bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of graft polymers by γ‐irradiation of natural rubber latex and methyl methacrylate
Authors: Cockbain E. G. , Pendle T. D. , Turner D. T. 
Published: April 2003

AbstractExposure of mixtures of natural rubber latex and methyl methacrylate to γ‐radiation from a Co‐60 source results in polymerization of the methyl methacrylate to give a mixture of the homopolymer and grafted polymer. The ratio of grafted polymer to homopolymer and the molecular weight of the homopolymer are both considerably higher than in similar systems where polymerization was initiated by a redox catalyst. The ability of the irradiated to form continuous films on drying is much greater than that of corresponding redox‐polymerized systems. This difference is attributed primarily to the location of the polymerized methyl methacrylate throughout the individual latex particles, the polymerized methacrylate being more uniformly distributed in the case of the irradiated latex. Use of polymerization retarders which are soluble in methyl methacrylate swollen rubber supplies evidence that an increased proportion of the polymerized methacrylate is located in the surface regions of the latex particles. Conversely, a more uniform distribution of the polymer is obtained by the use of water‐soluble retarders. The probable significance of these results in relation to emulsion copolymer systems is pointed out.
Orientation of isotactic polypropylene filament and its new crystalline structure produced by high stretching
Authors: Sobue Hiroshi , Tabata Yoneho 
Published: April 2003

AbstractOrientation of crystallites in stretched isotactic polypropylene filaments was examined by x‐ray diffraction. It was found that complete overall orientation parallel to the direction of stretching is obtained at a stretching ratio of 4 to 5. Preferential orientation was observed in the stretching process, that is, the orientation of the 010 plane along the fiber axis was predominant in the initial step of orientation and was complete by 100% stretching. It was found that a new crystal structure was formed on further stretching of completely oriented filaments at or slightly above room temperature. The crystal structure can be transformed to an ordinary stable crystal structure by treating the filaments at 100 to 150°C. for comparatively short time. The crystal structure may be a kind of metastable crystal, with nearly hexagonal projection in the plane perpendicular to the fiber axis.
The viscosities of concentrated polymer solutions. I. Moderately concentrated solutions
Authors: Hirai Nishio 
Published: April 2003

AbstractThe enormous increases of the viscosity, η, and the associated activation heat, Qη, in concentrated polymer solutions are attributed to the formation of intermolecular linkages between high polymer molecules and to the increase of glass transition temperature with increasing concentration of the solution. In this paper, the effects of the intermolecular linkages on the viscosity of moderately concentrated solutions were discussed. In this concentration range, η and Qη are represented by unique functions of reduced concentration, vR = BMv2, and the following equation was derived for Qη;

Here M is the molecular weight of the polymer, v2 is the volume fraction of the polymer, ΔE is the energy to form an intermolecular linkage, B is a constant for the solution, and Qη0 is the activation heat of viscosity for the solvent. The dependency of η on vR shifts from a first power proportionality to a third power at vR = 1/2. The theory was compared with experiments for solutions of cellulose tributyrate in trichloropropane, polyvinyl alcohol in water, polyvinyl acetate in acetone, and polyisobutylene in xylene.
The decomposition of benzoyl peroxide in polystyrene
Authors: Haas Howard C. 
Published: April 2003

AbstractThe rate of decomposition of benzoyl peroxide in polystyrene has been measured at 70.9, 80.1, and 89.5°C. The kinetics are strictly first order. There is no dependence of rate on concentration, which indicates that radical‐induced decomposition is absent. At 70–80°C., the Arrhenius relationship is k = 1.39 × 1017e−35,700/RT and at 80–90°C., k = 2.67 × 1013e−29700/RT. Above 80°C., the apparent second‐order transition temperature of polystyrene, the rates of decomposition correspond fairly closely to the rates of spontaneous decomposition of benzoyl peroxide in benzene. Below 80°C., the rates of decomposition of benzoyl peroxide in polystyrene are considerably smaller than those in benzene. Two possible explanations of this behavior are presented.
Stereospecific polymerization of isobutyl vinyl ether in homogeneous cationic systems
Authors: Okamura Seizo , Higashimura Toshinobu , Sakurada Ichiro 
Published: April 2003

