bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copolymerizations of N‐vinyluccinmmide and of N,N‐methyl vinyl p‐toluenesulfonamide with some vinyl compounds
Authors: Furukawa Junji , Tsuruta Teiji , Yamamoto Naoki , Fukutani Hideo 
Published: April 2003

AbstractThe copolymerizations of N‐vinylsuccinimide (VSI) and of N,N‐methyl vinyl p‐toluenesulfonamide (VSA) with vinyl acetate (VAc), acrylonitrile (AN), stryrene (St), methyl acrylate (MA), methyl methacrylate (MMA), and n‐butyl vinyl ether (BVE) were examianed at 60°C., using benzoyl peroxide or azobisiobutyronitrile as initiator. The monomer reactivity ratios and the monomer reactivity factors of VSI and VSA were as follows. VSI as monomer 1: r1 = 15, r2 = 0 (VBE); r1 = 0.09, r2 = 7.0 (St); r1 = 6.05, r2 = 0.185 (VAc); r1 = 0.4. r2 = 1.2 (MA); r1 = 0.16, r2 = 0.54 (AAAN), Q1 = 0.15, e1M/s = ‐0.26. VSA as monomer 1: r1 = 0, r2 = 0.42 (AN); r1 = 0, r2 = 4.68 (MMA) r1 = 0, r2 = 12.3 (St); Q1 = 0.092, e2 = ‐0.87. The difference in copolymeizability between VSI and VSA sesms to arise primarily from the difference in thieir polarity factors.
Infrared spectrum of polyvinyl chloride. I
Authors: Narita S. , Ichinohe S. , Enomoto S. 
Published: April 2003

AbstractIn order to assign the infrared spectrum of polyvinyl chloride, we obtained the polarized infrared spectra of polyvinyl chloride, the spectral changes of the molten sample, and the infrared spectrum of polyvinyl bromide. The polarized infrared spectra of polyvinyl chloride which we had obtained showed satisfactory agreement with previous reports. The infrared spectra of polyvinyl chloride and polyvinyl bromide resembled each other. From the frequency defferences of the corresponding bands of both polymers, we assigned the bands at 690, 635, and 615 cm.−1 to the CCl‐stretching modes in the spectrum of polyvinyl chloride. We found four bands in the CH‐ and CH2‐stretching region of polyvinyl chloride as Krimm and Liang stated in their paper.
The polymerization of allylidene diacetate
Authors: Hill Donand R. J. , Valentine Leslie 
Published: April 2003

AbstractThe benzoyl peroxide‐initiated polymerization of allylidene diacetate has been studied. Kinetic runs were carried out dilatometrically at 50, 60, and 80°C., a wide range of initiator concentration being studied at each temperature. In one separate experiment, the relative rates of peroxide consumption and polymer formation were determined. Polymer samples were isolated and studied for molecular weight and initiator fragment concentration. All the experiments showed the polymerization to be of the type described as degradative chain transfer. A kinetic scheme is proposed which envisages the formation of two distinct types of monomer radical depending on the direction of hydrogen transfer: one is propagating, the other stabilized and nonpropagating.
A radiotracer study of branch formation in polyacrylamide
Authors: Gleason E. H. , Miller M. L. , Sheats G. F. 
Published: April 2003

AbstractRadiotagged acrylamide was polymerized in a solution containing untagged polyacrylamide in order to study branch formation. Polymerizations were carried out at 50°C. and at 78°C. with a persulfate‐bisulfite catalyst. At 78°C., polymer with from one to seven branches was formed, while at 50°C. even with larger amounts of catalyst, the polymer was almost exclusively linear. The intrinsic viscosity of branched polyacrylamide, in water at 30°C., was compared with the predictions of the Zimm and Stockmayer equation for the intrinsic viscosity of trifunctionally branched molecules. This equation gave values which agreed well with measured values of the number of branches.
Probability model theory of chain‐end activated polymer degradation. I. First‐order radical termination
Authors: Gordon Manfred , Shenton L. R. 
Published: April 2003

