bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and polymerization of 1‐ and 2‐cyano‐1,3‐butadienes
Authors: Wei Peter E. , Milliman George E.
Published: April 2003

1‐Cyano‐1,3‐butadiene and 2‐cyano‐1,3‐butadiene were prepared and designated 1‐cyanoprene and 2‐cyanoprene, respectively. These compounds, and their intermediates, were characterized by their infrared and proton magnetic resonance spectra. Their polymerizations with lithium or aluminum alkyl catalysts are described. The synthesis of these monomers involves a thermal cracking process (400–500°C). The yield of monomer by this process depends on the positions of the cyano and acetoxy groups in the butene intermediate; if the cyano and the acetoxy groups are attached to the same allylic carbon, a low monomer yield is obtained. The polymers of 1‐cyanoprene are the results of 1,4‐enchainment (cis and trans) and are amorphous; the polymers of 2‐cyanoprene may involve 1,4‐enchainment but are partially crystalline. Both of these polymers are thermoplastic.
Four‐center type photopolymerization in the solid state. III. Polymerization of phenylene diacrylic acid and its derivatives
Authors: Suzuki Fusae , Suzuki Yasuzo , Nakanishi Hachiro , Hasegawa Masaki
Published: April 2003

The solid‐state photopolymerization of phenylene diacrylic acid (PDA) and its derivatives was studied as an application of solid‐state photodimerization of cinnamic acid to photopolymerization of corresponding bifunctional molecule which has two cinnamic units in a single molecule. p‐ and m‐PDA, and their esters and amides were prepared and investigated with respect to their photopolymerizability. Many of them have been found to polymerize into linear high polymers with the cyclobutane rings in the main chain on irradiation by ultraviolet or visible light. The polymerization process, the structure of the polymers, and their general properties were investigated in several ways. All the polymers are very similar to poly‐2,5‐distyrylpyrazine and poly‐1,4‐bis(β‐pyridyl‐2‐vinyl) benzene with respect to their polymerization behavior, polymer structure, and some polymer properties: these polymers are soluble in a limited number of solvents, they have a high melting point and an extremely high crystallinity. On the basis of chemical behavior of poly‐PDA and its phenyl ester the possible steric configurations of these polymers are discussed. It is demonstrated for the PDA series that solid‐state dimerization can be generally extended to solid‐state photopolymerization of the compound having two dimerizable units in a single molecule, although the crystal structure renders polymerization impossible in certain cases.
Polymers from 1,3‐dipole addition reactions. The nitrilimine dipole from tetrazoles
Authors: Stille J. K. , Gotter L. D.
Published: April 2003

Polymers containing pyrazole and triazole units in the polymer chain were obtained through the 1,3‐dipolar addition reaction of bisnitrilimines generated from tetrazoles with diynes and dinitrile dipolarophiles. The reaction of 2,2′‐diphenyl‐5,5′‐m‐ and p‐phenyleneditetrazole with the dipolarophiles m‐ and p‐diethynylbenzene, terephthalonitrile, tetrafluoroterephthalonitrile, perfluoroglutarylnitrile, and 4,4′‐dicyanobiphenyl gave a series of thermally stable polymers of high molecular weight. The polypyrazoles were soluble in acid and in some cases in chlorobenzene or 1,2,4‐trichlorobenzene and had intrinsic viscosities as high as 1.67, while the polytriazoles were soluble in 1,2,4‐trichlorobenzene and chlorobenzene, but not in acid, and had viscosities ranging up to 0.40. The thermogravimetric analyses of the finely powdered polymers showed breaks near 500°C in air and nitrogen atmospheres.
Phase diagram and X‐ray diffraction analysis of the acrylic acid–acrylamide system
Authors: Parrish C. F. , Kochanny G. L. , Rinn H. W.
Published: April 2003

The phase diagram of the acrylic acid–acrylamide system as determined by DTA and the supporting x‐ray diffraction data are presented. This diagram shows that the system forms a 1 : 1 addition compound which decomposes above 0°C. There is also one eutectic point at a 67 mole‐% acrylic acid composition.
Anionic graft polymerization of lithiated poly(2,6‐dimethyl‐1,4‐phenylene ether)
Authors: Chalk A. J. , Hoogeboom T. J.
Published: April 2003

Lithiated poly(2,6‐dimethyl‐1,4‐phenylene ether) has been used as an initiator for the graft polymerization of isoprene, methyl methacrylate, hexamethylcyclotrisiloxane, and phenyl isocyanate with the use of toluene and tetrahydrofuran as solvents. The products were examined by gel‐permeation chromatography for evidence of homopolymerization and graft polymerization. The composition of the graft copolymers was determined by NMR, and for isoprene and hexamethylcyclotrisiloxane, termination by trialkylchlorosilanes enabled chain lengths to be determined by NMR. The use of toluene gave rise to some homopolymerization, but with tetrahydrofuran, only hexamethylcyclotrisiloxane gave homopolymer. In all cases, graft copolymers were formed. With isoprene and methyl methacrylate, soluble graft copolymers were formed in good yield. In the former case approximately 60% 3,4 and 40% 1,4 addition was found. In the latter case 1,1‐diphenylethylene was used to reduce crosslinking, in its absence, methyl methacrylate gave only crosslinked gels in tetrahydrofuran. Hexamethylcyclotrisiloxane added only one molecule per lithium on the polymer, the remainder giving homopolymer. Phenyl isocyanate gave some soluble graft copolymer in toluene, but only crosslinked products were obtained when tetrahydrofuran was used as reaction solvent.
Kinetic study of γ‐radiation‐induced polymerization of ethylene in the presence of acetylene
Authors: Mitsui Hiroshi , Hosoi Fumio , Kagiya Tsutomu
Published: April 2003

