bluuebunny/crossref_metadata_2025 huggingface dataset:
γ‐radiation‐initiated polymerization of bulk styrene at high pressure
Authors: Moore P. W. , Ayscough F. W. , Clouston J. G.
Published: April 2003

The polymerization of styrene in bulk at pressures up to 273 MPa and temperatures between 3 and 49°C with the use of γ‐radiation as the initiator has been studied. The polymerization rate and the molecular weight of the polymer increased with increasing pressure; the molecular weight increased at a slightly faster rate. The difference in the rate is a theoretical expectation which has not previously been observed because chain‐transfer reactions obscure the effect in chemically initiated systems. A small but significant retardation of the initiation reaction occurs as the pressure is increased. The results of previous workers are critically reviewed. Chain transfer at 25°C for pressures below 220 MPa is negligible when γ‐radiation is the initiator. The activation energy for bulk polymerization decreased with increasing pressure from 28.1 kJ/mole at 0.1013 MPa to 22.3 kJ/mole at 203 MPa. Volumes of activation at 25°C for 0.1013 < p < 273 MPa were calculated to be Initiation, +4.0 < ΔV < +4.4 cm3/mole; polymerization; −Δ = −20.9 cm3/mole; degree of polymerization; ΔV = −25.3 cm3/mole; propagation/termination; −ΔV = −22.7 cm3/mole.
Electroinitiated polymerization of 2‐vinylnaphthalene
Authors: Phillips D. Colin , Davies D. H. , Smith J. D. B. , Spewock S.
Published: April 2003

As part of a program to extend the range of donor–acceptor‐initiated polymerization processes, the electroinitiation of 2‐vinylnaphthalene in a zinc chloride–sulfolane solution has been studied. Good conversion yields of well‐characterized (NMR, IR, GPC, elemental analysis) poly(vinylnaphthalene) were obtained with the process showing several mechanistic similarities to other donor–acceptor salt electropolymerization systems.
Synthesis of polyamide‐pyrazolones from 2,2′‐disubstituted bis(4‐ethoxymethylene‐5‐oxazolone) and aromatic dihydrazines
Authors: Ueda Mitsuru , Funayama Michio , Imai Yoshio
Published: April 2003

A new class of polyamide‐pyrazolones was synthesized by the vinylogous nucleophilic substitution polymerization, which was followed by rearrangement, from 2,2′‐p‐phenylenebis(4‐ethoxymethylene‐5‐oxazolone) and aromatic dihydrazines. Solution polymerization was carried out in polar aprotic solvents under mild conditions to yield polymers having inherent viscosities in the range of 0.5–1.2 quantitatively. The polymer derived from bis(4‐hydrazinophenyl) sulfone was readily soluble in strongly polar solvents, while that from bis(4‐hydrazinophenyl)methane was partially soluble or swelled in these solvents. The polyamide‐pyrazolones which are presumed to contain some intermediate oxazolone structure showed a low level of thermal stability.
Thermal properties and solubility of poly‐1,4,5,8‐naphthalenetetracarboxydiimides containing 1,3,5‐triazine rings
Authors: Takatsuka Ryozo , Unishi Terunobu , Honda Itaru , Kakurai Toshio
Published: April 2003

Aromatic polyimides were synthesized by polymerization of 1,4,5,8‐naphthalenetetracarboxylic dianhydride and 2‐dialkylamino‐4,6‐dihydrazino‐1,3,5‐triazines by a solution polymerization method followed by cyclodehydration. The polyimides had number‐average molecular weights over 13,000–16,000 or viscosity values of 0.23–0.65 dl/g. The x‐ray diffraction diagram of polyimide I showed a crystal pattern, but the pattern became less pronounced with increasing length of the polymer side chain, and thus polyimide V showed a typical amorphous pattern. Study of the thermal stability of the polyimides by thermogravimetric analysis showed that a steep weight loss occurred in the range 380–410°C. Among the polyimides, I had only poor solubility in organic solvent, while IV and V were soluble even in general organic solvents such as tetrahydrofuran and dioxane.
Studies with model membranes. IX. Evaluation of thermodynamic parameters from the transition state theory of rate processes for electrolyte diffusion through silver chloride parchment‐supported membranes
Authors: Siddiqi Fasih A. , Saksena Santosh K. , Khan Ibadur Rahman
Published: April 2003

