bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiolysis of polyisobutene. Part I. Yields of fractures, double bonds, and gas
Authors: Turner D. T.
Published: April 2003

Purified polyisobutene with approximately a random molecular weight distribution and a number‐average molecular weight of 3.5 × 105 was irradiated in vacuo at about 25°C. with 4 M.e.v. electrons. The degradation of the polymer was studied by osmometry and viscometry and the G (fracture) value determined as 4.1. The G value for total unsaturation was determined as 5.3 by a chemical method suitable for olefins branched in the vicinity of the double bond. Little or no internal unsaturation was detected by ozonolysis of the irradiated polymer. Hydrogen and methane were formed with G values of 1.3–1.6 and 0.8–0.5, respectively. At doses greater than about 10 Mrad all the above G values decreased. The G value for isobutene formation (≤ 0.1) remained approximately constant up to a dose of at least 150 Mrad. On lowering the temperature of irradiation to −196°C. the yield of fractures was markedly decreased while the yield of hydrogen plus methane was scarcely affected. This is interpreted as evidence that the degradation reaction is due predominantly to the direct fracture of carbon–carbon bonds rather than to any reaction associated with gas formation. The observed ratio of double bonds to fractures is shown to be consistent with this interpretation.
The chemistry of poly(vinyl chloride) stabilization. V. Organotin stabilizers having radioactively tagged Y groups
Authors: Frye Alfred H. , Horst Raymond W. , Paliobagis Marko A.
Published: April 2003

Experiments with a select group of radioactively tagged organotin stabilizers of the general formula Bu2Sn Y2, in which the radioactive atoms (14C) are located in the Y groups, have shown, that, under the conditions normally employed to evaluate and screen poly(vinyl chloride) heat stabilizers, a portion of that radioactivity becomes firmly associated with the resin. Under standard conditions, the extent of this association has been found to be dependent upon the nature of the Y group and the duration of the heat treatment. It is suggested that the stabilizing action of these organotin compounds arises in part from reactions between the polymer and the stabilizer wherein certain of the polymer's chlorine atoms are exchanged for the stabilizer's Y groups (or a portion thereof), the resulting structure being more stable toward degradative elimination. Other possibilities for reaction between the polymer and the stabilizer are also considered and it is shown how these can further supplement the organotin compound's stabilizing action and yet be rationalized within the experimental evidence.
Fine texture in necking portions of cold‐drawn polyethylene
Authors: Kasai Nobutami , Kakudo Masao
Published: April 2003

Continuous structure change in the necking part of the cold‐drawn polyethylene has been examined by the wide‐ small‐angle x‐ray diffractions. A specially designed microbeam x‐ray camera which permits both wide‐ and small‐angle diagrams to be obtained at the same position at the same time was used. With increasing draw ratio, along the center axis of the specimen, first the crystallites are aligned with the a axes perpendicular to the draw direction; this is followed by a gradual orientation of the c axis to the draw direction. On the other hand, an isotropic ring‐shaped small‐angle halo continuously changes to an elliptical halo with its minor axis on the meridian. After this stage, a meridional scattering in layer streaks appears superposed on the flat elliptical halo, then the elliptical halo disappears and the layer streaks on the meridian remain, and finally the quadrant meridional scattering appears as diffuse layer streaks with intensity maxima on both sides of the meridian. On the stream line, nearly the same variations of the wide‐ and small‐angle diagrams as those on the center axis are observed; however, the meridian of each diagram is not parallel to the draw direction but coincides with the tangent of the stream line at each irradiated position. The stream line was conventionally defined so as to divide the y coordinates from the center axis to the surface at every point on the line into the same ratio. One characteristic diagram along the stream line is a small‐angle oblique two‐point pattern, appearing as off‐meridian layer streaks. From each wide‐angle diagram, the average orientation angle between the c axis and the meridian, degree of crystallite parallelity, and the apparent crystallite size were estimated. The Bragg distance, identity period along the meridian, and the azimuthal angle on the film between the meridian and the direction from center to the diffraction peak were determined by the small‐angle scattering. In considering these results, a series of plausible models for continuous structure change in necking is presented.
Analysis of the gases evolved from irradiated polyethylene
Authors: Salovey R. , Pascale J. V.
Published: April 2003

Saturated hydrocarbons evolved during electron irradiation of polyethylene are characteristic of short side chains in the polymer. A convenient analysis is effected by programmed temperature gas chromatography. In order to minimize the relative concentrations of extraneous hydrocarbons, i.e., those not arising from selective scission of complete side chains, it is necessary to irradiate at low temperatures and doses. Such analyses of a high pressure polyethylene (DYNK) indicates that the two methyls per 100 carbon atoms detected in infrared absorption are probably equal amounts of ethyl and butyl branches. These arise by intramolecular chain transfer during polymerization. At a dose of 10 Mrad about 1/4% of the alkyl groups are removed. Methane is the only hydrocarbon detected on irradiation of polypropylene, indicating little combination of methyl radicals to form ethane during irradiation.
The reaction between dicumyl peroxide and butyl rubbers
Authors: Loan L. D.
Published: April 2003

