ring, yielding carbon monoxide and carbon dioxide in varying ratios. Another major decomposition product is a sublimate which seems to consist mainly of the phenolic component of the polyester. A polyester with a 2,2‐propylene linkage showed, as expected, early loss of methane. A pendent pentyloxy chain in one of the polymers is removed almost completely below 350°C with formation of alkanes and alkenes. Lack of oxygen in the fragments indicates that the main cleavage must occur between the ether oxygen and the aliphatic chain or with in the aliphatic chain.
Structure and reactivity of α,β‐unsaturated ethers. VIII. Cationic copolymerizations and acetal additions of propenyl and isobutenyl ethyl ethers
Authors: Okuyama T. , Fueno T. , Furukawa J. 
Published: April 2003

AbstractCationic copolymerizations of cis‐ and trans‐propenyl ethyl ethers (PEE) with isobutenyl ethyl ether (IBEE) were carried out in methylene chloride at −78°C with the use of boron trifluoride etherate as catalyst. Monomer reactivity ratios were r1 = 24.0 ± 2.4 and r2 = 0.02 ± 0.02 for the cis‐PEE (M1)–IBEE (M2) system and r1 = 19.1 ± 1.8 and r2 = 0.04 ± 0.02 for the trans‐PEE (M1)–IBEE (M2) system, indicative of the reactivity order: cis‐PEE > trans‐PEE ≫ IBEE. In separate experiments, these β‐methyl‐substituted vinyl ethers were allowed to react with various acetals in the presence of boron trifluoride etherate. The relative reactivities of these ethers were generally found to decrease in the order: cis‐β‐monomethylvinyl > vinyl > trans‐β‐monomethylvinyl > β,β‐dimethylvinyl. Comparisons of these results with previously published copolymerization data have permitted the conclusion that, in both the copolymerizations and acetal additions, the single β‐methyl substitution on vinyl ethers exerts little steric effect against their additions toward any alkoxycarbonium ion, whereas the β,β‐dimethyl substitution results in a large adverse steric effect toward both β‐monomethyl‐ and β,β‐dimethyl‐substituted alkoxycarbonium ions.
Thermal degradation of poly(methyl α‐phenylacrylate)
Authors: Cameron G. G. , Kerr G. P. 
Published: April 2003

AbstractVolatile products, molecular weight changes, and rates of volatilization have been examined during the thermal decomposition of poly(methyl α‐phenylacrylate) in vacuum at 210–280°C. In the early stages of the decomposition, initiation occurs at random within the polymer backbone to give radicals which unzip exclusively to monomer, with a kinetic chain length of about 500. Later in the reaction, chain‐end initiation becomes important and predominates beyond about 45% conversion. There is no evidence that transfer reactions occur during the degradation.
Kinetics of anionic polymerization of α‐methylstyrene in tetrahydrofuran
Authors: Hui K. M. , Ng T. L. 
Published: April 2003

AbstractThe kinetics of anionic polymerization of α‐methylstyrene have been studied in tetrahydrofuran at −30 to 10°C with Na+ and K+ as cations. In the Na+ system, a negative activation energy of −2 kcal/mole was observed in the temperature range −10 to +10°C. The results were analyzed in terms of propagation by both contact and solvent‐separated ion‐pairs. The relative proportions of the two types of ion‐pair were estimated by making use of our data and those of Dainton et al. for the same system at −60 to −30°C. The rate constants of solvent‐separated ion‐pairs, ks, were estimated as 4.2 and 0.64 1./mole‐sec at −31°C and −59°C, respectively. The discrepancy between our values of ks and Dainton's was discussed. It is concluded that poly‐α‐methyl‐styryl sodium has a higher tendency than polystyryl sodium to form solvent‐separated ion pairs. In the K+ system, our data at −30 to 10°C and those of Dainton et al. at −60 to −40°C fit well into a straight line in the same Arrhenius plot from which an activation energy of 5.2 kcal/mole and log A = 3.4 (1./mole‐sec) were obtained.
Monomer‐isomerization polymerization. V. Effects of transition metal compounds on monomer‐isomerization polymerizations of butene‐2 and pentene‐2
Authors: Otsu Takayuki , Shimizu Akihiko , Imoto Minoru 
Published: April 2003

