bluuebunny/crossref_metadata_2025 huggingface dataset:
Some properties of poly‐α‐piperidone
Authors: Tani Hisaya , Konomi Tuyoshi
Published: April 2003

The high molecular weight polymer of α‐piperidone, which had been unobtainable with the use of alkali metal, trialkyl aluminum, or Grignard reagent as catalyst, was prepared with M–AlEt3, (where M is alkali metal), MAlEt4 or KAlEt3 (piperidone) as catalyst and N‐acyl‐α‐piperidone as initiator. From the determination of the behavior of the solution viscosity of poly‐α‐piperidone in m‐cresol at 30°C. the value of 0.27 for the Huggins constant was obtained. Examination of the correlation between the number‐average molecular weight, determined by endgroup titration, and the intrinsic viscosity gave a somewhat small value for the endgroup COOH. This may be considered due to the consumption of N‐acyl‐α‐piperidone by a propagating polymer in the course of polymerization. The thermal stabilities of the polyamides, nylons 4, 5, and 6, was in the order nylons 6 > 5 > 4 according to differential thermal and thermogravimetric analyses, Poly‐α‐piperidone, which has a reduced viscosity of 0.7, shows a melting point of 270°C.. which was expected from the zigzag pattern of the correlation between melting points and numbers of CH2 groups for polyamino‐acid polymers.
Polymers from 1,3‐dipole addition reactions: The sydnone dipole
Authors: Stille J. K. , Bedford M. A.
Published: April 2003

An investigation of the suitability of certain 1,3 dipole addition reactions as polymerization reactions was carried out. Reaction of p‐phenylene‐3,3′‐disydnone and N,N′‐hexamethylenedisydnone with the dipolarophiles m‐ and p‐diethynylbenzene, m‐divinylbenzene, and p‐benzoquinone gave moderate molecular weight polymers containing pyrazole or pyrazoline units along the polymer backbone. The polymers are crystalline and have inherent viscosities of 0.4–0.6. The thermogravimetric analyses of the finely powdered polyprazoles showed breaks near 420°C. in air and 500°C. in nitrogen atmospheres.
Polycondensation equilibrium and the kinetics of the catalyzed transesterfication in the formation of polyethylene terephthalate
Authors: Fontana C. M.
Published: April 2003

The polycondensation equilibrium constant for bis(β‐hydroxyethyl) terephthalate was found to be 0.50. By means of this value for determining the relative reactivity of two kinds of hydroxyl groups, the kinetic data were found to fit a third‐order reaction for the transesterification: one order each with respect to hydroxyl group, methoxy group, and catalyst. An order with respect to hydroxyl group, which had previously been in doubt, was proved in a series of experiments in which the concentration of ethylene glycol was varied. Third‐order rate constants were determined for the reactions catalyzed by lead, zinc, and calcium salts, and the activation energies were found to be 12.5, 15.0, and 14.5 kcal./mole, respectively. The results are consistent with the author's theory of aromatic transition states and are difficult to explain on the basis of ionic theories of reaction mechanism.
Polymérisation “basse pression” de l'ethylène en préasence de noir de carbone
Authors: Donnet J. B. , Wetzel J. P. , Riess G.
Published: April 2003

The polymerization of ethylene with Ziegler‐Natta catalysts in the presence of carbon black has shown three characteristic features both with a heterogeneous catalyst, AlBu3TiCl4, and with a soluble catalyst, Cl2Ti(C5H5)2AlEt2Cl. They are, in order of increasing importance: reactivity of the organoaluminum derivatives with surface chemical groups of the carbon black, adsorption of a certain amount of organoaluminum compounds on the carbon black surface, and influence of the specific surface of carbon black, which controls the dispersion degree of the catalytic system. Furthermore, it was possible to obtain polyethylene by this procedure, containing different amounts and different types of carbon black.
Polymerization of cyclobutene rings. VI. Influence of the organometallic compound of the Ziegler‐Natta catalysts on the mechanism of polymerization of cyclobutene and 3‐methylcyclobutene
Authors: Dall'Asta G.
Published: April 2003

The polymerization of cyclobutene and 3‐methylcyclobutene in the presence of Ziegler‐Natta catalysts was studied especially in view of the influence of the metal alkyls on the course of polymerization. Several metal alkyls of the main groups I–IV of the periodic table of elements were investigated, vanadium halides being used as transition metal compounds. The influence of the metal alkyl was found not to be limited to the activity of the catalyst system, which is maximum for aluminum alkyl, but also to extend to the polymerization mechanism. Depending on the metal alkyl, the two cyclobutene monomers can in fact be polymerized by two different mechanisms, i.e., by opening of the double bond or by ring opening with retention of the double bond. No migration of the double bond is involved in these polymerizations. An interpretation of the different experimental observations is tentatively proposed, and the relationship with the stereospecific polymerization of the α‐olefins is stressed.
Polymerization of cyclobutene rings. VII. Polymerization of bicyclo[4,2,0]octa‐7‐ene and bicyclo[3,2,0]hepta‐2,6‐diene with Ziegler‐Natta catalysts and with group VIII metal halides
Authors: Dall'Asta G. , Motroni G.
Published: April 2003

