bluuebunny/crossref_metadata_2025 huggingface dataset:
Poly‐n‐octyl methacrylate. V. Dilute solution properties by viscosity and light scattering
Authors: Chinai S. N. , Resnick A. L. , Lee H. T.
Published: April 2003

Poly‐n‐octyl methacrylate, prepared by the emulsion technique, was fractionated three times by the fractional precipitation procedure to obtain eight fractions. Relationships between viscosity and weight‐average molecular weight were obtained in both an ideal solvent, n‐butanol, and a nonideal solvent, methyl ethyl ketone. These relationships are represented by the equations, [η] = 2.68 × 10−4M [η]23 = 4.47 × 10−5M, respectively. The effect of the size of the pendant groups (‐methyl, ‐ethyl, n‐butyl, ‐n‐hexyl, and ‐n‐octyl ester) on the degree of extension of macromolecules in ideal solvents is discussed. It was found that, initially, as we progress from polymethyl to poly‐n‐butyl methacrylate, the degree of flexibility of the macromolecule increases as the size of the pendant group increases. These results are believed to be due to the short‐range interference effect of the solvent molecule on the degree of free rotation of the macromolecule. However, it was found that poly‐n‐hexyl methacrylate chains have considerably greater chain extension than any of the other three polymers. This expansion of poly‐n‐hexyl methacrylate chains is a result of the steric effect of large pendant units. From the results obtained for n‐octyl polymer, it is evident that, in spite of further increase in the size of the pendant group by (CH2)2, there is a substantial contraction in the n‐octyl polymer chain. The reason for this reversal in the polymer chain expansion is not clearly understood at present.
Polyethers. VII. Aluminum catalysts for polymerization of ethylene oxide
Authors: Miller Richard A. , Price Charles C.
Published: April 2003

Aluminum alkoxide and aluminum alkyl catalysts have been found to convert ethylene oxide to high molecular weight polymer. Examination of the polymer for hydroxyl and olefin end groups, wing phthalic anhydride and bromine, revealed approximately one double bond per molwule but no detectable hydroxyl groups.
Polyethers. VIII. Isotactic polymerization of phenyl glycidyl ether
Authors: Noshay Allen , Price Charles C.
Published: April 2003

Phenyl glycidyl ether has been polymerized, using aluminum catalysts, to crystalline as well as amorphous polymers. The crystalline fraction is high melting (ca. 200°) and insoluble at room temperature. The amorphous fractions are soluble at room temperature and some show rubber‐like properties. The best yields of polymer were obtained when reactions were carried out in bulk, in open, stirred systems using aluminum isopropoxide and zinc chloride as cocatalysts.
Heterogeneous copolymerization of methacrylate esters with the methacrylate ion in aqueous media
Authors: Parsons R. J. , Warson H.
Published: April 2003

It is known from the Patent literature that many water‐soluble salts of copolymerizable acids can be copolymerized with water in soluble, polymerizable esters when the latter are dispersed as an aqueous emulsion. We have studied the copolymerization of methacrylate esters, especially methyl methacrylate, with sodium, methacrylate, the former being maintained in a fine particle size with the aid of a water‐soluble colloid and rapid stirring. Results have been reproducible. Analytical methods have been worked out for each monomer in the presence of the other, in order to follow the course of the reaction. Several ratios of methyl methacrylate and sodium methacrylate have been investigated under semi‐adiabatic conditions, using a persulfate as polymerization initiator. When the two monomers are polymerized together equimolecular ratios, there is a period of inhibition or retardation only in respect of the sodium methacrylate, but this can be avoided by adding methyl methacrylate to sodium methacrylate at incipient polymerization of the latter. It has been possible to deduce a general picture of polymerization, which is as follow: The polymerization of methyl methacrylate follows zero‐order kinetics for a large part of the reaction, while that of sodium methacrylate follows first‐order kinetics. On increased dilution of the system, the rate of polymerization of methyl methacrylate is increased. On the one hand, increase of methyl methacrylate keeping water and sodium methacrylate constant results in little difference in the rate of polymerization of sodium methacrylate or on the proportional rate of polymerization of methyl methacrylate. On the other hand, the actual rate of polymerization of methyl methacrylate is doubled. β‐Ethoxy ethyl methacrylate and ethyl methacrylate copolymerize to a lesser extent with sodium methacrylate in the examined ratios. In these cases a larger proportion of the sodium methacrylate remains unpolymerized when polymerized of the ester is virtually complete. Copolymerization is virtually nil between butyl and sodium methacrylates. The possible mechanism of the copolymerization is discussed.
The preparation and properties of grafts of polycaprolactam on vinyl copolymers
Authors: Chapman C. B. , Valentine L.
Published: April 2003

