bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymerization of styrene with the VOCL3–AlEt2Br catalyst system
Authors: Anand L. C. , Deshpande A. B. , Kapur S. L.
Published: April 2003

The rate of polymerization with the VOCl3–AlEt2Br catalyst system at 30°C. in n‐hexane reached a maximum at an Al/V molar ratio of 1.5. At this ratio, the rate of polymerization was first‐order with respect to catalyst and second‐order with respect to monomer concentrations. The apparent activation energy calculated was 6.4 kcal./mole. Diethylzine was found to act as a chain transfer agent. However, the molecular weights of polymers obtained were low. The possibility of bromide‐containing catalyst sites acting in the termination reaction has been investigated. The average valence of vanadium is discussed in relation to molecular weights.
Polymerization of itaconic acid derivatives
Authors: Ishida Shin'ichi , Saito Shizuko
Published: April 2003

The γ‐ray‐initiated polymerization of dimethyl itaconate was studied. Dimethyl itaconate was polymerized by γ‐irradiation at temperatures where the monomer does not polymerize thermally; so long as the monomer is kept in a liquid state, even at temperatures below the melting point, the polymerization takes place. Itaconic anhydride was polymerized in the solid state with γ‐irradiation or benzoyl peroxide. The molecular weight of the polymer increases with time or yield and is greater than that of polymer obtained by other methods. The kinetic study and crystallographic study indicate that the γ‐ray‐initiated solid‐phase polymerization is a first‐order reaction with respect to monomer and the rate‐determining step changes as the polymerization proceeds.
Identification of volatile products produced during the peroxide vulcanization of poly(vinyl alkyl ethers)
Authors: Lal Joginder , McGrath James E.
Published: April 2003

Volatile products are produced during vulcanization of the polymers of vinyl methyl, ethyl, isopropyl and n‐butyl ethers with dicumyl peroxide, both in the presence and, absence of added sulfur. They were identified and estimated by gas‐liquid chroma tography and mass spectrometry. The principal products formed during the vulcanization of poly(viny1 ethyl ether) with dicumyl peroxide were ethane and acetaldehyde and to a lesser extent methane. The addition of sulfur in the curing recipe resulted in a sharp increase in the proportion of ethyl alcohol, a large increase in methane, and a large decrease in ethane. The formation of these volatile products and the observed changes due to the presence of sulfur in the curing recipe can be accounted for on the basis of side‐chain scission of the polymer radicals produced during vulcanization. The length and/or shape of the alkyl group in poly(viny1 alkyl ether) determine the composition of the volatile products. The data are in harmony with the postulated chemistry of vulcanization of these polymers.
Effect of temperature and polymer type on gel permeation chromatography
Authors: Cantow Manfred J. R. , Porter Roger S. , Johnson Julian F.
Published: April 2003

A series of polyisobutene and polystyrene fractions was subjected to gel‐permeation chromatography at 150°C. The two types resulted in distinctly different calibration curves in a plot of projected, extended chain length versus elution volume. The average end‐to‐end distances of the samples were determined by intrinsic viscosity measurements. It was found that these data plotted versus elution volume could be represented by a common curve for both polymer types. The elution volumes of the polyisobutene series were determined at three additional temperatures, 35, 70, and 110°C. It could be shown that elution volume is again determined by polymer coil size at the temperature of measurement.
Electron‐transfer polymers. XXVIII. Synthesis of vinyl hydroquinone derivatives by means of the wittig reaction
Authors: Hashimoto Mutsuko , Uno Keikichi , Cassidy Harold G.
Published: April 2003

The Wittig reaction has been applied to unsubstituted, monomethyl‐, 3,6‐dimethyl‐, and trimethyl‐2,5‐dimethoxybenzyl chlorides to produce in quantitative to good yields the corresponding vinyl monomers, unsubstituted, monomethyl‐, 3,6‐dimethyl‐, and trimethyl‐2,5‐dimethoxystyrenes. The reaction is applicable also to 2,5‐dimethoxy‐4‐methylbenzaldehyde, and to O,O′‐bis‐(methoxymethyl)resorcinol‐4‐aldehyde to yield the corresponding vinyl monomers. The reaction is particularly suitable with all these compounds because it is run at room temperature or below and gives good to quantitative yields.
Studies of the micro‐brownian motion of a polymer chain by the fluorescence polarization method. III. Fluorescent conjugates of polyethyleneimine
Authors: Teramoto Akio , Morimoto Masayoshi , Nishijima Yasunori
Published: April 2003

Fluorescent conjugates of polyethyleneimine (PEI) were prepared by conjugation of fluorescent dyes, fluorescein isocyanate (FIC), and 1‐dimethylaminonaphthalene‐5‐sulfonyl chloride (DNS), to PEI. The degree of polarization of the fluorescence was measured as a function of temperature and solvent viscosity on aqueous solutions of the conjugates and the data thus obtained were analyzed in terms of an equation of the Perrin type to calculate the mean relaxation time of the conjugate. The mean relaxation times obtained for the two types of the conjugates, which differ in the excited lifetime by a factor of about three, practically agree with one another and are about 2.5 X 10−8 sec. The relaxation time of the DNS conjugate increases with increasing molecular weight of the conjugate from 2 X 10−8 to 4 X 10−8 sec. These values are much larger than those of the PAA conjugates reported in Part I of this series. The relaxation time of this order may correspond to that for the cooperative rotary motion of about ten monomeric residues on the PEI chain, that is, for the motion of an intermediate segment of the PEI molecule in solution. Finally, relaxation time–molecular weight relationships for various types of fluorescent conjugates are compared. It is suggested that these data may serve as a basis for elucidating the mode of motion of a given molecule in solution from the polarization data.
Studies on tacticity of polyacrylonitrile. I. High‐resolution nuclear magnetic resonance spectra of polyacrylonitrile
Authors: Yamadera Reizo , Murano Masao
Published: April 2003

