bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclopolymerization. I. Structure of polyacrylic anhydride
Authors: Mercier J. , Smets G.
Published: April 2003

The structure of the cyclopolymers of acrylic anhydride has been examined by infrared spectrometry (cyclized units) and by chemical analysis (bromometry for vinyl unsaturation). The infrared analysis was based on the study of the two carbonyl absorption bands at about 1750 and 1810 cm.−1; two types of cyclized hexaatomic anhydrides, different in their stereochemical structure, have been shown to be present. By comparison with the meso and racemic varieties of α,α′‐dimethyl glutaric anhydride, the syndiotactic structure (racemic) has been assigned to the polyanhydride obtained at 35°C. in cyclohexanone. By heating, or in the presence of traces of acid this variety isomerizes into the isotactic form (meso). Pentaatomic cyclized units are formed only by polymerization at high temperatures, e.g., 115°C. (bands at 1780 and 1860 cm.−1). On the other hand, residual unsaturation has always been found on the basis of the vinyl absorption band at 1625 cm.−1; its intensity increases with an increase of monomer concentration during polymerization. The chemical analysis of the cyclopolymers by bromometry makes it possible to evaluate quantitatively the ratio ke/kp of the rate constant of vinyl propagation to that of cyclization; at 35°C. this ratio is equal to 0.17. By analysis of the polymers obtained at 25, 45, and 70°C. it has been demonstrated that the cyclization reaction is enhanced by an increase of temperature; the difference between the activation energies of propagation and cyclization is equal to 2.4 kcal.
Structure of the normal crystal form of polyoxymethylene
Authors: Carazzolo Gian Alvisé
Published: April 2003

The structure of hexagonal polyoxymethylene has been re‐examined by means of x‐rays. The parameters of the elementary cell, the space groups, and the model of the spiral chain previously described in the literature for this polymer have been discussed. A new elementary cell and a new type of helical chain with a higher periodicity have been proposed. The condition of isomorphism for chains belonging to the same lattice, which had already been found in the case of orthorhombic POM, has also been found valid for hexagonal POM.
Mécanisme réactionnel de la polymérisation alcaline des lactames
Authors: Sekiguchi Hikaru
Published: April 2003

As a consequence of objections raised to our interpretation concerning the reaction mechanism of the alkaline polymerization of lactams, we have re‐examined and justified our anionic “lactamolytic” mechanism. The criticism of our opponent is invalidated by mechanisms of analogous reactions, such as the reactions of organometallic compounds and hydrolysis of esters and amides. The opposing mechanism is criticized from a theoretical point of view and disproved by experimental facts which plainly justify our interpretation. The growth mechanism through imide, which consists of a nucleophilic attack of the polarized carbonyl group by the lactam anion, followed by neutralization of the resulting carbinolate ion and opening of the penultimate ring, is thus unequivocally confirmed.
The infrared spectrum of crystalline polysaccharides. IX. The near infrared spectrum of cellulose
Authors: Bassett K. H. , Liang C. Y. , Marchessault R. H.
Published: April 2003

The near infrared region of the spectra of cellulose from about 4000 to 8000 cm.−1 was investigated and assignments made to the absorption bands in this region. Assignments were made on the basis of combinations and overtones of fundamental frequencies and were checked where possible by various chemical and physical sample modifications. The dichroism of all absorption bands in this region was very slight.
Preparation and properties of some poly‐α‐methylstyrenes
Authors: Burge David E. , Bruss Douglas B.
Published: April 2003

The preparation of 20–40 g. quantities of sharply defined fractions of poly‐α‐methylstyrene, for use as standards in the correlation of molecular weight methods, is described. The procedure involves a moderately careful synthesis and fractionation. Differences in the light‐scattering second virial coefficient appear to be indicative of differences in the stereoregularity of the polymers prepared by different initiators. The intrinsic viscosities of all of the polymers studied are expressed by a Mark‐Houwink equation that is the same in all cases.
Electron exchange polymers. XIX. Copolymerization behavior of vinylhydroquinone dibenzoate
Authors: Kamogawa Hiroyoshi , Cassidy Harold G.
Published: April 2003