AbstractSkellam and Shenton have recently described a theoretical approach to the treatment, in terms of probability models, of distributions associated with random walk and recurrent events. Within this framework, analytical solutions are here obtained for a number of problems in the kinetics of chain‐end activated depolymerization. The model employs the process of random drawing of chains from urns containing the three distributions which define the problem: the initial polymer chain distribution, the zip‐number distribution which is a function of time, and the zip‐length distribution. The validity and ease of the method is demonstrated by deriving, in somewhat improved form, the solution obtained by Simha, Wall, and Blatz for a special case, viz., a homodisperse polymer undergoing chain‐end activated degradation without chain transfer to polymer. As was recently shown by Gordon, the assumption of an initially exponential polymer chain distribution greatly simplifies the solution, and also makes the model more realistic for most synthetic polymers. The simplification is shown to arise in the present method, because the exponential distribution conveniently furnishes the kernel of a Laplace transform. Solutions are also obtained here for the polymer chains obeying λ‐fold self convolution of the exponential distribution. The case λ = 1, which is directly applicable to polymers formed under a regime of radical combination, yields a solution which, though new, is quite simple. The case λ = ∞ can be shown to revert to the case of a homodisperse polymer already mentioned. It is readily shown, and explained intuitively, that for all finite λ the convoluted exponential chain distributions revert asymptotically to the unconvoluted exponential distribution at high conversion (i.e., “zipping undoes convolution”). Accordingly, the kinetics approach asymptotically to a first order reaction. This is not true, however, of the monodisperse polymer case, in which λ is infinite. The linear superposition of polymer chain distributions with different values of λ is finally shown to be amenable to the present treatment, and yields analytic solutions for the pure chain‐end activated degradation of polymers under unrestrictive conditions: the initial polymer chain distribution requires to be expandable in the form Gram‐Charlier Type A, but the zip‐number and zip‐length distributions can be chosen at will. In the present paper, initiation is taken to be first order in the total chain‐end concentration, and termination is regarded as first order with respect to the radical concentration. Solutions appertaining to radical disproportionation, and to variously reactive chain‐ends, are reserved for a further paper.
Gamma irradiation of poly(alkyl methacrylates)
Authors: Graham Roger K. 
Published: April 2003

AbstractA series of poly(alkyl methacrylates) were prepared from monomer of high purity and subjected to gamma irradiation. Gelation in the n‐alkyl series was detected for poly (n‐heptyl methacrylate) at 15 Mreps; gel was detected at lower doses as the length of the alkyl group increased. No gelation was found on irradiation of poly (sec‐alkyl methacrylates) to relatively high doses; poly(sec‐nonyl methacrylate) remained soluble after 40 Mreps of irradiation. Correlation with earlier work on irradiation of poly(alkyl acrylates) is discussed.
Sedimentation, diffusion, and double refraction of flow studies on cetyl pyridinium hyaluronate
Authors: Varga Laszlo , Pietruszkiewicz Adolph , Ryan Marion 
Published: April 2003

AbstractCetyl pyridinium hyaluronate was prepared, and some of its main physicochemical characteristics were studied in nonaqueous media. The following parameters were obtained: sedimentation constant, D20 = 3.8 S; diffusion constant, D20 = 1.0 × 10−7 cm.2/sec.; partial specific volume, V = 0.86 cc./g. From these data were calculated molecular weight, M = 289,000; frictional ratio, f/fo = 2.4, corresponding to a molecular asymmetry of L/d 30; and finally, a molecular length of 900 A. Using a velocity gradient range of 2,500 to 15,000 see.−1, a molecular length of 2400 to 3100 A. was obtained with the double refraction of flow apparatus. The difference between the molecular length obtained by ultracentrifugal analysis and that obtained by the flow birefringence technique was attributed to an unfolding of the molecule under shearing stress. This view is supported by the calculation of the internal viscosity of cetyl pyridinium hyaluronate according to the method of Cerf. This was found to be ηi = 9.4 × 10−2. The stoichiometric reaction between hyaluronic acid and cetyl pyridinium chloride yields a derivative which, though differing significantly in some respects, still retains certain similarities to the naturally occurring polysaccharide. The electrical properties of hyaluronic acid are altered when sodium ions are replaced by the cetyl pyridinium group, and the material is no longer soluble in aqueous medium. Even with this structural modification, the molecule behaves in the manner characteristic of highly asymmetric particles. The sedimentation and diffusion patterns, like those of sodium hyaluronate, are positively skewed, indicating a polydisperse distribution which favors the higher molecular weight components.
Melt viscosity of polyethylenes. Shear dependence of viscosity
Authors: Marker Leon , Early Robert , Aggarwal Sundar L. 
Published: April 2003

