bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies on the biaxial stretching of polypropylene film. III. Electron microscopic observation of the one‐step biaxial stretching of isotactic polypropylene spherulites
Authors: Tanaka Hiroshi , Masuko Toru , Homma Keisuke , Okajima Saburo 
Published: April 2003

AbstractPolypropylene films of various isotacticities and crystallinities were stretched biaxially in one step in air at 140–152°C or polyaxially in poly(ethylene glycol) at 130–160°C, and the morphological changes were studied by electron microscopy (replica). In the initial stage of stretching, with vA = 1.4, the spherulites of one of the films used for the experiment were broken both from the centers and boundaries, and those of another film were broken mainly from the center. This difference in the deformation behavior seems to be characteristic of the film properties and independent of the method of stretching, although the factors involved are still unknown. On further stretching (vA = 22), well annealed spherulites were broken into many small blocklike fragments with unfolded fibrils running among them, particularly at the low stretching temperature (140°C), and fibrillation proceeded at the expense of the residual fragments. In the case of quenched or slightly crystallized material, the fragments were dendritic and divided into finer and finer fibrils on stretching. At elevated temperature, however, even for well annealed spherulites, the deformation behavior resembles that of the quenched material, and at a high degree of stretching the spherulites take on the fibrillar net structure in every case. In films containing a high amount of atactic fraction, radial, tangential, and boundary cracking occurred more easily, and broad fibrils were observed across the cracks.
Grafting acrylic acid monomer to poly‐(vinyl alcohol) and methyl cellulose by ceric ion
Authors: Mukhopadhyay Sailes , Mitra Bhairab Chandra , Palit Santi R. 
Published: April 2003

AbstractA graft copolymer of acrylic acid on poly(vinyl alcohol) was prepared by use of the ceric ion–polyol redox system in aqueous medium. The graft copolymer obtained was water‐soluble under the specified experimental conditions. The efficiency of grafting was determined by measuring carboxyl group content (as expected from acrylic acid unit) in the copolymer by applying the newly developed reverse dye‐partition technique. The graft copolymer was also characterized by viscosity and solubility measurements. The effect of varying concentration of catalyst, monomer, and grafting time has also been determined.
Solvent and salt effects on reaction of Na amalgam with acrylonitrile and methacrylonitrile
Authors: Arad Y. , Levy M. , Rosen H. , Vofsi D. 
Published: April 2003

AbstractThe reaction of acrylonitrile (AN) and methacrylonitrile (MeAN) with Na amalgam was studied in diglyme solution. It was shown that addition of dimethyl sulfoxide (DMSO) increases only the rate of hydrodimerization of AN to adiponitrile, while addition of water increases only the rate of hydrogenation of AN to propionitrile. The proposed mechanism assumes two separate intermediates for these two simultaneous reactions. The reaction of MeAN with Na amalgam was found to be 100 times slower than that of AN. DMSO increases the rate of both the hydrodimerization and hydrogenation reactions via the same intermediate. Addition of quaternary ammonium salts to AN in diglyme has an effect similar to that of DMSO. The salts, however, react at very low concentrations due to accumulation of the cations on the charged amalgam surface. The effect of the size and structure of the quaternary cations was studied and is discussed.
Self‐condensation reaction of aromatic tetraamines in polyphosphoric acid
Authors: Banihashemi A. , Fabbro D. , Marvel C. S. 
Published: April 2003

AbstractLadder and partial ladder polymers have been obtained by self‐condensation reactions of 1,2,4,5‐tetraaminobenzene, 3,3′,4,4′‐tetraaminodiphenyl ether, 3,3′‐diaminobenzidine and 3,3′,4,4′‐tetraaminodiphenyl sulfone in polyphosphoric acid. The products thus obtained are highly colored compounds with good thermal stability. They seem to be made up of polyquinoxaline or dihydrophenazine or a mixture of these two recurring units. They are slightly soluble in methanesulfonic acid and concentrated sulfuric acid and have inherent viscosities in the 0.2 to 0.4 range.
Polyperfluorobutadiene. II. Fractionation and crosslinking
Authors: Toy Madeline S. , Newman J. Melford 
Published: April 2003