The reaction between dicumyl peroxide and butyl rubbers has been followed by means of molecular weight measurements. In all cases except that of the rubber with highest unsaturation the molecular weight falls, and the scission efficiency of the peroxide is found to depend quite markedly upon the unsaturation. For the rubber of highest unsaturation a small overall crosslinking reaction was observed. The results are interpreted as showing that cumyloxy radicals react with isoprene units in the chain about 300 times as fast as with isobutylene units. The molecular weight depen dance upon time during the reaction has been investigated but has not been satisfactorily explained.
Radiation‐initiated copolymerization of styrene with unsaturated esters
Authors: Burlant W. , Hinsch J.
Published: April 2003

The kinetics of the γ‐ray‐initiated, gel‐forming copolymerization of styrene with the unsaturated ester containing 1.5 double bonds per molecule of number‐average molecular weight of 890 (derived from maleic anhydride, phthalic anhydride, and propylene glycol) have been studied with initial ester concentrations ranging from 65% to 2.4%. From experimentally determined gel fractions, rates of disappearance of styrene and ester unsaturation (measured up to complete conversion of ester unsaturation), and the degree of polymerization of the growing chains, a model is suggested based on a free radical copolymerization, assuming a single effective propagation and termination rate constant (kp and kt, respectively), and bimolecular chain termination except between a pair of immobile gel radicals. Three ester concentration ranges were considered. At high ester concentrations (≥ 50%), styrene and ester enter the gel at a constant rate (molar ratio of styrene:ester double bond of 2:1), precluding application of conventional copolymer composition theory. The rate at which overall unsaturation, α, disappears, is given by dα/dt = (kp2/kt)M2° where M2° is the initial molar concentration of ester unsaturation. The rate at which styrene, α1, disappears is given by dα1/dt = 2/3(kp2/kt)M2°(M1° + M2°)/M1°. The rate at which styrene is consumed in the dilute esterstyrene solutions (⩽4.6%), where M2° is negligibly small, is given by dα1/dt = kp(k1/2kt)1/2. Polymerization rates of the intermediate ester concentration ranges (10% to 30%) are higher than predicted from the simple model. An empirical rate expression is presented which describes these systems to 40% conversion of styrene: dα1/dt = (kp2/kt)M2° {[(1 + m)(r1 + M)]/(r1 + 2M)}, where M is the ratio of ester unsaturation to styrene in the starting mixture and r1 is the reactivity ratio for styrene, defined in the usual manner. For initial conversions of ester unsaturation (to 10%) dα/dt = (kp2/kt)M2°.
Poly(1,2‐dimethyl‐5‐vinylpyridinium methyl sulfate). Part I. Polymerization studies
Authors: Shyluk W. P.
Published: April 2003

1,2‐Dimethyl‐5‐vinylpyridinium methyl sulfate is readily polymerizable in aqueous solution under mild free radical conditions to a high molecular weight, cationic polyelectrolyte. A three‐halves order dependence of the rate of polymerization on monomer concentration is indicated for about 75% of the polymerization of 1,2‐dimethyl‐5‐vinylpyridinium methyl sulfate in aqueous solution with potassium persulfate as initiator. A normal dependence of the polymerization rate on the square root of the initiator concentration is also indicated by these data. The overall activation energy is estimated to be about 17 kcal./mole. Preliminary experiments related to the effect of changing the ionic strength of the reaction medium by addition of sodium chloride led to a change in the kinetics with a dramatic slowing‐down of the polymerization. Copolymerization studies indicate that the reactivity of this cationic monomer is higher than that of acrylamide, methacrylamide, and methyl methacrylate, but close to that of methacrylic acid.
Theoretical consideration of linear condensation polymerization in a dispersed medium
Authors: Nanda V. S.
Published: April 2003

The combinatorial approach to the problem of linear polymers, developed earlier, is applied in the present paper in order to study the statistical nature of condensation polymers obtained from a large number of very small systems. The results of the customary theory become inapplicable in such cases for sufficiently high degrees of polymerization which should be attainable experimentally. The possibility of realizing homogeneous samples by direct polymerization is discussed from a theoretical standpoint.
The polymerizing system: Vinyl acetate–diphenyl
Authors: Haas Howard C. , Husek Helen
Published: April 2003

The polymerization of vinyl acetate in the presence of diphenyl has been studied. A chain transfer constant for diphenyl of 6.4 × 10−4 was obtained from conventional kinetic analysis and Pn data. This value is in reasonable agreement with values obtained from an estimation of the combined diphenyl residues in the corresponding polyvinyl alcohols by ultraviolet spectroscopy. The conclusion, that diphenyl behaves in this system predominantly as a transfer agent and not as a comonomer, is supported by an evaluation of the data in terms of a kinetic scheme for retarded polymerization. Retardation of the rate of polymerization of vinyl acetate is observed in the presence of diphenyl and it is on this basis that abstraction of hydrogen from diphenyl as being the transfer step is discarded in favor of addition of the vinyl acetate radical chain to diphenyl. The ultraviolet dichroism of an oriented polyvinyl alcohol film containing combined diphenyl residues is presented.
Temperature‐independent viscosity characteristics of polymer systems
Authors: Vinogradov G. V. , Malkin A. Ya.
Published: April 2003