AbstractIsotactic polyisobutyl vinyl ether is generally less soluble in methyl ethyl ketone than is amorphous polymer, but the solubility of solid polymer in methyl ethyl ketone at room temperature is not always proportional to the crystallinity of polymer molecules. In this report it is made clear that the precipitation temperature can be utilized for the discrimination of the steric structure of polymer through comparative reference to x‐ray diagrams. Judging from the precipitation temperature, in the polymerization of vinyl isobutyl ether catalyzed by BF3·OEt2 at −78°C., the polyvinyl ethers obtained from a homogeneous polymerization system are of a more isotactic structure than those obtained from a related heterogeneous system, at low monomer concentration. In addition, the relative amounts of isotactic molecules are decreased in the cases of high monomer concentration and polar reaction systems. However, the wide differences in chain length of the polymers compared introduced doubt. These results do not indicate that stereospecific polymerization may proceed more easily in a heterogeneous system, as was considered to be the case.
Polysoaps. III. Polysoaps and related materials prepared by chemical modification of polystyrene
Authors: Medalia A. I. , Freedman H. H. , Sinha Sisir 
Published: April 2003

AbstractA detailed description is given of the preparation of an anionic polysoap, poly[styrene co potassium styrylundecanoate], or poly‐K‐SSU, by the following route. Polystyrene is alkylated with methyl undercylenate in the presence of aluminum chloride; the polyester is then saponsified. Only about 50% of the phenyl groups are alkylated; thus, the structure may be written:
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Products of molecular weight from 60,000 to 1,760,000 have been prepared. Another anionic polysoap has been made by alkylation with methyl oleate; here, only about 35–39% of the phenyl groups are alkylated, apparently due to steric hindrance. Nonionic polysoaps have been prepared by ester interchange of the unsaponfied methyl esters with methoxy polyethylene glycol. A sulfate ester polysoaps has also been prepared. The properties of poly‐K‐SSU have been studied in some detail. The solubilizing power, and the viscosity of the aqueous solutions, are comparable to ordinary soaps; but the surface tension of the aqueous solution is very close to that of pure water. The nonionic polysoaps are also good solubilizing agents, e.g., for cholesterol; possible medical applications are considered.
A theory of the thermodynamic behavior of nonelectrolyte solutions. II. Application to the system rubber‐benzene
Authors: Maron Samuel H. , Nakajima Nobuyuki 
Published: April 2003

AbstractThe thermodynamic theory of nonelectrolyte solutions proposed by Maron has been applied to the experimental data of Gee and Treloar on solutions of rubber in benzene at 25°C. The theory was found to be capable of representing these thermodynamic data very satisfactorily on the basis of a constant interaction parameter μ, and on the basis of the dependence of the heat of mixing on the derivative of μ with respect to temperature rather than μ itself. Further, by assuming the heat of mixing to be temperature independent, an expression was set up for μ as a function of the volume fraction, v2, and the temperature. This equation reproduces \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {\Delta F} _1 $\end{document} values measured at 100°C. with an accuracy of better than 4%, and shows that at temperatures above and below 25°C. μ is concentration‐ as well as temperature‐dependent.
The sulfinic acid‐initiated polymerization of methyl methacrylate
Authors: Overberger C. G. , Godfrey J. J. 
Published: April 2003

AbstractThe rate of polymerization of methyl methacrylate initiated by p‐methoxybenzenesulfinic acid, benzenesulfinic acid, and p‐trifluoromethylbenzenesulfinic acid in the absence of oxygen was studied. The p‐methoxy substituent accelerated the rate while the p‐trifluoromethyl substituent acted as a retarder. The order of the rate with respect to sulfinic acid concentration varied between 1 and 3/2; this is consistent with an initiation process of kinetic order between 2 and 3. Dilution of the monomer with benzene in an attempt to determine the order of the rate of polymerization with respect to monomer unexpectedly resulted in an increase in rate. Mixtures of p‐methoxybenzenesulfinic acid and p‐trifluoromethylbenzenesulfinic acid did not give an acceleration in rate. The rate of polymerization was accelerated by sulfonic acid, benzoyl peroxide, dicumyl peroxide, and di‐n‐butylamine hydrochloride. Decomposition of the very unstable 2,2′‐biphenyldisulfinic acid by disproportionation to the intramolecular sulfonic acid‐sulfenic acid was shown to be incompatible with the yield and rate of formation of the thiolsulfonate. The gross features of a mechanism consistent with the polymerization data is proposed.
Hydrolysis of methacrylic acid–methyl methacrylate copolymers
Authors: Loecker W. De , Smets G. 
Published: April 2003