AbstractThe melt index apparatus has been adapted for use as a simple rheometer. Changes in orifice diameter from 0.0425 to 0.2000 in. and in weight applied to the piston from 250 to 3250 g. permit an effective range of shear stress from 104 to 106 dynes/cm.2 With this apparatus, the fluidity of polyethylene as a function of shear stress was shown to be a linear function of the shear stress in the range studied. Consistent data using different orifices were obtained by correcting for the friction between piston and barrel. It was found that two parameters, the fluidity at zero shear rate and the shear‐stress dependence of fluidity, are sufficient for the characterization of the flow behavior of polyethylenes. In order to account for the effect of temperature on the shear dependence of viscous flow, as determined from measurements at several temperatures, two activation energies are needed, one corresponding to each of the two parameters mentioned.
Molecular distributions in polycondensations involving unlike reactants. V. Particularly narrow distributions
Authors: Case L. C. 
Published: April 2003

AbstractSeveral methods for the preparation of narrowly dispersed polymers by condensation polymerization are discussed in this paper. A general characteristic of narrowly dispersed condensation polymerizations is that they are built up by many stages of polymerization. Theoretical calculations of the polymeric distributions of the first two stages of polymerization for two different systems are given. These distributions are shown to be distributions for special types of coupled polymers, and become quite complex with increasing stages of reaction. The method of Kern for the production of narrowly dispersed polymers is discussed in detail. Also discussed in detail is a new method which shows promise of yielding essentially monodisperse polycondensates with a minimum of effort.
Calculation of the molecular weight distribution of polymers from experimental data
Authors: Koningsveld R. , Tuijnman C. A. F. 
Published: April 2003

AbstractDifferent methods of calculating the molecular weight distribution (MWD) of polymers from experimental data are discussed. The procedure without fractionation, making use of series expansions in orthogonal polynomials (method of moments), is of limited value. A reasonable approximation of the MWD can be obtained after fractionation of the polymer. The shape of the MWD may be strongly influenced by the treatment given the experimental fractionation data. Conventional methods assuming fraction distributions which cannot be physically real must be rejected. Good results can be obtained when the fraction distributions are represented by functions satisfying certain conditions. It is then necessary to determine at least two average molecular weights of each fraction. This is demonstrated for different functions with the aid of literature data.
The infrared dichroism of a stretched polymer. Part I. The theoretical treatment of rubberlike polymers
Authors: Marrinan H. J. 
Published: April 2003

AbstractBy representing the molecular structure of a polymer chain by a chain of randomly jointed links, as was done by Kuhn and Grün in their calculations of birefringence, an expression has been derived for the infrared dichroism of a stretched rubberlike polymer. Certain restricting conditions that have been imposed in previous work have been removed and a more general treatment of the problem is presented. It is shown that measurements of the infrared dichroism in rubberlike polymeric materials should provide information on the flexibility of the polymer molecules similar to that obtained from measurements of the stress‐optical coefficient. The relative merits of the two methods are discussed.
Polymerization of ethylene glycol dimethacrylate
Authors: Aso Chuji 
Published: April 2003

AbstractIn the polymerization of ethylene glycol dimethacrylate (EDMA), the content of pendant double bonds (PDB) in the polymer was found to be lower than expected, hence it was deduced that the intramolecular cyclizations occurred in the polymerization. The experimental result that the content of PDB decreases with dilution in the solution polymerization of EDMA will qualitatively support this assumption. A composition equation in which the bimolecular linear chain growth, crosslinking, and the unimolecular cyclization are simultaneously considered, is proposed. In this equation, reactivity ratios of EDMA and PDB (r1 and r2) are used with the cyclization coefficient rc, where rc is expressed as a ratio of kc (unimolecular reaction velocity constant of intramolecular cyclization) to k11 (bimolecular reaction velocity constant of addition of EDMA to an EDMA‐type radical, which was previously derived by addition of EDMA to a radical). By the copolymerization of methyl methacrylate with PDB in EDMA‐polymers, r1 = 7.5 ± 2.5 and r2 = 1 ± 1 were experimentally determined. It has been found that the PDB contents measured in the bulk polymerization of EDMA agree with those calculated from the integrated curve of the above theoretical equation when r1 = 7.5, r2 = 1/7.5, and rc = 4.0 moles/1.
On the electrostatic interactions between counterions and macroions in polyelectrolyte solutions
Authors: Liquori A. M. , Ascoli F. , Botré C. , Crescenzi V. , Mele A. 
Published: April 2003