The possibility of construction of temperature‐independent viscosity characteristics of polymer systems by means of a “reduced variables” method similar to that of Ferry is discussed. It is stated that the viscosity as a function of temperature and shear rate can generally be regarded as the product of two functions, one of which depends only on the temperature and the other only on the shear rate. It is shown by dimension analysis and by assuming the flow of polymer systems to be viscoelastic in nature, that the ratio of apparent viscosity to initial Newtonian viscosity is a temperature‐independent function of the product of the shear rate by the initial Newtonian viscosity. Hence, the latter (observed at shear rates tending to zero) appears to be a most important physical parameter governing the flow properties of polymer systems. At sufficiently low shear rates the apparent viscosity was found to be an exponential function of shear stress, so that the initial Newtonian viscosity can be determined by extrapolation. The above theoretical considerations were checked for the most reliable published data on the flow properties of condensed polymer systems over a wide range of shear rates and temperatures. Experimental results obtained for polymer systems of different nature can be represented satisfactorily by corresponding temperature‐independent viscosity curves.
Sorption and diffusion of water vapor by nylon 6
Authors: Kawasaki Koji , Sekita Yoshiyasu
Published: April 2003

The interaction between nylon 6 and water has been studied from water vapor sorption isotherms, diffusion of water vapor in the polymer, and nuclear magnetic resonance (NMR) properties. The variations in water sorption properties of various heat treated specimens seem to result from the difference in the degree of loose packing in the amorphous regions. From the effect of water vapor on NMR narrow line intensity, it has been found that there are two characteristic sorption types of water vapor in nylon 6, that is, water molecule is comparatively immobile at the lower water content, and considerably mobile at water contents above 4 wt.‐%. Furthermore, it may be supposed that there is in addition another sorption state of water vapor below 2 wt.‐% that corresponds to the monolayer capacity of water vapor in the polymer.
Synthetic polysaccharides. I. Methyl mono‐ and methyl di‐O‐allyl‐α‐D‐glucosides and their polymerization
Authors: Schweiger Richard G.
Published: April 2003

Methyl mono‐ and methyl di‐O‐allyl‐α‐D‐glucosides are prepared by the reaction of methyl α‐D‐glucoside with allyl chloride in alkali in a two‐phase system. The monoallyl ether consists mainly of a mixture of methyl 2‐, 4‐, and 6‐O‐allyl‐α‐D‐glucosides, the diallyl compound of 2,6‐ and 4,6‐di‐O‐allyl‐α‐D‐glucosides in approximately a 1 : 1 ratio. Both compounds are homopolymerized with oxygen as the catalyst. The poly(monoallyl glucoside) is a water‐soluble, brittle, clear resin with a softening point of 100–110°C. The poly(diallyl glucoside) is a brittle, clear, but completely insoluble resin with no softening point. Copolymerization with acrylamide under certain conditions yields water‐soluble polymers, aqueous solutions of which exhibit high viscosities and have the typical appearance and consistencies of those of polysaccharides.
Polymerization behavior of aziridines with 1,2‐epoxides
Authors: Overberger C. G. , Tobkes Martin
Published: April 2003

A number of Lewis acid catalysts have been investigated for the copolymerization of 1,2‐butylenimine with 1,2‐epoxides. The most active catalyst, boron trifluoride etherate, has been shown to give polymers containing a polyimine backbone in which the residual NH groups in the polymer chain are β‐hydroxyalkylated by the epoxide. It has been demonstrated that the imine is far more reactive than the epoxide under these conditions, regardless of the chain length of the epoxide monomer. The polyimine chain appears to grow to an appreciable extent before any epoxide enters the polymer. These results are interpreted as being due to the preferential complexing of the catalyst by the basic imine residues in the polymer, which renders the catalyst unavailable for polymerization of the epoxide. The homo‐ and copolymerization behavior of 1‐(p‐toluenesulfonyl)‐aziridine, N,N‐diphenyl‐1‐aziridinecarboxamide and N,N‐diethyl‐1‐aziridinecarboxamide with 1,2‐epoxides has been investigated under conditions of catalysis by boron trifluoride etherate and by triethylamine. In no instance could copolymers be obtained.
A series of poly(methylene acetals) derived from aliphatic aldehydes
Authors: Schonfeld Edward
Published: April 2003

A series of poly(methylene acetals) were prepared from 1,5‐pentanediol by systematically varying the aldehyde. The viscosity of each polymer was measured, and, for the first four members of the series, shown to vary inversely with the length of the pendant chain of the aldehyde. A comparison of the viscosity of a polyether (a polyoxypropylene glycol) in which the ratio of carbon to oxygen in the chain is 2/1 with that of a poly(methylene acetal) in which the carbon to oxygen ratio is 3/1 indicated a significant decrease in viscosity with increasing concentration of ethereal oxygen.
A poly(ethylene oxide)–mercuric chloride complex
Authors: Blumberg Avrom A. , Pollack Sidney S. , Hoeve C. A. J.
Published: April 2003

Oriented poly(ethylene oxide) fibers form a complex with mercuric chloride, with the empirical formula (CH2CH2O)4·HgCl2. Tentatively the unit cell of the complex is orthorhombic with dimensions 13.5, 17.1, and 11.6 A. (c, the fiber axis). In spite of a major change in the unit cell, fiber orientation is maintained. The infrared spectrum of the complex is more detailed than that of the polymer alone, a fact consistent with a change from trans to gauche state of one OC bond.
Kinetics of the γ‐radiation‐induced polymerization of ethylene in alkyl chlorides
Authors: Wiley Richard H. , Lipscomb N. T. , Parrish C. F. , Guillet J. E.
Published: April 2003