The reaction between vinyl polymers bearing reactive function (e.g., COOMe, COOH, NH2) and caprolactam should lead to the formation of grafted side chains of nylon 6 on a backbone of vinyl polymer. With styrene‐methyl acrylate (S/MA) co‐polymers in particular, the reaction initiated by water by 220–250°C. has been followed by measuring the melt viscosity, and the resultant polymers have been characterized. Combination takes place, but complication limit the extent of reation,e.g., loss of amino groups, crosslinking, inhomogeneity of the reaction melt. Soluble graft copolymers are formed only if the D.P. of the vinyl polymer is low, and the methyl acrylate content is high,e.g., 1:1 S/MA copolymers of D.P. 60 and 2:1 copolymer of D.P. 150 both give homogeneous graft copolymers. All other 1:1 and 2:1 copolymers of higher D.P. give insoluble products, because of crosslinking. For all copolymers in which the S/MA ratio is > 2:1, very little reaction occurs, and the products can be separated by solvent extraction into three fractions,viz.nylon 6, unchanged S/MA copolymer, and a graft copolymer. At high S/MA ratios, irrespective of the D.P., the two polymers are incompatible, and reaction is confined to the polyamide‐copolymer interfaces. The soluble graft copolymers were characterized by elemental and endgroup analysis, melting points, melt viscosity, soluble viscosity, and infrared spectoscopy. The interaction of styrene‐maleic anhydride and styrene‐acrylic acid copolymers with nylon 6 leads invariably to insoluble products.
A non‐hydrolytic polymerization of ϵ‐caprolactam. The polymerization initiated by hydrogen chloride
Authors: Van der Want G. M. , Kruissink Ch. A.
Published: April 2003

Some experiments are described which show that the polymerization of ϵ‐caprolactam (CL) can be accomplished by heating the lactam under anhydrous conditions in the presence of hydrogen chloride or of salts of strong acids and ammonia or amines at temperatures of 220–260°C. To study this type of polymerization more closely, two series of kinetic experiments with the sytem CL–HCl hae been performed (254°C.; initial molar ratios of HCl to CL, 0.025 and 0.0125). The progress of the reaction, characterized by the degree of conversion (determined by extraction of the unconverted lactam with water), is compared with the polymerization of CL initiated by corresponding amounts of water or of ϵ‐aminocaproic acid. The products obtained have been characterized by endgroup titration values and intrinsic viscosity. Some additional data have been obtained by chromatography and IR investigations. The titrations show that the molecules bear an amino group at one end of the chain; the nature of the other endgroup is still obscure. Reaction constants calculated for an uncatalyzed additon of CL to amino groups prove to be of about the same magnitude as those of the water‐initiated polymerization without additional HCl. At the same time some kinetic experiments with the system CLH2OHCl are presented. Both systems have some striking features in common. The catalytic effect of the HCl present in this system can be attributed to the rapid formation of amino groups in the very first moments of the reaction, thus leading to an enhanced rate of polymerization by addition of CL to amino groups.
Molecular weights and molecular dimensions of linear and branched polyethylenes
Authors: Trementozzi Q. A.
Published: April 2003

The behavior of linear polyethylene in various solvents has been investigated by the light scattering, osmotic pressure and viscosity methods. It is shown that polyethylene associates in α‐chloronaphthalene solution. The degree of association increases with molecular weight, but, at low molecular weights, it essentially vanishes. A comparison of molecular weights obtained from light scattering and osmotic pressure studies of solutions of polyethylene fractions in tetralin and‐p‐xylene yields no evidence of association over a broad range of molecular weights. The unperturbed molecular dimensions are shown to be considerably greater than those of polystyrene at the same degree of polymerization. In terms of Flory's theory of chain stiffness, linear polyethylene becomes competitive in stiffness with some cellulose derivatives of comparable temperatures. At a sufficiently high degree of polymerization, the Fox‐Flory equation is obeyed.
Relations among melt viscosity, solution viscosity, molecular weight, and long‐chain branching in polyethylene
Authors: Moore Louis D.
Published: April 2003

