bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vinyl polymerization. LXXIII. Polymerization and copolymerization of bornyl or isobornyl methacrylate
Authors: Imoto Minoru , Otsu Takayuki , Tsuda Kazuichi , Ito Toshio 
Published: April 2003

AbstractA study of the radical polymerization and copolymerization of bornyl (endo‐bornyl) methacrylate (BMA) or isobornyl (exo‐bornyl) methacrylate (IBMA) with styrene has been made at 50–70°C. BMA polymerized faster than IBMA, and the polymer obtained from BMA (PBMA) was higher in molecular weight than that from IBMA (PIBMA). From the results of the detailed kinetic investigation, it was found that the values of activation energy, activation entropy, and Q and e for BMA were nearly the same as those for methyl methacrylate (MMA), but those for IBMA differed somewhat in activation entropy and Q value from those for MMA. It was also found that PIBMA could be easily acetolyzed to give an atactic polymethacrylic acid, while PBMA was stable to acetolysis as well as PMMA. Accordingly, it might be concluded that endobornyl group in BMA showed the same electric and steric effects on the rate and the reactivity for radical polymerization to methyl group in MMA, while the exo‐bornyl group showed a somewhat increased steric effect.
Coloration in acrylonitrile polymers
Authors: Takata Toshihiro , Hiroi Iwao , Taniyama Masakazu 
Published: April 2003

AbstractThe heat coloration and alkali coloration of PAN was investigated with model compounds by measuring infrared absorption spectra and ultraviolet absorption spectra. Some of the information obtained from this work supported the opinion of Grassie et al., who proposed the formation of partly hydrogenated naphthyridine‐type structure to explain the alkali coloration of PAN. The intramolecular ring closure mechanism of the initiation to propagate to the partly hydrogenated naphthyridine‐type structure of heat‐treated PAN proposed by Grassie et al., which, however, may involve the dehydrogenated structure somewhere, was supported, too. On the other hand, the formation of intermolecular azomethine‐type crosslinking structure proposed by Schurz et al. was not supported by any results of the experiments with model compounds.
Rubber elasticity in highly crosslinked polyesters
Authors: Katz Dov , Tobolsky Arthur V. 
Published: April 2003

AbstractThree unsaturated polyesters were crosslinked with different amounts of styrene, and for the resulting polymers the 10‐sec. shear modulus was measured as a function of temperature. It was observed that the polymers have well defined glassy, transition, and rubbery regions. The equation for the shear modulus from the theory of rubber elasticity was applied for the plateau regions of the polymers.
Radiolysis of polyisobutene. Part II. Infrared and ultraviolet absorption spectra
Authors: Higgins G. M. C. , Turner D. T. 
Published: April 2003

AbstractPurified polyisobutene was irradiated in vacuo with 4 M.e.v. electrons and the changes in infrared and ultraviolet absorption recorded. R1R2CCH2 groups accounted for about 60% of the total unsaturation, and evidence could be adduced for the formation of R1R2CCHR3 groups. About one tert‐butyl group was formed per double bond. Qualitative evidence was obtained for formation of the group R1CH2CH2R2. Conjugated diene groups are formed proportional to the dose up to the maximum investigated of 1400 Mrad (G value about 0.1).
The chemistry of poly(vinyl chloride) stabilization. IV. Organotin stabilizers having radioactively tagged tin atoms
Authors: Frye Alfred H. , Horst Raymond W. , Paliobagis Marko A. 
Published: April 2003

AbstractThe chemistry of poly(vinyl chloride) stabilization by organotin compounds has been studied by the use of a radioactive tracer technique. The stabilizers studied were of the type [R2Sn Y2]n, where R was either butyl or octyl, Y either monomethyl maleate, oxooctylthioglycolate, or β‐mercaptopropanoate, and 113Sn was the radioactive tag. It was found that resins milled into films with the tagged stabilizers retain an appreciable amount of radioactivity after the films have been subjected to the conditions of accelerated thermal degradation, dissolution in tetrahydrofuran, and thereafter precipitated from solution by the addition of methanol. The amount of retained radioactivity varies with the duration of the heat treatment and with the nature of the Y group in a manner that parallels our findings in a previously reported study using a 14C tag in the stabilizers' butyl groups. We have also found that the amount of radioactivity retained by the precipitated resins decreases in a regular manner when the resins are subjected to a sequence of repeated dissolutions and precipitations. However, in the case of the resin stabilized with dibutyltin‐113Sn bis(monomethyl maleate) at least, the loss of radioactivity with repeated dissolution and precipitation appears to level off after 13–14 cycles and approach a constant value of retention. Treatment of the radioactive resins with anhydrous hydrogen chloride results in the loss of essentially all their radioactivity. On the basis of these findings, we suggest that in the performance of their stabilizing action, the organotin compounds undergo little or no cleavage of their carbon‐tin bonds. Further, the observed retention of radioactivity by the resin is best rationalized as due to the existence of a coordinative linkage formed between the stabilizer's tin atom and some donor atom present in polymer's molecular structure.
Polyesters and polyurethanes of dihydroxymethylxylitol and glucitol
Authors: Dick William E. , Whistler Roy L. 
Published: April 2003