A study has been made of the kinetics and mechanism of the liquid‐phase, γ‐radiation‐induced, alkyl chloride solution polymerization of ethylene. The γ‐radiation was provided by a 4.07 × 105 r/hr. Co60 source. The kinetics of these polymerizations were studied up to 10% conversion and over the temperature range 0 to −25°C. Three solvents (n‐propyl chloride, iso‐propyl chloride, and tert‐butyl chloride) were used with concentrations of ethylene ranging from 6.76 to 8.89 moles/l. Two different grades of ethylene were used: the first contained an upper limit of 1000 ppm of oxygen, the second 60 ppm. The ethylene containing only 60 ppm of oxygen was found to give a smaller induction period, and faster rate of polymerization than the ethylene containing 1000 ppm. Activation energies of 5.0 kcal./mole for the reaction in n‐propyl chloride and 7.4 kcal./mole for the reaction in tert‐butyl chloride were observed for the temperature range studied. These values were higher than the 4.4 kcal./mole obtained for the bulk polymerization of ethylene in this temperature range. The order of the reaction with respect to ethylene concentration in n‐propyl chloride at 0°C. was found to be 1.41. Although the heterogeneity of the system is a complicating factor, this rate expression agrees well with the general scheme proposed for other heterogeneous polymerizations. Molecular weight information which shows an increase in molecular weight with increasing temperature leads to the conclusion that a termination step involving weakly reactive solvent radicals may be important.
α,ω‐Glycols and dicarboxylic acids from butadiene, isoprene, and styrene and some derived block polymers, esters, and urethans
Authors: Hayashi Katsumi , Marvel C. S.
Published: April 2003

The living polymer technique of Szwarc has been employed to synthesize α,ω‐bifunctional derivatives of polybutadiene, polyisoprene, and polystyrene. The glycols derived from polybutadiene have been hydrogenated to give saturated glycols. The glycols from polyisoprene have been partially hydrogenated. Some block polymer esters and urethans have been characterized.
Ring‐opening polymerization of a sugar episulfide
Authors: Whistler Roy L. , Seib Paul A.
Published: April 2003

Ring‐opening polymerization of 5,6‐dideoxy‐5,6‐epithio‐1,2‐O‐isopropylidene‐α‐L‐idofuranose is catalyzed by boron trifluoride at 60°C. Soluble polymer is produced at monomer: catalyst ratio of 7 : 1 and monomer concentration 0.077M after 1 1‐hr. polymerization period. This polymer has a wide molecular weight distribution. A number‐average molecular weight of 72,000 is found for the first 40% of the polymer precipitated from a N,N‐dimethylformamide solution by the addition of water. Polymer is produced in increasing amounts as temperature is raised, catalyst concentration increased, and as water concentration is decreased. Transglycosylation may be the cause of branch formation or crosslinking. Hydrolysis of the soluble polymer removes isopropylidene groups to produce a water soluble reducing polymer which oxidizes with hypoiodite to a polymer containing carboxyl groups.
Polyphenylenebenzimidazoles
Authors: Iwakura Yoshio , Uno Keikichi , Imai Yoshio
Published: April 2003

The solution polycondensation of 3,3′ ‐diaminobenzidine tetrahydrochloride with aromatic dicarboxylic acid derivatives in polyphosphoric acid was found to give high molecular weight polyphenylenebenzimidazoles easily. Their preparation and physical properties, such as thermal stability, solubility, crystallinity, are described.
Polymerization in solid solutions of acrylamide in propionamide
Authors: Adler G. , Reams W.
Published: April 2003

It has previously been shown that the polymer formed in solid‐state polymerization of acrylamide is amorphous in spite of the fact that the reaction takes place within a crystalline solid. The stage at which it becomes amorphous is not known at present. Work with dilute solid solutions of acrylamide in propionamide suggests that this occurs after the addition of, at most, a very few monomer units.
Nuclear magnetic absorption in polystyrene‐styrene systems
Authors: Borsa F. , Lanzi G.
Published: April 2003

Measurements of line width at different temperatures for samples of styrene partially polymerized are reported. The results obtained point out the importance of segmental motion of polymer chains at low temperatures in relation to the motion of the monomer molecules still present. There is some experimental evidence that under certain conditions the monomer molecules can facilitate the motions of polymer molecules, which seem to pull along in their motion a lot of the monomer molecules.
Radiation‐induced copolymerization of acrylonitrile with methyl methacrylate
Authors: Tabata Yoneho , Hasizume Yoshio , Sobue Hiroshi
Published: April 2003

Radiation‐induced copolymerization of acrylonitrile (1) with methyl methacrylate (2) was investigated over a wide range of temperatures. The rate of copolymerization decreased linearly with the molar concentration of acrylonitrile in the liquid‐state copolymerization at 15°C. On the contrary, the rate of copolymerization increased linearly with the concentration of acrylonitrile in the solid state at −78°C. The rate of copolymerization was proportional to the square root of the dose rate in an equimolar mixture of the monomers at 15°C. The apparent activation energy of the copolymerization was 4.62 kcal./mole in an equimolar mixture of the monomers. Monomer reactivity ratios r1 and r2 were determined from the experiments at various temperatures. From these results, the differences of the activation energies in the propagation steps were obtained as follows: E‡11 − E‡12 = 2.76 kcal./mole; E‡22 − E‡21 = 2.58 kcal./mole.
Poly(xylylenylpiperazine), a novel polyamine
Authors: Klebe J. F.
Published: April 2003