AbstractSeveral copolymers of methacrylic acid and methyl methacrylate have been prepared with acid contents of 28.8, 50, 60, 66, 72, 83, and 86.5%; they have been hydrolyzed in acidic medium at 110°C. at different neutralization ratios r = [HA]/[A‐]. Except for those with the highest acid content, all the copolymers show a two‐step hydrolysis, in which the second step is about 1/6−1/7 slower than the first. The order of reaction is one with respect to the acid concentration and one with respect to the ester concentration. On the basis of general catalysis, as suggested by Brønsted, two hydrolysis rate constants kHA and kA‐ may be evaluated; they correspond to the hydrolysis catalyzed by undissociated carboxyl groups and by carboxylate groups. At 110°C., kHA and kA‐ are equal, respectively, to 1.5 × 105 and 1.0 × 105; consequently, the rates of hydrolysis are practically insensitive to the ratios of neutralization r, except when r = 3. From comparison of the behavior of these acid‐ester copolymers with that of a methyl methacrylic‐N‐vinylpyrrolidone copolymer in the presence of an acid‐buffered solution (acetic tic or polymethacrylic acid), it becomes evident that the hydrolysis reaction consists essentially of a functional interaction between an ester function on one side, and a carboxyl and/or a carboxylate directly neighboring function on the other side. Moreover, on the basis of structural probability calculations, the immediate vicinality effect is insufficient to explain the rates and limited degree of conversion of the hydrolysis reaction. For the copolymers with high acid content (C72, C83, and C86.6) at r = 3, the rate of reaction is triple that at the other r‐values. This strong increase of the reaction velocity is, as expected, characterized by an appreciable decrease in the energy of activation (16 kcal. instead of 23 kcal.) This behavior is attributed to a “concerted” mechanism which should be particularly enhanced at r = 3. It has been demonstrated that the stereochemical composition of these copolymers exerts a deep influence on the rate of hydrolysis as well as on the degree of conversion in these reactions.
Catalytic reactivity of organometallic compounds for olefin polymerization. II. Vinyl chloride polymerization catalyzed by binary systems involving organometallic compounds
Authors: Furukawa Junji , Tsuruta Teiji , Shiotani Shigeo 
Published: April 2003

AbstractThe behavior of vinyl chloride toward various binary systems involving organometallic compounds was studied. Molecular oxygen, peroxides, quinone, and salts of silver or copper were used as the second component. Of the ethyl derivatives of boron, aluminium, zinc, and cadmium, the first exhibited the largest activity for the polymerization with the exception of benzoquinone as cocatalyst. Organic hydroperoxide seemed to be the most prominent cocatalyst. Thus, it was possible, by the use of the system of triethylboron and cumene hydroperoxide, to obtain polyvinyl chloride in fair yield at temperature as low as −65°C. Triethylaluminum was the sole compound which was able to induce vinyl chloride polymerization in cooperation with benzoquinone. The polymerization described in the present paper is considered to be a new type of the redox polymerization.
The additivity of some energy factors in normal alkyl compounds
Authors: Davies Mansel 
Published: April 2003

AbstractData for the heats of evaporation (of liquids), heats of sublimation, and heats of solution for a number of homologous families of simple alkyl derivatives are presented. These show a linear dependence upon chain length which allows the group contributions to be evaluated. Much of the quantitative analysis of polymer behavior is dependent upon these factors and the need for further more precise data and the advantage of direct determinations are emphasized.
Interfacial polycondensation. III. Polyamides
Authors: Beaman R. G. , Morgan Paul W. , Koller C. R. , Wittbecker Emerson L. , Magat E. E. 
Published: April 2003