Diffusion rate of biologically important electrolytes through parchment‐supported silver chloride membrane have been determined by the use of Nernst‐Planck equation at various temperatures taking into account membrane resistance Rm, membrane potential Em, etc. The diffusion rates were found to be primarily dependent upon the difference in the hydration energies of the counterion in the external solution. On the basis of Eisenman‐Sherry theory the diffusion rate sequence of alkali metal cations point towards the weak field strengths of the fixed charge groups. The various thermodynamic parameters, namely, ΔH‡, ΔF‡, and ΔS‡ were evaluated. The values of ΔS‡ found to be negative, indicating that the diffusion is taking place with partial immobilization in the membrane phase. A formal relation between ΔHhydration, ΔFhydration, and ΔShydration of cations with the corresponding values of ΔH‡, ΔF‡, and ΔS‡ for diffusion was also found to exist for the investigated system.
Crystallization of polyterephthalates of bis(4‐hydroxy‐3‐chlorophenyl)‐2,2‐propane
Authors: Korshak V. V. , Babchinitser T. M. , Gorshkov A. P. , Vasnev V. A. , Vasilyev A. V. , Tsvankin D. Ya. , Vinogradova S. V.
Published: April 2003

Crystallization of polyterephthalates of bis(4‐hydroxy‐3‐chlorophenyl)‐2,2‐propane synthesized by an acceptor–catalytic polyesterification has been investigated quantitatively. It was found that in a homogeneous medium (in solvents for the polymer) amorphous polymers are formed, while polycondensation in a heterogeneous system (in nonsolvents for the polymer) gives rise to crystalline polyarylates, their degree of crystallization being dependent on synthesis conditions. Secondary treatment of resulting polymers can result in their crystallization and amorphization. Along with molecular weight the physicomechanical properties are significantly affected by the preparation method.
D2‐meta‐carborane‐siloxanes. IV. Synthesis of linear, high molecular weight polymers
Authors: Hedaya E. , Kawakami J. H. , Kopf P. W. , Kwiatkowski G. T. , McNeil D. W. , Owen D. A. , Peters E. N. , Tulis R. W.
Published: April 2003

A new facile route to linear, high molecular weight D2‐meta‐decacarborane‐siloxanes was developed based on the condensation reaction between bisureidosilanes and carborane disilanol. By using NMR to monitor the reaction stoichiometry, polymers with molecular weight ≥250,000 have been prepared. Moreover, because of the mild reaction conditions, structural modifications of the polymer backbone have been readily achieved. These linear, high molecular weight polymers overcome the fabrication difficulties encountered in previously prepared D2‐polymers.
Polymerization of vinyl chloride with organolithium compounds. V. Flow behavior of concentrated solutions of high molecular weight poly(vinyl chloride) in cyclohexanone
Authors: Kudrna M. , Jíšová V. , Kolínský M.
Published: April 2003

The flow behavior of 10, 15, and 25% solutions of high molecular weight, thermally stable poly(vinyl chloride) in cyclohexanone was studied in the temperature range 50–140°C with respect to fiber‐forming properties. The flow behavior of such solutions at shear rates ranging from 1–103 sec−1 is pronouncedly non‐Newtonian with the exception of the 10% solution at 70°C. It can be adequately described by known empirical linear relationships. The apparent viscosities and activation energies are considerably higher than those for the usual types of poly(vinyl chloride), but vary within limits acceptable for the preparation and spinning of solutions.
Curing of epoxide resins: Model reactions of curing with amines
Authors: Dušek K. , Bleha M. , Luňák S.
Published: April 2003