The polymerization of bicyclic olefins containing a cyclobutene and a higher‐membered ring was studied by using Ziegler‐Natta systems as well as group VIII metal halides as catalysts. Only the cyclobutene moiety of the monomers proved reactive in polymerization, whereas the higher‐membered ring moieties enter unchanged in the polymer chains as side groups. In spite of the considerable bulkiness of the monomers, homopolymerization by opening of the double bond as well as by ring opening take place readily. Steric isomerism of the monomer units and the problem of the site of opening of the cyclobutene ring are discussed.
Cationic polymerization of α,β‐disubstituted olefins. IV. Stereospecific polymerization of propenyl alkyl ethers catalyzed by BF3·O(C2H5)2 and Al2(SO4)3–H2SO4 complex
Authors: Higashimura T. , Kusudo S. , Ohsumi Y. , Mizote A. , Okamura S.
Published: April 2003

The cis‐ and trans‐propenyl alkyl ethers were polymerized by a homogeneous catalyst [BF3·O(C2H5)2] and a heterogeneous catalyst [Al2(SO4)3–H2SO4 complex]. Methyl, ethyl, isopropyl, n‐butyl and tert‐butyl propenyl ethers were used as monomers. The steric structure of the polymers formed depended on the geometric structures of monomer and the polymerization conditions. In polymerizations with BF3·O(C2H5)2 at −78°C., trans isomers produced crystalline polymers, but cis isomers formed amorphous ones except for tert‐butyl propenyl ether. On the other hand, highly crystalline polymers were formed from cis isomers, but not from the trans isomers in the polymerization by Al2(SO4)3–H2SO4 complex at 0°C. The x‐ray diffraction patterns of the crystalline polymers obtained from the trans isomers were different from those produced from the cis isomers, except for poly(methyl propenyl ether). The reaction mechanism was discussed briefly on these basis of these results.
Cationic polymerization of α,β‐disubstituted olefins. V. Reactivity of propenyl alkyl ethers in cationic polymerization
Authors: Higashimura T. , Kusudo S. , Ohsumi Y. , Okamura S.
Published: April 2003

To elucidate the effect of the introduction of a methyl group in the β‐position of a vinyl monomer, propenyl alkyl ethers were copolymerized with vinyl ethers having the same alkoxy group. Propenyl alkyl ethers with an unbranched alkoxy group (ethyl or n‐butyl propenyl ether) were more reactive than the corresponding vinyl ethers. This behavior is quite different from that of β‐methylstyrene derivatives. However, propenyl alkyl ethers with branched alkoxy groups at the α carbon atom (isopropyl or tert‐butyl propenyl ether) were less reactive than the corresponding vinyl ethers. Also, cis‐ isomers were more reactive than the trans isomers, regardless of the kind of alkoxy group and the polarity of the solvent.
Base‐catalyzed hydroxymethylation of phenol by aqueous formaldehyde. Kinetics and mechanism
Authors: Zavitsas Andreas A. , Beaulieu Raymond D. , Leblanc John R.
Published: April 2003

The effects of formaldehyde and hemiformal equilibria on the rates of the base‐catalyzed and hydroxymethylations of phenol by aqueous formaldehyde have been treated quantitatively. A kinetic model treating all seven simultaneous, parallel, consecutive, and competing reactions, as well as the equilibria, has been shown to apply to a wide variety of the conditions and to data from other works. Concentration‐induced solvent effects on the rates and on the ortho/para‐substitution patters have been studied. The temperature dependence of the rate constants, both for dilute systems and systems composed primarily of phenol and aqueous formaldehyde, has been determined.
Polymerization of 2,2,2‐trifluoroethyl vinyl ether
Authors: Chiklis C. K. , Haas H. C.
Published: April 2003

The polymerization of 2,2,2‐trifluoroethyl vinyl ether by six different catalyst systems was examined. Low‐temperature studies (−78°C) with boron trifluoride etherate catalyst in hydrocarbon and chlorinated solvents slowly yielded low molecular weight polymers which were amorphous and noncrystallizable upon cold drawing. Under similar conditions, polymerizations with boron trifluoride gas were spontaneous, quantitative, and gave relatively high molecular weight, form‐stable, amorphous polymer. Heterogeneous polymerizations with chromium trioxide crystals in toluene at 68°C and bulk reactions with ethylmagnesium bromide–carbon tetrachloride catalyst at 40°C failed to produce polymer. Room temperature runs with triisobutylaluminum–titanium tetrachloride catalyst gave amorphous, tacky material. Aluminum hexahydrosulfate heptahydrate (AHS) initiated polymerizations conducted at 25 and 60°C gave low yields of mixtures of amorphous and crystalline polymers, the ratio depending upon the polymerization solvent employed. The infrared spectra and x‐ray diffraction intensity curves of crystalline and amorphous poly(trifluoroethyl vinyl ether) are reported and compared herein for the first time.
1,5‐Polymerization of 1‐thioacylaziridines
Authors: Iwakura Yoshio , Nabeya Aiko , Nishiguchi Takeshi
Published: April 2003

Four thioacylaziridines, 1‐thioaroyl‐, 1‐(N‐phenylthiocarbamyl)‐, 1‐(aryloxythiocarbonyl)‐, and 1‐(aryldithiooxycarbonyl)aziridines, were found to undergo 1,5‐polymerization to giving polymers of polyiminothioether, polyisothiourea, polyiminothiocarbonate, and polyiminodithiocarbonate structure, respectively. The 1,5 polymerization may be explained by the kinetic factors rather than the thermodynamic ones.
Cupric sulfate–hydrazine system as an initiator of vinyl polymerization. II. Polymerization of methyl methacrylate in aqueous solution in the absence of oxygen
Authors: Bond Joan , Lee P. I.
Published: April 2003