The effects of acetylene on the γ‐radiation‐induced polymerization of ethylene were studied from the viewpoint of kinetics. The experiments were carried out under a pressure of 150–400 kg/cm2; the temperature was 30°C; the dose rates were 2.7 × 104 and 1.1 × 105 rad/hr; the acetylene content was 0–2.21%. Both the polymer yield and the molecular weight increased acceleratively with the reaction pressure in the polymerization containing 0.18% acetylene. The yield increased almost proportionally with the dose rate, and the molecular weight was found to be almost independent of the dose rate in the polymerization containing 2.21% acetylene. The polymerization rate and the molecular weight increased with reaction time, but the increment decreased with increasing acetylene content. The degree of increase in the molecular weight also decreased with increasing time. These results were analyzed by using a graphical evaluation method for kinetics, and the effects of acetylene on each elementary step in the polymerization discussed.
Condensation of benzyl chloride catalyzed by group II metals
Authors: Spanier Edward J. , Caropreso Frank E.
Published: April 2003

The polymerization of benzyl chloride in the presence of various group II metal salts has been investigated. The extent of reaction and the relative activities of various salts were determined by measurement of the evolved HCl as a function of time. Formation, in situ, of an active catalyst is proposed.
Effect of viscosity on termination rate constant in radical polymerization at low conversion
Authors: Ito Katsukiyo
Published: April 2003

By using the expression, kt = A1Ds for the chain termination rate constant (where A1 is a constant and Ds is the diffusion constant of radical chain end), a familiar chain termination rate constant, kt = A2/ηs (where A2 is a constant and ηs is solvent viscosity) was examined with variation of conversion x. It was found that the proportionality of chain termination rate constant and solution viscosity is a valid relation at conversion 0 but is approximate at conversion xc ≥ x > 0. Here xc denotes a critical conversion under the average distance around spherical polymers formed in polymerization solution is zero. At conversions above xc, the inverse relation between chain termination rate constant and solution viscosity is not correct.
Radiation‐induced polymerization of 1,1,2‐trichlorobutadiene in the solid state
Authors: Ito Katsukiyo , Matsuda Tatsuo
Published: April 2003

Changes in the polymerization and in the structure of the polymer formed during the course of polymerization of 1,1,2‐trichlorobutadiene in the solid state were studied. We observed that the rate of polymerization and the molecular weight of the polymers formed increasing conversion. The content of 1,4 units in the polymer also increases with increasing conversion.
Grafting with acrylonitrile with the redox system cellulose xanthogenate–hydrogen peroxide
Authors: Dimov Kyril , Pavlov Pavel
Published: April 2003

The possibility of obtaining modified cellulose products by reacting cellulose xanthogenate in solutions containing oxidizers and acrylonitrile was studied. The ability of the cellulose xanthogenate–hydrogen peroxide redox system to initiate graft copolymerization of acrylonitrile on the cellulose was demonstrated. The influence of various factors on the processes was investigated. An attempt was made to clarify the nature of the reactions involved.
Three‐component catalysts containing aldehydes for stereospecific polymerization of propylene
Authors: Watt W. R. , Fisher C. D.
Published: April 2003

Aldehydes, when added to mixtures of ethylaluminum dichloride and titanium trichloride under pressure of propylene, have been found to promote either propylation of benzene or stereospecific polymerization of propylene. Selectivity between the two reaction paths is influenced by the molecular structure of the aldehyde. Most aldehydes promote propylation of benzene to cumene and higher isopropyl benzenes. Propylation occurs with or without titanium trichloride present. Substituted aromatic aldehydes with three or more alkyl substituents promote stereospecific polymerization of propylene. Both reactions are dependent upon the ethylaluminum dichloride/aldehyde molar ratio.
Chain‐transfer constant of fluoroalcohols
Authors: Kar Indrajit , Mandal B. M. , Palit S. R.
Published: April 2003

Chain transfer constants of some fluoroalcohols [HCF2(CF2)n−1CH2OH, n = 2, 4, 6] in the catalyzed polymerization of vinyl acetate, styrene, acrylonitrile, and methyl methacrylate at 60°C have been evaluated by a method based on degree of polymerization. Since fluoroalcohols are normally nonsolvents for polymers, a homogeneous reaction phase is maintained by carrying out the polymerization in benzene (except in case of acrylonitrile, where no solvent was used). The transfer constants vary, depending on the reactivity as well as the polarity of the radicals, in the following order: vinyl acetate > styrene > methyl methacrylate > acrylonitrile. Of the three fluoroalcohols studied, the transfer constants increase with the increasing value of n. The results have been interpreted in terms of polar structure contribution in the transition state of the transfer reactions.
Photopolymerization of vinyl monomers in the presence of chlorosilane compounds
Authors: Minoura Yuji , Toshima Hiroyuki
Published: April 2003

The photopolymerization of vinyl monomers (methyl methacrylate and styrene) was investigated in the presence of chlorosilane compounds. It was found that these additives acted as photosensitizers. In the case of the photopolymerization of methyl methacrylate, the rate of polymerization was found to be proportional to the concentration of methyl methacrylate and to the square root of the chlorosilane concentration. The chain‐transfer constants of these photosensitizers, SiCl4, CH3SiCl3, (CH3)2SiCl2, (CH3)3‐SiCl, and (CH3)4Si, with ultraviolet irradiation were 25.6 × 10−3, 18.4 × 10−3, 17.5 × 10−3, 14.4 × 10−3 and 0.5 × 10−3, respectively, for methyl methacrylate.
Room‐temperature polycondensation of β‐amino acid derivatives VI. Synthesis of various N‐(hydroxyethyl) nylons
Authors: Ogata Naoya , Sanui Kohei
Published: April 2003