According to the segmental theory of flow, the viscosity ηm of a polymer melt should be given by

where the jump frequency J is a function of temperature and free volume, and a statistical factor F, depending on chain length, expresses the requirement that the motions of the segments be coordinated. Peticolas and Watkins found that, at the same weight‐average molecular weight, branched polyethylenes have considerably lower viscosities than linear polyethylenes. They attributed this reduction in viscosity to an increased free volume (which would increase the jump frequency) brought about by short‐chain branches. Marshall, however, pointed out that the required increase in free volume is not found by experiment. This paper presents an alternative theory whereby the reduction in viscosity is attributed to the presence of long‐chain branches which help coordinate the movement of the various segments and thereby reduce the coordination factor F. As a result of certain theoretical considerations, a linear relation is predicted between the log of the melt index and the intrinsic viscosity in an ideal or Θ‐solvent. This relation is confirmed by a plot of data from 27 samples of polyethylene obtained from four commercial sources and having melt indices ranging from 0.12 to 26.6. Bis(2‐ethvlhexyl) adipate at 145°C. was used as the ideal solvent. Further insight into the viscous and viscoelastic behavior of polyethylene samples was obtained when it was observed that detailed interpretation of light‐scattering data explained the fact that samples with practically the same melt indices had different solution viscosities in a good solvent such as Tetralin at 100°C. These variations were attributed to differences in the expansion factor α. This factor depends on molecular weight, long‐chain branching, and solvent power and probably reflects the ease with which a molecule may be deformed. This α‐factor then should probably be related to the spectrum of relaxation times which would influence such important processing variables as melt elasticity and non‐Newtonian flow.
The copolymerization of silicon‐substituted styrenes
Authors: Lewis Charles W. , Lewis Daniel W.
Published: April 2003

The monomer reactivities of p‐trimethylsilylstyrene and p‐trimethoxysilylstyrene have been invertigated. In both cases e is equal to the e of styrene. The former has a Q equal to that of styrene but the Q of the latter substituted styrene is about 40% greater.
Fractionation of chlorotrifluoroethylene polymer
Authors: Okamoto H.
Published: April 2003

Chlorotrifluoroethylene polymers were fractionated with the use of a fractionation apparatus designed for use at high temperatures. The solvent and the nonsolvent were the same as those used by Kaufman and Solomon. The relationship of specific viscosity and concentration was established in trifluoropentachloropropane by Schulz's formula. The differential distribution curves of Kel‐F and Daiflon‐B have maxima at lower viscosities and decrease more slowly than those of Daiflon‐A. This accords qualitatively with melt index data.
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

The 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

In 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

The 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

Radiotagged 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

Skellam 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

A 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

Cetyl 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

The 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

Several 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

Different 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

By 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

In 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

A 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

Polymerization 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

As 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

The 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

An 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

The 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.
Thermal polymerization of butadiene to solid polymer
Authors: Miller Glenn H.
Published: April 2003

That rate of formation of solid polymer has been determined for pure butadiene as well as for the two‐phase system of butadiene plus water, with and without the addition of added peroxides. Benzene‐insoluble polymer was formed only in the absence of added peroxides.
Investigations of the dynamic mechanical properties of some polyamides
Authors: Woodward A. E. , Crissman J. M. , Sauer J. A.
Published: April 2003

The 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

It 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

Linear 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.
Theory and application of two supplementary methods of constructing density gradient columns
Authors: Fortuin J. M. H.
Published: April 2003

Two supplementary methods of constructing density gradient columns are described. Formulas are derived for calculating the composition and mass of each of the two liquids used for the construction of a column with a given volume and a desired measuring range. The density of each layer of a column consisting of ideal or nonideal liquids can be accurately predicted. The persistance of a column is dependent on its length and diffusion coefficient, and can be approximately calculated by means of a formula derived from Fick's second law.
Organophosphorus polymers. I. Peroxide‐initiated polymerization of diethyl and diisopropyl vinylphosphonate
Authors: Pike Ronald M. , Cohen Ronald A.
Published: April 2003

It was shown that diethyl vinylphosphonate and diisopropyl vinylphosphonate are polymerized by peroxide initiators to clear, light‐yellow, viscous liquid polymers of low molecular weight. It was found that the yield of the isolated polymers varied directly, while the molecular weight varied inversely, with the concentration of the initiator. Infrared spectra of the monomers used and the polymers obtained established that polymerization occurs through the vinyl group. It is postulated that the low molecular weight is due to the result of chain transfer with polymer and/or monomer through the alkoxy groups attached to the phosphorus atom.
Studies on polyoxypropylene glycols. Part I. Vapor pressures and heats of mixing in the systems: Polyglycols–methanol
Authors: Lakhanpal M. L. , Conway B. E.
Published: April 2003