The cupric sulfate–hydrazine system has been used to initiate the aqueous solution polymerization of methyl methacrylate at pH 9.25 in the absence of oxygen. There is no decomposition of hydrazine on the surface of the reduced cupric hydroxide until a flocculant precipitate is formed (cupric sulfate concentration of about 10−3 mole/1). Below this concentration, the initiating reaction occurs solely in solution, the rate of polymerization decreasing when the reaction mixture becomes depleted in cupric ions. When a suitable surface area of the precipitated polymer is attained, adsorption and decomposition of hydrazine occurs on its surface, causing further initiation of polymerization.
Polymerization studies on allylic compounds. III. α(substituted methyl)styrenes
Authors: Baldwin M. G. , Reed Samuel F.
Published: April 2003

The free‐radical polymerization of a series of α‐(substituted methyl)styrenes was investigated. These compounds were found to be inactive in homopolymerizations but copolymerized with methyl methacrylate and styrene with a retarding effect. Copolymerization characteristics were followed by rate and viscosity measurements.
Syndiotactic and isotactic poly(tert‐butylethylene oxide)
Authors: Price Charles C. , Fukutani H.
Published: April 2003

The rate of polymerization of t‐BuEO by t‐BuOK in DMSO is about one‐tenth that of propylene oxide. The slow rate of propagation was accompanied by considerable chain transfer. In the absence of solvent, the polymer obtained was crystalline, different from the isotactic form and therefore must be syndiotactic. The NMR spectra indicate the isotactic polymer exists in solution preferentially in the skew1 form, while syndiotactic is about 60% skew1, 40% skew2. Amorphous polymer accompanying isotactic exists about 50% in the trans conformer, by NMR data.
Calorimetric investigation of polymerization reactions. I. Diffusion‐controlled polymerization of methyl methacrylate and styrene
Authors: Horie Kazuyuki , Mita Itaru , Kambe Hirotaro
Published: April 2003

The rate of bulk polymerization of methyl methacrylate and styrene was determined directly, continuously and over the whole range of conversion with a differential scanning calorimeter (DSC) operated isothermally. At the later stages of the accelerated polymerization of methyl methacrylate, a previously unknown inflection or peak in the rate of polymerization was observed. The variation of the rate after the onset of the gel effect, including this peculiar inflection, was interpreted on the basis of the diffusion behavior of monomer molecules and polymeric radicals in the polymer–monomer system, their diffusion rates being predicted from the free volume theory. The final conversion at which no further polymerization proceeds was determined for both monomers. It was affirmed quantitatively that the final conversion has a close relation with the transition of the polymer–monomer system from a viscous liquid to a glassy state.
Synthesis and investigation of properties of repeatedly grafted copolymers (pemosors)
Authors: Korshak V. V. , Mozgova K. K. , Egorova Yu. V.
Published: April 2003

Repeatedly grafted copolymers (pemosors) were obtained by grafting one and the same or different vinyl monomers onto heterochain polymers in a radical reaction. As starting polymers films of polyethylene terephthalate and poly‐ε‐caproamide were used. Styrene and methyl methacrylate were the grafted vinyl monomers. It has been shown that pemosors could be formed in yields of 500–1000% (of the starting sample weight) by multiple grafting on vinyl polymer. Pemosors differ in appearance both from the starting polymers and the single‐graft copolymers. Investigations of pemosor samples by electron microscope showed that the morphological structure of the surface was appreciably affected, the changes being more significant with increasing content of the grafted polymer. X‐Ray studies and NMR data on pemosors showed that multiple grafting of vinyl monomers does not change the crystal structure of the starting polymers, affecting only the supermolecular structure of the outer layer. Pemosors are polymers of a new type, differing in their properties from the starting polymers and the single‐graft copolymers. The grafting character and penetration depth of the grafted monomer depend on the packing compactness of the supermolecular structure of the polymeric base as well as on the chemical nature of the starting polymers and monomers. Pemosors possess considerable chemical resistance and withstand prolonged boiling in 40% alkali solution.
Hydrazine‐based polyimides and model compounds
Authors: Dine‐Hart R. A.
Published: April 2003

The reaction of hydrazine hydrate with aromatic anhydrides may give either N‐amino imides or cyclohydrazides. The conditions that favor the formation of N‐aminoimides, in which the imide contains respectively a 5‐ and 6‐membered ring, are discussed. These compounds may be reacted with aromatic anhydrides to give N‐N‐linked imides. The properties of a number of model compounds and polymers are described, and it is shown that those compounds which have alternating 5‐ and 6‐membered imide rings give the maximum oxidative stability in air at 400°C.
Investigation of the change in the fine structure of Valonia cellulose upon wet heating and mercerization
Authors: Okajima Saburo , Kai Akira
Published: April 2003

A Valonia cellulose (NV), a cellulose II derived from NV by mercerization (MV), and a cast cellulose II film (F) were deuterated repeatedly (wetting‐drying cycle) in vapor phase at 25°C; the integrated deuteration time amounts to 5 × 105 min. A region C, which cannot be attacked by the exchange reaction, exists in NV and MV, amounting to 80 and 18% in the respective samples. In the case of F, it could not be determined exactly due to the too large scattering of the data. On heating in liquid D2O for 5 or 10 min., OD groups develop within C above 190 and 170°C in NV and MV, respectively. Above 190°C. the exchange is larger in NV than in MV. These OD groups within the pre‐existing crystallites begin to disappear after treating with NaOH solution at the concentration at which cellulose begins to be converted to alkali cellulose I. The resistant OD groups developed within the amorphous and intermediate regions are rehydrogenated by the more dilute alkaline solutions.
Thermal degradation of nadic methyl anhydride‐crosslinked novolac epoxy resin
Authors: Freeman Eli S. , Becker Aaron J.
Published: April 2003