The condensation polymerization of α,α‐dichloroxylene and similar reactive halides with difunctional silylamines leads to novel high molecular weight polyamines of the type
magnified image
The halogen is eliminated in the form of halosilane which is inert in this reaction system and acts as a solvent for the polymer. The polymers can be cast from solution or pressed to strong films. They exhibit typical amine properties; they are soluble in inorganic and organic acids and form polyelectrolyte solutions, from which stable polyelectrolyte films can be cast. Reactions with alkyliodides lead to polyquaternary compounds. Ammonium salts and a cyclic sulfone were found to enhance catalytically the rate of reaction of benzylchloride with silylamines.
Preparation of polyamides, polyurethanes, polysulfonamides, and polyesters by low temperature solution polycondensation
Authors: Kwolek Stephanie L. , Morgan Paul W.
Published: April 2003

Solution polycondensation was used to prepare four classes of polymers. Polymers in each class were obtained with molecular weights high enough for formation into flexible, tough structures. In all instances the molecular weights were not as high as could be obtained from the same reactants by the interfacial polycondensation process. Many of the polyamides from aliphatic diamines were highly branched through diacylation of the amino groups. On the other hand, polysulfonamides were linear. Despite some limitations, as indicated above, the solution polycondensation process provides another route to forming condensation polymers and should be of special advantage in use with hydrolytically unstable intermediates, with water‐insoluble diamines and diols, and for forming uniform or block copolymers.
Amylose V complexes. II. Lower molecular weight ketones
Authors: Germino Felix J. , Moshy R. J. , Valletta Robert M.
Published: April 2003

The acetone‐ and methyl ethyl ketone‐amylose V complexes have been prepared and their unit cell dimensions calculated from their x‐ray powder patterns. This work demonstrates the size‐determining effect of these two ketones on the amylose V complex. The small unit cell, with a helix diameter of 13.0 A., observed with the wet methanol and ethanol complexes, is not found with the acetone and methyl ethyl ketone complexes. The wet ketone‐amylose V complexes and the thoroughly dried ketone complexes have the larger helix diameter of 13.7 A. This is the first report of an anhydrous amylose V complex with the expanded helix diameter. Thorough extraction of the methyl ethyl ketone‐amylose complex with methyl alcohol did not change the 13.7 A. helix diameter, although methyl alcohol‐extracted acetone‐amylose complex resulted in a mixture of the 13.0 A. and 13.7 A. helix diameter types. This work demonstrates the size effect of the lower molecular weight ketones on the amylose crystalline structure.
Redox polymerization of unsaturated polyester resins. I. Effect of metal species on polymerization rates in the presence of a variety of peroxides and hydroperoxides
Authors: Svoboda Glenn R.
Published: April 2003

A study of a series of metal compounds as promoters of acyl peroxide and hydroperoxide dissociation in an unsaturated polyester‐styrene resin solution has shown vanadie and vanadyl chelates to be the most active. All of the results were compared to a standard cobalt‐methyl ethyl ketone peroxide promoter‐catalyst system. It was found that the reactivity of 2 mg. of vanadium or vanadyl ion as vanadic or vanadyl acetyl acetonate with respect to 1% cumene hydroperoxide was greater than 24 mg. of cobalt as cobalt naphthenate with respect to 1% methyl ethyl ketone peroxide. This is significant, in that considerably less metallic promoter can be used at ambient temperatures for the fabrication of finished articles with considerably less associated color. Of the vanadium compounds studied, vanadic and vanadyl chelates were about equally reactive. Vanadyl acetyl acetonate was considered the promoter of choice, since vanadic acetyl acetonate solutions appeared to be air‐oxidized readily. Study has shown that benzene solutions of vanadic acetyl acetonate lost some activity after a week, whereas chloroform solutions of vanadyl acetyl acetonate remained stable for a period of six to nine months. The utility of vanadium promoters for ambient temperature redox polymerization would be enhanced if they could be incorporated into unsaturated polyester resins at the time of preparation. However, results obtained indicated that both vanadic and vanadyl chelates limit the stability of such prepromoted resins, normally leading to gelation in about 17 days. A further indication of the utility of vanadium chelates as redox promoters was the observation that these materials are reactive towards diacyl peroxides as well as hydroperoxides. Vanadium chelates were the only materials studied which showed this wide spectrum of reactivity.
Synthesis of new monomers and polymers. IV. Synthesis and properties of polydiphenyldiacetylenes
Authors: Teyssié Ph. , Korn‐Girard A. C.
Published: April 2003

Polymerization of diphenyldiacetylene was effected in the presence of Ziegler type catalysts. The polymers, studied as obtained from the polymerization or after further reaction, are soluble products of relatively low molecular weight with interesting properties: very high thermal resistance, continuous absorption in ultraviolet and near visible regions, broad visible fluorescence spectra, semiconducting and catalytic properties.
Vinyl polymerization. LXXIX. Effect of the alkyl group on the radical polymerization of alkyl methacrylates
Authors: Otsu Takayuki , Ito Toshio , Imoto Minoru
Published: April 2003

The effect of the alkyl group on the rates of polymerization of alkyl methacrylates initiated by α,α′‐azobisisobutyronitrile in benzene at 60°C. has been investigated. The rate of polymerization increased with increasing length of the alkyl group. This has already been attributed to the increased steric effect of the alkyl group in the termination process. In the present study, it was proved that the viscosities of alkyl methacrylate monomers increased with increasing length of the alkyl group, and that overall polymerization rate constants were inversely proportional to the viscosities. Accordingly, the above result might be explained by an increase in the contribution of the diffusioncontrolled termination with increasing length of the alkyl group in alkyl methacrylate.
Comparison of the effects of allylamine and n‐propylamine on cellulose
Authors: Segal Leon
Published: April 2003