The copolymerization behavior of vinylhydroquinone dibenzoate monomer (VHDB), in solution under free radical initiator conditions, with styrene, α‐methylstyrene, 4‐vinylpyridine, methyl methacrylate, and methyl acrylate, to less than 10% conversion, showed good copolymerizabilities with these conventional monomers. Rates of polymerization are greater in VHDB‐rich monomer compositions in spite of the bulky character of the benzoyl group. Q‐e values (Alfrey and Price) are given. The resonance term (Q1) for VHDB is near unity, which seems to indicate that the resonance effect in stabilizing the radical is almost as large as that of styrene The polarity term, e1, is assigned a positive value for VHDB. Ultraviolet absorption spectra of the copolymers imply neighboring group interactions in the copolymer chains—interactions implied by the observed Q‐e values, and implied in earlier work by electrometric titration behavior.
Phthalocyanine‐crosslinked polyvinylphthalic acid
Authors: Winslow Eugene C. , Gershman Nancy E.
Published: April 2003

Copper phthalocyanine‐crosslinked poly‐4‐vinylphthalic acid was prepared with the expectation that some increased thermal stability could be achieved with these thermally stable linkages. Thermal decomposition in air occurs at about 310°C. The crosslinked polymer proved to be less stable than the starting material, poly(4‐vinylphthalic acid). Analysis shows that an average of one copper phthalocyanine crosslink is formed for every twelve 4‐vinylphthalic acid segmers in the poly(4‐vinylphthalic acid) chain. A new compound, 4‐vinylphthalic anhydride, was produced in this investigation.
Polymeric derivatives of 3,3‐bis(aminomethyl)‐oxetane and of exoxysuccinyl chloride
Authors: Campbell Tod W. , McDonald Richard N.
Published: April 2003

Two monomers, bis(aminomethyl)oxetane (I) and epoxysuccinyl chloride (II)
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have been prepared and converted to condensation polymers, structurally similar to the epoxides. Both monomers were stable and easy to handle. The polymers crosslinked to insoluble, infusible products.
The influence of transition metal salts in polyglycol autoxidations
Authors: Lloyd W. G.
Published: April 2003

The addition of small amounts of transition metal salts, e.g., CuCl2, to low molecular weight polyoxyalkylenediols results in pronounced autoxidation inhibition. This is in contrast with McGary's findings that this same class of salts accelerates the autoxidative degradation of high molecular weight polyethylene glycols. Inhibition of diethylene glycol is shown to relate to catalyzed hydroperoxide decomposition. With polyoxyethylenediol of molecular weight 600 this inhibition with CuCl2 is less pronounced, and with both polyoxyethylene diols and polyoxypropylene diols the inhibitory effect gives way to a net accelerating effect with increasing polymer molecular weight. The inhibitory effect is insensitive to increasing medium polarity and to changes in oxygen pressure, but is markedly sensitive to terminal group capping. Combinations of appropriate metal salts and organic antioxidants produce synergistic stabilization. The results may be explained by postulating a competition between the normal radical‐generating reactions of hydroperoxides with transition metal ions and the formation of specific terminal‐hydroperoxide complexes which decompose heterolytically.
Heterogeneous membranes: Diffusion in filled rubber
Authors: Barrer R. M. , Barrie J. A. , Rogers M. G.
Published: April 2003

The diffusion and solution of propane and of benzene has been studied over a range of temperatures in a series of heterogeneous membranes of natural rubber and zinc oxide filler. The volumes of filler were 0, 5, 10, 20, 30, and 40%. Evidence was obtained of the interaction between rubber and filler, and that some of the membranes involved three phases: polymer, filler, and open gaps between filler particles. No rigorous treatment of diffusion in heterogeneous media exists, but the model of two interdispersed phases was developed and discussed in relation to permeation rates and diffusion coefficients. Differences between steady state and time‐lag diffusion coefficients were ascribed to different structure factors in steady and transient states of flow. Concentration dependences of the interdiffusion and intrinsic diffusion coefficients of benzene were measured. The influence of concentration dependence, filler, and structure factor was combined in one relationship relating the intrinsic diffusion coefficient in the filler rubber with that for diffusion in unfilled rubber, containing the same volume fraction of benzene. The resultant expression appears able to account qualitatively for some of the observed complex diffusion behavior.
The emulsion polymerization of 2,3‐dimethylbutadiene‐1,3
Authors: Morton Maurice , Gibbs William E.
Published: April 2003