The physicochemical high‐temperature reactions of a nadic methyl anhydride‐cross‐linked novolac epoxy resin were investigated by means of differential thermal analysis, thermogravimetric analysis, and by other analytical procedures. The thermogravimetric study revealed that decomposition involving weight loss occurred in two stages. Chemical analysis showed that the major gaseous products formed during weight loss were 2‐methylcyclopentadiene, carbon dioxide, and carbon monoxide. The formation of a fine mist of solid particles was observed during the second stage of degradation. Changing various experimental parameters affected the degradation processes. The kinetics of degradation were also investigated. The method of Freeman and Carroll was used to find that a zero‐order rate law was followed at the beginning of both first and second stages of reaction. The activation energy associated with the major portion of the first stage of weight loss was 15 kcal/mole. There was good agreement between the observed reaction rates and the reaction rates calculated from a theoretical model which depended on desorption as the rate‐controlling step. The activation energy for the beginning of the second stage of weight loss was 24 kcal/mole. By using DTA, the heat of exothermal reaction during this latter phase of decomposition was evaluated as 65 cal/g.
Emulsion polymerization. VI. Concentration of monomers in latex particles
Authors: Gardon J. L.
Published: April 2003

Nonpolymerizing latex particles surrounded by an aqueous phase saturated with monomer absorb only a finite amount of monomer, even if the monomer is a good solvent for the polymer, because the surface energy of each particle increases on swelling. At equilibrium the change in surface energy and the free energy of mixing exactly balance. Equations based on this thermodynamic principle predict with good accuracy the saturation swelling of crosslinked and uncrosslinked latex particles and the partitioning of monomer between the aqueous phase and latex particles at partial saturation. The available experimental data on swelling of latex polymers with monomers are reviewed. Earlier papers assumed that during emulsion polymerization the monomer concentration in the latex particles is independent of conversion as long as monomer droplets are present. This assumption is shown to be a justifiable approximation. The thermodynamics of the swelling of latex particles with a blend of two monomers is presented. The calculations indicate that copolymerization in emulsion should define reactivity ratios differing from those of homogeneous copolymerization by not more than 40% if the solubility of the comonomers in water is low. The reactivity ratio scheme is strictly applicable to emulsion copolymerization if the solvent properties of the two comonomers are identical.
Study on modification of polymers with the aid of the Schmidt reaction
Authors: Ravve A.
Published: April 2003

A study of the Schmidt reaction on several polymers with pendant carboxylic and ketone moieties was carried out. Four polymers were used as starting materials: (1) poly(methyl vinyl ketone), (2) poly(acrylic acid), (3) a copolymer of methyl vinyl ketone and acrylic acid, and (4) a copolymer of styrene and acrylic acid. Most reactions were conducted in an acetic acid medium with the exception of one reaction on poly(acrylic acid) which was done in dioxane and another on copolymer of styrene and acrylic acid done in chloroform. It was found that a Schmidt reaction on poly(acrylic acid) in acetic acid solution will lead to intermolecular reactions of the intermediate with the solvent in preference to reactions with neighboring carboxyl groups on the polymer backbone. A tendency of poly(acrylic acid) to form cyclic anhydrides under these reaction conditions interferes with the yield of acetamide units.
Aminobutadienes. X. Polymerization and copolymerization of 2‐phthalimidomethyl‐1,3‐butadiene
Authors: Murata Kenichi , Terada Akira
Published: April 2003

The polymerization and copolymerization of 2‐phthalimidomethyl‐1,3‐butadiene were investigated. This monomer was easily polymerized by benzoyl peroxide catalyst in bulk or in solvent, and by γ‐radiation in the solid state to give polymers having a softening point of 135–145°C. Although these resulting polymers did not give x‐ray diffraction patterns, they showed crystalline patterns by electron diffraction. On the other hand, cationic polymerization with the use of boron trifluoride diethyl etherate in chloroform was attempted, but no formation of the polymer was observed. Also, this monomer was easily copolymerized with styrene in N,N‐dimethylformamide. The monomer reactivity ratios and Alfrey‐Price Q and e values calculated from the copolymerization data of this monomer (M1) with styrene (M2) were r1 = 2.0 ± 0.13, r2 = 0.15 ± 0.02, and Q1 = 2.78, e1 = 0.30.
Soluble high polymers from allyl methacrylate
Authors: Higgins J. P. J. , Weale K. E.
Published: April 2003

Allyl methacrylate has been polymerized by free‐radical methods and found to yield a soluble polymer in carbon tetrachloride, dioxane, and diallyl ether solutions. The overall rate equation in diallyl ether is Rp = k[ln]0.7[M]1.6. It is suggested that propagation and cyclization reactions proceed only via addition to the methacrylyl groups of the monomer. Some degradative chain transfer occurs with the allyl groups, and it is considered that the solvents may ensure the production of soluble polymers by reactions in which allyl–radical side chains are terminated without crosslinking.
1,2‐Dinitrile polymers. I. Hompolymers and copolymers of fumaronitrile, maleonitrile, and succinonitrile
Authors: Liepins R. , Campbell D. , Walker C.
Published: April 2003