AbstractSeveral linear polyesters and polyurethanes containing 2,3,4‐tri‐O‐methylxylitol, or 2,3,4,6‐tetra‐O‐methyl‐D‐glucitol, were prepared. Solution polymerization of either of the methylated derivatives with methylenebis(4‐phenyl isocyanate) affords polyurethanes having molecular weights of about 30,000. Thermal polymerization of either methylated derivative with terephthaloyl chloride or mixtures of terephthaloyl chloride and sebacoyl chloride yields polyesters in the 4000–7000 molecular weight range. Films from these polyesters are brittle, with tensile strengths up to 32 kg./mm.2
Clay‐catalyzed reactions of olefins. II. Catalyst acidity and mechanism
Authors: Bittles James A. , Chaudhuri A. K. , Benson Sidney W. 
Published: April 2003

AbstractEvidence is presented for the heterogeneity of olefin reactions on acid clay surfaces and for the inherent acidity of the catalyst. Catalyst activity was shown to be due to an active proton probably associated with tetrahedral aluminum. Deactivation of catalyst was observed with proton accepting contaminants such as water, amines, and basic olefins. Surface acidities and total exchangeable hydrogen in the catalyst were determined by gas phase absorption and by deuterium analysis, respectively. The measurements were correlated with previous acidity measurements, styrene polymerization rates, and polymerization mechanism. Polymerization rates were measured by time‐temperature observations and by analyses of monomer. Exchangeable hydrogen was determined by deuterium exchange and density measurements. Exchange was 90% complete before polymerization began. The equilibration of a classical carbonium ion from styrene by a sorption–desorption process was definitely indicated and we propose that these ions are the active intermediates in the initiation, propagation, transfer, and solvent termination processes.
Emulsion copolymerization of some halogenated olefins. I. Vinyl chloride in ternary copolymerizations
Authors: Ley Dean E. , Fowler W. Frank 
Published: April 2003

AbstractIn the emulsion polymerization of vinyl chloride with various monomers, the rate and completeness of polymerization of this monomer depended upon the copolymerizing monomer. Vinyl chloride homopolymerized rapidly at first but did not go to completion; addition of a small percentage of acrylic acid reduced the initial rate of polymerization of vinyl chloride but complete conversion occurred. Copolymerization of vinyl chloride with alkyl acrylates having various side‐chain lengths proceeded at different rates, depending inversely on the alkyl acrylate side‐chain length. Effects on rate and completeness of polymerization of vinyl chloride with various alkyl acrylates and methacrylates (alkyl chain = 1–8 carbon atoms) and of the addition thereto of small percentages of acrylic acid are also described. In the ternary systems, an ideal acrylate ester side‐chain length of 4 carbon atoms was apparent in the presence of which most rapid and possibly most homogeneous copolymerization occurred. The phenomenon is discussed with respect to currently accepted emulsion polymerization theory.
Topochemical control of solid‐state polymerization
Authors: Hirshfeld F. L. , Schmidt G. M. J. 
Published: April 2003

AbstractA survey of compounds that undergo polymerization in the solid state supports the topochemical postulate that such a reaction is possible only if the monomer crystal structure affords close contact between the reactive centers of neighboring molecules. Even when this condition is fulfilled, chain propagation may be diffusion‐limited because of the contraction of the chain on polymerization. When the crystal structure makes such contraction unnecessary, polymerization can proceed without diffusion and the crystal can exert a direct control over the geometric course of the reaction. Several kinds of structures are known in which such behavior has been demonstrated or can be expected.
Some considerations of the kinetics of the acid hydrolysis of poly‐ and oligosaccharides. II. The trisaccharides, isomaltotriitol, panitol, and isomaltotriose
Authors: Meller Alexander 
Published: April 2003