Thermodynamic studies have been made on various fractions of polyoxypropylene glycols of molecular weights from 150 to 3350 in methanol. Vapor pressures of the solvent and the relative lowering of vapor pressure of the solvent by the polymer have been determined in a special differential manometer over the temperature range −30°C. to 28°C. Heats of mixing for the systems have been determined in an isothermal phase‐change calorimeter empolying diphenyl ether as the dilatometric fluid. The relative partial molar free energies are derived for the solvent and solute.
Inhibition and retardation of polymerization of methyl methacrylate
Authors: Funt B. Lionel , Williams Fredrick D.
Published: April 2003

The kinetics of the polymerization of methyl methacrylate in the presence of p‐benzoquinone were investigated. The course of the reaction was followed by dilatometry and with tracer methods. Alternate experiments were performed C14‐tagged azobisisobutyronitrile initiator and inactive p‐benzoquinone and, alternatively, radioactive initiator and inactive retarder being used. These data, coupled with number average molecular weights determined by osmometry, served to determine the number of fragments of initiator and retarder incorporated per polymer molecule. It was found that the reaction was retarded at low concentrations of p‐benzoquinone but showed a definite transition to inhibition at higher concentrations. Analysis of the data showed that the number of initiator fragments incorporated per polymer molecule was independent of retarder concentration, but that the number of retarder molecules per polymer molecule increased. The results indicate that the rate of chain initiation decreases with retarder concentration until inhibition is observed. The data are interpreted on the basis of interaction of benzoquinone with primary radicals generated by the initiator. The results also furnish distinct evidence against the acceptance of copolymerization or chain transfer as significant steps in the reaction mechanism.
The viscosity of concentrated polymer solutions
Authors: Gillespie Thomas
Published: April 2003

The general equation for pseudoplasticity previously derived by an extension of Goodeve's impulse theory of viscosity is derived specifically for polymer solutions by a consideration of the rate of energy dissipation in a sheared solution. Its general application to polymer solutions is discussed with particular reference to the fact that unlike other theories it is capable of explaining the linear relation between fluidity and shear stress at very low shear stress, frequently observed, as well as the dependence on the square of the shear stress predicted by other theories. The application to data obtained with aqueous methyl cellulose solutions at moderate shear rates is outlined. The onset of structural viscosity at a more or less critical concentration is explained by a definite type of mechanical interlocking which does not occur in dilute solutions. The average binding energy of an effective molecular entanglement was estimated at about 7kT units and was independent of concentration. The rate constants for shear induced link formation and rupture appeared to be independent of concentration. The corresponding rate constants in the absence of shear appeared to decrease with increased concentration, presumably due to a decreased rate of diffusion as suggested by the theories of Smoluchowski and Kramers.
Polyaddition reaction of polymethylene bis‐N,N‐ethyleneurethane and polymethylene dimercaptan
Authors: Iwakura Yoshio , Sakamoto Munenori
Published: April 2003

Polyaddition reactions between polymethylene bis‐N,N‐ethyleneurethanes and polymethylene dimercaptans were investigated. The most successful polyaddition was carried out in dimethylformamide at 75°C. in the presence of triethylamine as catalyst; a fiber‐forming polyurethane sulfide having an intrinsic viscosity of 1.05 was obtained in about 90% yield. Arguments for the linear structure of the product are given.
X‐Ray determination of the crystallite orientation distributions of polyethylene terephthalate films
Authors: Heffelfinger C. J. , Burton R. L.
Published: April 2003

A set of definitions is proposed to describe uniquely the six types of orientation possible in semicrystalline polymeric films. Oriented polymer films were studied by a new x‐ray diffraction technique which permits rotation of a sample about a number of independent axes yielding orientation distributions of the crystalline regions. The definitions and the method of measuring the crystallite‐orientation distributions have been applied to polyethylene terephthalate films.
Light scattering and small angle x‐ray scattering by macromolecular coils with finite persistence length
Authors: Peterlin Anton
Published: April 2003

The angular distribution of scattering intensity depends on all intramolecular distances through terms of the form 〈sin ksrmn/ksrmn〉. In the case of statistically coiled linear macromolecules with finite valency angle, exact calculation of these averages is possible by numerical calculation (Monte Carlo method). In the range of light‐scattering experiments, the results agree with previous approximate calculations by Peterlin and, in the range of small‐angle x‐ray scattering, with those by Porod, with the slight modification that with rather short chains the plateau in the plot of Ps2 versus s has a finite slope. At nearly 20 statistically independent chain elements, however, the plateau is virtually horizontal, and the flection at ksa = 2, used for determination of the persistence length a, is well developed. As by‐products of the calculation, the average end‐to‐end distance 〈r 〉and its inverse 〈1/r〉, were obtained. The product 〈r〉〈1/r〉 rather slowly approaches the limit π/4 corresponding to Gaussian distance distribution.
Grundlinien der Chemie hochmolekularer anorganischer Verbindungen
Authors: Thilo Erich
Published: April 2003