The nuclear magnetic resonance spectra of polyacrylonitriles prepared under various polymerization conditions were measured in NaCNS–D2O solution. The methylenic proton resonance could be separated into two triplets: one is due to the protons of the syndiotactic methylene groups and the other is due to the isotactic ones. The tacticity of polyacrylonitrile could be determined by the ratio of the integrated intensities of the two triplets. Polyacrylonitriles prepared with radical catalysts are approximately 75% syndiotactic, and polyacrylonitriles prepared by the anionic polymerization at low temperature, γ‐irradiation in the solid state, Mg molecular beam, and γ‐irradiation on the urea canal complex are more isotactic but have no remarkable stereoregularity.
Effects of metal salts on polymerization. Part III. Radical polymerizabilities and infrared spectra of vinylpyridines complexed with zinc and cadmium salts
Authors: Tazuke Shigeo , Okamura Seizo
Published: April 2003

Radical polymerization of 4‐vinylpyridine (4‐VP), 2‐vinylpyridine (2‐VP), and 2‐methyl‐5‐vinylpyridine (MVP) was studied in concentrated DMF solutions of ZnCl2, ZnBr2, ZnI2, Zn(CH3COO)2, and Cd(CH2COO)2 at 50°C. Polymerization of 4‐VP and MVP was accelerated by the addition of the metal salts, while the polymerization of 2‐VP was greatly retarded. The sequence of the accelerating effect of metal salts for 4‐VP was in the following order: Cd(CH3COO)2 > ZnCl2 > Zn(CH3COO)2 > ZnBr2 > ZnI2. This sequence is almost the same as that reported in a previous report for MVP. However, the order was reversed for the retarding effect on the polymerization of 2‐VP. At the intermediate concentration of metal salts, polymerization of 4‐VP proceeded heterogeneously, which was explained by considering crosslinking of poly‐4‐VP by the metal ion. Since a linear correlation between the rate Rp and the degree of polymerization was observed for the 4‐VP–Zn(CH3COO)2 system, the accelerating effect was postulated to be due to the enhancement in kp. Results of copolymerization of VP with styrene as M2 in a concentrated solution of Zn(CH3COO)2 indicated the strong activation of 4‐VP by complex formation (r1 = 2.7 ± 0.5, r2 = 0.08 ± 0.03), whereas the change in the monomer reactivity of MVP is smaller (r1 = 2.0 ± 0.2, r2 = 0.35 ± 0.05). The behavior of 2‐VP was abnormal (r1 = 3.35 ± 0.3, r2 = 0.55 ± 0.15, then r1r2 > 1), which was attributed to the steric effect by complex formation. Solid complexes formed between pyridine, 4‐VP, 2‐VP, or MVP and zinc salts were prepared as samples for infrared spectroscopy. The shifts in infrared absorption bands of these amines were studied by comparing the infrared spectra of the amines before and after the complex formation, and the results were interpreted in terms of electronic as well as steric interactions of metal salts with ligands. Conjugation of the metal salt with the ligand π‐orbitals was necessary to explain both infrared spectra and polymerization results.
Applications of limiting conversion free‐radical polymerizations. II. Azobisisobutyronitrile‐initiated polymerization of methyl methacrylate in benzene
Authors: Indictor N. , Mogolesko P. , Jaffe H.
Published: April 2003

Data for the azobisisobutyronitrile‐initiated polymerization of methyl methacrylate in dilute benzene solution is presented at 80, 100, and 126°C. in terms of Tobolsky's limiting conversion kinetics. Number‐average molecular weights were obtained viscometrically. Attempts to evaluate the relative amounts of combination and disproportionation in the chain‐terminating reaction were foiled by the discovery that under the conditions reported the initiator efficiency is temperature‐dependent decreasing markedly with increasing temperature.
Homopolymerization of ethylene and copolymerization with 1‐butene in the presence of bis(cyclopentadienyl)titanium dichloride and diisobutylaluminum chloride
Authors: Rubin I. D.
Published: April 2003

Ethylene was homopolymerized and copolymerized with 1‐butene in benzene at 30°C. with the use of bis(cyclopentadienyl)titanium dichloride and diisobutylaluminum chloride as catalyst. Both freshly prepared catalyst and catalyst which had been aged up to 114 hr. were used. When the catalyst was aged prior to adding the monomer, the yields were lower and the products had higher molecular weights. In the case of copolymers, aging of the catalyst also affected the relative concentrations of the comonomers in the products. 1‐Butene was an effective chain transfer agent under all reaction conditions. The data were found to be consistent with the previously suggested mechanism according to which different species initiate polymerizations with freshly mixed and aged catalysts.
Stereoregularity of poly(vinyl ether)
Authors: Matsuzaki Kei , Hamada Minoru , Arita Koichiro
Published: April 2003

α‐Methylvinyl isobutyl and methyl ethers were polymerized cationically and the structure of the polymers was studied by NMR. Poly(α‐methylvinyl methyl ether) polymerized with iodine or ferric chloride as catalyst was found to be almost atactic, whereas poly(α‐methylvinyl isobutyl ether) polymerized in toluene with BF3OEt2 or AlEt2Cl as catalyst was found to be isotactic. In both cases, the addition of polar solvent resulted in the increase of syndiotactic structure as is the case with polymerization of alkyl vinyl ether. tert‐Butyl vinyl ether was polymerized, and the polymer was converted into poly(vinyl acetate), the structure of which was studied by NMR. A nearly linear relationship between the optical density ratio D722/D736 in poly(tert‐butyl vinyl ether) and the isotacticity of the converted poly(vinyl acetate) was observed.
Reactivity ratios of styrene and methyl methacrylate at 90°C
Authors: Meyer Victor E.
Published: April 2003