AbstractA number of polyelectrolytes of known molecular structure and varying concentration of ionizable groups along the chain have been prepared and the activity coefficient of sodium counterions has been measured as a function of dilution. When the spacing of ionizable groups along the chain is smaller than a certain value, the activity coefficient has been found to be particularly low and almost invariant with concentration. Above this value, the behavior approaches that commonly observed for low molecular weight electrolytes. A very simple theoretical treatment due to Oosawa has been found to explain satisfactorily the most essential features of the experimental results and has given the basis for a relationship between degree of dissociation and molecular structure of polyelectrolytes.
Stereospecific polymerization considered as copolymerization
Authors: Schuerch Conrad 
Published: April 2003

AbstractPolymerization of an unsymmetrically substituted olefin can be considered as an example of copolymerization of two stereoisomers with four typical propagation rates k** and probabilities P**. Stereospecific catalysts which operate only by increasing the probability of Pdd over Pdl and Pll over Pld produce isotactic polymers of the same sequence length distribution as typical copolymers with like propagation probabilities. Stereospecific catalysts with stereoisomeric sites at which Pdd ≠ Pdl should be capable of producing isotactic polymers in which sequences of a single configuration on each polymer chain are greatly preferred.
Thioglycol polymers. III. Copolymerization of thiodiglycol and similar thioglycols with aliphatic hydroxy compounds
Authors: Andrews K. J. M. , Rosser R. J. , Woodward F. N. 
Published: April 2003

AbstractAs thiodiglycol (TG) condenses with itself in the presence of phosphorus pentoxide, sulfuric acid, or potassium hydrogen sulfate at 50–200°, its reaction with di‐ and trihydroxy compounds and with 2‐hydroxyethane‐1‐thiol (MTG) under similar conditions would be expected to give straight‐chain and crosslinked polymers. With certain polyfunctional compounds this has been found to be the case. Some indication of copolymerization was observed with diethylene, trimethylene, and the butylene glycols and with ricinoleic acid, and solid polymers resulted from the interaction of thiodiglycol with tricarballylic acid, 2,2′‐dihydroxydiethyl disulfide (DTG), MTG, and glycerol, respectively. The reactions with the last three hydroxy compounds were studied in detail and the properties of the copolymers produced assessed visually. MTG was found to undergo rapid autocondensation to form brittle solids. Similar polymers were obtained in about 70% yield with small amounts of TG in the reaction mixture; on an increase in the initial TG content, waxy solids, similar to those obtained from TG alone, resulted. As the glycerol content in TG/glycerol mixtures increased up to 40%, the copolymers formed changed from friable gels to brittle solids; any further increase resulted in viscous liquid products only. These results may be attributable to the fact that the reaction is a two‐stage one. TG‐MTG mixtures were reacted with glycerol with a view to improving the tensile strength of the product. This was successful, and the TG‐MTG‐glycerol (50:45:4) mixture, when heated at 154° for 6.5 hr. gave a white, elastic solid, very difficult to cut or break, which could be milled and pressed although tending to swell in benzene and dichlorodiethyl ether. The properties and structures of these new thioplasts made, where possible, from equimolecular quantities of the monomers, are recorded and compared with those of the commercially available Thiokols. Attempts to copolymerize TG with compounds (I), (II), and (III), which contain the reactive 2‐hydroxyethylthio group were unsuccessful.
γ‐Radiation‐induced polymerization of ethenesulfonamide
Authors: Wiley Richard H. , Gensheimer David E. 
Published: April 2003

AbstractThe Co‐60 γ‐radiation‐induced polymerization of ethenesulfonamide is extremely rapid. The monomer is converted to polymer at the rate of 75%/hr. at 4200 r/min. as compared to rates of 1–17%/hr. for other monomers under similar conditions. The polymer shows the viscosity characteristics of a polyelectrolyte (intrinsic viscosity of 0.5 at 0.125% in dimethylformamide) and is estimated to have molecular weight of M̄n 12,000 and M̄w 50,000 from a preliminary evaluation of viscosity, osmotic, and light scattering data, Gi values of 170–40 are indicated for the polymerization on the basis of estimated molecular weights of 12,000–50,000.
Selectivity of polymer fractionation. I
Authors: Broda Andrzej 
Published: April 2003