Various N‐(hydroxyethyl)amino acid esters having a methyl substituent or phenyl group between amine and ester groups have been synthesized and their polycondensation behavior was investigated. These substituted amino acid esters gave amorphous polyamides which were soluble in alcohol. A model reaction between N‐(hydroxyethyl)‐amine and carboxylic acid ester was carried out in order to elucidate the role of hydroxyethyl group on the polycondensation. It was found that the amidation reaction took place rapidly at room temperature when the alkyl group of the carboxylic acid was small. N‐(Hydroxyethyl) polyamides were obtained from N,N′‐(bishydroxyethyl)‐dicamines and dicarboxylic acid esters. The reaction mechanism of the room‐temperature polycondensation reaction is discussed.
Anionic polymerization of o‐ and p‐methoxystyrene
Authors: Geerts J. , Van Beylen M. , Smets G.
Published: April 2003

The butyllithium‐initiated polymerization of o‐ and p‐methoxystyrene was studied in toluene at 20°C by dilatometry. Initiation of o‐methoxystyrene was found to be instantaneous as evidenced by the absence of any induction period. The propagation rate proceeds by an internal first order with respect to the monomer concentration while the order with respect to the living chain ends varies from 0.67 to 0.51 over a concentration range from 4.5 × 10−4 to 1.8 × 10−2 mole/1. The rate may thus be expressed by the equation,

where [M] and [PLi] denote concentration of monomer and poly‐o‐methoxystyryllithium, respectively, and n varies from 0.67 to 0.51. It is assumed that the propagation proceeds exclusively via the monomeric form of the ion‐pairs in analogy with the polymerization of styrene. The variable order results from the relatively high value of the dissociation equilibrium constant of dimeric into the monomeric ion‐pairs K that was evaluated graphically to be 10−3 instead of 10−6 for styrene. The propagation rate constant kp was found to be equal to about 50 l./mole‐min; the propagation activation energy is equal to 12 kcal/mole. No appreciable termination was found in the polymerization of o‐methoxystyrene. On the contrary, no quantitative data could be obtained for the polymerization of p‐methyoxystyrene due to a slow initiation and a relatively fast termination reaction with formation of a precipitate of highly branched or crosslinked polymer. It is assumed that this precipitate results from a secondary ring metallation reaction.
Thermal degradation of polymers with phenylene units in the chain. II. Sulfur‐containing polyarylenes
Authors: Ehlers G. F. L. , Fisch K. R. , Powell W. R.
Published: April 2003

Poly(p‐phenylene sulfide), a poly(arylene sulfone), and a poly(arylene sulfonate) were subjected to thermal degradation in vacuo, at temperatures between 250 and 620°C. The volatile and solid degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. The major decomposition product of poly‐(phenylene sulfide) is a condensate, which consists of di‐ and trimeric chain fragments, dibenzothiophene, and possibly thianthrene. The residual polymer loses two thirds of its sulfur as hydrogen sulfide, however, one third is retained even at 620°C. The most characteristic decomposition reaction of the polysulfone and of the polysulfonate is the almost complete removal of the sulfur as sulfur dioxide. The elimination of sulfur dioxide is practically complete at 450°C for the polysulfone and at 350°C for the polysulfonate.
Thermal degradation of polymers with phenylene units in the chain. III. Polyarylates
Authors: Ehlers G. F. L. , Fisch K. R. , Powell W. R.
Published: April 2003

The thermal decomposition of three aromatic polyesters was studied in vacuo. The degradation products were analyzed by mass spectroscopy, infrared spectroscopy, and elemental analysis. Breakdown mechanisms are proposed. Primary cleavage of the ester linkages appears to take place either between the carbonyl and the oxygen or between the oxygen and the ring, yielding carbon monoxide and carbon dioxide in varying ratios. Another major decomposition product is a sublimate which seems to consist mainly of the phenolic component of the polyester. A polyester with a 2,2‐propylene linkage showed, as expected, early loss of methane. A pendent pentyloxy chain in one of the polymers is removed almost completely below 350°C with formation of alkanes and alkenes. Lack of oxygen in the fragments indicates that the main cleavage must occur between the ether oxygen and the aliphatic chain or with in the aliphatic chain.
Structure and reactivity of α,β‐unsaturated ethers. VIII. Cationic copolymerizations and acetal additions of propenyl and isobutenyl ethyl ethers
Authors: Okuyama T. , Fueno T. , Furukawa J.
Published: April 2003

Cationic copolymerizations of cis‐ and trans‐propenyl ethyl ethers (PEE) with isobutenyl ethyl ether (IBEE) were carried out in methylene chloride at −78°C with the use of boron trifluoride etherate as catalyst. Monomer reactivity ratios were r1 = 24.0 ± 2.4 and r2 = 0.02 ± 0.02 for the cis‐PEE (M1)–IBEE (M2) system and r1 = 19.1 ± 1.8 and r2 = 0.04 ± 0.02 for the trans‐PEE (M1)–IBEE (M2) system, indicative of the reactivity order: cis‐PEE > trans‐PEE ≫ IBEE. In separate experiments, these β‐methyl‐substituted vinyl ethers were allowed to react with various acetals in the presence of boron trifluoride etherate. The relative reactivities of these ethers were generally found to decrease in the order: cis‐β‐monomethylvinyl > vinyl > trans‐β‐monomethylvinyl > β,β‐dimethylvinyl. Comparisons of these results with previously published copolymerization data have permitted the conclusion that, in both the copolymerizations and acetal additions, the single β‐methyl substitution on vinyl ethers exerts little steric effect against their additions toward any alkoxycarbonium ion, whereas the β,β‐dimethyl substitution results in a large adverse steric effect toward both β‐monomethyl‐ and β,β‐dimethyl‐substituted alkoxycarbonium ions.
Thermal degradation of poly(methyl α‐phenylacrylate)
Authors: Cameron G. G. , Kerr G. P.
Published: April 2003

