bluuebunny/crossref_metadata_2025 huggingface dataset:
The electrolytic reduction and sodium reduction‐polymerization of acrylonitrile
Authors: Murphy Sister Mary , Carangelo Maria G. , Benedicta Ginaine M. , Clare Markham M.
Published: April 2003

The reduction of acrylonitrile at mercury electrodes has been studied both polarographically and coulometrically at controlled potential. The half‐wave potential is about 1.6 v. versus a mercury pool both for pure acrylonitrile and for acrylonitrile in dimethylformamide, in the presence and absence of water. As long as water is present the diffusion current is directely proportional to the concentration of acrylonitrile, at least up to 0.2 mg./ml. In the absence of water, reduction of acrylonitrile in dimethylformamide at this potential leads to condensation of reactions initiated by the carbanion. The diffusion current is no longer proportional to the concentration. Comparison of electrolytic‐ and sodium‐reduction products of acrylonitrile gives information about the mechanisms of these reductions and the role of water in the polarographic analysis. A new yellow sodium‐reduction polymer of acrylonitrile is described, and data on the ultraviolet and infrared spectra are presented.
The adsorption of polydimethylsiloxanes from solution
Authors: Perkel Robert , Ullman Robert
Published: April 2003

The adsorption of polydimethyl siloxane polymers from solution onto polar surfaces has been studied. The amount of polymer adsorbed is unusually sensitive to the presence of moisture, which strongly inhibits adsorption. The adsorption increases with the molecular weight of the polymer and depends on the solvent because of the polymer‐surface, solvent‐surface, and polymer‐solvent interactions. The dependence of adsorption on temperature was studied, as was adsorption‐desorption equilibrium. A few experiments were carried out on the adsorption of polypentamethyldisiloxane methacrylate, a material which, in its adsorption behavior, is intermediate between polydimethyl siloxane and vinyl polymers with polar substitutents. The relationship of the results obtained here to various models of polymer chain configuration at the liquid‐solid interface is considered.
Rubber elasticity and chain configuration
Authors: Tobolsky A. V. , Carlson D. W. , Indictor N.
Published: April 2003

Various theories accounting for the existence of a front factor in the equation of state for rubber elasticity are reviwed. It is shown that a front factor which may be different from unity exists whether or not intramolecular energy effects are present. A unified theory is presented which is applicable both to Gaussian chains and to chains with intramolecular folding energy. Stress‐temperature measurements were used to obtain values of the intramolecular folding energy ϵ′ for numerous crosslinked polyacrylates and polymethacrylates. The values of ϵ′ for almost all of the polyacrylates were found to be approximately zero; the values of ϵ′ for the polymethacrylates varied generally between ‐350 and ‐700 cal./mole, indicating a preference for folded configurations. The front factors were also determined for these crosslinked polymers at 60°C. The front factor appears relatively independent of the degree of crosslinking. There appears to be a general trend to smaller front factors as the size of the alkyl chain increases in both series. An interpretation in terms of network interpenetration is given in the text. The variation of ϵ′ with copolymer composition has been determined for a series of butyl acrylate‐butyl methacrylate copolymers. The value of ϵ′ for isotactic amorphous poly(1‐pentene) was also measured and found to be zero. Finally, the effect of diluent on the front factor is discussed for the case where diluent is present during the crosslinking process and for the case where it is added after crosslinking.
The dielectric properties of polyelectrolyte solutions
Authors: Johnson G. A. , Neale S. M.
Published: April 2003

Measurements of the dielectric constants and dielectric loss factors of aqueous solutions of potassium chondroitin sulfate, poly‐L‐lysine hydrobromide, sodium ribonucleate, sodium desoxyribonucleate, and two polymetaphosphates, Calgon glass and Maddrell salt, are presented. The data are analyzed by the Cole‐Cole are method1 and relaxation times are calculated by the method of Zaromb.2 Except in the case of sodium ribonucleate the solutions are shown to behave as linear polyelectrolytes and the data are shown to fit the ionic model proposed by O'Konski.3 Sodium ribonucleate does not show the characteristics of a linear polyelectrolyte but appears to behave more like a protein in solution.
Determination of molecular weight distribution in polyvinyl acetate by selective adsorption technique
Authors: Kangle P. J. , Pacsu Eugene
Published: April 2003

The present work deals with the molecular weight distribution in polyvinyl acetate, a synthetic polymer, determined by the technique of fractionation by selective adsorption onto activated carbon. The different variables in the process of selective adsorption of smaller molecules are studied in detail. The critical factors influencing the selectivity of adsorption are adsorbent to polymer ratio and initial concentration of polymer in solution. Sharp fractions are obtained by the technique of elution of adsorbed polymer from the adsorbent with a suitable solvent. The adsorption of polymer from the solution phase onto adsorbent depends on the polymer‐solvent system. The viscosity behavior of PVAc at high dilutions is studied, and it is suggested, that the extension and disentanglement of polymer chains at high dilutions depend upon the solvent used.
Copolymerization parameters
Authors: Young Lewis J.
Published: April 2003

Copolymerization parameters, Q and e, have been calculated for several monomers whose relative reactivity ratios, r1 and r2, are available. The ratios and parameters are tabulated in an effort to bring the various data in the literature to a single source of reference.
Crystallite orientation and spiral structure of cotton. Part I. Native cottons
Authors: DeLuca Lloyd B. , Orr Rollin S.
Published: April 2003