The reaction of tetrafunctional diamines and bifunctional amines with monoepoxy compounds was investigated by gel‐permeation chromatography. At a stoichiometrically equivalent ratio of the functional groups or excess of amine, the consecutive reaction of the epoxide groups with the hydrogen atoms of the amino groups is the only reaction that is taking place; if epoxide is present in excess, the OH groups formed in the reaction are gradually added to the epoxide groups. The ratio of the rate constants of the reaction of the epoxy group with the hydrogen atoms of the primary and secondary amino group was calculated from the concentrations of the reaction products at various excess amounts of amines. The ratio is in good accord with the value calculated from the gel points and limiting stoichiometric ratios in the curing of diepoxides with diamines.
Investigations on poly(vinyl chloride). III. Effects of metal oxides upon thermal decomposition of poly(vinyl chloride)
Authors: Iida Takeo , Gotō Kunio
Published: April 2003

Thermal decomposition mechanisms of poly(vinyl chloride) (PVC) and the effects of a few metal oxides on the pyrolysis of PVC were previously reported. In the present work, 33 metal oxides were investigated to determine their effects on the thermal decomposition of PVC, by using a pyrolysis gas chromatograph. Most acidic oxides accelerate the recombination of chlorine atoms with double bonds, since PVC containing these metal oxides easily release lower aliphatics, toluene, ethylbenzene, o‐xylene, and chlorobenzenes. On the other hand, most basic metal oxides, such as oxides of alkaline earths or silver, inhibit the recombination. These tendencies observed in the thermal decomposition of PVC agree with the contributions of corresponding metal salts to the dehydrochlorination of PVC proposed by other workers. This means that thermal decomposition or dehydrochlorination of PVC is affected by irregularities in head‐to‐tail linkages formed by the recombination of chlorine atoms during heat treatment of PVC.
Polymerization of aromatic nuclei. XVI. Mechanism of chain propagation in the polymerization of benzene by aluminum chloride–cupric chloride
Authors: Engstrom Gary G. , Kovacic Peter
Published: April 2003

A study was made of the mechanism of benzene polymerization by aluminum chloride‐cupric chloride. Our main effort was devoted to propagation with the aim of resolving a literature conflict as to whether a cationic or radical pathway is involved. When equimolar mixtures of benzene and haloarene are polymerized, the resulting copolymers are composed almost exclusively of benzene monomer. This approach is based on the known relative reactivities of the monomers toward electrophilic and radical species. The amount of haloaromatic present in the copolymer was determined by elemental analyses and confirmed by infrared spectroscopy. These results are strongly indicative of propagation by an electrophilic moiety. The presence of oxygen in the reaction mixture was found to have no significant effect on the rate or yield of the polymerization, in contrast to a previous published report. The progress of the reaction was followed by titration of the evolved hydrogen chloride. Phenyl radicals, obtained by the thermal decomposition of benzoyl peroxide in benzene, were found to be incapable of initiating the polymerization in the presence of cupric chloride. Increased yields of biphenyl and the presence of chlorobenzene point to oxidation of intermediate radicals by cupric chloride. None of the experimental evidence is satisfactorily interpreted by radical propagation. The data are nicely rationalized on the basis of cationic chain extension, apparently via a radical cation initiator.
Hydrophobicities in the domains of polyelectrolytes
Authors: Abe Koji , Koide Mikio , Tsuchida Eishun
Published: April 2003

The interactions of integral‐or pendant‐type polycations with sodium‐1‐anilino‐8‐naphthalene sulfonate (ANS) were studied by means of their fluorescent spectra. The emission maxima shift to the lower wavelength and fluorescent intensities increase greatly as a result of such complexations. This result may be attributed to the electrostatic interaction and the specific nonpolar environment around the bound ANS. The hydrophobic property in the domain formed by a polycation chain depends on the increase of methylene groups or the existence of a xylylene group between two adjacent cationic sites on the main chain, the existence of benzyl groups on the side chains, and the increase of their molecular weights. It is shown that the hydrophobicities in the domains of polyelectrolytes also change with their conformational changes, i.e., the more contracted their conformations are, the stronger their hydrophobicities are.
Polymerization initiation by in situ initiator formation. II. in situ formation of several peroxydicarbonates and diisobutyryl peroxide
Authors: Ravey M.
Published: April 2003