Allylamine partially penetrates the cellulose crystal lattice and effects only partial transformation to the cellulose‐amine complex. The 101 interplanar spacing of the allylamine complex is similar to that of the propylamine complex. Differences in amme interaction with cellulose are not explained by considerations of base strength of amines, stereochemistry, or degree of association of the amines. Cellulose treated with ethylamine, then allylamine is completely transformed to what seems to be the cellulose‐allylamine complex. Slow evaporation of allylamine from the cellulose I complex seems to produce cellulose III; from the cellulose II complex, cellulose II. Fast evaporation of ethyl‐, propyl‐, or allylamine from amine‐wet cellulose restores the initial cellulose lattice. Slow evaporation of ethylamine produces cellulose III; of propylamine a mixed lattice of cellulose I with little cellulose III and much of the complex.
Polymerization of butadiene in the presence of triethylaluminum and n‐butyl titanate
Authors: Dawes D. H. , Winkler C. A.
Published: April 2003

Measurement of butadiene absorption at constant volume, and of polymer formation, indicated that the rate of polymerization was first order in monomer concentration, up to 1.5 mole/l., and also in initial total catalyst concentration, for given molar ratio of alkyl to titanium ester. The overall activation energy was 11.5 kcal./mole. A fast initiation, accompanied by the evolution of ethylene or a mixture of ethane and ethylene, a relatively slow propagation, and chain transfer to monomer, appeared to be the main steps of the reaction. Termination was essentially absent. Insoluble, gellike material was formed roughly at 20% conversion and was attributed to a random crosslinking, involveing very few crosslinks per molecule, or possibly trifunctional branching. The molecular weight distribution was very narrow. A polymer of over 80% in 1,2 units, having a predominantly syndiotactic structure and about 10% crystallinity, was obtained. In the absence of monomer, the catalyst components reacted rapidly to form complexes, accompanied by strong ethane evolution. A complex series of reactions leading to the possible formation of more than one active species was indicated. The active catalyst suffered bimolecular decomposition on prolonged standing. For optimal molar ratio of alkyl to ester of 5/1, the concentration of active species was estimated as having an upper limit of 4.8 × 10−6 mole/l.
Temperature coefficient of unperturbed polymer dimensions from thermoelastic properties
Authors: Ciferri A.
Published: April 2003

Results enabling the determination of the temperature variation of the unperturbed mean‐square end‐to‐end distance r02 for linear polymer chains from stress–temperature measurements are surveyed. Out of 31 polymer systems which have been studied, only two show a clear decrease of r02 with temperature. An increase or an independence of r02 upon temperature is the most common trend. These results appear at variance with expectations and with theoretical considerations. Experimental difficulties and possible limitations of said theories are discussed.
Polymerization of styrene in N,N‐dimethylformamide and N,N‐dimethylacetamide
Authors: George M. H.
Published: April 2003

The polymerization of styrene in N,N‐dimethylformamide and N,N‐dimethylacetamide at 60°C. initiated by 2,2′‐azobisisobutyronitrile has been studied. Rates of polymerization were measured dilatometrically and gravimetrically, and degrees of polymerization were determined viscometrically. The transfer constants to N,N‐dimethylformamide and N,N‐dimethylacetamide are 4.0 × 10−4 and 4.6 × 10−4, respectively. None of the existing reaction mechanisms of vinyl polymerization can account for all the experimental results, and various alternatives are examined.
Clay‐catalyzed reactions of olefins. III. Kinetics of polymerization of styrene
Authors: Bittles James A. , Chaudhuri A. K. , Benson Sidney W.
Published: April 2003

The polymerization of styrene in the presence of acid clay catalysts has been reported previously. The kinetics were studied in solution at 0°C. by a dilatometric method relating monomer concentration to volume and heat of reaction. An approximately linear rate law was derived which fit the data over a 100‐fold range of concentration. The integrated rate equation is:

The equilibrium constant KM for monomer absorption was found to be 863 ± 70 cc./mole and the propagation constant kp was found to be 191 ± 14 cc./mole/sec. An Arrhenius plot is in accord with the equation k′p = Ae−7.7/RT with an activation energy 7.7 ± 1.5 kcal. and an Arrhenius factor of 3.39 × 108 cc./mole/sec. The effect of added inhibitor I was interpreted qualitatively on the basis of an exact rate equation which in differential form is:

The factor KI[I]/[I0] was estimated from the equation:

and found to be negligible at 0.1M monomer concentration and consistent with experiment. An explanation for low values of kp in the presence of added inhibitor was proposed based upon the exact rate law.
1,3‐Cyclohexadiene polymers. Part II. Copolymerization of 1,3‐cyclohexadiene and isoprene
Authors: Dawans F.
Published: April 2003

Reactivity ratios of isoprene and 1,3‐cyclohexadiene were determined during copolymerization runs carried out with several initiators, such as titanium tetrachloride, n‐butyllithium, and Ziegler‐type catalysts. Reactivity ratios observed are in general very similar and are influenced by the nature of the initiator and of the reaction medium.
Investigations on the radiation‐produced peroxide of poly(methyl methacrylate) and its copolymers
Authors: Połowiński Stefan , Turska Eligia , Kroh Jerzy
Published: April 2003