A method is demonstrated by which both crystallite orientation and spiral angle can be directly determined from the x‐ray tracings of the 002 diffraction arcs of combed bundles of cotton fibers. Sisson has shown, qualitatively, that the 002 arcs displayed by fibers with a spiral structure can be explained by assuming two equal crystallite distributions separated by twice the spiral angle. If this distribution of crystallites is assumed to be Gaussian, the experimental are can be generated theoretically. Such an analysis is applied to several cottons of widely different orientations and the calculated parameters are compared with those of the gross arcs.
Effect of asymmetric centers on free radical polymerization and the properties of polymers: Methacrylyl alanine, methacrylyl glutamic acid, acrylyl glutamic acid, and their polymers
Authors: Kulkarni R. K. , Morawetz H.
Published: April 2003

Methacrylyl‐D‐alanine, methacrylyl‐L‐glutamic acid, and acrylyl‐L‐glutamic acid were homopolymerized or copolymerized with their enantiomorphs in dioxane, aqueous 0.1N HCl, and in water at 90% neutralization of the monomer. The homopolymerization of the optical isomer and copolymerization of racemic mixtures proceeded at identical rates for the first two monomers at 90% neutralization and for methacrylalanine in 0.1N HCl and in butanol, while with methacrylyl glutamic acid in 0.1N HCl the racemic monomer polymerized slightly more slowly than the pure optical isomer. The optical activities of the homopolymers in water varied with the polymerization medium, probably because of differences in the degree of stereoregulation. Optical activities of copolymers prepared from a mixture of the enantiomorphic monomers containing 85% of L and 15% of D isomer were mostly lower than 70% of that of the L homopolymer, which suggests that the growing chain radical has a bias toward an alternation of the steric configurations of the monomer units. Changes in the optical activities of the homopolymers with degree of ionization were compared with the behavior of pivalyl‐L‐alanine, pivalyl‐L‐glutamic acid, and isobutyryl‐L‐glutamic acid. Poly(methacrylyl‐D‐alanine) behaved in a manner similar to that of its analogue, but the changes in the optical activities of the methacrylyl‐ and acrylyl glutamic acid polymers followed a complex pattern quite different from that of their analogues. The results were interpreted on the assumption that (1) in the polymer the intrinsically more weakly acidic γ carboxyls ionize first since their ionization leads to a lower charge density than the ionization of α‐carboxyl groups and (2) the extension of the polymer backbone affects the optical activity by modifying the conformational distribution in the side chains. It is not believed that, in the cases investigated, helix formation makes an appreciable contribution to the difference between the optical activities of the polymer and their analogues.
The polymerization of styrene sulfide
Authors: Noshay Allen , Price Charles C.
Published: April 2003

Styrene sulfide autopolymerizes at room temperature to low molecular weight polymer. Considerably higher molecular weights are obtained with certain Lewis acid‐type catalysts, i.e., [η] = 2.05 with chlorocadmium butyl mercaptide. The molecular weight is inversely proportional to the polymerization temperature. Polystyrene sulfide is obtained in about 50% conversion as a soluble, amorphous, white solid which softens at about 50°C. and which forms fairly tough, rubbery films. Styrene sulfide dimerizes in the presence of dimethyl sulfate to 2,5‐diphenyl‐p‐dithiane. Oxidation of polystyrene sulfide gives polystyrene sulfone. Polystyrene sulfide is relatively unstable toward heat and ultraviolet light, both in the presence and absence of air. The cyclic dimer is one of the products obtained in the thermal degradation of the polymer prepared with chlorocadmium butyl mercaptide.
Indirect evaluation of orientation in polycrystalline materials
Authors: Sack R. A.
Published: April 2003

For a polycrystalline material with partial orientation, relations are established between the mean square cosines of the angles ρ between the axis of orientation and lines fixed with the lattice. Experimentally, the mean orientation f = <3/2 cos2ρ−1/2> for the normal to a lattice plane can be determined from the intensity distribution of the corresponding Debye‐Scherrer ring. As already shown by Wilchinsky, the mean orientation for any line can, in general, be expressed as a linear function of the values of f for five other lines, with coefficient depending on the directions of the lines within the lattice, but not on the degree of orientation of the material. For crystallites with monoclinic or higher symmetry or lamellar shape, or if all the lines considered lie within one lattice plane or along its normal, the number of independent determinations reduces to 3 or 2, for needle‐shaped crystallites even to 1.

The same number of measurements are needed if the rings contain several unresolved reflections. If more than the minimum number of observations are available, more accurate results can be obtained by a least square formalism; with composite rings the strongest reflections do not necessarily possess the highest statistical weight. The accuracy of the calculated results is estimated in terms of the errors of the experimental data.

The new formalism is applied to a fresh analysis of the measurements by J. J. Hermans, P. H. Hermans, Vermaas, and Weidinger on regenerated cellulose.
Molecular weight distribution of graham salt
Authors: Martens William S. , Rieman Wm.
Published: April 2003

A method is described for determining the molecular weight distribution of Graham salt (sodium polyphosphate) by fractional precipitation with acetone. The method differs from that of Van Wazer4 in the following respects. (1) The use of smaller samples permits the fractionation to be performed in less time with consequent less hydrolytic degradation during the process. (2) Fractions are refrigerated from the moment of separation until the analysis; this further decreases degradation. (3) Homogeneous precipitation gives a smoother curve of molecular weight distribution. (4) More fractions are obtained. (5) Cyclic compounds are determined both in the original sample and in those fractions where they occur in significant quantity, and corrections for their presence are applied.
Studies in condensed phosphates. Part I. Sodium metaphosphates and their derivatives with calcium, barium, and zinc salts
Authors: Mehrotra R. C. , Gupta V. S.
Published: April 2003