The rate of formation of a number of dialkyl peroxydicarbonates and one acylperoxide under in situ conditions were followed by using a simulated suspension polymerization system. Results confirm previous findings based on polymer conversions and indicate that for dialkyl peroxydicarbonates, the in situ mode is suitable only for the lower alkyl derivatives.
The flammability properties of copolyesters and copolycarbonates containing acetylenes
Authors: Quinn C. B.
Published: April 2003

The flammability properties of copolyesters and copolycarbonates containing varying percentages of 2‐butyne‐1,4‐diol and 2,4‐hexadiyne‐1,6‐diol were studied by use of oxygen index and dynamic thermogravimetry. The char formation was found to increase with increasing polymer unsaturation. For nonconjugated acetylenes there is an increase in the oxygen index with increasing unsaturation in a polymer. In contrast, conjugated acetylenes dramatically decrease the oxygen index of a polymer system.
Henry's law and diffusion constants of vinyl chloride in poly(vinyl chloride) at high temperature
Authors: Brown Daniel W. , Lowry Robert E.
Published: April 2003

The Henry's law and diffusion constants of vinyl chloride in poly(vinyl chloride) were determined at temperatures of 24, 90, 120, 150, and 170°C for weight fractions of vinyl chloride between 0.2 × 10−3 and 0.8 × 10−3. Above 90°C, Henry's law applies; values of the constant increase with temperature from 1.8 × 102 to 5.5 × 102 atm per unit weight fraction of dissolved vinyl chloride. The heat of desorption is about 15 kJ/mole. At 24°C, the nominal Henry's law constant was smaller than would have been obtained by extrapolating the values found at higher temperature. The diffusion constants increase with temperature from about 2 × 10−13 to 3 × 10−7 cm2/sec. The activation energy for diffusion is about 110 kJ/mole between 90 and 170°C. Although all values were determined in the absence of air, it is likely that they apply to polymer in air. They may, therefore, be used to calculate the vinyl chloride content in the gas above poly(vinyl chloride) under specific processing conditions.
Stereochemistry in cationic polymerization of alkenyl ethers. I. 1H‐ and 13C‐NMR spectra of poly(propenyl ethers)
Authors: Higashimura Toshinobu , Hoshino Mitsuru , Hirokawa Yoshitsugu , Matsuzaki Kei , Uryu Toshiyuki
Published: April 2003

Benzyl, ethyl, and deuterated ethyl propenyl ethers (BzPE, EPE, and EPE‐d5, respectively) with different cis/trans isomer ratios were polymerized by BF3O(C2H5)2 at −78°C in toluene, methylene chloride, and nitroethane solvents. Poly(propenyl alcohol) [poly(PA)] was also prepared by treating poly(BzPE) with HBr gas. The steric structure of these polymers was studied by 1H‐ and 13C‐NMR spectroscopy. The poly(EPE‐d5) obtained from a trans‐rich monomer mixture was crystalline, while one from a cis‐rich monomer mixture was amorphous. Poly(BzPE) was always amorphous. Poly(BzPE), poly(PA), and poly(EPE‐d5) gave 1H‐NMR spectra with two β‐methine peaks, relative intensities of which depended on the geometric structure of the monomers. Their spectra of β‐methyl protons decoupled from β‐methine proton were also split into two peaks, relative intensities of which corresponded to those of the two α‐methine peaks. 13C‐NMR spectra of α‐OCH2 and β‐CH3 of poly(EPE), respectively, consisted of two peaks. These observations show that the poly(propenyl ethers) examined, whether crystalline or amorphous, have only two dyad structures (probably threo or erythro‐meso and racemic), and that their α‐ and β‐carbons have the same dyad structure, irrespective of the kind of the alkoxyl groups.
Copolymerisation radicalaire du méthacrylate de méthyle et du chlorure de vinylidène avec ou sans dérive de composition
Authors: Chiang Ta Chi , Graillat Ch. , Guillot J. , Pham Q. T. , Guyot A.
Published: April 2003