AbstractIn order to clarify the correlation between polymerization and monomer isomerization in the monomer‐isomerization polymerization of β‐olefins, the effects of some transition metal compounds which have been known to catalyze olefin isomerizations on the polymerizations of butene‐2 and pentene‐2 with Al(C2H5)3–TiCl3 or Al(C2H5)3–VCl3 catalyst have been investigated. It was found that some transition metal compounds such as acetylacetonates of Fe(III), Co(II), and Cr(III) or nickel dimethylglyoxime remarkably accelerate these polymerizations with Al(C2H5)3–TiCl3 catalyst at 80°C. All the polymers from butene‐2 were high molecular weight polybutene‐1. With Al(C2H5)3–VCl3 catalyst, which polymerizes α‐olefins but does not catalyze polymerization of β‐olefins, no monomer‐isomerization polymerizations of butene‐2 and pentene‐2 were observed. When Fe(III) acetylacetonate was added to this catalyst system, however, polymerization occurred. These results strongly indicate that two independent active centers for the olefin isomerization and the polymerizations of α‐olefins were necessary for the monomer‐isomerization polymerizations of β‐olefins.
Radiation‐induced solid‐state polymerization of methacrylic acid. I. Crystalline transition of the monomer
Authors: Sakai Yoshiro , Iwasaki Machio 
Published: April 2003

AbstractThe anomalous crystalline transition of methacrylic acid found by broad‐line NMR measurements was studied in connection with the build‐up and decay of trapped radicals. The build‐up of radicals is smaller and the decay rate of the trapped radicals is faster in the low‐temperature range (phase II), which gave the narrower maximum slope distance ΔHmsl of the NMR spectrum, than those in the higher temperature range (phase I), which gave the broader ΔHmsl. From these experiments it was concluded that in phase I the crystals have a more closely packed structure, resulting in a more rigid matrix for the trapped radicals than those in phase II. This interpretation is consistent with the temperature dependence of the ESR spectrum of the trapped propagating radicals previously reported. The existence of the crystalline transition was also confirmed by DSC measurements, and the effects of the crystallization conditions on the transition were investigated and were discussed with reference to the results of broad line NMR measurements.
Thermal decomposition products of poly(vinyl alcohol)
Authors: Tsuchiya Yoshio , Sumi Kikuo 
Published: April 2003

AbstractThe thermal decomposition of poly(vinyl alcohol) is known to occur in two stages. In a study of first‐stage decomposition, this polymer was pyrolyzed in vacuum at 240°C for 4 hr and the products were determined by using gas chromatography. The main products were water, aldehydes having the general formula and methyl ketones having the formula , where n = 0, 1, 2, 3, etc. Mechanisms for the formation of these carbonyl compounds are discussed.
Radiation‐induced solid‐state polymerization of methacrylic acid. II. In‐source polymerization
Authors: Sakai Yoshiro 
Published: April 2003

AbstractThe in‐source polymerization of methacrylic acid in the solid state with γ‐rays was studied. The conversion rates at various temperatures were obtained as well as the radical concentrations by the measurements of ESR spectrum. The rate of polymerization was found to be proportional to I0.65 at 0°C. The results could be interpreted on the basis of the assumption that the rate of propagation is proportional to the concentration of the propagating radical, of the monomer, and of the polymer. The addition of water to the monomer seems to accelerate the polymerization reaction. The change of the line shape of the propagating radical during polymerization was interpreted in terms of the change of the matrix which surrounds the propagating radical.
Radiation‐induced solid‐state polymerization of methacrylic acid. III. Post‐polymerization
Authors: Sakai Yoshiro 
Published: April 2003

AbstractThe post‐polymerization of methacrylic acid in the solid state was studied. The decay of the trapped radicals was also observed by ESR measurements. The decay of trapped radicals is a first‐order reaction below 0°C but a second‐order reaction at + 10°C. The results of the post‐polymerization were compared with the results of radical decay measurements. A kinetic scheme was proposed for the post‐polymerization of methacrylic acid. The effect of conditions of monomer crystallization on the polymer yield was also investigated. Fine crystals gave a greater limiting conversion than large crystals. The addition of water to the monomer increased the polymer yield. The change in the ESR spectrum during post‐polymerization was interpreted in terms of the change in the matrix which surrounds the propagating radicals.