Derivatives with the formulas [Na4Ca(PO3)6]n, [Na4Ba(PO3)6]n, and [Na4Zn(PO3)6]n have been prepared by heating together mixtures of NaH2PO4.2H2O, CaO (or Ba(OH)2.‐8H2O or ZnO), and (NH4)2HPO4 in the molar ratios of 4:1:2 at 700 and 800°C. for 1 hr. The number‐average molecular weights of these derivatives have been measured by the endgroup titration method. Their conductance has been measured in aqueous solution of varying concentration, and their properties compared with those of Graham's salt (NaPO3)n prepared under similar conditions.
Preparation of polymeric materials with semiconductor properties
Authors: Geĭderikh M. A. , Davydov B. E. , Krentsel' B. A. , Kustanovich I. M. , Polak L. S. , Topchiev A. V. , Voĭtenko R. M.
Published: April 2003

Thermal treatment of polyacrylonitrile synthesized by means of ionic polymerization, radiation polymerization, or redox initiation yielded substances giving signals in the EPR spectrum and possessing semiconductor properties. From the temperature dependence of the electroconductivity the activation energy was determined, and from the data on the EPR spectra the number of unpaired electrons (1018–5 × 1019/g.) was calculated. The thermoelectromotive force was determined and the existence of a Hall effect established. Addition of copper, iron, and chromium ions to the initial polymer lowers the activation energy and increases the width of the EPR signal. On dehydrobromination of natural rubber bromides and dehydrochlorination of polyvinyl chloride, conjugated double bond polymers were obtained, and their electrical properties were determined. Semiconductor properties were found in condensation products of phthalic anhydride with hydroquinone and the activation energy of these compounds was determined.
Chlorination of phenol‐aldehyde resins
Authors: Rabek T. I. , Kosmider J.
Published: April 2003

The chlorination of phenol formaldehyde and cresol‐formaldehyde resins has been carried out with sulfuryl chloride in the presence of free radical catalyst (benzoyl peroxide azobisisobutyronitrile). Independently of the amount of sulfuryl chloride and of the reaction conditions, some aromatic substitution occurs besides the introduction of labile chlorine in the methyl group. The chlorinated novolacs are unable to react with hexanemethylenetetramine. In the chlorination, 33.4% chlorine participates, i.e., 1.7 chlorine atoms per structural unit of cresol novolac, of which 16.2% (0.82 chlorine/unit) was bounded as aliphatic chlorine. The corresponding values for phenol novolac were: 20.4% chlorine (0.78 atom/unit) and 2.7% aliphatic (0.1 atom/unit). The synthesis of phenolic and cresolic resites, at different ratios of phenol/formaldehyde and in the presence of different amounts of catalyst, has been carried out. Resites obtained at a ratio of 1 mole NaOH and 1.5 moles formaldehyde for 1 mole phenol, and submitted to a post‐heating at 100–110°C., show the strongest swelling in such solvents as benzene, dioxane and chloroform; this fact is essential for the efficiency of the chlorination. During the reaction in benzene, 7% of labile chlorine is introduced in the cresolic resite. Phenolic resites, chlorinated in the same conditions, show no labile chlorine in agreement with the results obtained during the chlorination of the novolacs. By chlorination of a resite, strongly swollen in dioxane (100%), 12% mobile chlorine is incorporated, i.e., 1 chlorine atom for two rings. During the chlorination in benzene as well as in dioxane an appreciable degradation of the resite was observed; 40 to 50% of the resite become soluble, and this solution gives on precitation a resin which is analogous to the chlorinated novolaces. The degree of degradation depends on the resite type; for example, the degradation is particularly pronounced during the chlorination of ammoniacal resins. The resites obtained without excess of formaldehyde and in the presence of small amounts of a strong base as catalyst are the chemically most stable substances.
Condensation polymers of ferrocene derivatives
Authors: Knobloch F. W. , Rauscher W. H.
Published: April 2003

Experimental details are given for the preparation of 1,1′‐ferrocenedicarboxylic acid and 1,1′‐ferrocenedicarbonyl chloride. Ferrocenedicarbonyl chloride was used to prepare novel condensation polymers containing the ferrocene nucleus as part of the main polymer chain. Interfacial polycondensation was used for the preparation of polyamides from ethylenediamine, hexamethylenediamine, piperazine, and p‐phenylenediamine. The polyamide from piperazine was obtained in crystalline form from tetrachloroethane. Polyesters were prepared from 4,4′‐ isopropylidinediphenol and hydroquinone. The polyester from ethylene glycol was prepared in low molecular weight from 1,1′‐dicarbomethoxyferrocene by transesterification.
Preparation and crosslinking properties of silicon tetrachloride‐tetramethyldisiloxane diol condensation products
Authors: Mayo Frank R.
Published: April 2003

Benzene‐soluble copolymers have been produced in high yields by the reaction of silicon tetrachloride with tetramethyldisiloxane diol and pyridine in very dilute solution in benzene. These copolymers average one to four dimethylsiloxane units per SiO2 unit. The copolymers have been equilibrated to insoluble resins by the action of heat alone or a basic catalyst. They also will effect crosslinking of silicone gum rubbers by equilibration. An improved preparation of octamethylspiro[5.5]pentasiloxane is described.
Studies in condensed phosphates. Part II. Viscosities of simple and complex sodium metaphosphate solutions
Authors: Mehrotra R. C. , Gupta V. S.
Published: April 2003