A study has been carried out on the kinetics of the emulsion polymerization of 2,3‐dimethylbutadiene‐1,3. The kinetic treatment of Smith and Ewart was applied for the direct determination of the absolute propagation rate constant kp. The following expression was obtained: kp = 8.9 × 107 exp {−9000/RT} liter/mole/sec. A previously developed treatment was applied to the determination of the relative and absolute crosslinking rates of 2,3‐dimethylbutadiene‐1,3. The results led to the following expression for the absolute crosslinking rate constant kx: kx = 3.0 × 106 exp {−14400/RT} liter/mole/sec. A comparison of these rate constants was made for the three dienes, viz., butadiene, isoprene, and dimethylbutadiene. The propagation rate constants were found to vary only by a factor of 2–3. However, the crosslinking rates were found to decrease considerably in going from butadiene to isoprene to dimethylbutadiene. This was attributed, mainly, to the decreased side‐vinyl content of the latter two monomers, compared to butadiene, as well as to the steric hindrance imposed by the presence of the methyl group.
Transannular polymerization of 1,5‐cyclooctadiene
Authors: Reichel Bernd , Marvel C. S. , Greenley R. Z.
Published: April 2003

The polymerization of 1,5‐cyclooctadiene to a low molecular weight polymer utilizing a Ziegler‐type catalyst composed of triisobutylaluminum and titanium tetrachloride is reported. Although the structure of the polymer has not been definitely established its spectral and other physical properties suggest it to be poly‐2,6‐bicyclo(3,3,0)octane. Under the same conditions 1,4‐cyclohexadiene did not undergo a transannular polymerization reaction but rearranged and yielded poly‐1,3‐cyclohexadiene.
Polymerization in liquid sulfur dioxide. Part XIII. Polymerization of styrene derivatives in liquid sulfur dioxide
Authors: Tokura Niichiro , Matsuda Minoru , Ogawa Yasuo
Published: April 2003

p‐Bromostyrene, p‐methylstyrene and α‐methylstyrene were subjected to polymerization in liquid sulfur dioxide with α,α'‐azobisisobutyronitrile as an initiator at polymerization temperatures of 0–60°C. In case of polymerization of p‐bromostyrene, only polysulfones of 1:2 molar ratio between sulfur dioxide and p‐bromostyrene were obtained. No cationic polymerization was observed. In case of polymerization of p‐methylstyrene polysulfone having 1:2 composition, a radical polymerization product, as well as poly‐p‐methylstyrene, a cationic polymerization product, as obtained, revealing concurrent and competitive occurrence of both polymerizations. The cationic polymerization was explained as the result of the electron‐donating property of the para‐methyl substituent and the catalytic action of sulfur dioxide or sulfurous acid formed with a minute amount of water contained in liquid sulfur dioxide. In liquid sulfur dioxide, the cationic polymerization was perfectly inhibited by DMF and the radical polymerization was not affected by the presence of DMF. In a system in which the radical polymerization alone proceeded in liquid sulfur dioxide, the overall rate of the polymerization was proportional to the concentration of AIBN in the order of 0.7. This was interpreted to indicate that the strong solvation between sulfur dioxide and the terminal radical of the growing radical due to hyperconjugation of the p‐methyl group may stabilize the terminal radical, leading to a unimolecular termination. In the polymerization of α‐methylstyrene, the addition of AIBN did not give polysulfone, but gave poly‐α‐methylstyrene alone as a result of cationic polymerization.
Some applications of afterglow studies of luminescent compounds in solid polymers
Authors: Czarnecki Stefan , Kryszewski Marian
Published: April 2003