Volatile products, molecular weight changes, and rates of volatilization have been examined during the thermal decomposition of poly(methyl α‐phenylacrylate) in vacuum at 210–280°C. In the early stages of the decomposition, initiation occurs at random within the polymer backbone to give radicals which unzip exclusively to monomer, with a kinetic chain length of about 500. Later in the reaction, chain‐end initiation becomes important and predominates beyond about 45% conversion. There is no evidence that transfer reactions occur during the degradation.
Kinetics of anionic polymerization of α‐methylstyrene in tetrahydrofuran
Authors: Hui K. M. , Ng T. L.
Published: April 2003

The kinetics of anionic polymerization of α‐methylstyrene have been studied in tetrahydrofuran at −30 to 10°C with Na+ and K+ as cations. In the Na+ system, a negative activation energy of −2 kcal/mole was observed in the temperature range −10 to +10°C. The results were analyzed in terms of propagation by both contact and solvent‐separated ion‐pairs. The relative proportions of the two types of ion‐pair were estimated by making use of our data and those of Dainton et al. for the same system at −60 to −30°C. The rate constants of solvent‐separated ion‐pairs, ks, were estimated as 4.2 and 0.64 1./mole‐sec at −31°C and −59°C, respectively. The discrepancy between our values of ks and Dainton's was discussed. It is concluded that poly‐α‐methyl‐styryl sodium has a higher tendency than polystyryl sodium to form solvent‐separated ion pairs. In the K+ system, our data at −30 to 10°C and those of Dainton et al. at −60 to −40°C fit well into a straight line in the same Arrhenius plot from which an activation energy of 5.2 kcal/mole and log A = 3.4 (1./mole‐sec) were obtained.
Monomer‐isomerization polymerization. V. Effects of transition metal compounds on monomer‐isomerization polymerizations of butene‐2 and pentene‐2
Authors: Otsu Takayuki , Shimizu Akihiko , Imoto Minoru
Published: April 2003

In order to clarify the correlation between polymerization and monomer isomerization in the monomer‐isomerization polymerization of β‐olefins, the effects of some transition metal compounds which have been known to catalyze olefin isomerizations on the polymerizations of butene‐2 and pentene‐2 with Al(C2H5)3–TiCl3 or Al(C2H5)3–VCl3 catalyst have been investigated. It was found that some transition metal compounds such as acetylacetonates of Fe(III), Co(II), and Cr(III) or nickel dimethylglyoxime remarkably accelerate these polymerizations with Al(C2H5)3–TiCl3 catalyst at 80°C. All the polymers from butene‐2 were high molecular weight polybutene‐1. With Al(C2H5)3–VCl3 catalyst, which polymerizes α‐olefins but does not catalyze polymerization of β‐olefins, no monomer‐isomerization polymerizations of butene‐2 and pentene‐2 were observed. When Fe(III) acetylacetonate was added to this catalyst system, however, polymerization occurred. These results strongly indicate that two independent active centers for the olefin isomerization and the polymerizations of α‐olefins were necessary for the monomer‐isomerization polymerizations of β‐olefins.
Radiation‐induced solid‐state polymerization of methacrylic acid. I. Crystalline transition of the monomer
Authors: Sakai Yoshiro , Iwasaki Machio
Published: April 2003

The anomalous crystalline transition of methacrylic acid found by broad‐line NMR measurements was studied in connection with the build‐up and decay of trapped radicals. The build‐up of radicals is smaller and the decay rate of the trapped radicals is faster in the low‐temperature range (phase II), which gave the narrower maximum slope distance ΔHmsl of the NMR spectrum, than those in the higher temperature range (phase I), which gave the broader ΔHmsl. From these experiments it was concluded that in phase I the crystals have a more closely packed structure, resulting in a more rigid matrix for the trapped radicals than those in phase II. This interpretation is consistent with the temperature dependence of the ESR spectrum of the trapped propagating radicals previously reported. The existence of the crystalline transition was also confirmed by DSC measurements, and the effects of the crystallization conditions on the transition were investigated and were discussed with reference to the results of broad line NMR measurements.
Thermal decomposition products of poly(vinyl alcohol)
Authors: Tsuchiya Yoshio , Sumi Kikuo
Published: April 2003

The thermal decomposition of poly(vinyl alcohol) is known to occur in two stages. In a study of first‐stage decomposition, this polymer was pyrolyzed in vacuum at 240°C for 4 hr and the products were determined by using gas chromatography. The main products were water, aldehydes having the general formula and methyl ketones having the formula , where n = 0, 1, 2, 3, etc. Mechanisms for the formation of these carbonyl compounds are discussed.
Radiation‐induced solid‐state polymerization of methacrylic acid. II. In‐source polymerization
Authors: Sakai Yoshiro
Published: April 2003