The viscosity‐average molecular weights M̄w of [Na4Ca(PO3)6]n and [Na4Ba(PO3)6]n polymers determined by Staudinger's equation in 0.0035N NaCl solution were found to be lower than their number‐average molecular weights M̄n determined by endgroup titration. The above anomaly has been shown to be owing to the effect of bivalent cations liberated in equilibria of the type:

This has been further confirmed by measurments of M̄w by the light scattering method. In aqueous solutions the greater change in viscosity of [Na4Ca(PO3)6]n solution with dilution is also ascribed to the secondary dissociation of the polymeric anions at lower concentrations.
A study of vinylidene chloride‐ vinyl chloride copolymers
Authors: Enomoto Satoru
Published: April 2003

Vinylidene chloride (VDC) and vinyl chloride (VC) copolymers were prepared in various feed ratios. A composition equation given by Mayo and Lewis was discussed in respect to the feed ratios and the corresponding composition ratios of the copolymers. Three kinds of CH deformation modes, assigned respectively to VC in the three combinations of monomer units, VDC‐VC*‐VDC, VDC‐VC*‐VC, and VC‐VC*‐VC, were deduced from their infrared spectra. The assignments were confirmed with the infrared spectra of copolymers of 80:20 feed ratio at various conversions. The CH deformation mode of VC* in the VDC‐VC*‐VDC part appears at 1197 cm. −1 (λ1 band), in the VDC‐VC*‐VC part, at 1235 cm. −1 (λ2 band), and in the VC‐VC*‐VC part, at 1247 cm.−1 (λ3 band). These bands became strong as the conversion increased, and this agreed with the variation of the chlorine contents of the copolymers at 80:20 feed ratio. A new method of obtaining the distribution of the composition of VDC‐VC copolymer and the lengths of their sequences was established. The monomer reactivity ratios obtained with the new method are r1 = 3.15 and r2 = 0.23.
The adsorption of polymethyl methacrylate from solution
Authors: Ellerstein Stuart , Ullman Robert
Published: April 2003

Polymethyl methacrylate has been adsorbed from solution onto glass and iron (oxide coated) surfaces. The adsorption isotherms have been studied as a function of solvent, molecular weight of polymer, and temperature. The solvent effect is significant and complicated depending on the interactions between polymer and solvent, polymer and surface, and solvent and surface. The amount of polymer adsorbed is relatively independent of molecular weight, and in all cases studied the amount adsorbed decreased with increasing temperature. It was found that the adsorption process was often not reversible in the usual time scale of an experiment. It was emphasized that thermodynamic and statistical thermodynamic arguments are not valid in these cases where adsorption is reversible.
Polymerization of vinyl monomers containing boron. I. B‐trivinyl‐N‐triphenylborazine and B‐triallyl‐N‐triphenylborazine
Authors: Pellon Joseph , Deichert W. G. , Thomas W. M.
Published: April 2003

Synthesis of B‐trivinyl‐N‐triphenylborazine is reported. Polymerization of this compound and of B‐triallyl‐N‐triphenylborazine is discussed. The vinyl derivative does not homopolymerize, but the allyl compound polymerizes with difficulty, yielding a gel. Both of these borazines copolymerize with styrene and with methyl methacylate. The vinyl compound is comparable to these reference monomers in reactivity toward their radicals. These results are explained by assuming that the steric effect of phenyl groups makes adjacent vinyl groups inaccessible to hindered reactants. This steric effect prevents an assessment of stabilization of vinyl radicals by resonance and polarity in the borazine ring.
Chlorinated isotactic polyhydrocarbons
Authors: Campbell Tod W. , Lyman Donald J.
Published: April 2003

Chlorinated polyethylene has been known for some time, but is too low melting for many uses. Chlorination of high‐melting isotactic polyhydrocarbons by techniques similar to those used on polyethylene has given similar products, but with higher melting points. Flame‐resistant films and fibers have been prepared by conventional techniques.
Molecular vibrations and structure of high polymers. II. Helical parameters of infinite polymer chains as functions of bond lengths, bond angles, and internal rotation angles
Authors: Miyazawa Tatsuo
Published: April 2003

Helical conformations of infinite polymer chains may be described by the helical parameters including ρi (the distance of the ith atom from the helix axis), dij (the translation along the axis), and θij (the angle of rotation about the axis on passing from the ith atom to the jth). For the polymer main chain (M)∞, (M1M2)∞, (M1M2M3)∞, (M1M2M3M4)∞, (M1M2M3M4M5)∞, (M1M2M3M4M5M6)∞ concise mathematical equations for the helical parameters are given in terms of the internal coordinates, such as the bond lengths, the bond angles, and the internal rotation angles. These equations are useful in calculating the internal coordinates and in selecting likely structure models from the helical parameters experimentally determined. The internal coordinates and helical parameters of polyethylene, polytetrafluoroethylene, sulfur, selenium, tellurium, isotactic polypropylene, poly‐4‐methyl‐1‐pentene, poly‐m‐methylstyrene, poly‐o‐methylstyrene, polyoxymethylene, polyisobutylene, polypeptides (α helix, parallel‐chain, or antiparallel‐chain extended form), polyglycine II, polyethylene glycol, and syndiotactic polypropylene were calculated and were used for discussing the structure of these helical polymers.
The preparation of membrances
Authors: Carnell Paul H. , Cassidy Harold G.
Published: April 2003