The afterglow (β‐band luminescence) observed in polymethyl methacrylate activated with different hydrocarbons such as naphthalene and its derivatives was found to be sensitive to the influence of oxygen. The sharp boundary between the luminescent and nonluminescent area is due mainly to the diffusion of oxygen and shifts with time from the edges to the center of the specimen. The recovery of the afterglow results on H2 diffusion into the polymer sample or after ultraviolet irradiation. An interpretation of the observed phenomena as well as the application of the afterglow moving boundary technique to the determination of diffusion coefficients of gases in polymers and to the studies of some related processes is suggested.
Fibrous structure in stretched crystalline elastomers
Authors: Walters M. H.
Published: April 2003

Stress‐induced crystallinity in elastomers produces a strengthening structure, and tearing the rubber along the axis of extension leaves this structure outlined in the rupture surface. By maintaining the initial elongation, and taking replicas of this torn surface, the morphology of stress crystallinity has been examined in the electron microscope. The crystallites were found to be closely spaced fibers, rounded in section, and oriented in the direction of elongation. The fibers were usually between 100 and 1000 A. in diameter, and individual crystallites could be traced for distances of several microns before disappearing beneath the exposed surface. Noncrystallizing polymers showed no structure in the rupture surface. The addition of fine particle fillers had little effect on the structures observed in crystallizing polymers. In amorphous polymers traces of structure were observed, apparently consisting of groups of carbon black particles linked by rubber molecules.
Zone‐refining fractionation of polymers
Authors: Loconti Joseph D. , Cahill John W.
Published: April 2003

The unidirectional freezing of dilute solutions of polystyrene in benzene yields a frozen charge with a high concentration gradient, low in the first part frozen and highest in the last. A substantial heterogeneity in molecular weights is also noted, the highest molecular weight being found in the first part and progressively lower molecular weights toward the terminal end of the charge. Both concentration and molecular weight changes are strongly dependent upon freezing rate, low rates favoring maximum concentration changes and intermediate rates favoring maximum molecular weight separation. The application of these observations to a polymer fractionation system is reported.
Rheological measurements on polycarbonate
Authors: Baumann Gert F. , Steingiser Samuel
Published: April 2003

Rheological properties of polycarbonate were measured at constant shear stress and at constant shear rate using a capillary rheometer. The melt viscosity of polycarbonate was determined as a function of: (1) weight‐average molecular weight and molecular weight distribution in the range of M̄w = 13,000–80,000 and M̄w/M̄n = 1.1–3, respectively; (2) temperature at 260–316°C.; (3) shear rates of 1–300 sec.–1; (4) “Processability” as experienced in the injection‐molding range. A straight‐line relationship between long ηm and log M̄w was found with a slope of 3.2. A plot of log ηm against log M̄n resulted in a family of straight lines of the same slope but whose intercepts depended on the polydispersity ratios. The activation energy of viscous flow was calculated from a plot of log ηm versus 1/T at various shear rates. It varied from 26–30 kcal./mole at low shear rates to about 16 kcal./mole at higher shear rates. A shear stress versus shear rate plot showed that polycarbonate exhibited almost Newtonian behavior at temperatures above 290°C. Finally, a good correlation was established between the data obtained on the capillary rheometer and that obtained in an injection‐molding test using a spiral mold.
Electron spin resonance studies of the reaction of gases with the radicals formed in irradiated polytetrafluoroethylene
Authors: Ueda Hisashi , Kuri Zenichiro , Shida Shoji
Published: April 2003

The effect of O2, SO2, NH3, H2S, and NO on the ESR of irradiated PTFE were studied. Radicals were produced by (1) irradiation of PTFE in an atmosphere of one of these gases and (2) by the postirradiation reaction of PTFE with this same gas. These radicals were subsequently reacted with each of the remaining four gases, and the resulting spectra were studied. The radical produced in PTFE by the irradiation in vacuum is quenched by NO. In this reaction, the relation between the number of quenched radicals and the pressure of NO was measured, showing that the relation can be expressed by Freundlich's equation for adsorption equilibria. From these data, the bonds formed by the reaction between the gases and the radicals, the classification of the radical and the structure of these radicals were discussed.
Monte‐carlo calculations of the dimensions of coiling type polymers in solutions of finite concentration
Authors: Bluestone Sydney , Vold Marjorie J.
Published: April 2003