Homopolymers and copolymers of fumaronitrile, maleonitrile, and succinonitrile have been prepared by using medium high temperature free‐radical initiators. Black, nonfusible but soluble polymers were obtained. The spectroscopic and chemical evidence indicated a structure containing α‐pyrrolenine rings and no free nitrile groups in the fumaronitrile and maleonitrile polymers and 1‐pyrroline rings and free nitrile groups in the succinonitrile polymers. The polymers possessed good thermal stability, free spin concentration of 1017–1018 spins/g, and an ac conductivity at room temperature in nitrogen of 10−6 to 10−8 ohm−1 cm−1.
Metal‐containing initiator systems. IV. Polymerization of methyl methacrylate by systems of some activated metals and organic halides
Authors: Otsu Takayuki , Yamaguchi Masami
Published: April 2003

A study of the polymerization of methyl methacrylate initiated by the binary systems of some activated metals and organic halides has been made. It was found that the initiator activities of these systems were greatly dependent on the kind and the preparation or activation method of the metals (i.e., oxidation potential, surface area, and purity), and also on the kind of organic halides (i.e., bond‐dissociation energy of their carbon–halogen bonds). From the kinetic studies of the polymerization at 60°C with the system reduced nickel–carbon tetrachloride, the rate of polymerization was found to be proportional to the monomer concentration and to the square root of concentration of both nickel and carbon tetrachloride at the lower concentration range of carbon tetrachloride, indicating that the system induced the radical polymerization. A similar conclusion was also obtained from the copolymerization with styrene with this system at 60°C, i.e., the resulting copolymer composition curve was in agreement with that obtained with azobisisobutyronitrile (AIBN). The apparent overall activation energy for the methyl methacrylate polymerization with this system was estimated to be 7.5 kcal/mole, which was considerably lower than that with AIBN. On the basis of the results obtained, an initiation mechanism for the polymerization with these initiator systems is presented and discussed.
Olefin polymerizations and copolymerizations with aluminum alkyl–cocatalyst systems. I. Cocatalysis with brönsted acid systems
Authors: Kennedy J. P.
Published: April 2003

Certain aluminum alkyls and aluminum dialkyl halides in conjunction with suitable simple cocatalysts generating proton or carbonium ion exhibit high polymerization activity and produce high molecular weight polyolefins, diolefins and/or copolymers at comparatively high temperatures. In this paper we report our investigations with AlEt2Cl–Brönsted acid systems used for polymerizing isobutylene and copolymerizing isobutene‐isoprene mixtures for high molecular weight products. The cocatalyst is not specific in these reactions. Highly active systems can be obtained with HCl, HBr, CCl3COOH, etc. Evidently proton donors in general (Brönsted acids) may function as cocatalysts in this system. The sequence of polymerization initiation activity of various Brönsted acids in conjunction with AlEt2Cl is HCl, HBr ≫ HF, H2O > CCl3COOH ≫ CH3OH > CH3COCH3. The effect of temperature on the molecular weights was studied. In contrast to linear plots of log molecular weight versus 1/T, obtained for polyisobutylene or isobutylene‐isoprene copolymers with conventional Friedel‐Crafts halides in the −30 to −100°C range, this Arrhenius plot showed a marked maximum near −70°C for polymers prepared with AlEt2Cl–HCl catalyst systems. Features of this polymerization reaction are discussed.
Radiation‐induced copolymerization of ethylene and sulfur dioxide in the liquid and gas phases
Authors: Colombo P. , Fontana J. , Steinberg M.
Published: April 2003

The radiation‐induced copolymerization of ethylene and sulfur dioxide has been studied in the liquid and gas phases. In the liquid phase, the copolymer composition remained equimolar over a temperature range of 20–160°C. and ethylene pressures of 50–680 atm. The rate of copolymerization in the liquid phase at 680 atm. increased with temperature to a maximum value at ∼80°C. Above this temperature the rate steadily decreased to zero at 157°C. because of temperature‐dependent depropagation reactions. In the gas phase, copolymers were formed that contained from 9 to 46 mole‐% sulfur dioxide. Under constant conditions of temperature, pressure, and radiation intensity, the copolymerization rate in the gas phase increased with increasing sulfur dioxide in the initial gas mixture. The propagating species for the liquid‐phase experiments is considered to consist of an equimolar complex molecule of ethylene and sulfur dioxide. For gas mixtures containing an excess molar concentration of ethylene, the propagating species are ethylene and the complex molecule. Infrared spectra show polysulfone structures. Calorimetric and x‐ray diffraction analyses indicate crystalline structures for copolymers in the range 9–50 mole‐% sulfur dioxide, although a melt transition temperature could not be observed for copolymer containing >31 mole‐% sulfur dioxide. Clear uniform film was obtained with copolymers containing up to 31 mole‐% SO2.
Isomerization of cis‐1,4‐polybutadiene by RhCl3·3H2O
Authors: Hrabak Frantisek
Published: April 2003

The isomerization of cis‐1,4‐polybutadiene by RhCl3 in aqueous emulsion was studied. The reaction was found to be slowed down by air and by base but not by quinone and was independent of the polymer solvents. Quinone did not suppress polymer gel formation. The results obtained suggest a nonradical mechanism of these reactions.
Kinetics of high‐intensity electron‐beam polymerization of a divinyl urethane
Authors: Labana S. S.
Published: April 2003