From the conversion–composition data of Gruber and Elias, the reactivity ratios of styrene (M1) and methyl methacrylate (M2) were calculated to be r1 = 0.55 ± 0.02 and r2 = 0.58 ± 0.06 at 90°C. The least‐squares method was then used on these and literature values at other temperatures to obtain the Arrhenius expressions: In r1 = 0.04736 – (235.45/T), and ln r2 = 0.1183 – (285.36/T). Using literature values for the homopolymerization steps, A11 = 2.2 × 107l./mole‐sec., E11 = 7.8 kcal./mole, and A22 = 0.51 × 107 l./mole‐sec.−1, E22 = 6.3 kcal./mole, activation energies and frequency factors were then calculated for the cross‐polymerization steps: A12 = 2.1 × 107 l./mole‐sec., E12 = 7.3 kcal./mole, and A21 = 0.45 × 107 l./mole‐sec., E21 = 5.7 kcal./mole.
Kinetics and mechanism of acrylonitrile polymerization by p‐toluenesulfinic acid. II. Polymerization mechanism
Authors: Amdur S. , Shavit N.
Published: April 2003

The retardation of acrylonitrile (AN) polymerization by p‐toluenesulfinic acid (TSA) in the presence of relatively strong acids has been further investigated. Conductance measurements supported the hypothesis that an ionic complex, presumably RSO2H2+, is obtained by a reaction of the sulfinic acid with a proton. It is postulated that this complex is a chain transfer agent for the observed retardation. On the basis of this assumption, a kinetic scheme was developed involving additional termination steps by the complex. The scheme accounts for the maximum in initial rate observed on increasing the concentration of added sulfonic acid at a constant TSA concentration. It also provides an explanation for the elimination of the autoacceleration in the bulk polymerization of AN when strong acids are added. The orders derived from the kinetic equations are in good agreement with the orders evaluated from the kinetic experiments.
Kinetics and mechanism of acrylonitrile polymerization by p‐toluenesulfinic acid. III. Initiation through disproportionation
Authors: Amdur Shimon , Shavit Nehemia
Published: April 2003

A mechanism for radical formation from aromatic sulfinic acids through the disproportionation reaction is suggested. It is postulated that two parallel steps, one a bimolecular reaction and the other involving a trimer of sulfinic acid, yield sulfenyl sulfonate. This labile compound decomposes into free radicals or reacts with another molecule of sulfinic acid producing thiol sulfonate and sulfonic acid. This mechanism explains the variety and unusually high orders encountered in polymerization initiated by sulfinic acid initiators. The proposed kinetic scheme is in agreement with the proton dependence found for both the initiation as well as the disproportionation reactions.
Diffusion in ethylene–propylene rubber
Authors: Laurence R. L. , Slattery J. C.
Published: April 2003

A study of sorption in a copolymer of ethylene and propylene is presented. Long‐time sorption and desorption measurements provided the actual diffusion coefficient in the limit of zero concentration gradient. An analysis of the diffusion–sorption data reinforced the Frisch hypothesis about diffusion in a polymer matrix. The better solvent deforms the microstructure, allowing a more marked dependence of the diffusivity upon concentration.
Thermodynamics of polymerization. Part IV. Free energy changes of binary copolymerization systems
Authors: Sawada Hideo
Published: April 2003

Using a statistical thermodynamic method we discuss the general shape of a free energy change versus composition curve for a binary copolymerization system. This simple theoretical approach gives reasonable agreement with the experimental results.
Radiation‐induced bulk polymerization of maleimide
Authors: Kagiya Tsutomu , Izu Masatsugu , Kawai Shunzo , Fukui Kenichi
Published: April 2003

Radiation‐induced bulk polymerization of maleimide in both solid and liquid states was studied. Benzoquinone inhibited the liquid‐state polymerization and retarded solid‐state polymerization. The results of ESR study showed that solid monomer irradiated at 61°C. gave a spectrum, the concentration of which slowly decreased without changing the shape at 61°C. The radical detected at 61°C. was shown not to be the main propagating species. Overall rate polymerizations in the liquid and solid states were expressed, respectively, by first‐order and zero‐order rate equations with respect to the concentration of monomer. The overall rate constants in liquid and solid states were proportional to I0.9 and I1.0, respectively.
Environmental effects in free‐radical polymerizations. Part III. Vinyl chloride and n‐butyraldehyde
Authors: Burnett G. M. , Ross F. L. , Hay J. N.
Published: April 2003

The properties of poly(vinyl chloride) samples prepared by a free‐radical process in the presence of n‐butyraldehyde have been studied from the point of view of polymer tacticity, branching, molecular weight, and relative crystallinity. The postulate of a polymer radical–aldehyde complex, invoked to explain the increased crystallinity, was tested. The polymers had a lower degree of polymerization and branching than normal, and these parameters rather than increased syndiotacticity were responsible for the high degree of crystallinity. Both molecular weight and branching affect the crystallinity, since polymer samples prepared in the presence of various transfer agents with similar molecular weights were less crystalline than those prepared in aldehyde, but yet more crystalline than high molecular weight bulk polymer. Polymers prepared in aldehyde had a lower degree of branching than those formed in other transfer agents. It was concluded that aldehyde was effective in increasing the crystallinity of poly(vinyl chloride) in these two ways, and so appeared to be unique among the transfer agents. There was no evidence for assuming any complexing between polymer radicals and aldehyde.
Polymers of the vinyl esters of perchlorocyclopentadiene adducts of petroselinic and oleic acids
Authors: Liepins R. , Marvel C. S. , Lyon C. K.
Published: April 2003