AbstractExperimental details are given for the interfacial polycondensation of thirteen polyamides having widely different structures. The method involves the fast, room‐temperature reaction in a two‐phase system between diamines and diacid chlorides. Aliphatic, alicyclic, and aromatic reactants, primary and secondary diamines, and many reactants containing other functional groups are all operable. The preparations illustrate a variety of procedural modifications and point up the simplicity, rapidity, and broad applicability of the method.
Interfacial polycondensation. IV. Polyphthalamides
Authors: Katz Manfred 
Published: April 2003

AbstractHigh molecular weight polyphthalamides melting above 325°C. were prepared from piperazine, 2‐methylpiperazine, and 2,5‐dimethylpiperazine by interfacial polycondensation. The melt temperatures and decomposition points of the polyphthalamides, polyisophthalamides, and polyterephthalamides of the above diamines were determined. Only low molecular weight polyphthalamides were obtained from primary diamines. Copolymers of high molecular weight were prepared from piperazine and 2,5‐dimethylpiperazine with phthaloyl chloride containing various proportions of terephthaloyl chloride, isophthaloyl chloride, adipoyl chloride, or ethylene bis(chloroformate).
Interfacial polycondensation. IX. Polysulfonamides
Authors: Sundet S. A. , Murphey W. A. , Speck S. B. 
Published: April 2003

AbstractPolysulfonamides may be prepared readily in high molecular weight by interfacial polycondensation. They are formed rapidly at room temperature when a disulfonyl chloride in an organic solvent is emulsified with a diamine in water containing an acid acceptor. The highest polymers have been obtained from aliphatic diamines and aromatic disulfonyl chlorides. Aromatic diamines have given only low molecular weight materials. Reaction conditions for preparing poly(hexamethylene‐1,3‐benzenedisulfonamide) are briefly described. Reactants must be very pure. Dichloromethane and chloroform have been the most useful organic solvents and must be pure and dry. The best concentrations are about 0.1M. The pH and the ionic strength of the aqueous phase exert a power ful effect on the desired partition of diamines between the two phases and the undesired hydrolysis of the sulfonyl chloride. Thus, sodium carbonate works better than sodium hydroxide as an acid acceptor and, in some cases, bicarbonate has been used to avoid imide formation and consequent branching.
Interfacial polycondensation. X. Polyphenyl esters
Authors: Eareckson William M. 
Published: April 2003

AbstractThe interfacial polycondensation method has been used for the preparation of polyphenyl esters. Polyphenyl esters can be prepared easily and reproducibly in high molecular weight by mixing in a home blender an aqueous solution of the sodium salt of the bisphenol and a dispersing agent with a solution of the diacid chloride in a water immiscible organic solvent. The organic solvent should be a solvent or swelling agent for the polymer being prepared. Polyphenyl esters with inherent viscosities as high as 2.3 have been prepared by this method. This system is widely applicable to a large number of bisphenols and dibasic acid chlorides, although aromatic acid chlorides, in general, give higher molecular weight polymer than aliphatic acid chlorides. Bisphenols containing negative substituents do not readily give high molecular weight, tough polymers because of the reduced basicity of the phenoxide ion. A series of copolymers of 2,2‐bis(4‐hydroxyphenyl)propane with isophthaloyl and terephthaloyl chlorides has been prepared and the physical properties, such as melting point, glass transition temperature, solubility, and inherent viscosity, have been measured. All of the polymers melt above 225°C. and have glass transition temperatures above 180°C. Polymers with inherent viscosities greater than 0.4 form tough films.
A further interpretation of resonance and electrical factors affecting copolymerization
Authors: Schwan T. C. , Price C. C. 
Published: April 2003

AbstractNew equations for evaluation of resonance (q) and electrical (ϵ) factors affecting copolymerization have been derived:

The new equations will apply over any temperature range, and will express ϵ in terms of e.s.u. and q in kcal./mole. These factors were determined for an extensive list of monomers and were tabulated. Agreement with Hammett σ values and other kinetic and theoretical considerations were found.
Crystallization behavior and melting properties of m‐phenylene group containing polyesters
Authors: Conix A. , Van Kerpel R. 
Published: April 2003