The in‐source polymerization of methacrylic acid in the solid state with γ‐rays was studied. The conversion rates at various temperatures were obtained as well as the radical concentrations by the measurements of ESR spectrum. The rate of polymerization was found to be proportional to I0.65 at 0°C. The results could be interpreted on the basis of the assumption that the rate of propagation is proportional to the concentration of the propagating radical, of the monomer, and of the polymer. The addition of water to the monomer seems to accelerate the polymerization reaction. The change of the line shape of the propagating radical during polymerization was interpreted in terms of the change of the matrix which surrounds the propagating radical.
Radiation‐induced solid‐state polymerization of methacrylic acid. III. Post‐polymerization
Authors: Sakai Yoshiro
Published: April 2003

The post‐polymerization of methacrylic acid in the solid state was studied. The decay of the trapped radicals was also observed by ESR measurements. The decay of trapped radicals is a first‐order reaction below 0°C but a second‐order reaction at + 10°C. The results of the post‐polymerization were compared with the results of radical decay measurements. A kinetic scheme was proposed for the post‐polymerization of methacrylic acid. The effect of conditions of monomer crystallization on the polymer yield was also investigated. Fine crystals gave a greater limiting conversion than large crystals. The addition of water to the monomer increased the polymer yield. The change in the ESR spectrum during post‐polymerization was interpreted in terms of the change in the matrix which surrounds the propagating radicals.
Reaction of poly(vinyl chloride) with magnesium and grignard reagents
Authors: Minoura Yuji , Hironaka Hisashi , Kasabo Toshiyuki , Ueno Yukio
Published: April 2003

Reaction of poly(vinyl chloride) with magnesium under various conditions was attempted, but poly(vinyl chloride) did not react with magnesium. The reactions of poly(vinyl chloride) with benzylmagnesium chloride and allylmagnesium chloride as Grignard reagents were carried out in tetrahydrofuran at reflux temperature. It was found that the chlorine atoms in the poly(vinyl chloride) were replaced by benzyl and allyl groups by the coupling reaction, and a small amount of Grignard reagent of poly(vinyl chloride) was formed by the magnesium–halogen exchange reaction. The extent of the substitution increased with increasing reaction time and concentration of the Grignard reagent.
Metal‐containing initiator systems. V. Radical and cationic polymerizations with initiator systems of reduced nickel and chlorosilanes
Authors: Otsu Takayuki , Aoki Shuzo , Nishimura Masato , Yamaguchi Masami , Kusuki Yoshihiro
Published: April 2003

The polymerizations of methyl methacrylate, styrene, and isobutyl vinyl ether with the binary systems of reduced nickel and chlorosilanes [(CH3)nSiCl4−n, n = 0–3] have been investigated. It was found that these systems could act as both radical and cationic initiators, depending on the nature of vinyl monomers used. The kinetic investigations indicated that methyl methacrylate polymerized via a radical mechanism, and the initiating activity of chlorosilanes decreased in the following order: SiCl4 > CH3SiCl3 > (CH3)2SiCl2 > (CH3)3SiCl ≃ 0. Cationic initiations were observed in the polymerizations of styrene and isobutyl vinyl ether. In the latter case, the activity of chlorosilanes was in the following order: (CH3)3SiCl > (CH3)2SiCl2 > CH3SiCl3 ≃ SiCl4. From the results obtained, a possible mechanism of selective initiation with these systems is proposed and discussed.
Heterogeneous copolymerization of acrylamide with maleic acid in dioxane
Authors: Myagchenkov V. A. , Kurenkov V. F.
Published: April 2003

Heterogeneous copolymerization of acrylamide with maleic acid has been investigated. The process was carried out at 70°C in 1,4‐dioxane. The polarographic method of analysis was applied. The analysis of the experimental and theoretical composition distribution curves has shown an anomalously large composition polydispersion for the experimental distribution curves. This is attributed to the heterogeneity of the copolymerization process.
Copolymerization of trialkylvinylgermane
Authors: Minoura Yuji , Sakanaka Yasuhiro
Published: April 2003

The polymerization of trimethylvinylgermane (TMGeV) with the use of γ‐ray, radical, and ionic initiator was attempted, but homopolymer was not obtained. This monomer did not undergo polymerization by itself, but polymerized with high concentration of n‐BuLi. Copolymerization of TMGeV with styrene (St) and methyl methacrylate (MMA) was carried out by using radical initiator. From the results obtained by the copolymerization, monomer reactivity ratios and Q–e values were obtained as follows: for the system St(M1)–TMGeV (M2), r1 = 24.4, r2 = 0.009, Q2, = 0.0049, e2 = 0.43; for the system MMA (M1)–TMGeV (M2), r1 = 19.98, r2 = 0.05; Q2 = 0.037, e2 = 0.43., The polymerizability of TMGeV is discussed on the basis of the Q and e values obtained.
Decomposition of peroxycarbamates and their initiation of vinyl polymerization
Authors: Baines F. C. , Grezlak J. H. , Tobolsky A. V.
Published: April 2003

A review is given of the synthesis, physical properties, and decomposition kinetics of organic peroxycarbamates. The activity of these compounds in initiating free‐radical vinyl polymerization is discussed. The decomposition of hexamethylene N,N′‐bis‐(α‐cumyl peroxycarbamate) has been measured in different solvents between 65 and 95°C and found to be a first‐order reaction governed by the specific rate constant kd = 2.21 × 1016 exp {−34 100/RT}. The initiator exhibits normal free‐radical polymerization kinetics and in polymerization of styrene at 80°C shows an initiating efficiency of 0.53. Cobalt naphthenate can act as both accelerator and retarder of styrene polymerization, depending upon its concentration and the temperature of the polymerization.
Vapor‐phase graft copolymerization of vinyl chloride and vinylidene chloride onto polypropylene fibers by simultaneous irradiation technique
Authors: Kawase Kaoru , Hayakawa Kiyoshi
Published: April 2003