A membrane is defined as a solid, porous sheet which, when placed between two phases, may allow the passage of small particles but hinder or prevent the passage of large particles. With this definition as a basis a review is given of methods employed to prepare membranes, with special emphasis on the preparation of organic membranes. Directions are then given for the preparation of thin, uniform membranes 100 to 1500 A. or thicker. Membranes of 500 or 600 A., in thickness with a variation of less than 25 A. across a section as large as 3.5 cm. sq. are described, together with evidence for physical and chemical stability. These are prepared from pyroxylin. Thin membranes were also prepared from Formvar 15/95 E (polyvinylformal from Shawinigan Resins Corp.) and VYDR, blend 7 (a high molecular weight vinylchloride‐acetate resin containing approximately 96% vinylchloride and 4% vinylacetate, from Bakelite). No success was achieved with DYNH (a polythylene from Bakelite); and polyisobutylmethacrylate (Monomer‐Polymer).
Infrared spectra of cis and trans isomers of poly(1,4‐cyclohexylenedimethylene terephthalate)
Authors: Boye C. A.
Published: April 2003

Infrared spectra have been recorded for cis and trans isomers of poly (1,4‐cyclohexylenedimethylene terephthalate) (PCHDT). Infrared dichroisms were determined and band assignments were made. From spectra of polymers in both the crystalline and amorphous phases it was determined that the crystalline bands for trans‐PCHDT are virtually the same as those for poly(ethylene terephthalate) (PET), while cis‐PCHDT showed very little change in its spectrum upon a change in phase. The same was found to be true of model compounds of PCHDT and PET. Of the series of compounds—ethylene glycol dibenzoate, 1,3‐propanediol dibenzoate, and 1,6‐hexanediol dibenzoate— the first two compounds exhibited the same crystalline bands as the PET and trans‐PCHDT polymers, but 1,6‐hexanediol dibenzoate showed that the crystalline bands were shifted for the longer glycol chain. It was concluded that not only are the crystalline bands associated with the ‐OCC6H4CO‐ framework of these molecules but they also depend on the rigidity of the esterifying groups or glycol chain segments.
X‐Ray diffraction studies of poly(1,4‐cyclohexylenedimethylene terephthalate)
Authors: Boye C. A.
Published: April 2003

X‐ray diffraction methods were employed to determine a‐triclinic unit cell that describes the crystal lattice of poly (trans‐1,4‐cyclohexylenedimethylene terephthalate) (PCHDT). The crystal density was calculated as 1.265 g./cc., assuming one polymer repeat unit per unit cell. The fiber repeat period. 14.2 A., of the trans polymer was compared with the calculated length, 14.7 A., of the fully extended repeating unit. From this comparison, it was concluded that the trans‐PCHDT had the equatorally substituted chair form of the cyclohexane ring, and that the contraction of 0.5 A. Was probably due to toration about the O—CH2—CH bond. The repeat period that and the dimensions of a section of the unit cell, taken normal to the repeat period direction, were determined for cis‐PCHDT. These values give a crystal volume of 346 cu. A. and a true crystal density of 1.313 g./cc. for one polymer repeat per unit cell. A tentative triclinic unit cell was also determined for cis‐PCHDT that accounts for all but three of the diffraction maxima observed. These might be accounted for by another crystal species. X‐ray diffractometer traces were obtained on samples of PCHDT that had varying cis/trans rations. These curves indicated that there is a continuous deformation of the crystal lattice between 15 and 100% trans concentration. It was determined that cross‐stretching and heat‐setting of films of trans‐PCHDT tend to produce alignment of the crystallites such that the 100 planes are roughly parallel to the plane of the film. Low‐angle x‐ray diffraction patterns were obtained and indicated a repeated crystallike structure with a period of 154 A. for cis‐PCHDT and 145 A. for the corresponding trans isomer. Diffraction broadening calculations indicated a crystallite size of 6.3 A. for the trans isomer. This value corresponds to about one‐half the repeat period calculated from the low‐angle x‐ray diffraction pattern. Thus, the repeat period probable corresponds to the length of one crystallite and an adjecent amorphous region of nearly equal size. If the size of the crystallite determined for the trans Polymer is representative, the Polymer molecular weight of 10,000 might paprticipate in as many as five crystallites, while molecules in the prepolymer state with viscosities near 0.3 could participate in only one crystallite.
Polymerization of 2,4‐dimethyl‐6‐vinyl‐s‐triazine
Authors: Coscia Anthony T. , Kugel Robert L. , Pellon Joseph
Published: April 2003

2,4‐Dimethyl‐6‐vinyl‐s‐triazine (A) is readily polymerized by free radical initiators to a high molecular weight product. Copolymerization studies with reference monomers

(M1), styrene and methyl methacrylate, gave reactivity ratios with styrene: r1 = 0.12, r2 = 0.92; with methyl methacrylate: r1 = 0.37, r2 = 1.75. The following Q−e values were calculated: with styrene Q2 = 12, e2 = +0.92; with methyl methacrylate Q2 = 2.6, e2 = +1.09. These values indicate that the dimethyl triazinyl moiety is a radical stabilizing and electronegative substituent. Poly(2,4‐dimethyl‐6‐vinyl‐s‐triazine) (PDMVT) is soluble in water and in all the common organic solvents with the exception of aliphatic hydrocarbons. Poly(isopropenyl‐s‐triazine) (PIT) is soluble only in dimethylformamide and chloroform. The latter also softened at a much higher temperature than PDMVT. These differences were considered a result of hydrogen bonding between chains in PIT.
Block copolymers based on 2,2‐bis(4‐hydroxyphenyl)‐propane polycarbonate. I. Preparation and properties of copolymers from a variety of homopolymers
Authors: Merrill Stewart H.
Published: April 2003