The kinetics of high‐intensity electron beam‐induced polymerization of di(2′‐methacryloxyethyl)‐4‐m‐phenylenediurethane during the network formation has been studied up to complete gelation and up to 56% conversion of unsaturation. From experimentally determined gel fractions, rate of disappearance of unsaturation, kinetic chain length, and intensity dependence, it is proposed that the polymerization takes place in a swollen network where the growing chains undergo unimolecular termination, and where gel‐gel reaction is prohibited. The rate expression derived is: In [α(1 − g)0.545] = In α0 − 2.51 kikpt/kt where α is the total unsaturation and g is the gel fraction. The value of kp/kt is found to be 2.1 and that of GR, the free radical yield per 100 eV absorbed, to be 16; these high values are ascribed to the high viscosity of the polymerizing system.
Extrathermodynamic approach to the study of the adsorption of organic compounds by macromolecules
Authors: Hansch Corwin , Helmer Friederike
Published: April 2003

By using substituent constants and regression analysis, an analysis has been made of the binding of derivatives of aniline and acetanilide to nylon and rayon, the experimental data of Ward and Upchurch being used. The amount of organic compounds bound from an aqueous solution by these two types of synthetic macromolecules is shown to be related to the octanol–water partition coefficients P. In the case of the aniline derivatives, where the basicity of the compounds varied considerably, a good model describing binding results from the linear combination of the two parameters related to free energy, i.e., log P and ΔpKa. The latter term is the difference between pKa for aniline and a particular derivative. For the neutral acetanilides a simple linear free‐energy relation between log P and log K is found. Of special note is the fact that the dependence of binding of these two classes of compounds to two classes of synthetic macromolecules as indicated by the coefficient with the log P term very closely parallels that found for a variety of biopolymers. The mechanism of hydrophobic binding seems to be the same in both the synthetic and natural polymers.
Thermal degradation of copolymers of methyl methacrylate and methyl acrylate. I. Products and general characteristics of the reaction
Authors: Grassie N. , Torrance B. J. D.
Published: April 2003

The technique of thermal volatilization analysis (TVA), applied to methyl methacrylate–methyl acrylate copolymers having molar composition ratios 112/1, 26/1, 7.7/1, and 2/1, has demonstrated that the stabilization of poly(methyl methacrylate) by copolymerized methyl acrylate is due to inhibition of the depolymerization initiated at terminally unsaturated structures, probably by direct blockage by methyl acrylate units. The molecular weight of the copolymers decreases rapidly during degradation, suggesting that a random scission process is involved. The products of degradation consist of the monomers, carbon dioxide, chain fragments larger than monomer, and a permanent gas fraction which is principally hydrogen. Infrared and ultraviolet spectral measurements suggest that the residual polymer, which is colored, incorporates carbon–carbon unsaturation. The complete absence of methanol among the products is surprising in view of its abundance among the products of degradation of poly(methyl acrylate). These observations have been accounted for qualitatively in terms of acceptable polymer behavior.
Thermal degradation of copolymers of methyl methacrylate and methyl acrylate. II. Chain scission and the mechanism of the reaction
Authors: Grassie N. , Torrance B. J. D.
Published: April 2003

It has been established that one molecule of carbon dioxide is produced for each chain scission during degradation of methyl methacrylate–methyl acrylate copolymers with molar compositions in the ratios 112/1, 26/1, 7.7/1, and 2/1. Thus the relatively simple measurement of the production of carbon dioxide can be used to determine the extent of chain scission. In this way the relationships between chain scission and volatilization, zip length, copolymer composition, and the production of permanent gases have been established. The rate of chain scission is proportional to a power of the methyl acrylate content of the copolymer less than 0.5, from which it has been concluded that a significant proportion of the initial production of radicals and the subsequent attack of these radicals on the polymer chains is at random and not specifically associated with the methyl acrylate units. A mechanism for the overall thermal degradation process in this copolymer system is presented in the light of these observations.
Anionic copolymerization of 1,1‐diphenylethylene and 2,3‐dimethylbutadiene
Authors: Yuki Heimei , Hatada Koichi , Inoue Tadanori
Published: April 2003

1,1‐Diphenylethylene (M2) and 2,3‐dimethylbutadiene (M1) were copolymerized with n‐butyllithium in tetrahydrofuran. The rate of consumption of each monomer was followed by the change of high resolution NMR spectra of the reaction mixture. The copolymerization proceeded alternately, if the ratio of initial monomer concentrations, [M2]0/[M1]0, was sufficiently larger than unity. By assuming the rate constant k22 to be zero, the constants k21 were obtained from the consumption rates of the monomers. In the alternating copolymerization, 2,3‐dimethylbutadiene was incorporated into the copolymer only as the 1,4‐structure, while the 1,2‐structure was predominant in homopolymerization.
Syntheses of aromatic polyketones and aromatic polyamide
Authors: Iwakura Y. , Uno K. , Takiguchi T.
Published: April 2003

High molecular weight aromatic polyketones were prepared from p‐ and m‐phenoxybenzoic acid in polyphosphoric acid by heating the reaction mixture at 100°C. High molecular weight aromatic polyamide was derived from the polyketone obtained through Schmidt reaction or Beckmann rearrangement. The polyamide obtained by Schmidt reaction was found to have some regularity in an arrangement of its repeating units. The thermal stability of the polyketone and the polyamide were good.
Polyhydrazides. I. N‐alkylated polyhydrazides from diesters and hydrazine
Authors: Iwakura Yoshio , Uno Keikichi , Hara Shigeyoshi , Kurosawa Shigeru
Published: April 2003