The concentration of peroxide groups produced in poly(methyl methacrylate), (PMMA) and PMMA–styrene copolymers (random, graft, and block) irradiated in the presence of air by γ‐rays from Co60 was determined. The dependence of the above concentration on the radiation dose and polymer composition was investigated. In copolymers containing more than 10% styrene the number of peroxide groups corresponding to PMMA decreases as the concentration of styrene increases. This phenomenon is ascribed to the transfer of energy toward benzene rings. The influence of these rings is much stronger in block and graft copolymers then in the statistic ones. In the case of small quantities of polystyrene in random copolymers there was a certain increase of the number of peroxide groups in comparison with pure PMMA.
γ‐Irradiation‐ and radical‐initiated polymerization of N,N‐dimethylethenesulfonamide
Authors: Wiley Richard H. , Jäger Peter
Published: April 2003

The γ‐irradiation‐induced polymerization of N,N‐dimethylethenesulfonamide, m.p. −3 to −2°C., has been studied in the liquid, supercooled liquid, and solid states from −50 to +42°C. The polymerization is relatively slow (0.8%/hr.) at 0.13 Mr/hr. and is inhibited in the solid state. The activation energy (−16°C. super‐cooled liquid to 42°C.), −2.4 kcal./mole, indicates an ionic process. The radical‐initiated (peroxide, azobisisobutyronitrile, ultraviolet) polymerization gives low molecular weight products. The marked decrease in rate for the N,N‐dimethyl derivative as compared to that for ethenesulfonamide itself is attributed to an increased irradiation instability associated with N‐methyl structures which parallels that for amides and N‐methylamides in carbon tetrachloride.
Stereospecific polymerization of menthyl methacrylate
Authors: Sobue Hiroshi , Matsuzaki Kei , Nakano Shintaro
Published: April 2003

Menthyl methacrylate was polymerized with phenylmagnesium bromide, n‐butyllithium, benzoyl peroxide, azobisisobutyronitrile, and γ‐rays as initiators. The polymers obtained were converted to poly(methyl methacrylate) (PMMA). From the infrared spectra and high resolution NMR spectra of PMMA derived, the stereoregularity of poly(menthyl methacrylate) (PMnMA) was estimated. PMnMA's polymerized with phenylmagnesium bromide and n‐butyllithium have an isotactic structure and those prepared with radical initiators have an atactic structure. The probability of isotactic addition σ of PMnMA polymerized with radical initiators was larger than that for PMMA. The optical activity of PMnMA increased with decreasing isotacticity, but the change is slight as compared with the variation of the stereoregularity of the polymers. It was concluded that PMnMA molecules would not form helices in solution.
Synthesis of a polymer chain having conjugated unsaturated bonds by dehydrohalogenation of polyhalogen‐containing polymers
Authors: Tsuchida Eishun , Shih Chung‐Nan , Shinohara Isao , Kambara Shu
Published: April 2003

Polyvinyl chloride (I), polyvinylidene chloride (II) and further chlorinated products of polyvinyl chloride (III) can be completely dehydrohalogenated if appropriate conditions are chosen. The elementary analyses of the products fit the formula (CH)n. The infrared spectra and x‐ray diffraction patterns indicate that the structure of the products is similar to that of noncrystalline, trans‐polyacetylene. The absorption band due to CHCH (trans) is observed for all products; for the products from (II) and (III), the band due to CC also appears. All products show paramagnetic properties. The highest value of specific resistivity is about 104 ohm‐cm.
Stress relaxation in fibers: Effect of water and temperature
Authors: Whitney Cynthia Kolb , Hamilton R. L.
Published: April 2003

The effect of water on stress relaxation was studied for several fibers as a function of water temperature and other parameters. A quantitative measure of the effect was developed. A statistical model was developed, and it was found that the observed behavior could be interpreted in terms of a redistribution of forces among the various bonds within the fiber. The measure of the water effect, as defined here, could be used to study the connection between stress relaxation and other fiber properties.
General conclusions about the copolymerization of ethylene with other monomers by free radical catalysis
Authors: Brown Francis E. , Ham George E.
Published: April 2003

The behavior of ethylene in copolymerization with methyl acrylate, methyl methacrylate, vinyl acetate, diethyl fumarate, and diethyl maleate was investigated, and reactivity ratios for these systems reported. Significant deviations of all systems investigated, except ethylene–vinyl acetate, from the conventional copolymerization equation are noted and interpreted on the basis of substantial penultimate and penpenultimate effects. The consistency of the reactivity ratios developed in the systems ethylene–methyl acrylate and ethylene–methyl methacrylate with reported values for methyl acrylate–methyl methacrylate is shown by application of the relationship PabPbcPca = PacPcbPba.
Proof of validity of expanded copolymerization equations
Authors: Ham George E.
Published: April 2003

Generalized copolymerization equations which accounted for wide deviations from conventional copolymerization behavior of numerous systems involving highly polar or sterically hindered monomers had been previously proposed. This paper offers, for the first time, rigorous proof of the expanded equations for systems where one monomer is incapable of addition to its own radical. Empolying these equations, effects as far removed as four units from the end of the growing chain can be accounted for.
Radiation‐induced polymerization of 2‐methyl‐5‐vinyl‐pyridine
Authors: Tabata Yoneho , Kitano Hirokimi , Sobue Hiroshi
Published: April 2003