Low molecular weight 2,2‐bis(4‐hydroxyphenyl)propane polycarbonate was block‐copolymerized with the bischloroformate of polymeric glycols of a variety of structural types. Poly(ethylene oxide), polytetrahydrofuran, and hydroxy‐terminated polystyrene gave the highest molecular weight copolymers with the polycarbonate. The presence of flexible blocks along the chain promoted the crystallization of the polycarbonate, which resulted in flexible polymers with high melting points. The polytetrahydrofuran copolymer was an elastomer. Preparative details and thermal and mechanical properties of cast films are given.
Studies of the ethylenediamine‐cellulose complex. IV. Decomposition of the complex by dimethylformamide
Authors: Segal Leon
Published: April 2003

Dimethylformamide applied at 100°C. and at the boil to ethylenediamine–cellulose complexes decomposed the complexes, giving products whose x‐ray diffractograms are almost identical with that of cellulose IV prepared by means of glycerol at 250°C. The product derived from cellulose II has a 002 interplanar spacing of 4.04 A., those from cellulose I and III have a spacing of 3.98. The 101 and 101 interplanar spacings are the same for all the products, 5.71 A. The infrared spectra of the products are markedly similar to those of the original cellulosic starting materials, except in the case of cellulose III. This modification has a cellulose II type of infrared spectrum; that of the product is markedly similar to the infrared spectrum of cellulose I. Application of sodium hydroxide solution and of ethylenediamine to the decomposition products of the complexes produced cellulose II and the ethylenediamine‐cellulose complexes, respectively. Anhydrous ethylamine failed to produce cellulose III.
Differential thermal analysis of silicones
Authors: Brown G. P. , Hill J. A. , Murphy C. B.
Published: April 2003

Differential thermal analysis has been applied to several silicone polymers and compounds with the use of oxidative conditions. The model compounds gave melting points corresponding to literature values. However, volatilization gave a broad endotherm much lower than extrapolated boiling points. The order, in oxidative resistance, was dimethyl silicone oil, silphenylene, methyl phenyl silicone oil.
Spherulitic crystallization and cracking during heat aging of polypropylene
Authors: Inoue Masakazu
Published: April 2003

The spherulitic crystallizations of polypropylene were investigated by a polarizing microscope. At high temperature, crystallization proceeds through the process of dendritic mechanism. Long needles grow rapidly at first from the nucleus to the supercooled melt, and then they fan out around each needle by branching. The rates of these two processes depend on the polymer and the condition of crystallization. In large well‐grown spherulites, cracks are formed both between radial fibers and at boundaries during heat aging. The cracks are void and single spherulites are separated. The boundary cracks are also caused by thermal decomposition of molecules and the radial cracks by stresses due to the rearrangement of molecules or the perfection of spherulites.
Ultraviolet irradiation of plastics. I. Degradation of physical properties
Authors: Stephenson C. V. , Moses B. C. , Wilcox W. S.
Published: April 2003

Polyethylene, Teflon, nylon, Mylar, and Acrilan have been irradiated in vacuo and in an atmosphere of nitrogen with narrow bands of ultraviolet radiation centered at 244, 314, and 369 μ and with monochromatic ultraviolet light of wavelength 253.7 μ. The physical properties of all these polymers are ultimately degraded by ultraviolet light of any of these wavelengths, but the shorter wavelengths are much the more effective in producing changes. The degradation of polyethylene, nylon, Mylar, and Acrilan is faster when irradiation is in an inert atmosphere of nitrogen than it is when irradiation is in vacuo. Teflon, however, degrades more rapidly in vacuo than in a nitrogen atmosphere.
Ultraviolet irradiation of plastics III. Decomposition products and mechanisms
Authors: Stephenson C. V. , Lacey J. C. , Wilcox W. S.
Published: April 2003

Volatile decomposition products of ultraviolet‐irradiated polyethylene, nylon, Mylar, and Acrilan have been analyzed. The principal decomposition products of polyethylene are hydrogen and methane. Besides hydrogen and methane, carbon monoxide occurs in considerable amounts in the decomposition products of the other polymers. There is a considerable difference in the relative abundances of methane and hydrogen in the decomposition products, depending on whether irradiation was performed in a vacuum or in nitrogen. Decomposition products of ultraviolet‐irradiated nylon include all of the primary amines from methyl through hexyl. Mechanisms consistent with the observed results of photolysis are proposed.
A study of the efficiency of oxidation inhibitors for rubber at various temperatures
Authors: Angert L. G. , Kuz'Minskiǐ A. S.
Published: April 2003

A kinetic study of the oxidation of butadiene–styrene and butadiene polymers in the presence of secondary aromatic amine inhibitors has been made over the temperature range 70–150°C. The rate of the inhibited oxidation has been found to depend upon the inhibitor concentration. In contrast with other inhibited processes, this relation is described by a curve with a minimum. The concentration corresponding to the latter depends upon the oxidation temperature, polymer reactivity, and lability of the imino hydrogen of the inhibitor molecule. Experimental data and kinetic computation have shown that the extreme on the efficiency–concentration curve is due to the fact that the amine not only exerts a retarding but also an initiating effect on the polymer oxidation process. The latter is due to direct interaction of the amine and molecular oxygen during the inhibited oxidation of the polymer. The kinetics of oxidation of the amine have been investigated. The duration of the induction period of the polymer oxidation process does not increase in proportion with the inhibitor concentration. The relation between the length of the induction period and rate of oxidation of the polymer for various inhibitor contents has been investigated and discussed. The inhibitor concentration exerts a marked influence on the overall rate of structural changes undergone by the polymer in the oxidation process and also on the ratio of the degradation and structuration velocities of the molecular chains. The change in efficiency of the inhibitor with respect to the oxidation temperature has been examined.
Graft and block photopolymerization
Authors: Smets G. , De Winter W. , Delzenne G.
Published: April 2003