AbstractOn the basis of the rate data of Jones, Dimler, and Rist on the acid‐catalyzed hydrolysis of isomaltotriitol it is shown that the kinetics can be described by rate equations derived by assuming a combination of two interdependent simultaneous (“parallel”) and consecutive reactions according to the scheme:
magnified image
where A is isomaltotriitol; (B), B, and B* are glucose; C is isomaltitol; D and (D) are sorbitol; and E is isomaltose present at any instant; k1 and k2 are specific rates at which the two glucosidic bonds are hydrolytically cleaved in isomaltotriitol; k3 is the specific rate of hydrolysis of isomaltitol (known); and k4 is the specific rate of hydrolysis of isomaltose (known). Values for the constants k1 and k3 have been computed from the experimental values of the composition of the hydrolysis reaction mixture and the known values for k2 and k4. The yields of glucose and sorbitol as well as the extent of hydrolysis have then been calculated using the values for k1 and k3 (computed) and k2 and k4 (known) by means of rate equations corresponding to the above scheme. They are in very good agreement with the experimental values.
The kinetics of the acid hydrolysis of isomaltotriose can also be described by rate equations corresponding to a kinetic scheme:
magnified image
where A″ is isomaltotriose; (B″), B″, B″*, and B**″ are glucose; (C″) and C″ are isomaltose at any instant; k5 and k6 are the specific rates of hydrolytic cleavage of the two glucosidic bonds in isomaltotriose, and k4 is the specific rate of hydrolysis if isomaltose (known). Assuming that k5 = k4/1.3 and k6 = k4/1.5, values for the extent of hydrolysis (expressed in terms of glucosidic bond cleavage for 100 bonds) have been calculated by means of rate equations derived on the basis of the above scheme. They show good agreement with the experimental values. However, transposing the values for k5 and k6 does not alter the calculated values. Thus, only the following conclusions seem to be permissible: the glucosidic bonds in isomaltotriose most likely hydrolyze at a lower rate than isomaltose; the two bonds do not hydrolyze at the same rate; whether the rate of hydrolysis of the glucosidic link of the reducing unit is slower than that of the nonreducing unit or the reverse, remains to be established. Attention is drawn to the role of the theoretical carbohydrate structural chemist who may offer an explanation for the deductions of the kineticist in the field of both trisaccharide and disaccharide hydrolysis.
Electron exchange polymers. XX. Preparation and polymerization of vinylbis(1‐ethoxyethyl)‐hydroquinone
Authors: Moser Robert E. , Kamogawa Hiroyoshi , Hartmann Heinrich , Cassidy Harold G. 
Published: April 2003

AbstractThe monomer vinylbis(1‐ethoxyethyl)hydroquinone, [vinylhydroquinonebis(ethyl acetal)], was prepared by reacting bromohydroquinone with vinyl ethyl ether, α‐chloroethyl ethyl ether being used as catalyst with great care to exclude moisture. The resulting bromohydroquinonebis(ethyl acetal) was subjected to lithium–bromine exchange followed by reaction with ethylene oxide. The resulting β‐hydroxyethylhydroquinone bis(ethyl acetal) was dehydrated to the desired monomer over potassium hydroxide at 235°. The overall yield from bromohydroquinone to purified monomer averaged 42%. The monomer polymerized under radical or anionic initiation. Polymer produced under radical initiation showed (in most instances) an intrinsic viscosity in benzene of the order of 0.32 at 29.7°C. The polymer is readily cleaved by dilute methanolic hydrochloric acid to give a polyvinylhydroquinone. A polyvinylhydroquinone prepared under anionic initiation showed an intrinsic viscosity of 0.34 in 90% methanol at 29.7°C. The polymer showed redox properties.
γ‐Radiation‐induced changes in the structure of polyethylenes
Authors: Sears W. C. 
Published: April 2003

AbstractThe concentrations of trans‐vinylene groups in Marlex 50 and DYNH polyethylenes were determined from infrared spectra before and after irradiation of polyethylene films with gamma rays. Values of G for trans‐vinylene growth were found to be 2.2 and 1.7 for Marlex 50 and DYNH polyethylenes, respectively. trans‐Vinylene decay constants and concentrations at infinite dose were evaluated. The growth and decay of vinyl unsaturation and growth of vinylidene unsaturation in Marlex 50 are discussed. Assignment was made of polyethylene bands at 889 and 894 cm.−1 to vinylidene unsaturation and to ethyl groups in saturated paraffins, respectively, on the basis of different means of saturating the double bond. The frequencies of new bands produced in Marlex 50 and DYNH by irradiation were correlated with those of substituted cyclopentanes and cyclohexanes. It was concluded that a complex mixture of these cyclic compounds was formed in Marlex 50 and DYNH. There appeared to be no correlation between the frequencies of these irradiation‐induced bands and frequencies known to be characteristic of conjugated double bonds.
Polybenzimidazoles. III
Authors: Plummer L. , Marvel C. S. 
Published: April 2003