Radiation‐induced polymerization of 2‐methyl‐5‐vinylpyridine was investigated in bulk in the temperature region of 50 to −196°C. The activation energy was found to be 5.7 kcal./mole for the liquid‐phase polymerization and 0.3 kcal./mole for the solidphase polymerization. It was observed that the rate of polymerization is proportional to the square root of the dose rate in the liquid‐phase polymerization and is proportional to the dose rate in the solid‐phase polymerization. DPPH and benzoquinone inhibited strongly the liquid‐phase polymerization, while the same inhibitors did not inhibit appreciably the solid‐phase polymerization. On the other hand, the solid‐phase polymerization was completely inhibited by acetone, pyridine, and methanol, while the liquid‐phase polymerization was not inhibited by the same additives. It was concluded that the polymerization in the liquid phase proceeds by a radical mechanism and the polymerization in the solid phase proceeds by a nonradical mechanism, probably an ionic or electronic mechanism.
CH2 rocking vibrations of linear oligomers of poly(p‐ethylene oxybenzoate) having hydroxyl and carboxylic acid endgroups
Authors: Ishibashi Matahumi
Published: April 2003

Infrared spectra of poly(p‐ethylene oxybenzoate) and four of its oligomers (from monomer to tetramer) having hydroxy and carboxylic acid endgroups have been obtained in the range of 400–4000 cm.−1. An assignment of the CH2 rocking vibrations of the ethylene glycol linkage in the oligomers has been made on the basis of analysis of the spectra of the related compounds containing the OCH2CH2OH endgroup linked to phenyl residue, and containing the OCH2CH2O group between phenyl and benzoyl residues. This assignment suggests that the ethylene glycol linkages of the oligomers exist in a trans conformation. The similarity of the CH2 rocking vibrations in both the noncrystalline and crystalline phases of poly(p‐ethylene oxybenzoate) suggests that the ethylene glycol linkages exist essentially in the same (trans) conformation in both phases.
Probability theory of asymmetric chain growth in polymerization
Authors: Fueno Takayuki , Furukawa Junji
Published: April 2003

Probability theory of Markov chains has been applied to the chain propagation step of binary and multicomponent copolymerizations. General equations are presented for the calculation of the fractional distribution of monomer units in linear copolymers of any arbitrary degree of polymerization. It is shown that in ordinary Markov processes, the effect of initiation progressively becomes unimportant as the chain length increases and that the polymer composition approaches its stationary limit determined by the transition probabilities alone. The possibility of preparing optically active polymers is discussed in the light of the theoretical results obtained.
Polyethylene crystallized from the melt under elevated pressure
Authors: Wunderlich Bernhard , Arakawa Tamio
Published: April 2003

Polyethylene of the linear, low‐pressure type has been crystallized under pressure (up to 5400 atm.) from the melt. Crystallization conditions of constant supercooling and constant cooling rates were employed. The resulting solid was analyzed at atmospheric pressure. In contrast to solution crystallization under pressure above 2000 atm., extended chain lamellae of increasing thickness become dominant. These show a maximum melting point of 140°C. and in this research, densities of up to 0.994 g./cm.3. Combining these data on large crystals with the experimental maximum melting temperatures and thickness data on low and atmospheric pressure crystallized lamellae yields a surface free energy of 91 ergs/cm.2 for folded chain lamellae crystallized at low pressure.
The unperturbed dimensions of nylon 66
Authors: Saunders P. R.
Published: April 2003

Light‐scattering and viscosity measurements have been performed on nylon 66 fractions dissolved in an ideal solvent. The relation between intrinsic viscosity and weight‐average molecular weight in this solvent is [η] = 19.2 × 10−4 Mw1/2, which indicates that nylon 66 obeys random coil statistics in solution. The unperturbed coil dimensions are given by the parameter (r02/M)1/2 = 96 × 10−10 cm. mole1/2 g.−1/2.
Polymer deformation. III. Annealing of drawn polyethylene single crystals and fibers
Authors: Geil P. H.
Published: April 2003

Polyethylene single crystals plastically deformed by drawing as much as 100% and fibers that occasionally form during this deformation have been annealed at 121 and 125°C. Striations with a spacing similar to that measured with small‐angle x‐ray diffraction are observed on the fibers in contact with a substrate. No readily apparent change occurs during the annealing of freely suspended fibers. Similar striations are observed along slip bands and other grossly deformed regions within the crystals. Recrystallization through an “ameboid” motion occurs in both drawn and undrawn crystals on Mylar substrates and results in an irregular crystal boundary. The more usual type of recrystallization involving an increase in fold period appears to occur more readily at a given temperature in undrawn crystals than in the plastically deformed ones. The b axis in drawn crystals was found to rotate during the annealing treatment so as to be nearly perpendicular to the draw direction. Any polymer in the monoclinic unit cell returns to the more stable orthorhombic unit cell.
Polymer deformation. IV. Drawing of nylon 6 and polyoxymethylene crystals
Authors: Geil P. H.
Published: April 2003

Electron micrographs of nylon 6 and polyoxymethylene crystals drawn on a Mylar substrate at room temperature indicate that the deformation of these crystals occurs through a combination of plastic deformation and the formation of cracks. In nylon 6 cracks are formed preferentially between hydrogen‐bonded planes but can also form so as to result in rupture of the hydrogen bonds. There was no evidence for twinning or a crystal transformation during the deformation of either polymer.