The vapor‐phase graft copolymerization of vinyl chloride and vinylidene chloride onto polypropylene fibers was studied by a simultaneous γ‐irradiation technique. The weight increase during irradiation due to the grafting in monomers at constant vapor pressure was measured by a sensitive spring balance. The sorption of both monomers onto unirradiated polypropylene fibers was also measured. The graft copolymerization reaction was suppressed with increasing irradiation temperature, and the overall activation energies of grafting were negative in both monomers, −2.4 kcal/mole for vinyl chloride and −6.3 kcal/mole for vinylidene chloride. The initial rate of grafting increased linearly with the vapor pressure of monomers. The above dependence was found to parallel the sorption of monomers on polypropylene fibers. The reaction rates were proportional to the 0.9 power of the dose rate in both monomers. The relationship between the grafting and the sorption of monomers was discussed on the basis of kinetics.
Photodecomposition of polymethylsiloxane
Authors: Delman Alvin D. , Landy Milton , Simms Bernard B.
Published: April 2003

Infrared spectroscopy studies were undertaken to determine the effects of ultraviolet light radiation on a methylsiloxane resin. The results indicate that SiCH2Si linkages were formed as a result of irradiation at wavelengths above 281 mμ from a xenon are lamp; on the other hand, SiOH and SiCH2CH2Si linkages were formed instead when the resin was exposed to the lower wavelengths emitted from a mercury vapor lamp. The different effects on the resin induced by the two ultraviolet light sources are attributed to the fact that only the energies from the mercury vapor lamp radiation are sufficient to cause the excitation of oxygen molecules in the air surrounding the irradiated polymer. The excited oxygen molecules prevented the formation of SiCH2Si structures by interacting with active %tbond;Si units that were formed as a result of SiC bond rupture to produce SiOH; SiCH2CH2Si linkages were formed as the result of a secondary reaction.
Phenylated polyquinoxalines from bis(phenylglyoxaloyl)benzene
Authors: Wrasidlo W. , Augl J. M.
Published: April 2003

Phenyl‐substituted polyquinoxalines of unusually high oxidative‐thermal stability were prepared by one‐step solution condensations of aromatic tetraamines with 1,4‐bis‐(phenylglyoxaloyl)benzene and 1,3‐bis(phenylglyoxaloyl)benzene. The final polymers thus obtained show exceptionally good solubility in a variety of common organic solvents, such as chloroform, tetrachloroethane, dichlorobenzenes, and certain phenols. Polymerizations in these solvents lead to polyquinoxalines of high molecular weight at reaction rates which depend upon the solvent used. The phenylated polyquinoxalines exhibited glass transition temperatures between 253 and 317°C and polymer decomposition temperatures between 515 and 540°C, depending upon structure. Isothermal decomposition at 400°C in air showed a strong dependency of weight loss on structure. Tough, flexible films were cast from solutions.
Morphology of polyethylene crystals as polymerized by γ‐radiation
Authors: Toyota Nobuhiro , Machi Sueo
Published: April 2003

The morphology of polyethylenes formed upon polymerization by γ‐radiation below the melting point in various reaction media was investigated by using electron microscopy and scanning electron microscopy. When the polymerization was carried out in bulk at 30°C and in methanol, the polymer was fibrillar, and a small‐angle x‐ray scattering curve of the polymer did not indicate the existence of a long period. This suggests that the chains in the crystals have an extended conformation. When the polymerization was carried out in the presence of xylene at 30°C, platelet crystals having a folded structure were obtained. It was thus shown that the morphology of the growing polymer crystals is very much affected by the solubility of the polymer in the reaction medium. The effect of stirring during polymerization on the crystalline morphology was also studied.
Cyclic stress–strain behavior of the dry polycarbonate craze
Authors: Kambour R. P. , Kopp R. W.
Published: April 2003

Equipment and methods have been developed which allow photomicrographic determination of the stress–strain properties of the individual craze. Serial cyclic tensile tests on polycarbonate crazes are described. Under stress the typical dry polycarbonate craze thickens solely by straining; no adjacent polymer of normal density is converted to craze material. The craze exhibits a yield stress followed by a recoverable flow to roughly 40–50% strain at 6000–8000 psi. On return to zero stress the craze exhibits creep recovery at a decelerating rate. The yield stress and loss factor of each cycle decrease with increasing initial strain and cycles initiating at 50% strain or more show completely Hookean behavior. Creep recovery results in recovery of yield stress and loss factor also. Craze tensile behavior is suggested to be essentially an extension of the craze formation process. Decrease in elastic modulus and yield stress with increasing strain are rationalized in terms of strain‐produced decrease in density and resultant increase in stress concentration factor on the microscopic polymer elements of the craze. Polymer surface tension and the large internal specific surface area of the craze are suggested to be important factors in the large creep recovery rates of the craze.
Grüneisen constant and thermal properties of crystalline and glassy polymers
Authors: Wada Yasaku , Itani Akira , Nishi Toshio , Nagai Satoshi
Published: April 2003