By polymerization of vinyl monomers in the visible light in the presence of dyes (eosin, safranine, acridine orange), ascorbic acid, and oxygen, following the method of Oster, the dye is incorporated as a leuco form into the polymer molecule. In the synthesis of N(eosin) polyvinylamine, one tenth of the amino groups carries a coloured group. This polymer was used for the synthesis of graft polymers with acrylamide, acrylic acid, acrylonitrile, and styrene. The graft polymers were isolated by fractionation; the yield is particularly high with acrylamide and acrylic acid. The per cent contents in the second monomer were 41 (acrylamide), 38 (acrylic acid), 14 (acrylonitrile), and 36 (styrene). The method also makes possible the synthesis of polymers with branches of different chemical structure by successive photopolymerizations of two different monomers, e.g., acrylamide and acrylic acid. Similarly, starting from ω‐N‐(eosin) polymethyl methacrylate, block polymers were synthesized with styrene and acrylamide; the contents in the second monomer was 40 and 79%, respectively. By hydrolysis experiments it was demonstrated that the leuco dye group constitutes the intermediate link in these block polymers between the two monomer sequences.
Radiation‐induced crosslinking and degradation of vinyl chloride‐vinylidene chloride copolymers
Authors: Harmer David E. , Raab Joseph A.
Published: April 2003

While it is accepted that the high‐energy irradiation of poly (vinyl chloride) produces a predominately crosslinked material, confusion exists about the vinyl chloride–vinylidene chloride copolymer system. Degradation is generally assumed. We have shown that crosslinking (or endlinking) predominates over chain scission in several poly (vinyl chloride–vinylidene chloride) systems. The relative amounts of the two reactions are a function of vinylidene chloride content in the copolymer. While crosslinking is increased at increased temperatures during irradiation, and decresed in the presence of oxygen, a much larger effect is exerted by the physical form (or heat history) of the solid copolymer itself.
Stereospecific polymerization of isobutyl vinyl ether at elevated temperatures
Authors: Iwasaki K.
Published: April 2003

Isotactic polyvinyl isobutyl ether was obtained using chromium trioxide as catalyst at elevated temperatures, even at 80°C. Polymerization was carried out in a heterogeneous system. A stirring device to mill the catalyst is necessary to obtain polymer which has a high crystalline fraction. The crystalline fraction, whose melting point is over 140°C., was separated by extracting the amorphous portion with methyl ethyl ketone, and was between 20 and 30% weight of the total polymer. In this connection, other transition metal oxides were examined but chromium oxides of lower valence than 6 had little activity toward polymerization. Moreover, molybdenum trioxide, vanadium pentoxide, and nickel monoxide showed activity toward polymerization, but the polymers obtained with these catalysts had no crystalline fraction.
The swelling of polymer systems in solvents. I. Method for obtaining complete swelling–time curves
Authors: Buckley Donald J. , Berger Martin , Poller Dennis
Published: April 2003

A photometric method for measuring the swelling of polymers in solvents from zero time to equilibrium has been described. The method consists in following continually the growing “shadow” of the specimen as it imbides the solvent. Equipment details and method of operation are discussed. Typical swelling–time curves for butyl vulcanizates are reported. These serve as examples of the rapidity and reproducibility of the method and also as demonstrations of the completeness of solvent uptake. Essential agreement between the results on volume swelling at equilibrium obtained by the photometric method and by the conventional gravimetric method is observed. The new method is important in that the rate of swelling can be measured. Its use in this regard in studying the diffusion of liquids in polymers will be referred to subsequent papers in this series.
Thermal coloration and insolubilization in polyacrylonitrile
Authors: Grassie N. , Hay J. N.
Published: April 2003

The thermal coloration reaction in polyacrylonitrile is shown to be similar to that which occurs in polymethacrylonitrile, consisting essentially of the linking up of adjacent nitrile groups to form conjugated carbon‐nitrogen sequences. Thus infrared spectral changes in both polymers consist of a decrease in CN absorption accompanied by the development of CN and conjugated CN absorption. The reactions are accelerated similarly, by nucleophilic reagents such as acids either copolymerized into or external to the polymer chains. There are, however, two major differences between the coloration behaviors of these two materials. Firstly, while polymethacrylonitrile remains color‐stable below 200°C. in the absence of nucleophilic initiating agents, pure polyacrylonitrile colors at a finite rate which is not reduced by further attempts at monomer purification. This is due to the fact that the tertiary CH structures in polyacrylonitrile, absent in polymethacrylonitrile, are capable of initiating coloration. It seems more likely that this occurs intramolecularly than intermolecularly. Secondly, while polymethacrylonitrile remains soluble even when extensively colored, polyacrylonitrile rapidly insolubilizes. This is not due to crosslinking in an intermolecular self‐initiation process; rather, it appears that the successive linking up of nitrile groups can move. from molecule to molecule in polyacrylonitrile owing to the more intimate packing of the chains, so that “propagation crosslinks” are produced. This theory of “propagation crosslinking” is supported by the observed influence of various comonomers in inhibiting crosslinking.
Properties of polyvinylidene fluoride. Part III. Viscous behavior and thermal stability
Authors: Bagley Edward B. , Wentink Tunis
Published: April 2003