AbstractContrary to what has been thought before, polyesters containing meta phenylene groups can be crystallized. The entropies and enthalpies of melting of isomeric poly‐isophthalates and polyterephthalates have been determined. It is shown that the lower crystal melting points of the polyisophthalates are due mainly to a greater entropy of melting.
Polymerization of β‐pinene with ziegler‐type catalysts
Authors: Marvel C. S. , Hanley James R. , Longone Daniel T. 
Published: April 2003

AbstractThe effect of Ziegler‐type catalysts on β‐pinene and camphene was investigated. The use of the cocatalyst system aluminumtriisobutyl–titanium tetrachloride proved to give a higher yield of polymeric material having a higher inherent viscosity than did the use of an equivalent amount of titanium tetrachloride alone. The polymers prepared by Ziegler‐type catalysts appear to be identical with those of the commercial type resin prepared by Friedel‐Crafts catalysis. The use of aluminumtriisobutyl with titanium trichloride gave only a very low yield of methanol insoluble resin. Ziegler‐type catalysts did not initiate polymerization of camphene.
Dead‐end polymerization with redox initiators
Authors: O'Driscoll K. F. , McArdle S. A. 
Published: April 2003

AbstractA general method has been developed to describe the course of a free radical polymerization initiated by a redox system which produces free radicals via a second‐order rate process. The method is verified experimentally, the system dimethylaniline–benzoyl peroxide being used to initiate styrene polymerization.
Sorption and flow of gases in polyethylene
Authors: Michaels A. S. , Parker R. B. 
Published: April 2003

AbstractSolubilities and diffusivities of N2, O2, CO2, and He in a variety of polyethylenes were measured in the temperature range 0–50°C. Polyethylene films studied covered a range of crystallinities (43–82%) and branching indices, and were prepared under a variety of known thermal histories. Diffusivities were determined by the time‐lag method; solubilities, by time‐lag, and also by a newly developed and more accurate static method. Solubilities were found to obey Henry's Law; the solubility constants determined by both methods were found to agree within the limits of accuracy, confirming the applicability of the unsteady‐state diffusion equation to essentially isotropic crystalline polymers. For a given gas at constant temperature, the solubility constant is directly proportional to the volume fraction of amorphous material in a polyethylene sample (as determined by density), irrespective of its origin or thermal history; the concept of the crystallites as an impermeable, dispersed phase thus appears justified. Diffusivities were found to vary widely (nearly fivefold) depending on polymer crystallinity and thermal history and were as much as tenfold lower than the values estimated for completely amorphous polyethylene. Application of principles of flow through porous media to this system leads to a conclusion that abnormally low diffusivities arise predominantly from the impedance to gas flow offered by the dispersed crystalline phase. Variations in diffusivity with branching index and thermal history correlate qualitatively with expected corresponding variations in crystallite growth kinetics and shape; the existence of highly anisometric, laminar crystallites in annealed linear polyethylene is indicated from these studies. The combined influence of crystallinity on solubility and diffusivity permits as much as a tenfold variation in gas permeability of polyethylene depending on polymerization method or fabrication process.
Stereoregulated polymerization in the free propagating species. III. Effect of temperature on the polymerization of vinyl chloride
Authors: Fordham J. W. L. , Burleigh P. H. , Sturm C. L. 
Published: April 2003

AbstractTheoretical treatment had shown that syndiotactic propagation should be slightly favored energetically over isotactic propagation in free radical vinyl chloride polymerization. This prediction has been confirmed experimentally by x‐ray and infrared investigations of vinyl chloride polymers prepared at various temperatures. The initiator was a peroxide, azodiisobutyronitrile, or tri‐n‐butylboron, and had no detectable influence on the x‐ray and infrared results. As the polymerization temperature is lowered, the number of lines or arcs in the x‐ray diffraction pattern and their sharpness gradually increase as a result of the increased crystallinity arising from improved regularity. The regular sequences are indicated to have the syndiotactic configuration from the chain repeat distance. The change in the infrared absorbance ratio of two carbon‐chlorine stretching bands with polymerization temperature can be interpreted in agreement with increasing syndiotacticity at decreasing temperature. With the use of simplifying assumptions, the activation energy difference between isotactic and syndiotactic propagation is estimated to be of the order of one‐half kcal/mole. The stereoregulated free radical polymerization of vinyl chloride is thus qualitatively similar to that disclosed for other monomers.