The mean end‐to‐end distances for linear polymers of 101 segments has been computed for nonintersecting random walks on a five‐choice cubic lattice on which a second chain is also present, as a function of the distance between the two chains (i.e., polymer concentration). The polymer dimensions appear to decrease with concentration, linearly at first and then more slowly. The results compare favorably with experiment and with some of the approximate analytic theories and poorly with others.
Linear condensation polymers from phenolphthalein and related compounds
Authors: Morgan P. W.
Published: April 2003

Phenolphthalein, phenolphthalimidine, phenolisatin, and similar compounds were found to react as bisphenols with aliphatic and aromatic diacid chlorides, bischloroformates, and phosgene to form linear, high molecular weight products. Interfacial and low and high temperature solution polycondensation procedures were used. The polymers were colorless and readily formed films or fibers from a wide variety of solvents. Several peculiarities in solubility behavior were encountered. The glass transition and melting temperatures of all of the polymers were much higher than values for similar polymers derived from bisphenol A. Water absorption was relatively high, and stability to discoloration by ultraviolet light was good. The majority of the products did not crystallize readily.
Polymers from sulfamide. I. Preparation
Authors: Smith H. Q. , Scott F. L.
Published: April 2003

Sulfamide and formaldehyde react at pH 10 to give a polymeric white solid (A) which decomposes at 234–235°C. A similar material results at pH 7. Modification of A was achieved by inclusion of melamine in the polymeric matrix. Sulfamide‐melamine‐formaldehyde polymer had a melting point of 261–265°C., was insoluble in organic solvents, and formed a cohesive film on compression. The polymer was obtained when sulfamide, formaldehyde, and melamine were all allowed to react simultaneously, or when a methylol melamine derivative was first prepared and then crosslinked with sulfamide. Sulfamide appears to be a more rapid crosslinking agent than urea for this system. Other aminotriazines were used in place of melamine and some 1,3‐dialkyl‐sulfamides were employed in place of sulfamide, but no significant improvement in thermal stability of the polymers was achieved.
Polymers from sulfamide. II. Evaluation and structure
Authors: Florentine R. A. , Barth‐Wehrenalp G. , Mockrin I. , Popoff I. , Riordan R.
Published: April 2003

Acid‐ and base‐catalyzed polymers involving sulfamide, melamine, and formaldehyde have been prepared and investigated. The products are insoluble and their thermal stability does not exceed 225°C. in N2.
Base‐catalyzed solution polymerization of octamethylcyclotetrasiloxane
Authors: Morton Maurice , Deisz M. A. , Bostick E. E.
Published: April 2003

A study has been carried out on the effect of solvent polarity on the base‐catalyzed polymerization of octamethylcyclotetrasiloxane. The solvents used were decalin, p‐chlorotoluene, o‐dichlorobenzene, and nitrobenzene. In accordance with the ionic mechanism proposed by Grubb and Osthoff, it has been found that the polymerization rate increases with solvent polarity, presumably bp increasing the concentration of silanolate ions. In addition, a better correlation has been obtained between molecular weights and initiator concentration, and the effect of monomer concentration on equilibrium conversion has also been elucidated.
Gel permeation chromatography. I. A new method for molecular weight distribution of high polymers
Authors: Moore J. C.
Published: April 2003