AbstractPerfluorobutadiene was polymerized in bulk under low pressure and temperature in the presence of diisopropyl peroxydicarbonate, bis(trifluoromethyl) peroxide, and benzoyl peroxide. Fractional solvent extraction of polyperfluorobutadiene by n‐hexane and hexafluorobenzene into three polymeric fractions was described. The hexafluorobenzene‐soluble fraction was used for crosslinking studies. Direct fluorination of solid polyperfluorobutadiene required no catalyst. The fluorine–polyperfluoropolyene reactions furnished a mechanism for crosslinking the unsaturated chains. Fluorination by gaseous fluorine formed free radical sites on the polymer chains besides saturation reactions. The presence of excess monomer in contact with these partially fluorinated solid polyperfluorobutadienes under controlled conditions were capable of crosslinking and grafting to the linear chains. Direct fluorination of solid polyperfluorobutadiene tends to involve reaction with the internal double bonds rather than the pendant perfluorovinyl group; the converse is true for crosslinking with hexamethylenediamine. The mechanisms are discussed.
Studies on the polymerization of ethyl acrylate. II. Chain transfer studies
Authors: Raghuram P. V. T. , Nandi U. S. 
Published: April 2003

AbstractTransfer constants for different solvents representing hydrocarbons, halogenated compounds, alcohols, ketones, acids, and esters were determined in the thermal polymerization of ethyl acrylate at 80°C and they are compared with the available data on methyl acrylate and ethyl methacrylate. It was observed from the values of transfer constants that ethyl acrylate radicals are a little more effective than methyl acrylate or ethyl methacrylate in abstracting hydrogen atom from hydrocarbons and alcohols. In acetic and n‐butyric acid media, it has been found, by the aid of endgroup analysis, that the derived solvent radicals from transfer reactions are not too efficient to start a new chain.
Block polymers of isocyanates and vinyl monomers by homogeneous anionic polymerization
Authors: Godfrey R. A. , Miller G. W. 
Published: April 2003

AbstractThe “living” polymer method was used to prepare block polymers of vinyl monomers and isocyanates at low temperatures in toluene–tetrahydrofuran mixtures. Vinyl monomers and diisocyanates, which have one hindered isocyanate group, as in 2,4‐toluene diisocyanate, form block polymers which contain pendant reactive isocyanate groups. These block polymers can be crosslinked with water, diols, diamines, etc. The polymerization is apparently limited to block polymer formation, since the polyisocyanate anion is incapable of initiating the polymerization of common vinyl monomers.
Grafting of poly(ethylene oxide) on poly(methyl methacrylate) by transesterification
Authors: Twaik Menahem A. , Tahan Menashe , Zilkha Albert 
Published: April 2003

AbstractThe grafting of the potassium alkoxide derivative of poly(ethylene oxide) on poly(methyl methacrylate) in homogeneous solution in toluene was studied. The alkoxide was prepared by reaction with potassium metal with methanolic potassium methoxide, or with potassium naphthalene. The last was the most suitable for the systematic investigation of the grafting process. Soluble graft polymers were formed, and essentially the initial poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) participated in the production of graft polymer. The composition of the graft polymers and the frequency of grafting of the side chains were determined by NMR. The solubility of the graft polymers in methanol and water increased with increasing PEO contents, while the melting ranges decreased. Fractionation of the crude graft polymers showed that the grafting reaction was random, and graft polymers containing one PEO side chain per about 10–170 MMA units were obtained.
Polymers with quinoxaline units. V. Polymers with quinoxaline and dioxin units
Authors: Wolf Rainer , Marvel C. S. 
Published: April 2003

AbstractLadder or partly ladder polymers have been prepared by condensation of tetraphenols with tetrachloroquinoxaline compounds in melt, or in pyridine, naphthalene, and nitrobenzene reaction media. The polymers are dark‐colored, powdery materials with good thermal stability. Some of the samples are slightly soluble in sulfuric acid, while others are completely insoluble. No other solvents were found.
Block copolymerization with trapped radicals
Authors: Minoura Yuji , Ogata Yayoi 
Published: April 2003

AbstractAcrylonitrile–styrene, vinyl chloride–styrene and vinyl chloride–methyl methacrylate block copolymers were obtained by employing trapped radicals in polyacrylonitrile or poly(vinyl chloride) formed in a heterogeneous system by tri‐n‐butylboron in air as initiator. The trapped polymer radicals were activated on addition of dimethylformamide as solvent. Confirmation of block copolymers was carried out with solvent extractions, elementary analysis, and turbidimetry. In block copolymerization, the polyacrylonitrile trapped radical was more active than the poly(vinyl chloride) radical. Results of kinetic studies were used to consider the mechanism of polymerization.
Calorimetric investigation of polymerization reactions. II. Copolymerization of diethyl fumarate with styrene
Authors: Horie Kazuyuki , Mita Itaru , Kambe Hirotaro 
Published: April 2003