Two sets of methylmethacrylate‐vinylidene chloride copolymers were prepared via radical copolymerization in dimethylformamide. The first set is carried out in batches. Gas‐chromatographic analysis of samples allows a kinetic study from which the reactivity ratios rM ‐ 2.73 and rC ‐ 0.24 are derived. For the second set a new apparatus, briefly described, has been used. It permits to keep constant the composition of the monomer mixture, through addition of methyl methacrylate, monitored by a chromatographic analysis. The two sets of copolymers are analyzed using nuclear magnetic resonance (60 MHz) leading to the triad distribution, from which the reactivity ratios are derived. Owing to the composition drift, the method cannot be applied to the first set of copolymers; but in that case, it is possible to calculate the triad distribution, the knowledge of the reactivity ratios, and the calculation fits quite well the experimental results.
Thermal properties and solubility of ordered aromatic polyamides containing a methyl‐substituted phenylene linkage
Authors: Takatsuka Ryoza , Uno Keikichi , Toda Fujio , Iwakura Yoshio
Published: April 2003

Ordered aromatic polyamides and copolyamides were prepared by the polycondensation of terephthaloyl and isophthaloyl dichlorides with symmetrical diamines containing preformed amide linkages derived from unsymmetrical methyl—substituted aromatic diamines at low temperature. Thermal properties and solubilities of the ordered polyamides were compared with those of the corresponding random polyamides. There was little difference between thermal stabilities of the ordered polyamide and the corresponding random one, while the former was less soluble in organic solvents than the latter, depending on the extent of hydrogen bonding of the amide groups. The thermal stability of the alternating copolyamides containing both terephthaloyl and isophthaloyl groups as acid components was less than that of the corresponding homopolymers having either a terephthaloyl or an isophthaloyl group, and the solubility of the former resembled that of the corresponding ordered homopolysiophthalamides in accord with the extent of hydrogen bonding of the amide groups in both polymers.
Syntheses of polystyrene–covalently bonded metalloporphyrin complexes and their reaction with molecular oxygen
Authors: Hasegawa Etsuo , Kanayama Tatsuya , Tsuchida Eishun
Published: April 2003

The copolymer of styrene with protoporphyrin IX styrylamide, prepared by the reaction between the porphyrin di(acid chloride) and p‐aminostyrene, was synthesized by radical copolymerization and characterized. The metal complexes of the copolymer were prepared by incorporating corresponding metal ions. It was found by electron spin resonance measurements that the cobalt(II) complex is able to absorb molecular oxygen reversibly in toluene at low temperature.
Dilute solution properties of poly(1,4‐phenylene terephthalamide) in sulfuric acid
Authors: Baird D. G. , Smith J. K.
Published: April 2003

The intrinsic viscosity [η] of dilute solutions of poly(1,4‐phenylene terephthalamide) (PPPT) is found to depend strongly on sulfuric acid strength, exhibiting a maximum at about 100% H2SO4. This behavior instigated measurements of [η] and light scattering from dilute solutions of unfractionated PPPT in concentrated (≈96%) and 100% H2SO4. From [η] and weight‐average molecular weight Mw relationships, Mark‐Houwink exponents a were determined to be 1.36 in 96.6% and 1.62 in 100.2 ± 0.2% H2SO4, indicating that the PPPT molecule can undergo considerable expansion in 100% H2SO4. For the case of 100% H2SO4, a noticeable polyelectrolyte effect is observed in the reduced viscosity versus concentration curves. This result suggests that the repulsive charges generated along the PPPT backbone may be responsible for the change in configuration of PPPT upon increasing the acid strength from 96.6% to 100% H2SO4. It is pointed out that there is considerable experimental difficulty in measuring consistent values of Mw, and this may be the reason for the variation among published data.
Synthesis and properties of alkylene‐linked aromatic polyimides
Authors: Charbonneau L. F.
Published: April 2003