Viscosity measurements were made on the plastic polyvinylidene fluoride at 240°C. The flow properties continually change with time, the viscosity increasing steadily at constant stress and temperature. This is probably due to slight simultaneous evolution of HF gas and crosslinking of the polymer chains.
Sur la polymérisation à l'etat solide de l'acrylamide
Authors: Sella C. , Bensasson R.
Published: April 2003

No. Abstracts
Primary and secondary hydroxyl group content of polypropylene glycols
Authors: Hanna J. Gordon , Siggia Sidney
Published: April 2003

When propylene oxide is polymerized or when it is added onto an alcohol or phenol, the terminal hydroxyl groups can be of primary or secondary types, depending on how the epoxide ring opens. The nature of the terminal hydroxyl group becomes important if the polyglycol ether is reacted further, as in the case of polyurethane foams. The primary hydroxyl group reacts much more rapidly with isocyanates than the secondary hydroxyl group, and hence the performance of the polyglycol varies with the ratio of primary to secondary hydroxyl group content. An analytical method has been developed to differentiate the primary from the secondary hydroxyl groups on polypropylene glycol, and a study was made of the variation in the ratios of the two hydroxyl types versus molecular weight of the polyglycol and versus other chemical treatments to which the polyglycol was exposed.
Polyethylene unit cell variations with temperature
Authors: Swan Paul R.
Published: April 2003

The unit cell dimensions of a linear polyethylene are reported as determined by x‐ray diffraction measurements at five‐degree intervals from −70°C. to +130°C. and at −196°C. The relative expansion coefficient of the a dimension of the orthorhombic unit cell was found to increase from 1.1 × 10−5/°C. at −196°C. to 22 × 10−5/°C. at 30°C. to 58 × 10−5/°C. at 138°C., the melting point of the crystal. The coefficient of the b dimension was found to vary from −2.8 × 10−5/°C. at −196°C. (questionable) to +3.8 × 10−5/°C. at 30°C., and then to −7.3 × 10−5/°C. at 138°C. These values were obtained from series expansion analytical fits to the experimental points, and are less accurate at the ends of the temperature range; the 30°C. values are probably correct to a few per cent.
Heterogeneous hydrolysis of cellulose with high polymer acids. Part 3. The acid hydrolysis of cellulose with finely divided cation‐exchange resin in the hydrogen form
Authors: Hartler Nils , Hyllengren Kari
Published: April 2003

General aspects of acid hydrolysis of glycosidic bonds are presented. Homogeneous versus heterogeneous hydronium ions and glycosidic bonds, and also their various combinations, are especially noted. Cation‐exchange resin of the strongly acid type in the hydrogen form is shown to have little or no hydrolysis effect on the glycosidic bonds in cotton. The results obtained can probably be completely explained in terms of the effect of low molecular weight acids arising from degradation of the resin. The composition of small amounts of dissolved carbohydrates was the same whether a cationexchange resin or a low molecular weight acid was used.
The application of copolymerization theory on memory devices
Authors: Ham George E.
Published: April 2003

Advances in the mathematical treatment of copolymerization phenomena, which allow for the influence of units at any distance from the growing chain ending on reactivity with monomers, have suggested means of treating the influences of memory and nonmemory factors on the making of simple decisions and their application to memory devices. Genetics and reproduction and brain functions are believed to be influenced by considerations of the type discussed. The equations may be applied also to the preparation of proteinlike copolymers and the elucidation of sequence distributions in natural and synthetic polypeptides.
Polymer—diluent interactions. II. Polyvinyl chloride—diluent interactions
Authors: Anagnostopoulos C. E. , Coran A. Y.
Published: April 2003

The solvent power of a variety of diluents with polyvinyl chloride was evaluated in terms of the polymer—diluent interaction parameter χ and heat of mixing parameter B by means of a micromethod reported in the first part of this series. Among the diluents investigated are esters of phthalic, fumaric and maleic acids, alkyl‐substituted benzenes, and condensed and conjugated aromatic ring systems. Relationships between solvency and diluent structure were sought in terms of the intermolecular forces involved in polymer—diluent associations. A condition found necessary for good solvency is that both the dispersion and dipolar forces acting between solvent molecules be similar in strength to the corresponding forces acting between polymer macromolecules. Steric hindrance of the carbonyl dipoles in the ester molecules, or of the aromatic nuclei in the hydrocarbon molecules, has a pronounced effect on the values of B. The extent of resonance interactions in the hydrocarbon molecules influence their solvent power. Where such interactions are reduced due to steric effects, solvency is also reduced.
Thermodynamic properties of moderately concentrated polyisobutylene–chlorobenzene solutions
Authors: Leonard J. , Daoust H.
Published: April 2003

The recent Fixman's variational theory devised to compute the osmotic pressures of high polymer solutions in the moderate concentration range has been applied to the polyisobutylene—chlorobenzene system at 25°C and 40°C. The osmotic pressures have been measured with an osmometer similar to that described previously by Flory and Daoust. As predicted by the theory, a plot of the apparent osmotic second virial coefficient against concentration gives a curve which rises then flattens out as concentration increases, at both temperatures. Correlation between experimental data and theory is slightly better if the Kurata‐ Yamakawa theory is used to calculate the linear expansion factor of the polymer coil α and to define the second virial coefficient A2.