Homopolymers of vinyl 5‐(1,4,5,6,7,7‐hexachloro‐3‐undecylbicyclo [2.2.1]5‐hepten‐2‐yl)‐pentanoate and vinyl 8‐(1,4,5,6,7,7‐hexachloro‐3‐octylbicyclo [2.2.1]5‐hepten‐2‐yl)‐octanoate were prepared, as well as their copolymers with a vinyl tetrahydroabietate—tetrahydropimarate mixture, vinyl 12‐hydroxystearate, and vinyl chloride. The vinyl octanoate—12‐hydroxystearate copolymer gave light‐weight urethane foams with practically no volume change upon humid aging. The vinyl pentanoate and vinyl octanoate monomers lose hydrogen chloride during polymerization. The vinyl pentanoate homopolymer was hydrolyzed in an attempt to establish the position of the loss of hydrogen chloride. Fractionation of vinyl chloride copolymers of the vinyl petanoate and the vinyl octanoate derivatives showed that they possessed a rather homogeneous composition. Incorporation of the vinyl pentanoate monomer in a poly(vinyl chloride) copolymer imparted some internal plasticization with serious loss of tensile strength.
Kinetics of the bulk polymerization of dioxolane in the presence of water
Authors: Kučera Miloslav , Hladký Eduard , Majerová Karla
Published: April 2003

The polymerization of dioxolane initiated by the ∼Si⊕HSO ion pair is greatly influenced by water which changes the overall polymerization rate. Particularly great changes are brought about at certain higher conversions (whose values are also a function of an initial concentration of water). The polymerization practically stops at these conversions and the system appears to be close to a monomer—polymer equilibrium. It is shown that the equation Voverall = f([H2O]), which describes the dependence of the overall rate of polymerization on the concentration of water and which was originally derived for the polymerization of trioxane, holds also for the polymerization of dioxolane. The decrease of water concentration during the polymerization was measured and the observed equilibrium was shown to be a kinetic phenomenon.
Copolymerization of tetraoxane with styrene catalyzed by BF3·O(C2H5)2
Authors: Higashimura T. , Tanaka A. , Miki T. , Okamura S.
Published: April 2003

The copolymerization of tetraoxane with styrene catalyzed by BF3·O(C2H5)2 was studied at 30°C. to determine whether a cyclic monomer can copolymerize with a vinyl monomer. The formation of the copolymer was confirmed by elementary analysis of both benzene‐soluble and benzene‐insoluble fractions of the polymer obtained. It was found by gas chromatography that a fairly large amount of 4‐phenyl‐1,3‐dioxane and a small amount of trioxane were formed in the present system, in addition to polymers. Roughly a third of the total amount of the monomers reacted was consumed in the formation of methanol‐insoluble polymer, a third for 4‐phenyl‐1,3‐dioxane, and another third for trioxane and unknown products which could not be indentified. The formation of these cyclic compounds during the copolymerization may be explained in terms of a back‐biting (or intramolecular transacetalization) reaction. The cationic reactivity of tetraoxane was found to be similar to that of styrene on the basis of both the consumption rate of each monomer in the copolymerizing system and the composition of the methanol‐insoluble polymer obtained.
Cyclopolymerization of diallylamine derivatives in dimethyl sulfoxide
Authors: Negi Youji , Harada Susumu , Ishizuka Osamu
Published: April 2003

Diallyl quaternary ammonium chlorides, bromides and N‐alkyldiallylamine hydrochlorides were polymerized with ammonium persulfate (APS) in dimethyl sulfoxide (DMSO). The dependences of yield and molecular weight of polymers on polymerization conditions were examined and quaternary ammonium chlorides were found to have better polymerizability than bromides. The poly(diallyl quaternary ammonium chlorides) obtained with APS—DMSO system are expected to have quite high molecular weights, as determined from the measurement of limiting viscosity numbers of the polymers in NaCl aqueous solution.
The polymerization of styrene oxide by the triisobutylaluminum–water system
Authors: Stille J. K. , Hillman J. J.
Published: April 2003

Styrene oxide has been polymerized by the triisobutylaluminum–water catalyst system. Kinetic studies of the effects of varying the monomer, triisobutylaluminum, and water concentrations in benzene solutions have been made. Styrene oxide was consumed in two reactions: an initial fast one producing trimer and a slower reaction forming higher molecular weight polymer.
Cyclopolymerization of diastereomeric diepoxides
Authors: Stille J. K. , Hillman J. J.
Published: April 2003

The meso‐ and d,l‐diastereomers of o‐bis(epoxyethyl)benzene have been synthesized and identified. The diastereomers were polymerized by a variety of catalysts to give a polymer which has mainly isochroman recurring units as a result of a cyclopolymerization mechanism. Some features of the polymerization with the triisobutylaluminum catalyst system have been studied. The rates of polymerization of the monomers and the transition temperatures of the resulting polymers have been determined. The results are explained on the basis of a controlled intramolecular propagation and a stereospecific polymerization.
Catalysts for asymmetric‐induction polymerization of benzofuran. II. Properties and catalyses of some binary systems containing the menthoxy group
Authors: Hayakawa Yoshihiro , Fueno Takayuki , Furukawa Junji
Published: April 2003