AbstractThe bulk copolymerization of diethyl fumarate with styrene initiated by benzoyl peroxide or azobisisobutyronitrile was investigated with a differential scanning calorimeter (DSC) operated isothermally. The heat of copolymerization decreased almost linearly with the increase in diethyl fumarate content in the copolymer. The heat of homopolymerization for diethyl fumarate was equal to 15.5 ± 0.3 kcal/mole. Monomer reactivity ratios at 100°C were also determined. The rate of copolymerization was followed over the whole range of conversion. A gel effect was noticed in copolymerizations at lower but not at higher temperatures. The initial rate of copolymerization exhibited a maximum at an intermediate monomer feed composition, differing from the previously reported tendency. The difference was found to be due to the method used for determining the rate of copolymerization, and the superiority of the DSC method was proved. The mechanism of the radical‐radical termination process was discussed. From the viewpoint of chemically controlled termination, the cross‐termination factor ϕ was estimated to be 2.0, which is reasonable considering the steric hindrance; assumption of the predominance of a diffusion‐controlled termination reaction was also consistent with the results.
Crosslinking polyferrocenylenes by polymethylol compounds
Authors: Bilow N. , Landis A. L. , Rosenberg H. 
Published: April 2003

AbstractPolyferrocenylenes with mean molecular weights of 500–4 000 have been converted into thermosetting polymers by reaction with xylylene glycol and telomers thereof. The prepolymers have been used successfully as molding materials and laminating resins. Glass fiber‐reinforced laminates have been made with flexural strengths of 63 × 103 psi and flexural moduli of 4–5 × 106 psi. Ferrocene–xylylene glycol copolymers were also prepared, and 1,1′‐bis(hydroxymethyl)ferrocene was used as a polyferrocenylene crosslinking agent. Laminates were also made from the 1,1′‐bis(hydroxymethyl)ferrocene‐based polymers.
Importance of the diamine reactant in the production of polyphosphonamides by the interfacial technique
Authors: Carraher Charles E. , Winthers D'Orsay , Millich Frank 
Published: April 2003

AbstractThe stirred interfacial polycondensation of phenylphosphonic dichloride and 1,6‐hexanediamine has been studied as a function of several reaction variables. The reaction is rapid, being completed in less than 1 min. When organic solvent is varied and reactant molar ratio is varied with an excess of the acid chloride, yield is constant. When reactant molar ratio is varied polymer yield increases with increase in amine concentration. When reactant concentration is increased yield increases. With the addition of a soluble salt in the aqueous phase yield is increased. The above indicates that the diffusion of the amine to the reaction zone is of primary importance in determining polymerization rate and that the diffusion of the acid chloride is relatively unimportant. Polymer yield was found to be dependent on the pH of the amine in the aqueous phase. The observed trend is related to the apparent solubility of the amine in the aqueous phase such that the greater the apparent solubility of the amine, the less the polymer yield. Polymer molecular weight is found to be independent of reaction variables tested. Polymer was also formed from the condensation of phenylphosphonic dichloride with p‐phenylenediamine, H2N‐D‐NH2 (where D is a 36‐carbon hydrocarbon chain), 1,3‐di‐4‐piperidylpropane, and 4‐aminomethylpiperidine; phenyl phosphorodichloridate with 1,6‐hexanediamine; chloromethyl phosphonic dichloride with 1,6‐hexanediamine.
Anionic polymerization of styrene in the presence of different anisoles
Authors: Geerts J. , Van Beylen M. , Smets G. 
Published: April 2003