AbstractPolybenzimidazoles have been prepared from 2,3‐, 2,7‐, and 2,6‐naphthalenedicarboxylic acids, 1,1′ ‐ferrocenedicarboxylic acid, maleic acid, fumaric acid, 4,5‐imidazole‐dicarboxylic acid, perfluoroglutaric acid, perfluorosuberic acid, and 3,3′ ‐diaminobenzidine. A copolymer has been prepared from a mixture of terephthalic acid and 2,2′‐diphenic acid. Thermogravimetric curves have been obtained for most of these polymers.
Association of organic quaternary ammonium cations with polyacrylates. Conductivity and viscosity measurements
Authors: Packter A. 
Published: April 2003

AbstractThe association of series of alkyl and aryl quaternary ammonium cations with polyacrylate and acrylate copolymers (with acrylamide, butyl acrylate, and styrene) was studied by combined conductivity and viscosity measurements on the organic ammonium polysalts. The degree of counterion binding in the low molecular weight alkyl trimethylammonium polysalts is basically determined—as with small organic counterions—by the distance between the carboxylate groups on the polyion backbone, i.e., electrostatic effects predominate with these cations. However, the counterion‐polyion interaction decreases significantly with increase in counterion size and steric effects from tetramethyl‐ to hexyltrimethylammonium cation. In the octyl‐ and decyltrimethyl ammonium polysalts, van der Waals' effects become more effective and the degree of association then increases with increase in counterion size. Phenyl‐ and naphthyltrimethylammonium cations behave similarly to the lower alkyl homologs. Pyridine‐ and quinolinemethonium cations interact more markedly with polyacrylates, especially with the butyl acrylate and styrene copolyacrylates. Van der Waals' interaction between the organic sections of counterion and polyion backbone is indicated with these cations: the estimated free energy due to this effect (with these cations) is 0.2–0.5 RT cal./g. mole.
Incorporation of hydroxyl endgroups in vinyl polymer. Part I. Initiation by hydrogen peroxide systems
Authors: Ghosh Premamoy , Mukherjee Asish Ranjan , Palit Santi R. 
Published: April 2003

AbstractHydroxyl endgroups were incorporated in polymers of methyl methacrylate obtained by initiation with hydrogen peroxide with the monomer in bulk and in aqueous solution. Hydroxyl endgroups in the respective polymer samples were estimated by means of the dye interaction technique. Aqueous photoinitiation with hydrogen peroxide was found to incorporate an average of about 1–1.5 hydroxyl endgroups per polymer chain, depending on the concentration of the initiator used. Aqueous thermal (60°C.) polymerization leads to an average of nearly 1 hydroxyl endgroup per chain. Polymerization in the dark at room temperature was carried out by activation with Fe2+ and Fe3+ ions, and an average of nearly 1 hydroxyl endgroup per chain was obtained in both cases. Bulk polymerization (photo‐ and thermal) produces polymer having nearly 1.3–1.7 hydroxyl endgroups per chain.
Radiation‐induced post polymerization of trioxane in the solid state
Authors: Hayashi K. , Ochi H. , Okamura S. 
Published: April 2003

AbstractTrioxane, the cyclic trimer of formaldehyde, is easily polymerized by ionizing radiation in the solid state at a temperature slightly below the melting point. It was found that this post‐polymerization is analogous to the in‐source polymerization, but its overall activation energy is more than 40 kcal./mole, which is much larger than for in‐source polymerization. A kinetic scheme is proposed for the post‐polymerization which accounts for the experimental results. In‐source polymerization probably occurs by an ionic mechanism, but three co‐exist two different mechanisms in the post‐polymerization. One is probably initiated by the decomposition of a product produced by the ionizing radiation in the presence of oxygen. The other has not yet been clarified, but it does not seem to be due to trapped radical or ionic species. The thermal decomposition of the polymer formed and the influence of additives, such as methanol, and benzene, on post‐polymerization were also studied.
Origins of x‐ray line broadening in polyethylene single crystals
Authors: Thielke H. G. , Billmeyer F. W. 
Published: April 2003