Als hochmolekulare anorganische Verbindungen sind nur solche zu bezeichnen, deren Bausteine durch kovalente Bindungen untereinander verbunden sind. Um die Gesetzmässigkeiten ihrer Bildung und ihres Abbaues zu erkennen, wurden zunächst die linearpolymerenn Verbindungen untersucht. Drei Typen lassen sich phänomenologisch unterscheiden. Typ 1—z.B. die Polyarsenate—sind in wässeriger Lösung unbeständig und werden zu den monomeren hydrolysiert. Beim Typ 2—z.B. AsOCl—stellen sich in AsCl3—Lösungen Gleichgewichte zwischen Molekülen verschiedenen Polymerisationsgrades ein. Typ 3—z.B. die Polyphosphatc—sind in wässeriger Lösung unter normalen Bedingungen praktisch beliebig lange metastabil. Der Unterschied awischen diesen Typen ist nicht prinzipieller Natur, sondern nur graduell. Der mittlere Polymerisationsgrad P, der sich in Lösungen oder Schmelzen dieser Substanzen einstellt, gehorcht, dem allgemeinen Gesetz:

Bei konstanter Konzentration cL des die Endgruppen der Polymeren liefernden Lösungsmittels vereinfacht sich die Gleichung zu P̄ = 2c/[(4ck + k2)1/2 − k], bei konstanter Konzentration c an Grundmolekülen der Polymeren zu P̄ = (k′/cL)1/2. Am Beispiel des NaH3SiO4 und AsOCl einerseits, und am Beispiel der Polyphosphate andererseits wird die Gültigkeit dieser Beziehungen erwiesen.
Anionic polymerization of styrene by sodium naphthalene
Authors: Allen G. , Gee Geoffrey , Stretch C.
Published: April 2003

Polymerization of styrene in dioxane solution by sodium naphthalene proceeds in accordance with the anionic mechanism proposed by Szwarc. Values of Eact = 9 ± 3 kcal and A = 5 × 107 l./mole−1 sec.−1 have been obtained for the anionic propagation reaction.
Sur la structure des polyéthylènes greffes par la technique de préirradiation
Authors: Sella Claude
Published: April 2003

On étudie par diffraction des rayons X aux grands angles et aux petits angles, ainsique par microscopic électronique, la structure et la morphologie des copolymères préparés par greffage sur des polyéthylènes preirradiés aux rayons γ, de différents monomères tels que le styrène, l'acétate de vinyle, l'acrylonitrile, le méthacrylate de méthyle. L'anslyse des diagrammes de rayons X aux grands angles permet de suivre les variations de cristillinité du polymère soumis à la rèaction de greffage ainsi quc les déformations de la maille cristallographique du polyéthylène en fonction de la nature, de la fréquence et de la longueur des séquences greffées sur les chaînes polyéthyléniques. La diffusion centrale des rayons X donne des renseignements importants sur la distribution des dimensions des cristaux et permet de montrer, comme d'ailleurs la diffraction aux grands angles, que les réactions de greffage sont souvent héterogénes et conduisent à la coexistence de trois phases, l'une constituée par du polyéthylène non greffé, la seconde par le copolymère greffé, et la troisième par un homopolymère. On peut déduire de l'analyse aux rayons X une méthode quantitative de dosage de ces trois phases. La microscopie électronique confirme ces conclusions et permet de voir en part,iculier la forme ct la distribution des précipités d'homopolymère en fonction d'une part des conditions dans lesquelles s'est effectué le greffage (conditions de préirradiation, de températnre de greffage, etc.) et d'nutre part de l'histoire thermique (recuit, trempe, etc.…) du copolymère grcffé. Ces différcntes techniques permettent d'aborder les problèmes importants tels quc cclui de l'isomorphisme entre le polyéthylène non greffé et les copolymères dérivés, celni de la comptabilité entre polyéthylène, copolymère greffé et homopolymère et celni de l'influence des traitements thermiques du polymère greffé sur sa structure fine et ses propriétés physiques et mécaniqnes.