It has been found that the equimolar binary system consisting of aluminum trichloride and (−)‐menthoxytriethyltin, ‐germanium or ‐silicone is effective for the asymmetric‐induction polymerization of benzofuran in toluene at −78°C. The specific rotation [α]D of the resultant polybenzofuran ranged from +10° to +40°, depending on the polymerization conditions as well as the metal atoms constituting the menthoxy compounds. The 1:1 ethylaluminum dichloride—menthol system was also effective for the same polymerization. It was confirmed that these binary systems easily undergo an exchange reaction, giving a dimeric menthoxyaluminum dichloride, (Men*OAlCl2)2, m.p. 72–75°C. A toluene solution of the crystalline dimer polymerized benzofuran into a high polymer having as large an [α]D value as +79.4°, although polymerization with the dimer was much slower than that with the parent binary mixtures. All these results lead to the conclusion that the true catalytic species of our multicomponent systems is most probably the dimeric menthoxyaluminum dichloride.
Ring‐opening polymerization of unsaturated alicyclic compounds
Authors: Calderon Nissim , Ofstead Eilert A. , Judy W. Allen
Published: April 2003

The ring‐opening polymerizations of cyclooctene, cyclododecene, 1,5‐cyclooctadiene, 1,5,9‐cyclododecatriene, 3‐methylcyclooctene, and 3‐phenylcyclooctene have been carried out by using a two‐component catalyst system composed of ethylaluminum dichloride and tungsten hexachloride. NMR and infrared analyses of the respective polymers indicate structures which are consistent with a ring‐cleavage mode of propagation. No evidence for double‐bond shifts or transannular reactions during the polymerizations of 1,5‐cyclooctadiene, 1,5,9‐cyclododecatriene, 3‐methylcyclooctene, and 3‐phenylcyclooctene was found. The polymerizability of substituted, unsaturated, mediumsized alicyclic monomers suggests a convenient method for synthesis of certain perfectly alternating terpolymers. Since polymerizations occurred rapidly with little evolution of heat, it was concluded that entropy is a substantial contributor to the free energy of the ring‐opening polymerization of medium‐sized, unsaturated alicyclic monomers.
Aminobutadienes. V. Polymers of 1‐phthalimido‐1,3‐butadiene and 1‐succinimido‐1,3‐butadiene
Authors: Terada Akira , Murata Kenichi
Published: April 2003

The radical polymerizations of 1‐phthalimido‐1,3‐butadiene (1‐PB) and 1‐succinimido‐1,3‐butadiene (1‐SB) were carried out in bulk and in solution. The polymers obtained had reduced viscosities in the ranges of 1.0–4.0 (1‐PB) and 0.2–0.6 (1‐SB). Both polymers had a similar softening point of 190–200°C. The radical polymerization of 1‐phthalimido‐1,3‐butadiene clearly showed a tendency to give crosslinked polymer. Steric arguments about these polymer structures as a result of the infrared and ozonolysis data led to the conclusion that these polymers contained approximately 20% of the 3,4 form but no 1,2 configuration, and, therefore, that the 1,4 addition was preferred.
Polymerization of β‐cyanopropionaldehyde. II. Crystalline poly(cyanoethyl)oxymethylene
Authors: Sumitomo Hiroshi , Kobayashi Kazukiyo
Published: April 2003

Additional investigation was made on the polymerization of β‐cyanopropionaldehyde at −78°C. with triethylaluminum and triethylaluminum—titanium tetrachloride complexes as initiators. The complexes give a higher polymer yield than triethylaluminum alone. The yield—Ti/Al plot also has a maximum at a Ti/Al mole ratio of about 0.2 at constant Al(C2H5)3 concentration. The rate of polymerization seems to be increased in the following order: toluene < methylene chloride < tetrahydrofuran. This order is reversed with regard to the content of DMF‐insoluble fraction mentioned below. The polymer obtained consists of two fractions: one is soluble in dimethylformamide (DMF) and the other is not. The former consists of an amorphous polymer and the latter of crystalline polymer. It was found that the infrared absorption bands at 790, 1258, and 1375 cm.‐1 were characteristic of crystalline polymer and were assigned to crystalline bands. Those at 1270 and 1345 cm.‐1 are characteristic of amorphous bands. The crystalline bands and COC bands show very intense infrared dichroism, whereas the nitrile band does not. The crystal data obtained from the analysis of the x‐ray diffraction pattern, including the fiber repeat distance of 4.95 A. and other unit cell dimensions in a triclinic system, were compared with those reported for various aldehyde polymers. The unit cell dimension a′ or the maximum interplanar distance is somewhat smaller, suggesting that the molecules are more tightly packed than poly(n‐butyraldehyde), in which the side chain has the same carbon number as that of poly‐(cyanoethyl)oxymethylene. Internal rotation angles and a radius of helix were calculated for an isotactic fourfold helical model of the polymer. Some other characterizations of the polymer were also made.
Effect of impurities and the initiation and transfer rate constants on the statistical character of anionic polymers
Authors: Nanda V. S. , Jain R. K.
Published: April 2003

The simultaneous effect of impurities, hite rate of initiation, and chain transfer through the monomer on the size distribution in anionic polymers is investigated. It is assumed that monomer is added to the system containing monofunctional initiators in small doses 80 that there is no accumulation of the monomer or the impurities at any stage of the reaction. Firstly, by using the continuum approach, expressions for the size distribution and the averages are derived for the case when initiation is infinitely fast and chain transfer is absent. These results are compared with those obtained by Oroho and Wenger by a more rigorous analysis, and the adequacy of the simpler results is established. The complexities arising from the finite rate of initiation and chain transfer are considered subsequently. Finally, we describe a procedure for the determination of the initiation and transfer rate constants in terms of propagation rate constant and the fraction of impurities in the monomer supply.
Kinetics of emulsion polymerization
Authors: Ugelstad J. , Mörk P. C. , Aasen J. O.
Published: April 2003