Polystyrene gels crosslinked in the presence of diluents have been made in fine‐mesh bead form suitable for packing into chromatographic columns. A series of narrow molecular weight range polymer fractions was eluted through such columns with aromatic and chlorinated solvents. Effluent concentrations were detected and recorded by a continuous differential refractometer. The fractions were shown to be efficiently separated. Columns capable of separating adjacent polymeric samples of high molecular weight were prepared from gels crosslinked in the presence of large amounts of diluents having little or no solvent action on polystyrene. Smaller proportions of diluents and those with more solvent action yielded columns with lower molecular weight permeability limits. Such studies provided a unique quantitative view of the topology of the gels. They also demonstrated that rapid repetitive molecular weight distribution data can be obtained in this way on polymers for which solvents compatible with the gels are available.
Electroinitiated anionic polymerization of acrylonitrile
Authors: Funt B. Lione , Williams Fredrick D.
Published: April 2003

Polymer was formed by an electrolytically initiated reaction in solutions of acrylonitrile and other monomers in dimethylformamide saturated with sodium nitrate. From analysis of copolymer compositions it was established that the polymer was formed at the cathode by an anionic propagation mechanism. The nature of the chain initiating step was investigated through polarographic measurements. These clearly suggest that chain initiation proceeds via direct electron addition to the double bond. A close correlation between the tendency to form anionic polymer and the polarographic potentials is indicated. The effects of current, time, and monomer concentration on the production of polymer were delineated. The yield of polymer increased linearly with time at fixed current density and showed first order dependence on monomer concentration. The absolute current efficiencies were extremely high and ranged to over 3 polymer molecules formed per electron transferred at the electrode. The molecular weights of the polymers are remarkably independent of monomer concentration, rate, and current density. A reaction scheme is proposed which postulates chain transfer to monomer. A kinetic analysis confirms the consistence of the scheme with experimental findings. Coloration and crosslinking found in some of the polymers are interpreted, and a mechanism is proposed.
Studies in the kinetics of removal of water from cellulosic fibers
Authors: Daruwalla E. H. , Shet R. T.
Published: April 2003

A study has been made of the kinetics of the removal of water from native, alkaliswollen, and regenerated cellulosic fibers under well defined conditions of experiment. In all cases, the rate of evaporation curve appears to be made up of five distinct and separate portions, and there are four points on each curve at which sudden changes of direction take place. From the changes in the rates of removal of water, attempts have been made to determine the amounts of water present in cellulosic fibers with different degrees of association with the fiber substance and to compare these values with those recorded by other workers employing different techniques. Removal of primary adsorbed water from different cellulosic fibers could be best represented by three distinct phases, the first two of which obey kinetics of reaction of first order and with apparent activation energy of the order of 8–9 kcal./mole. An attempt has also been made to calculate the radii of capillaries present in water‐swollen cellulosic fibers.
Photosensitized polymerization of acrylic monomers. II. Kinetics of polymerization in the presence of oxygen
Authors: Delzenne G. , Dewinter W. , Toppet S. , Smets G.
Published: April 2003

The kinetics of the photopolymerization of acrylamide and methacrylic acid in aqueous and semi‐organic solutions have been examined; the initiating redox system used in the presence of oxygen were eosin‐thiourea, eosin‐1‐ascorbic acid, or in some cases riboflavine. The rates of photopolymerization were determined by measuring the thermal rise of the reaction cell using a thermistor technique. In aqueous and in semi‐organic solutions, the rate is proportional to the square of the monomer concentration in both cases. Below a critical concentration of sensitizer the rate of polymerization of monomers is proportional to the square root of sensitizer concentration (acrylamide in the presence of riboflavine, methacrylic acid in the presence of eosin‐ascorbic acid); above it, the rate becomes inversely proportional to the square root of the sensitizer concentration. With respect to the reducing agent concentration, the exponent for thiourea is located between 0.5 and 1 in the case of acrylamide and 0.5 for methacrylic acid. Finally with respect to the oxygen concentration the rates are proportional to the square root of its concentration, at least below a given oxygen‐concentration where the induction period becomes predominant. These results are interpreted assuring a participation of the monomer in the initiation step, and a low initiation efficiency of the primary radicals (cage recombination). A kinetic scheme is presented and the experimental results discussed on the basis of it.
Free radical homopolymerization and copolymerization of vinyl phosphines, oxides, and sulfides
Authors: Rabinowitz Robert , Marcus Ruth , Pellon Joseph
Published: April 2003