Alkylene‐linked aromatic polyimides were prepared from a family of new dianhydride monomers and aromatic diamines. The dianhydrides were synthesized by Friedel‐Crafts catalysis of the condensation of ditertiary alcohols with o‐xylene, subsequent oxidation of the aryl methyl groups to carboxy, and finally, dehydration of the ortho‐carboxy substituents to anhydride groups. Alkylene‐linked aromatic polyimides, with up to 8 methylene groups in the polymer chain, are stable to 400°C in air and can be extruded or compression‐molded at 300°C. In addition, these polymers are soluble in solvents within the solubility parameter range of 10.4 ± 1.2.
Polymerization of α,α‐disubstituted β‐propiolactones and lactams. VII. Stereoregular polymers from optically active lactones
Authors: D'Hondt Christian G. , Lenz Robert W.
Published: April 2003

Optically active α‐phenyl‐ααethyl‐β‐propiolactone of high optical purity was prepared and polymerized by homogeneous anionic initiation to the isotactic polyester. The racemic and isotactic polymers had apparently different crystalline properties suggesting that the former may be syndiotactic or may crystallize with unit cells containing both R and S blocks. Similar attempts to prepare α‐methyl‐α‐isopropyl‐β‐propiolactone of high optical purity were unsuccessful although a partially crystalline polymer was obtained from the racemic monomer.
Formation of the radical‐cation of monomer in the photoinduced polymerization of isobutylene in the presence of SnCl4
Authors: Toman L. , Pilař J. , Marek M.
Published: April 2003

Spectra of isobutylene with SnCl4 were studied at the temperature of 113°K in the dark and under illumination. Radical‐cations of isobutylene are formed by irradiation of the isobutylene–SnCl4 mixture in n‐heptane substantially more slowly than in the isobutylene–TiCl4 mixture. Polymerization of isobutylene occurs after increasing the temperature up to the melting point of this mixture. The yield of polymer depends on the duration of preirradiation, while the molecular weight of polyisobutylene (Mη) does not depend on the preirradiation of reaction mixture.
Preparation of triblock styrene–tert‐butylstyrene–styrene copolymers by living radical polymerization with a heterogeneous polymeric initiator
Authors: Bigdeli Ebrahim , Lenz Robert W. , Oster Bernd , Lundberg Robert D.
Published: April 2003

Triblock copolymers containing the sequence styrene, p‐tert‐butylstyrene, styrene were prepared in an emulsion system by using isotactic polypropylene hydroperoxide as the initiator together with triethylenetetramine as an activator, according to the method of Mikulasova and co‐workers. Polymerization of styrene continued after removal of the initiator from the emulsion by filtration and eventually reached 100% conversion after 4 hr at 35°C. tert‐Butylstyrene at 80°C and styrene at 35°C were added successively to the system, with each polymerization reaction carried to 100% conversion before the next monomer was added. Thin‐layer chromatography was used to separate the homopolymers and block copolymers in order to determine the purity of the product. Monomer compositions of the block copolymers was verified by infrared analysis. The existence of two separate phases in the extracted block copolymer was indicated by the observation of two distinct glass transition temperatures.
Synthesis of polyamides from active 2‐benzothiazolyl dithiolesters and diamines under mild conditions
Authors: Ueda Mitsuru , Sato Akira , Imai Yoshio
Published: April 2003