The quantitative theory of the free‐radical mechanism in emulsion polymerization is reexamined. A mechanism involving desorption and reabsorption of radicals is discussed. The average number of radicals per particle has been calculated as a function of three parameters. A simplified, approximate solution for the average number of radicals per particle is given for cases where this number is low.
Poly(Aryl ethers) by nucleophilic aromatic substitution. II. Thermal stability
Authors: Hale W. F. , Farnham A. G. , Johnson R. N. , Clendinning R. A.
Published: April 2003

The thermal stability and degradation process for a specific poly(aryl ether) system have been studied. In particular, the polymer which is available from Union Carbide Corporation as Bakelite polysulfone has been examined in detail. Polysulfone can be prepared from 2,2‐bis(4‐hydroxyphenyl)propane and 4,4′‐dichlorodiphenyl sulfone by nucleophilic aromatic substitution. Because of a low‐temperature transition at − 100°C. and a glass transition at 195°C., polysulfone retains useful mechanical properties from −100°C. to 175°C. A number of experimental methods were utilized to study the thermal decomposition process for this polymer system. Polysulfone gradually degraded in vacuum above 400°C. as demonstrated by mass spectrometry. Thermogravimetric analysis in argon, air, or high vacuum indicated that rapid decomposition began above 460°C. From gas chromatography, mass spectrometry and repeated laboratory pyrolyses, a number of products from polymer decompositions were identified. The most important degradation process in vacuum or inert atmosphere was loss of sulfur dioxide. Several model compounds representative of portions of poly(aryl ether) molecules were synthesized and the relative thermal stabilities determined. Possible mechanisms for pure thermal decomposition of polysulfone were derived from the product analyses, model studies, and consideration of bond dissociation energies.
New high temperature polymers. VI. Ordered heterocycle copolymers
Authors: Preston J. , Black W. B.
Published: April 2003

A new class of linear, thermostable polymers is reported. The compositions are ordered heterocycle copolymers in which two different heterocycles alternate regularly along the polymer chain. Examples of combinations studied are: oxadiazole–benzimidazole, oxadiazole–pyromellitimide, and thiazole–pyromellitimide. The heterocycle copolymers, or alternatively, the corresponding precursor polymers, were prepared by condensing preformed di‐or tetrafunctional blocks which contain one type of heterocycle with a second di‐ or tetrafunctional monomer under such conditions that no rearrangement of bonds occurred. The polymers are characterized in general by neither melting nor decomposing below 500°C. when heated in an inert atmosphere at a rate of about 10°C./min. Some of the copolymers are readily soluble in organic solvents; many, however, are soluble only in solvents such as concentrated sulfuric acid. In the case of the more intractable polymers, soluble precursor polymers can usually be prepared. In such precursor polymers only one of the heterocycles is preformed; the second heterocycle is formed by post‐treatment after the polymer has been fabricated into an end product. All of the polymers yielded self‐supporting films, some having very high strength; films of several of the polymers were hot‐drawable. Drawn film of an ordered oxadiazoleimide copolymer was shown to be well oriented and moderately crystalline.
Stereospecific polymerization of methacrylonitrile. III. Some new catalysts for isotactic polymethacrylonitrile
Authors: Joh Yasushi , Yoshihara Toshio , Kotake Yahide , Imai Yoshikatsu , Kurihara Seiki
Published: April 2003

Some classes of organometallic catalysts what induce stereospecific polymerization of methacrylonitrile have been found. They include organolithium aluminum compounds of the type LiAlR4, Li[R3AlOAlR2], and Li[R3AlN(R)AlR2], organosodium aluminum compounds of the type NaAlR4, organolithium zinc compounds of the type LiZnR3 and Li2ZnR4, organomagnesium aluminum compounds of the type RMg[AlR4] and Mg[AlR4]2, and organomagnesium compounds containing an MgN bond, such as magnified image and their related compounds. One of the features of the polymerization with these catalysts was that the crystalline polymers were formed at moderately high temperatures. Total conversion, solubility index, and molecular weight of the polymer increased with increasing polymerization temperature, as observed in the case of polymerization with diethylmagnesium catalyst. Catalysts with an MgN bond were found to be highly effective for the stereospecific polymerization. The acetone‐insoluble fractions of the polymers gave x‐ray diagrams identical to the crystalline polymer produced with diethylmagnesium. This indicates that the acetone‐insoluble crystalline polymers produced with these catalysts have an isotactic structure. The viscosity–molecular weight relationship for crystalline polymer was conveniently determined in Cl2CHCOOH at 30°C.; [η] = 2.27 × 10−4 M0.754.
Gel permeation properties of cellulose. I. Preliminary comparison of unmodified and crosslinked, decrystallized cotton cellulose
Authors: Martin L. F. , Rowland S. P.
Published: April 2003

Decrystallized cotton cellulose was found to be have gel permeation properties comparable to those of the highly crosslinked dextran and polyacrylamide gels used in chromatography. Partial separations of pairs of sugars, ranging in molecular weight from 120 to 738, were studied by determining the optical rotations of fractions eluted from chromatographic columns, employing a sensitive automatic polarimeter. The elution volumes of individual sugars of known molecular weights provide a quantitative measure of changes produced in the cellulose polymer structure by crosslinking. A significant difference was found between unmodified cellulose and the same material crosslinked by formaldehyde treatment; although crosslinking reduced permeability to larger molecules, the crosslinked material was found to be more permeable than the untreated cellulose to compounds having molecular weights below approximately 1000.
On the chromophore of polyacrylonitrile
Authors: Peebles L. H.
Published: April 2003