Polymer crystals are characterized by strong anisotropy of binding forces among units, i.e., the intrachain force constant f is much larger than the interchain force constant g. The anisotropic lattice is reduced to an isotropic one, in which each lattice point represents N* units (segment) along the chain axis of the anisotropic lattice [N = 2(f/g)1/2]. Vibrational modes of the reduced lattice correspond to interchain modes of the original lattice, i.e., modes whose frequencies are governed by interchain potential. Anharmonicity of crystalline force field is assumed to be related predominantly with interchain force alone. Thermodynamic and transport equations for a simple lattice are applied to the reduced, isotropic lattice, and numerical results are obtained for high‐density polyethylene. The Grüneisen constant γ was obtained from the pressure dependence of sound velocity. The heat capacity of the reduced lattice, Cinter (interchain specific heat), was calculated from Grüneisen's equation, α = γβCinter (where α = thermal expansion coefficient, β = compressibility), and the mass of a segment m* was estimated from Dulong‐Petit's equation, Cinter = 3ρk/m* (where ρ = density, k = Boltzmann constant). The value of m* is consistent with N* from force constants, m* = N*m (where m = mass of a unit in the original lattice). m*θ3 (where θ denotes the Debye temperature of the reduced lattice) is calculated from low temperature specific heat. The value of m* calculated from m*θ3 and θ from other sources agrees with that from the estimate by Dulong‐Petit's equation. The high‐temperature thermal conductivity K was calculated through Leibfried‐Schloemann's equation by employing γ and m*θ3 as estimated as described above; satisfactory agreement was obtained with experiment. Poly(methyl methacrylate) and polystyrene were also studied by similar methods.
Intrinsic viscosities of polymers in mixed solvents
Authors: Dondos A. , Patterson D.
Published: April 2003

The intrinsic viscosity of a polymer in a solvent mixture is related to the excess free energy of the solvents. Intrinsic viscosities at different temperatures are obtained for poly‐2‐vinylpyridine–chloroform–ethyl alcohol, poly(methyl methacrylate)–chloroform–ethyl alcohol, polystyrene–cyclohexane–benzene, polystyrene–dioxane–chloroform, and polystyrene–cyclohexane–ethanol. Qualitative, but not quantitative, agreement is found between theory and experiment.
Compressibility of polymers
Authors: Haward R. N.
Published: April 2003

The compressibility of polyisobutylene and polystyrene above their glass transition temperature is treated as the sum of two parts; a free‐volume compressibility and, as originally suggested by Bridgman, a compressibility of the molecules themselves. Two different models are used to treat the free‐volume compressibility, and as a result values for the molecular compressibility are estimated. These are in reasonable agreement with other values in the literature. The magnitude of this “molecular compressibility” is then considered in relation to some existing treatments of intermolecular forces. These suggest that intermolecular contacts are more compressible than covalent bonds, and on this basis the observed levels of molecular compressibility can be explained.
Effect of birefringence on low‐angle light‐scattering patterns from oriented polymer films
Authors: Stein R. S. , Erhardt P. F. , Chu W.
Published: April 2003

The effect of birefringence of a polymer film upon its photographic light‐scattering pattern is considered for the case of a single, anisotropic, two‐dimensional spherulite imbedded in a birefringent matrix. It is shown that for the case of a polarizer and analyzer crossed at +45° and −45° to the analyzer, the scattering pattern is modified in a manner agreeing with experimental observation.
Effect of birefringence on the scattering of light
Authors: Legrand D. G.
Published: April 2003

The effect of birefringence on light scattering is considered, using classical theory. It is shown that in conjunction with polarized light scattering, the use of birefringence can aid in the reduction of experimental errors; also how new checks on theory can be made. The treatment is applied to scattering from simple gaseous molecules and thin polymeric films.
Influence of superimposed steady shear flow on the dynamic properties of polyethylene melts
Authors: Kataoka Tadao , Ueda Shigeyuki
Published: April 2003

Experiments in which an oscillatory shear flow is superimposed on a steady state shear flow were performed on polyethylene melts by the use of a cone and plate type rheogoniometer. The phase difference between oscillatory shear stress and shear strain increases in all cases and for all frequencies with the increase of the superimposed shear rate. Between ω0, the frequency at which the phase difference is π/2 and the steady shear rate \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma $\end{document}, as found by Booij for polymer solution, the relation ω0 = 1/2 \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma$\end{document}. holds also for polyethylene melts. The significance of this relation is discussed briefly from the viewpoint that the entanglement density decreases with the increase of the imposed shear rate.
Effects of orientation on dynamic shear behavior of some amorphous polymers from 4.2° to 300°K
Authors: Frosini V. , Woodward A. E.
Published: April 2003

The dynamic shear behavior of four highly amorphous polymers in the unstretched and stretched states (draw ratios 3:1 to 6:1) was investigated with a torsion pendulum at temperatures from 4.2°K to 180–300°K and frequencies from 0.4 to 3.2 cps. The polymers studied were polystyrene, poly(vinyl acetate), poly(vinyl propionate), and poly(isobutyl vinyl ether). Previously unreported loss maxima were found at 48°K (1.5 cps) and 149°K (1.3 cps) for poly(vinyl proplonate), at 10°K (1.0 cps) for poly(vinyl acetate) and at 9°K (1.6 cps) for poly(isobutyl vinyl ether). Uniaxial orientation increased the shear storage modulus G, measured with the torsion axis parallel to the stretch direction and caused changes in the loss peaks which depended on the polymer material studied.
Small‐angle x‐ray scattering from poly(tetramethyl‐p‐silphenylene) siloxane (TMPS) fractions
Authors: Pollack S. S. , Magill J. H.
Published: April 2003

Small‐angle x‐ray scattering studies were made on bulk‐crystallized samples and annealed oriented films of TMPS. The temperature dependence of the small‐angle scattering was determined over a range of annealing conditions. The effect of sample molecular weight on the small‐angle peaks was also studied. The peak intensity, measured at room temperature after annealing, was strongly dependent on the annealing conditions. The position of the peak gradually moved to smaller angles (largerdspacings) as the annealing temperature was raised. Surface free energies were deduced from the melting point dependence of the crystallite size. This surface energy was found to increase with molecular weight in accord with values deduced for spherulite growth rate‐temperature dependence.
Unperturbed dimensions of poly(ethylene oxide)
Authors: Beech D. R. , Booth C.
Published: April 2003