AbstractThe butyllithium‐initiated polymerization of styrene has been studied in toluene solution at 20°C in the presence of anisole, o‐ethylanisole, and p‐ethylanisole. The concentration of styrene was 0.16 mole/1.; the concentration of ether varied from 0.8 to 0.33 mole/1. The rates of initiation were followed spectrophotometrically at γmax 330 mμ; they increased with increasing concentration of ether. The rates of propagation were measured dilatometrically. In the presence of anisole and p‐ethylanisole, the rate expression is Rp = [M][PLi]1/2(k1 + k2 [ether]), where k1 is the propagation rate constant in pure hydrocarbon, k2 that of the ether solvated chain end, and [PLi] denotes the concentration of polystyryllithium. On the contrary, o‐ethylanisole did not affect the rate of propagation of styrene, possibly on account of the steric hindrance of the o‐ethyl group. The apparent first‐order termination rate constants were also determined spectrophotometrically at 20°C and compared to those of poly‐o‐ and p‐methoxystyryllithium. The following decreasing order of rate constant was found: poly‐p‐methoxystyryllithium > polystyryllithium‐anisole > polystyryllithium–4‐ethylanisole > polystyryllithium‐2‐ethylanisole > poly‐o‐methoxystyryllithium.
Cyclopolycondensation. XII. Polymerization mechanism of polybenzoxazinones in polyphosphoric acid medium
Authors: Kurihara Masaru , Saito Hazime , Nukada Kenkichi , Yoda Naoya 
Published: April 2003

AbstractThe polymerization mechanism of polyphosphoric acid (PPA) solution polymerization of an aromatic diaminodicarboxylic acid with aromatic dicarboxylic acid derivatives was studied. By means of NMR methods, the initiation process for the polymerization of polybenzoxazinone in PPA medium was elucidated. The NMR spectra of a series of compounds were taken, and the salt formation of amino groups of monomer with PPA and the equilibrium between the salt and the free amino group were determined. It was established that the polymerization proceeded through the formation of phosphorylated intermediates to give the salt of amino groups of monomer with PPA. In the second step, the amine–PPA salt dissociates into the free amino group and PPA at the polymerization temperature above 140°C. Polymerization proceeds through the attack of “free” amino on phosphorylated carbonyl compounds to form polyamide acid of high molecular weight, and on subsequently being heated in PPA at higher temperatures, it undergoes an intramolecular cyclodehydration along the polymer chain to form polybenzoxazinones.
Lactone polymers. III. Polymerization of ε‐caprolactone
Authors: Lundberg R. D. , Koleske J. V. , Wischmann K. B. 
Published: April 2003

AbstractPolymerization of ε‐caprolactone catalyzed by dibutylzine and triisobutylaluminum has been examined. Monomer conversion and polymer molecular weight increase simultaneously during the polymerization suggesting a living polymer system. Also, molecular weight is proportional to the reciprocal of catalyst concentration. However, the polymer molecular weights are three to five times that which would be calculated from the catalyst concentration assuming a living polymer system. In addition, fractionation of poly‐ε‐caprolactone prepared with dibutylzinc revealed that the distribution is considerably broader than expected for a Poisson distribution. While no mechanistic explanation for the broad molecular weight distribution observed has been defined, examination of the metal alkyl‐catalyzed polylactones shows that the molecular weight distributions can and do change with time. This change is due to an ester interchange process occurring subsequent to polymerization. This phenomenon can be used to change the molecular weight distribution from very broad to the most probable distribution.
Bond structure in the alkaline ferric–tartrate system
Authors: Hanby John E. , Johnson Donald C. 
Published: April 2003

AbstractThe bond structure of the complex in the alkaline ferric–tartrate system (FeTNa) was examined and related to the cellulose‐dissolving ability of the system. The subject of bonding was approached by magnetic susceptibility and absorption spectrophotometric techniques. The magnetic moment of the Fe(III) in the iron–tartrate system was found to depend on the pH of the system. With an iron molarity of 0.1 an iron/tartrate mole ratio of 1 : 3, and 2 moles of NaOH/mole of tartaric acid, a minimum magnetic moment of 3.9 BM was observed. In alkaline media the magnetic moment depended on the Fe(III) concentration and the iron/tartrate ratio. The Fe(III) in the cellulose–solvent FeTNa was found to be in a high–spin state (5.9 BM). With a large excess of tartrate, the absorption spectrum of the alkaline FeTNa was recorded and analyzed in terms of the Tanabe–Sugano determinants. Values of 13200 cm−1 and 0.66 were obtained for the parameters Δ and β, respectively. In addition, it was shown that the Fe(III) in the cellulosesolvent FeTNa is coordinated with less than the maximum possible amount of tartrate. This tartrate deficiency is apparently responsible for the solvent properties of the system. From the use of glycerol as a model for cellulose, it appears that cellulose coordinates with the iron in the solvent FeTNa in much the same manner as does additional tartrate.
Relationship between chain termination rate constant and conversion in radical polymerization
Authors: Ito Katsukiyo 
Published: April 2003