Further evidence is presented to show that the chromophore of polyacrylonitrile is formed by polymerization of the nitrile groups, rather than by dehydrogenation of the polymer backbone. The polyimine structure formed is resistant to hydrolysis; hence, the nitrogen content of hydrolyzed polymer increases with increased chromophore formation.
Diels‐Alder polymers. III. Polymers containing phenylated phenylene units
Authors: Mukamal H. , Harris F. W. , Stille J. K.
Published: April 2003

The Diels‐Alder reaction of biscyclopentadieneones with diacetylenes produces colorless, soluble, phenylated polyphenylenes of high molecular weight (M̄n≃ 40,000) in nearly quantitative conversions. The polymers are noncrystalline, form clear films, and are stable in air to 550°C. Under nitrogen, the polymers lost approximately half the phenyl groups attached to the phenylene main chain to give brown‐black insoluble polyphenylenes of very low crystallinity.
Effect of oxygen on the γ‐radiation‐induced polymerization of ethylene
Authors: Mitsui Hiroshi , Machi Sueo , Hagiwara Miyuki , Hosoi Fumio , Kagiya Tsutomu
Published: April 2003

The effects of oxygen on the γ‐radiation‐induced polymerization of ethylene were studied at a temperature of 30°C.; the pressure was 400 kg./cm.2, the dose rate was 1.9 × 105 rad/hr.; and oxygen content was from 1–2000 ppm. The main product was solid polymer, and no liquid product was found. The gaseous products were hydrogen, acetylene, higher hydrocarbons, carbon dioxide, aldehydes, and acids. Several kinds of carbonyls similar to those formed in γ‐ray oxidized polyethylene were observed in the polymer. The polymer yield and the degree of polymerization decreased markedly with increasing oxygen content, while the amount of carbonyls in the polymer increased. The number of moles of polymer chain and the amounts of hydrogen and acetylene were found to be almost independent of the oxygen content. The polymerization of pure ethylene was not affected by carbon dioxide and formic acid. On addition of acetaldehyde, the polymer yield and the degree of polymerization decreased markedly, while the number of moles of polymer chain increased. In the polymerization of ethylene containing oxygen, both the rate of oxygen consumption and the carbonyl content of the polymer increased, while the inhibition period decreased by the addition of acetaldehyde. It was found that the degree of polymerization after the inhibition period is almost independent of the reaction time in the presence of acetaldehyde, while it increases with the time in the absence of acetaldehyde.
Effects of carbonyl and aldehyde groups in the graft copolymerization of methyl methacrylate on cellulose with a ceric salt
Authors: Ogiwara Yoshitaka , Ogiwara Yukie , Kubota Hitoshi
Published: April 2003

Graft copolymerization of methyl methacrylate on cellulosic materials of various carbonyl and aldehyde contents with the use of a ceric salt as an initiator was studied. It was found that the concentration of the ceric salt which gives the maximum per cent grafting is in good agreement with the equivalent of total carbonyl content in the cellulosic material, and the number of grafted chains in copolymers is roughly proportional to it. However, the molar ratio of the number of grafted chains to total carbonyl content is quite small, being approximately 1:50, and the graft copolymerization can be explained kinetically on the assumption that the number of radicals produced on cellulose by the ceric salt leading to branching is very much smaller than the number of radicals destroyed by the ceric salt, and growing radicals can be stabilized by the termination reaction with the ceric salt or with a cellulose radical. Although both aldehyde and carbonyl groups contribute to the formation of grafted chains, the former are effective mainly at low concentrations of the ceric salt; both groups participate in the production of graft copolymers showing the maximum per cent grafting.
Role of para‐substituted phenols in curing resole‐type phenolic resins
Authors: Rodia Jacob S.
Published: April 2003

Certain para‐substituted phenols, namely, those phenols without ortho substituents and containing an electron‐attracting atom or group in the para position, e.g. p‐nitro‐, p‐bromo‐, and p‐chlorophenol, hasten gelation of etherified phenolic resoles. A mechanism involving cleavage of dibenzyl ether linkages in these resins is proposed to explain gelation.
Kinetics of γ‐ray polymerization of formaldehyde in the presence of carbon dioxide
Authors: Yokota Hisao , Otsuka Yozo , Kagiya Tsutomu , Fukui Kenichi
Published: April 2003

A kinetic study of the γ‐ray polymerization of formaldehyde in toluene solution in the presence of carbon dioxide was carried out at temperatures of + 13 to −17°C. Two modes of the polymerization, spontaneous and γ‐ray polymerization, occur in this system. The γ‐ray polymerization, experimentally separated from the spontaneous polymerization, was investigated. The rate of γ‐ray polymerization increased slightly with the square root of carbon dioxide concentration. The rate of polymerization was also found to be proportional to the dose rate and the square of monomer concentration. The molecular weight of polymer formed was independent of the reaction condition. The apparent activation energy was estimated to be 10.3 kcal./mole. The kinetics of the γ‐ray polymerization in the presence of carbon dioxide are explained quantitatively by a cationic mechanism, and the role of carbon dioxide is as an action of retardation for neutralization of the cationic initiating species, which was produced by γ‐radiation, by means of a reverse reaction with an electron. Physical and mechanical properties of the polymer obtained by γ‐ray polymerization were also investigated.
Stereoregularity of polyacrylonitrile determined by NMR
Authors: Svegliado G. , Talamini G. , Vidotto G.
Published: April 2003