N‐Alkylated polyhydrazides containing 1,3,4‐oxadiazole linkages in them were prepared by solution polycondensation of dicarboxylic acid diesters with hydrazine in fuming sulfuric acid or polyphosphoric acid. Their preparation, characterization, and some physical properties are described.
Electron‐transfer polymers. XXXVII. Preparation and redox behavior of polycarbonates with incorporated hydroquinone units
Authors: Wegner Gerhard , Nakabayashi Nobuo , Duncan Stephen , Cassidy Harold G.
Published: April 2003

Preparation of polycarbonates from a quinonediol and phosgene, and from the quinonediol and various bischloroformates, is described. Some of the bischloroformates were prepared from poly(ethylene oxides) with two terminal hydroxyl groups by phosgenation. The quinone groups incorporated into the polymer chain were reduced to hydroquinone groups. Some of these polymers were titrated oxidatively in 90% acetic acid. Their redox behavior cannot be described by a simple Nernst equation. It is assumed that the differences between theoretically expected and experimentally obtained potentials express the amount of work needed to reshape the polymer coil according to a thermodynamically stable distribution of the redox groups.
Optical studies of the stress‐induced crystallization of rubber
Authors: Yau W. , Stein R. S.
Published: April 2003

The low‐angle light scattering by films of stretched natural and synthetic rubbers was investigated. Intense Vv scattering is found under conditions when crystallization occurs which is characteristic of the scattering from aggregates of dimensions comparable with the wavelength of visible light. These were identified with the γ fibrils described by Andrews. The dependence of scattering was studied as a function of light polarization direction, orientation direction, elongation, temperature, degree of swelling, type of swelling liquid, and degree of crosslinking. It was concluded that the scattering unit consists of an assembly of crystals with their chain axes parallel to the stretching direction, but (in the case of natural rubber at high elongations) with the fibril axis at a slight angle to the stretching direction. The scattering is not affected much by swelling but is decreased upon increasing the temperature. Upon recooling the scattering returns, but does so over several hours, indicating that much of the scattering arises from secondary crystallization.
Stress relaxation of monodisperse poly‐α‐methylstyrene
Authors: Fujimoto Teruo , Ozaki Noriyoshi , Nagasawa Mitsuru
Published: April 2003

The viscoelastic properties of monodisperse poly‐α‐methylstyrenes of molecular weights of 4 × 104 to 50 × 104 were studied by the tensile stress‐relaxation method. The relaxation‐time spectra as well as the steady‐flow viscosity, the steady‐state compliance, the maximum relaxation time, and the modulus associated with the maximum relaxation time were determined. The molecular weight dependences of these quantities were compared with the theory of Rouse and Bueche as modified by Ferry, Landel, and Williams, as well as with data on other polymers reported in the literature.
Dimensional stability of regenerated cellulose film in relation to orientations of crystalline and noncrystalline phases
Authors: Takahara Hirokazu , Nomura Shunji , Kawai Hiromichi , Yamaguchi Yutaka , Okazaki Kazumi , Fukushima Akio
Published: April 2003

The dimensional stability of regenerated cellulose film on swelling with water is discussed in relation to the biaxial orientation of the two kinds of structural units, cellulose II crystallites and noncrystalline chain segments, and their anisotropic swelling (anisotropic absorption of water). Considerable dimensional stability in the plane of the film but enormous instability of thickness on swelling in water of some commercial cellophanes is qualitatively interpreted in terms of the planar orientation of crystal (101) planes along the film surface and the orientation of the noncrystalline chain segments parallel to the film surface. The dimensional changes on swelling from the completely dry state to 10% moisture regain were further interpreted quantitatively in terms of the degrees of biaxial orientation of the two kinds of structural units and their degrees of anisotropic swelling by modifying the Hermans monophase model for crystalline and noncrystalline biphase structures. The following degrees of anisotropic swelling of the structural units were thus obtained: qc, [101] = 0.40%, qc, [101] = −0.33%, and qa = 2.42%.
Effect of morphology in the surface region of polymers on adhesion and adhesive joint strength
Authors: Schonhorn Harold , Ryan Frank W.
Published: April 2003

The morphological character of the surface region of polyethylene has been considered with respect to adhesion and adhesive joint strength. By melting polyethylene onto a high‐energy surface (e.g., aluminum) we have provided for extensive nucleation and the formation of a transcrystalline region in the polymer. Dissolution of the metal rather than peeling the metal from the polymer leaves the surface region of the polymer intact. The polymer sheet is now amenable to conventional adhesive bonding and forms a strong adhesive joint. We conclude from this study that the occurrence of the normal weak boundary layer is a consequence of the morphology of the surface region of the material and is, therefore, influenced by the method of preparation.
Network relaxation properties of crosslinked poly(ethyl acrylate) and polydimethylsiloxane in the rubbery plateau region
Authors: Sperling L. H. , Tobolsky A. V.
Published: April 2003

The stress relaxation properties of poly(ethyl acrylate) and polydimethylsiloxane were investigated under conditions where oxidative degradation was minimized. The relaxation observed is thought to result from the continued approach to equilibrium of the network chains with cooperative thermal motion. These elastomers, representing two new classes of polymer, and two new types of crosslinking, were found to behave surprisingly like natural rubber and butadiene–styrene copolymer. Relaxation was found to obey a power law in time, with a negative exponent of 0.22 for both polymers.
Liquid–liquid phase separation in multicomponent polymer solutions. III. Cloud‐point curves
Authors: Koningsveld R. , Staverman A. J.
Published: April 2003