AbstractAt low and high conversions, the chain termination rate constant for bimolecular termination between polymeric radicals given by kt = AtDs, where At is a constant and Ds is the diffusion constant of radical chain end, is completely correct. This termination rate constant does not depend on solution viscosity, but conversion.
Monomer‐isomerization polymerization. VI. Isomerizations of butene‐2 with TiCl3 or Al(C2H5)3–TiCl3 catalyst
Authors: Shimizu Akihiko , Itakura Keisuke , Otsu Takayuki , Imoto Minoru 
Published: April 2003

AbstractA study of the isomerization of butene‐2 with TiCl3 or Al(C2H5)3–TiCl3 catalyst in n‐heptane has been investigated at 60–80°C to elucidate further the mechanism of monomer‐isomerization polymerization. It was found that positional and geometrical isomerizations in the presence of these catalysts occurred concurrently with activation energies of 14–16 kcal/mole. The presence of Al(C2H5)3 with TiCl3 catalyst could accelerate the initial rates of these isomerizations and initiate the monomer‐isomerization polymerization of butene‐2. From the results obtained, it was concluded that the isomerization of butene‐2 proceeds via an intermediate σ‐complex between the transition metal hydride and butene isomers.
Polymerization of aromation amines with ferric chloride to produce thermally stable polymers
Authors: Bingham A. , Ellis Bryan 
Published: April 2003

AbstractSimple aromatic amines have been polymerized by use of ferric chloride as a combined Friedel‐Crafts catalyst and oxidant to yield polymers which are both thermally and oxidatively stable. Under certain reaction conditions a polydiphenylamine was prepared which was stable in air up to 465°C as shown by thermogravimetric analysis. This polymer has a softening point of ca. 80–100°C and is soluble in some organic solvents. Such a polydiphenylamine and other polymers with similar properties are regarded as useful for conversion to thermally stable Phillips‐type resins by crosslinking with conventional difunctional agents.
Polymerization of methyl methacrylate with dimethylbenzylanilinium chloride
Authors: Otsu Takayuki , Sato Tsuneyuki , Ko Munan 
Published: April 2003

AbstractIn order to clarify the mechanism of initiation by dimethylbenzylanilinium chloride (DMBAC), the polymerization of methyl methacrylate with DMBAC has been investigated at 60–80°C. From the results of kinetic and tracer studies, it was found that this polymerization proceeded via a radical mechanism and benzyl radical was not an initiating species. However, it was also noted that DMBAC easily dissociated into dimethylaniline and benzyl chloride under the present conditions, and the overall activation energy for the methyl methacrylate polymerization was 14.6 kcal/mole. These observations indicate that initiating radicals other than benzyl radical, i.e., phenyl or methyl radicals, may be produced through a redox interaction between DMBAC and dimethylaniline dissociated from DMBAC.
Studies on the biaxial stretching of polypropylene film. V. Orientation mechanism of the one‐step biaxially stretched film
Authors: Tanaka Hiroshi , Masuko Tōru , Okajima Saburo 
Published: April 2003

AbstractThe molecular orientation behavior during one‐step biaxial stretching in air of a quenched, low crystalline film differs from that of a slightly crystallized, highly crystalline film. In the case of a quenched film a plot of −Δnss versus \documentclass{article}\pagestyle{empty}\begin{document}$ 1/\sqrt {va} $\end{document} is composed of three intersecting straight lines with different slopes, −Δnss and vA being the birefringence with respect to the normal to the film surface and the degree of stretching in area, respectively. On the other hand, −Δnss of crystalline film changes somewhat differently. It does not increase up to fairly high stretching ratio. When a film with surface layers of different crystallinity was stretched biaxially, the relations between −Δnss and \documentclass{article}\pagestyle{empty}\begin{document}$ 1/\sqrt {va} $\end{document} for the two surface layers differ, that is, a surface layer of low crystallinity shows a change of −Δnss for the two surface layers differ, that is, a surface layer of low crystallinity shows a change of −Δnss like that of a quenched film type and the surface layer of higher crystallinity, follows the behavior typical of highly crystalline film. However, a commercial film having different crystallinites on the two surface layers exhibits another type of −Δnss change, which may be ascribed to the stress remaining frozen in the film in the manufacturing process. In addition, it is found that an Abbé refractometer can give the refractive indices of both the upper and lower surface layers of a film when the film structure is not the same on both surface layers.