The NMR spectrum of polyacrylonitrile is interpreted and the tacticity of three polyacrylonitrile samples prepared at different temperatures in the range from −78 to 120°C. determined. The ratio between isotactic and syndiotactic units is about 50:50 for all the three samples examined.
Copolymerization of trans‐2,6‐diazido‐hexaphenylcyclophosphonitrile tetramer with 1,4‐bis(diphenylphosphino)butane or 4,4′‐bis(diphenylphosphino)biphenyl
Authors: Bilbo Andrew J. , Sharts Clay M.
Published: April 2003

Polymers [N(PN)4(C6H5)6NP(C6H5)2(CH2)4P(C6H5)2]x and [N(PN)4(C6H5)6NP–(C6H5)2C6H4C6H4P(C6H5)2]x have been formed by thermal copolymerization of trans‐2,6‐diazidohexaphenylcyclophosphonitrile [N3(PN)4(C6H5)6N3] with either 1,4‐bis‐(diphenylphosphino)butane [(C6H5)2P(CH2)4P(C6H5)2] or 4,4′‐bis(diphenylphosphino)‐biphenyl [(C6H5)2C6H4C6H4P(C6H5)2]. The maximum molecular weights obtained were about 10,000. A polymer endcapped with triphenyl phosphine was stable to 400°C.
Changes in concentration of tetraoxane produced during the solution polymerization of trioxane catalyzed by BF3·O(C2H5)2
Authors: Miki T. , Higashimura T. , Okamura S.
Published: April 2003

The behavior of tetraoxane produced during the polymerization of trioxane was investigated kinetically. In the polymerization of trioxane, a short induction period for the formation of methanol‐insoluble polymer was observed and during the induction period a certain amount of tetraoxane, depending on the polymerization conditions, was produced. This amount was independent of the initial concentration of catalyst but increased with an increase in the polymerization temperature and in the initial concentration of trioxane. So this amount was found to be determined by the equilibrium between the formation and consumption of tetraoxane. On the other hand, in the early stage of polymerization of trioxane, the formation of an appreciable amount of soluble polymer was estimated. Consequently the formation of tetraoxane was explained in terms of the “back‐biting” reaction of the soluble growing chain with depolymerization.
Effect of solvent on the amount of tetraoxane produced in the solution polymerization of trioxane catalyzed by BF3·O(C2H5)2
Authors: Miki T. , Higashimura T. , Okamura S.
Published: April 2003

The amounts of tetraoxane produced in the polymerization of trioxane catalyzed by BF3·O(C2H5)2 were measured in various solvents. The maximum amount of tetraoxane produced depends on the nature of solvent used. This amount was independent of the initial concentration of the catalyst in ethylene dichloride and in nitrobenzene. On the other hand, in benzene, the amount of tetraoxane produced decreased slightly with increasing initial catalyst concentration. This result was explained by the reaction of tetraoxane produced with the residual catalyst as well as with the active center. The maximum amount of tetraoxane produced decreased, other conditions being similar, in the order, nitrobenzene > ethylene dichloride > benzene solvent. This order may be explained in terms of a longer lifetime of the active center in the more polar solvent, leading to the formation of tetraoxane.
Transition of nylon 6 γ‐phase crystals by stretching in the chain direction
Authors: Miyasaka Keizo , Makishima Kunio
Published: April 2003

A crystal transition was found in nylon 6 fibers from the γ‐phase to α‐phase on stretching in the chain direction. The γ‐phase fiber prepared by iodine treatment was stretched under constant load and the crystal deformation was observed by an x‐ray method. The critical stress for the transition was estimated as 4 × 103 kg./cm.2 at room temperature. For this crystal transition the following conditions must be satisfied: (1) extension of the γ‐phase chain to untwist the chain around the amide groups, (2) translational mobility of the chain to change the stacking in the crystallite. At the critical stress, the chain in the crystal is extended to nearly the same length as that of α‐phase. The translational movement occurs under stress higher than about 3 × 103 kg./cm.2, and the pseudohexagonal cell is deformed into a monoclinic form. However, the monoclinic crystallites present at a stress lower than the critical value estimated above are unstable and may be brought back to the original form by head treatment at 100°C. No crystal transition occurs at low temperature.
Hydrodynamics of a porous sphere molecule
Authors: Seely Truman
Published: April 2003

A mathematical model is proposed which treats a hypothetical polymer molecule as a porous sphere. Fluid flow within the sphere obeys Darcy's law while the creeping motion equations are used outside the sphere. Equations are derived relating the permeability and radius of the sphere to hydrodynamic properties of dilute solutions of the polymer. In checking against experimental data, it is found that the model, despite its simplicity, may be useful in explaining the hydrodynamic behavior of molecules which are highly branched or crosslinked.
Viscosity of polydimethylsiloxane blends
Authors: Kataoka Tadao , Ueda Shigeyuki
Published: April 2003

Zero shear viscosities of two‐component blends of polydimethylsiloxane with different molecular weights were measured over the whole range of composition. Results are analyzed on the basis of the conventional treatments for the viscosity of polymer blends and some comments are made on such treatments of data. After that, an empirical equation is derived:

where η is the viscosity, v the volume fraction, subscripts 1, 2, and bl denote the lower and higher molecular weight component and the blend, respectively, and a is a constant independent of composition. The equation is not only applicable to all series of blends of polydimethylsiloxane but also to other polymers.