AbstractAn analysis of the dependence of selectivity of polymer fractionation on the properties of the system polymer‐liquid is given. It was found that it is possible for an ideal nonselective separation to exist not only in critical conditions but also in uncritical ones. The possibility of the existence of the negative values of the α parameter was affirmed. This is possible when the precipitate is richer in low‐molecular compounds than was the initial polymer (x1 < x0). The distribution of an infinitestimal fraction was analysed for the most probable distribution of the initial polymer. In this case the first infinitesimal fraction is characterized as having a distribution function analogous to that of the initial polymer.
Relative reactivities of polymer radicals
Authors: Okamura S. , Katagiri K. , Yonezawa T. 
Published: April 2003

AbstractThe present investigation is concerned with the relationship between P, the reactivity of a radical, and Q that of a monomer in the propagation reaction. At first, P values are calculated from the accumulated data of the rate constants of the propagation reaction. From these results, the relation is shown to be represented by the following equation:

where k and a are constants. The P values in the termination reaction (Pt) are also calculated, and the relation between these values and Q values are examined. The results show that the similar relation found in the propagation reaction holds in this step too. By applying the method of Evans and co‐workers, a sufficient explanation for this equation is not obtained, but the analogous equation can be derived. The present authors suggest that the inverse proportion between log P and Q appears to be based on the following different principles: (1) the inverse proportion between the magnitude of localization energy of the radical and that of monomer, and (2) the linear free energy relationship found in organic chemistry.
Investigations of the dynamic mechanical properties of some polyamides
Authors: Woodward A. E. , Crissman J. M. , Sauer J. A. 
Published: April 2003

AbstractThe damping, resonant frequency, and dynamic elastic storage modulus of five polyamides have been investigated at resonant frequencies ranging from 100 to 2000 cycles/sec. at temperatures in the 100 to 450°K. region. Specimens of poly(hexamethyleneadipamide) containing 0, 0.9, 3.3, and 6.4 wt.‐% water were studied and it was found that with increasing water content: the loss peak and associated modulus dispersion at 170°K. in the dry material decreased; the loss peak and modulus dispersion at 370°K. in the dry material shifted to lower temperatures reaching a value of 280°K. for 6.4% water; a third damping peak appeared at 240 to 245°K. and the modulus in the 150 to 250°K. region increased while above and below this range the reverse was true. A poly(hexamethylene adipamide) specimen containing 10.5 wt.‐% methanol exhibited one broad peak at about 255 to 260°K. Dry specimens of poly(hexamethylene sebacamide), poly(decamethylene sebacamide), 17% N‐methylated poly(decamethylene sebacamide), and 58% N‐methylated poly(decamethylene sebacamide) were also investigated. For the latter three specimens the principal amorphous transition shifted from 340 to 285°K. and the area under the loss peak increased greatly in going from 0 to 58% N‐methylation, while the low temperature transition remained at 160 to 170°K. essentially unchanged. Of the five polymers studied the 17% N‐methylated poly(decamethylene sebacamide) exhibited the highest apparent modulus in the 110 to 160°K. region; and at all temperatures below the principal amorphous transition this material had a higher modulus than the unmethylated parent polymer.
Electron spin resonance spectra of polymethyl methacrylate and polyethyl methacrylate
Authors: Ungar I. S. , Gager W. B. , Leininger R. I. 
Published: April 2003

AbstractIt is shown that there exists a difference in the electron spin resonance spectra of commercial‐grade and laboratory‐purified samples of polymethyl methacrylate and polyethyl methacrylate. This difference arises because of the presence of monomer. The spectra of the pure polymers show only partial resolution, while the spectra of samples containing monomer have the nine‐line pattern as previously reported.
Electron exchange polymers. XIV. Steric hindrance in the chemical modification of high polymers
Authors: Kun Kenneth A. , Cassidy Harold G. 
Published: April 2003

AbstractLinear polyvinyl methyl ketone, a linear copolymer with styrene, and crosslinked copolymers with styrene all proved completely unreactive in the Meerwein‐Ponndorf‐Verley‐Oppenauer reaction with aluminium alkoxides, but both a linear and a crosslinked polymer were reduced by lithium aluminum hydride. A linear and a crosslinked polyalcohol were unreactive toward aluminum alkoxide plus methyl ethyl ketone. The unreactivity of the polymers is laid to the stringent spatial reaquirements for the formation of the pseudo‐cyclic six‐membered transition state which is hindered from forming by the polymer chain.