AbstractIf multiple orders of x‐ray diffraction can be observed, the origins of line broadening in the diffraction pattern can be unambiguously assigned. In the absence of such data, rare in polymers, firm conclusions cannot be drawn. Line broadening data for single crystals of polyethylene, where multiple orders of diffraction were not observed, are consistent with the following origins: for planes with indices (hk0), a size of 200 A. and 1.3% strain: for the (002) plane, a size of 105 A. (in good agreement with the lamellar thickness) if 1.3% strain is assumed, or 70A. (a lower limit) if no strain is assumed.
Carborane polymers. I. Polyesters
Authors: Green Joseph , Mayes Nathan , Cohen Murray S. 
Published: April 2003

AbstractPolyesters containing a unique polycycloborane in the polymer structure have been prepared. The boron hydride moiety, C2B10H10, has been named carborane and approximates in size a sphere with an effective van der Waals radius of 4 A. Polyesters of 2000–3000 molecular weight were prepared by allowing carborane monomers to react with each other or with organic or fluorocarbon diols or diacids. A polyester of approximately 20,000 molecular weight was prepared and it was demonstrated that molecular weight obtainable was a function of monomer ratio and purity. It was demonstrated that polyesterification of adipic acid with a carborane diol was significantly slower than the analogous reaction with 1,4‐butanediol. Reactions of carborane diols with carborane diacids were shown to occur with difficulty or not at all. Transesterification of carborane malonates also occurred with difficulty. The inhibitions of carborane materials toward polyesterification was attributed to both steric and polar influences with the former being more significant. The effect of the bulky carborane group in the polyester chain on the properties of the polymer was demonstrated by the preparation of polyadipates from 1,2‐bis(hydroxymethyl)carborane, 1,4‐butanediol, and 1,4‐butynediol. The first product was a liquid which showed no tendency to crystallize. The noncarborane polyesters were crystalline waxes at equivalent chain length. The bulk of the carborane group apparently inhibited close packing and subsequent crystallization. A comparison of the carborane polyadipate and polysuccinate showed that the latter was a hard glass, apparently due to a decrease in chain flexibility.
Analytical and preparative vapor‐phase chromatographic separation of divinylbenzene mixtures
Authors: Wiley Richard H. , Dyer Rolla M. 
Published: April 2003

AbstractThe analytical vapor‐phase chromatographic separation of commercial divinylbenzene mixtures with a polypropylene glycol liquid phase on Chromosorb W support has been adapted to the preparative scale separation of a 2:1; 9:1 and 99.8+% pure mixtures of m‐ and p‐divinylbenzenes and to the purification of synthetic p‐divinylbenzene.
Polymerization in liquid sulfur dioxide. Part XVIII. Polymerization of p‐isopropylstyrene and its copolymerization with styrene in liquid sulfur dioxide
Authors: Tokura Niichiro , Matsuda Minoru , Arakawa Koji 
Published: April 2003

AbstractWhen p‐isopropylstyrene was polymerized in liquid sulfur dioxide with a free radical initiator, simultaneous radical polysulfone formation and cationic homopolymerization of the olefin occurred. When dimethylformamide was added to the system, cationic polymerization was completely inhibited and only a polysulfone containing p‐isopropylstyrene and sulfur dioxide in the ratio 2:1 was obtained, similar to previously reported reactions with styrene, p‐bromostyrene, and p‐methylstyrene. The overall reaction rate of the radical polymerization was proportional to the initial concentration of the initiator to the order 0.62, indicating that both unimolecular and bimolecular termination was occurring. The radical polymerization of the three‐component mixture, styrene–p–isopropylstyrene–liquid sulfur dioxide, resulted in a copolysulfone which always contained about 33 mole‐% sulfur dioxide and could be considered a copolymer of three different 2:1 olefin : sulfur dioxide units.
Morphology of polyethylene crystallized from the melt under pressure
Authors: Geil Phillip H. , Anderson Franklin R. , Wunderlich Bernhard , Arakawa Tamio 
Published: April 2003

AbstractThe morphology of linear polyethylene crystallized under pressures up to 5300 atm. has been investigated. Electron micrographs of fracture surfaces obtained from these samples show that the majority of the polymer, at the highest pressures, crystallizes in the form of extended chain lamellae which can be as thick as 3 μ. Electron diffraction patterns show that the molecules are normal to the lamellae. At lower pressures part of the polymer crystallizes in the form of folded chain lamellae, the proportion increasing with decreasing pressure. Well defined kink bands can be observed in the thicker extended chain lamellae. It is suggested that either molecular weight fractionation or an end‐to‐end alignment of the molecules and subsequent folding takes place during the growth of the extended chain lamellae.