A variety of free radical catalysts failed to homopolymerize diphenylvinylphosphine and diisobutylvinylphosphine oxide. Oligomeric products were obtained with diphenylvinylphosphine oxide and sulfide. It was shown that in the homopolymerization of the oxide at 100 and 130°C., the molecular weight is independent of catalyst concentration. Further a minimum kinetic chain length for the 0.10 mole‐% di‐tert‐butyl peroxideinitiated bulk polymerization at 130°C. was calculated to be 500 units. Reactivity ratios with styrene and methyl methacrylate (MMA) were obtained from copolymerization data (phosphorus monomer is M2). The following r1 values were obtained (all r2 values were close to zero): with diphenylvinylphosphine sulfide: styrene (2.1 ± 0.3), MMA (13 ± 3); with diphenylvinylphosphine oxide: styrene (5 ± 1), MMA (11 ± 4); with diphenylvinylphosphine: styrene (7 ± 1), MMA (5.1 ± 0.2); with diisobutylvinylphosphine oxide: styrene (17 ± 5), MMA (30 ± 10). It was concluded that the phosphorus groups do not exert strong conjugative stabilization of an adjacent carbon radical but can be considered as mildly activating on the basis of a comparison of the relative reactivities of these monomers and a series of common monomers toward a styryl radical.
Synthesis, polymerization, and copolymerization of diphenyl‐p‐styrylphosphine, phosphine oxide, and phosphine sulfide
Authors: Rabinowitz Robert , Marcus Ruth , Pellon Joseph
Published: April 2003

Diphenyl‐p‐styrylphosphine (I), prepared by the reaction of diphenylchlorophosphine with p‐styrylmagnesium chloride, was converted to the corresponding oxide (II) and sulfide (III) by treatment with tert‐butyl hydroperoxide and sulfur, respectively. These substituted styrenes polymerize readily with thermal or free radical initiation to high molecular weight polymers. These polymers are somewhat more thermally stable than polystyrene. Thus their Ti's in air were in the range 320–365°C. and in nitrogen, 375–395°C. Their T10's were in the 390–415°C. range in air and 425–435°C. in nitrogen. Polystyrene in air has a Ti of 263°C. and a T10 of 340°C. The monomers copolymerize readily with styrene and methyl methacrylate, the low conversion polymers always containing more phosphorus than the monomer mixtures. Reactivity ratios were determined, from which Q and e values were calculated. These values for the following monomer pairs are (phosphorus monomer M2): styrene‐I, r1 0.52, r2 1.43, Q2 1.34, e2 −0.30; styrene‐II, r1 0.42, r2 1.40, Q2 1.34, e2 −0.07; styrene‐III, r1 0.43, r2 1.49, Q2 1.37, e2 −0.13; MMA‐I, r1 0.32, r2 0.91, Q2 1.58, e2 0.80; MMA‐II, r1 0.38, r2 1.46, Q2 1.42, e2 −0.35; MMA‐III, r1 0.29, r2 1.22, Q2 1.58, e2 −0.62. Analysis of these data indicates that these phosphorus moieties are activating through strong electronegative effects. The extent of activation is intermediate in intensity between mildly activating groups (e.g. Cl) and strongly activating groups (e.g. CN or NO2). The behavior of diphenyl‐p‐styrylphosphine is of particular interest in this respect, since its electronegativity points to strong electron delocalization.
Vinyl polymerization. LXXIII. Polymerization and copolymerization of bornyl or isobornyl methacrylate
Authors: Imoto Minoru , Otsu Takayuki , Tsuda Kazuichi , Ito Toshio
Published: April 2003

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

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

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

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

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

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

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

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

The potentiometric behavior of polymethacrylic acid is discussed in terms of a conformational transition. A thermodynamic treatment of this transition is presented. The titration curve of polymethacrylic acid is analyzed in a detailed way and quantitative information regarding the transition is obtained.
Topochemical control of solid‐state polymerization
Authors: Hirshfeld F. L. , Schmidt G. M. J.
Published: April 2003

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

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

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

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

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

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

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