The intrinsic viscosities of fractions of poly(ethylene oxide) in the molecular weight range 1.5 × 103 to 106 have been measured at 25°C in benzene, carbon tetrachloride, and acetone; at 35°C in 0.45M aqueous potassium sulfate; and at 50°C in methyl isobutyl ketone and diethylene glycol diethyl ether. The latter three are practically theta solvents. The value of (r02/M)1/2 for poly(ethylene oxide) is calculated to be 0.84 Å from the molecular weights of the high molecular weight fractions, and their intrinsic viscosities in the theta solvents and acetone. Erroneous values result if the usual methods of determination are applied to the data obtained for the low molecular weight (<104) fractions or to the intrinsic viscosities in the very good solvents, benzene and carbon tetrachloride.
Glass transition temperatures of several fluorine‐containing polymers
Authors: Brown Daniel W. , Wall Leo A.
Published: April 2003

The glass transition temperatures Tg of several fluorine‐containing polymers were determined by use of the differential scanning calorimeter. Values between −3 and 230°C were obtained. In polymers of α‐olefins, Tg increases with the fluorine content of the backbone and the length of the n‐perfluoroalkyl branch. In styrene polymers Tg also is higher if the backbone contains fluorine but nearly the same Tg's are found for polymers with phenyl and pentafluorophenyl groups. Saturated polymers of perfluoro‐α,ω‐dienes have lower Tg's than polyperfluoro‐α‐olefins. The Tg's of chloroperfluoropolymers are higher than those of perfluoropolymers. Polyperfluoropentadiene‐1,3 has the lowest Tg of the polymers examined. Polyperfluoropentadiene‐1,3 forms by 1,4‐addition.
Styrene‐methyl acrylate copolymers and acrylate homopolymers in solution
Authors: Matsuda H. , Yamano K. , Inagaki H.
Published: April 2003

Molecular weight determinations by light scattering and osmometry and intrinsic viscosity measurements were made in various solvents on fractions of styrene–methyl acrylate copolymers with different compositions and on acrylate homopolymers prepared by free‐radical reaction. Relations between intrinsic viscosity [η] and molecular weight M thus established are compared with those reported by other authors. 2‐Methylcyclohexanol was found to be a theta solvent for the copolymers and both parent homopolymers, and isoamyl acetate was a theta solvent for poly(methyl acrylate). From theta point viscosity data obtained with these solvents, unperturbed chain dimensions were estimated. The results are compared with the unperturbed dimensions estimated from the [η]–M relations obtained in good solvents. On the basis of the experimental data it was found that the unperturbed dimension depends linearly on the copolymer composition, in contrast to the case of styrene–methyl methacrylate copolymers. Composition dependences of the theta temperature and of the parameter describing the long‐range interactions between nonadjacent segments in polymer chains were investigated. The result implies that long‐range interactions between monomeric units never disappear even when those between the same monomeric units vanish. The Huggins constant for copolymer is discussed in terms of the excluded volume variable.
Effect of finite extensibility on the viscoelastic properties of a styrene–butadiene rubber vulcanizate in simple tensile deformations up to rupture
Authors: Smith Thor L. , Dickie Ray A.
Published: April 2003

Stress–strain and rupture data were determined on an unfilled styrene–butadiene vulcanizate at temperatures from −45 to 35°C and at extension rates from 0.0096 to 9.6 min−1. The data were represented by four functions: (1) the well‐known temperature function (shift factor) aT; (2) the constant strain rate modulus, F(t,T), reduced to temperature T0 and time t/aT, i.e., T0F(t/aT)/T; (3) the time‐dependent maximum extensibility, λm(t/aT); and (4) a function Ω(χ) where χ = (λ − 1)λm0/λm, in which λ is the extension ratio and λm0 is the maximum extensibility under equilibrium conditions. The constant strain rate modulus characterizes the stress–time response to a constant extension rate at small strains, within the range of linear response; λm is a material parameter needed to represent the response at large λ; and Ω(χ) represents the stress–strain curve of the material in a reference state of unit modulus and λm = λm. The shift factor aT was found to be sensibly independent of extension. At all values of t/aT for which the maximum extensibility is time‐independent, the relaxation rate was also found to be independent of λ. These observations indicate that the monomeric friction coefficient is strain‐independent over the ranges of T and λ covered in the present study. It was found that λm0 = 8.6 and that the largest extension ratio at break, (λb)max, is 7.3. Thus, rupture always occurs before the network is fully extended.
Lactone polymers. I. Glass transition temperature of poly‐ε‐caprolactone by means on compatible polymer mixtures
Authors: Koleske J. V. , Lundberg R. D.
Published: April 2003

Dynamic mechanical properties determined with a torsion pendulum were used to ascertain the glass transition temperature Tg of poly‐ε‐caprolactone. By measurements on compatible blends of poly‐ε‐caprolactone and poly(vinyl chloride), the Tg of amorphous poly‐ε‐caprolactone was shown to be 202°K at about 1 cps. This is 16°K lower than the Tg of annealed, crystalline polymer. The blend transition data were well fitted by both the Fox and the Gordon‐Taylor expressions. The Fox expression was also used to describe the decrease from 233°K of the secondary low‐temperature relaxation due to poly(vinyl chloride) by assuming the low temperature relaxation of poly‐ε‐caprolactone, 138°K, was responsible for the decrease in the blends. The 138°K relaxation due to poly‐ε‐caprolactone was decreased when more than 50% poly(vinyl chloride) was present.