Cloud‐point curves (CPC) were calculated on the basis of the Flory‐Huggins free‐energy relation for various hypothetical polymer samples dissolved in a single solvent. Molecular weight distributions varying widely in shape and width were examined. The shape of the CPC reflects details of the molecular weight distribution. This appears from the location of the critical point on the right‐hand branch of the CPC. The latter often shows a depression, which becomes more distinct as the Mz/Mw value increases. These theoretical results were confirmed experimentally with the system polyethylene–diphenyl ether. With the aid of the theoretical data collected it was possible to explain the remarkable agreement between the θ temperatures determined by light‐scattering and by the Shultz‐Flory method. The latter method is basically incorrect, since it identifies the polymer solution with a binary mixture. An explanation could also be given for the empirical relation which McIntyre et al. recently found between the shape of the top of the CPC and the width of the molecular weight distribution.
Secondary processes of poly(methyl methacrylate) and their activation energies as determined by shear and tensile creep compliance measurements
Authors: Thompson Edward V.
Published: April 2003

The results of measurement of the shear and tensile creep compliance of poly(methyl methacrylate) between −150 and 75°C. are presented. The master curves show the creep behavior from essentially elastic response to the onset of the α‐process. The logarithmic retardation spectra and shear loss compliance reveal two molecular processes, one process being partially obscured by the α‐process and therefore not as well defined as the other. These processes manifest themselves as breaks in an Arrhenius plot of the shift factors at about −35 and +25°C. The activation energies in the −35 to 25°C. and 25 to 80°C. ranges are 17.8 kcal./mole and 42.2 kcal./mole, respectively. The former temperature range and activation energy corresponds to the well‐known ß‐process in poly(methyl methacrylate), the latter to a process which is apparently detectable using various long‐time experimental techniques but whose molecular interpretation is at present obscure. The activation energy in the −150 to −35°C. range is about 8.7 kcal./mole.
On the possibility of chain folding in solutions of normal paraffins and polyethylene
Authors: Liu Kang‐Jen , Ullman Robert
Published: April 2003

A simple statistical thermodynamic argument is presented in which the probability of intramolecular chain folding of normal paraffins and polyethylene in solution is examined. This possibility is based on the existence of low‐energy intramolecular conformations which are stable enough to overcome the tendency of a chain molecule to assume a random arrangement in solution. Some rough estimates of the magnitudes of energetic interaction in straight‐chain hydrocarbons are made to demonstrate the plausibility of this hypothesis. The experimental support for this model arises from NMR spectra of normal paraffins in aromatic hydrocarbon solvents.
Electronic and ionic conductivity in nylon 66
Authors: Seanor D. A.
Published: April 2003

The conductivity of dry poly(hexamethylene adipamide) (nylon 66) was measured as a function of time and temperature. Three temperature ranges were observed in which the time dependence of conductivity differed: (a) below 80°C. the conductivity decreased continuously with time; (b) between 80°C. and 110°C. the conductivity remained constant over long periods; (c) above 120°C. a continuous decrease in conductivity was again observed. In other experiments the volume of gas evolved from the nylon film was measured under continuous potential and compared with the total current passed through the sample. It was observed that above 120°C. the gas evolved corresponded to about one‐half the volume calculated if the conduction process involved only protons. Below 120°C. the gas evolved corresponded to an increasingly small fraction of the total current until below 90°C. no evolution of gas was observed. This suggests that at temperatures above 120°C. conduction involves the transport of both protons and electrons, whereas at lower temperatures it is electronic. Mechanisms of conduction are discussed.
Variation of polymer chain dimensions with temperature below the theta point
Authors: Orofino T. A.
Published: April 2003

The temperature dependence of the intrinsic viscosity [η] for the system polystyrene‐cyclohexane in the interval −20 < (T − ψ) ≤ 0 near the ideal temperature ψ has been investigated. The observed diminution in size of the molecular coil with decreasing temperature is attributable to attractive net polymer‐solvent interactions, denoted by negative values for the excluded volume parameter z. The data thus comprise an interesting selection for comparison with the predictions of various excluded volume theories. Among the approximate, closed‐form expressions the functional relationship of Flory (x5 − α3 ∼ z) appears to describe best the variation of [η] with temperature in the region examined. The behavior of the Huggins constant k′ derived from the intrinsic viscosity plots is also examined, in accordance with the Peterson‐Fixman model, suitably extended to the temperature region below ψ.
Magnetic bearing torsional creep apparatus
Authors: Plazek Donald J.
Published: April 2003

A torsional creep and recovery apparatus has been designed and constructed to measure extremely wide ranges of recoverable creep compliance (10−10 to 10−2 cm.2/dyne) and viscosity (10−1 to 1016 poises) within the temperature range −60 to 220°C. Friction is avoided by supporting the moving element, the rotor, in a magnetic field, inducing the required torque with a drag cup motor, and monitoring the angular displacement with a light lever and a light following recorder. Measurements of recoverable compliance can be made further into the region of time scale which is dominated by viscous deformation than has been heretofore possible. In situ sample manipulation of viscoelastic liquids is utilized. Measurement is made on liquid cylinders between circular stainless steel platens. Results which have been obtained on a 1.22 × 105 molecular weight polystyrene are presented to illustrate the range of possible measurements and to indicate the value of such results covering up to six logarithmic decades of time scale.