Novel examples were presented of the use in polyamide synthesis of active 2‐benzothiazolyl dithiolesters for which aminolysis is assisted by a neighboring group. Solution polycondensation of new dithiolesters, 2,2′‐(adipoyldithio)bisbenzothiazole and 2,2′‐(isophtahloyldithio)bisbenzothiazole, with both aliphatic and aromatic diamines in polar aprotic solvents (N‐methyl‐2‐pyrrolidone and hexamethylphosphoramide) took place rapidly at room temperature yielding polyamides with high molecular weight. The interfacial polycondensation in a chloroform–water system was also successful for polyamide formation. S,S′‐Di‐p‐nitrophenyl dithioisophthalate reacted much more slowly toward diamines than the 2‐benzothiazolyl dithiolesters. Prior to polymer synthesis, the aminolysis of active monothiolesters was carried out as a model compound study.
Polycycloalkylene‐siloxane polymers: Synthesis and thermal study
Authors: Kim Yung K. , Bourrie Daniel B. , Pierce Ogden R.
Published: April 2003

Based on dicyclopentadiene and silacyclopentene, two linear polycycloalkylene‐siloxane polymer systems have been synthesized and the thermal stability of the raw polymers evaluated by differential scanning calorimetry and thermal gravimetric analysis. The DSC data in nitrogen indicate that both polymer systems have excellent thermal stability. In air, these polymers begin to oxidize at approximately 150°C, with catastrophic oxidation occurring at about 400°C.
A theoretical approach to the kinetics of polymer degradation in solution
Authors: Ito Katsukiyo
Published: April 2003

After main‐chain scission in a polymer, the frequency of encounter between segments in the different fragments is related to the separating process between the fragments. The relationship obtained shows that the separating time is proportional to M½, where M is the molecular weight, when the excluded volume disappears. When good solvent is used, the half‐time for the separation is obtained as τ½ = const. M0.16–0.22, which is approximated to the experimental data obtained previously (τ½ = const. M0.34 and τ½ = const. M0.22) for the degradations of polyisobutene and poly(phenyl vinyl ketone), respectively. The increase of the half‐time with increasing coil density can be explained by the excluded volume. The inverse proportionality of the diffusion of segments to solvent viscosity explains the proportionality of the half‐time to microviscosity. The above separating process reverses the reaction between polymer radicals. From their dependence on the chain length, τ½/kD = const. M½ (where kD is the specific rate for the reaction), is estimated. Such an approximation holds, regardless of the type of solvent.
Improved synthesis of 5(6)‐vinylbenzimidazole: Some polymerization studies
Authors: Overberger C. G. , Mathias L. J.
Published: April 2003

A general one‐step reduction ring closure of o‐nitroacetanalides is applied to the synthesis of 5(6)‐acetylbenzimidazole and 5(6)‐acetyl‐2‐methylbenzimidazole in good yield. The former is readily converted to the vinyl monomer by reduction and dehydration. Polymerization of this monomer with free‐radical initiation under a variety of conditions gives polymers with essentially identical nuclear magnetic resonance (NMR) spectra, implying no basic change in polymer structure.
Polyaddition of bisketenimines. II. Synthesis of poly(N‐acylamides) from bisketenimines and dicarboxylic acids
Authors: Kurita Keisuke , Sakata Hikaru , Iwakura Yoshio , Koyanagi Mutsuo
Published: April 2003

Poly(N‐acylamides) were synthesized by polyaddition of bisketenimines with dicarboxylic acids. Yields and inherent viscosities of these polymers were low, presumably because of side reactions. The thermal stability and solubility of the polymers were studied.
Alternating copolymerizations of styrene and acrylic monomers initiated with carbanions in the presence of ZnCl2
Authors: Yamazaki Noboru , Nakahama Seiichi , Noda Masami , Nishiwaki Isao
Published: April 2003

On electrochemical initiation of alternating copolymerizations of styrene–acrylonitrile (AN) and styrene–diethyl fumarate (DEF) in the presence of ZnCl2, radical anions of AN–ZnCl2 and DEF–ZnCl2 complexes produced at the cathode were assumed to initiate copolymerization. In analogy with the cathode‐initiated copolymerization, the radical anions of AN–ZnCl2 and DEF–ZnCl2, generated with the carbanions such as sodium naphthalene, disodium α‐methylstyrene tetramer dianion, and butyllithium, were also found to produce alternating copolymers of styrene–AN and styrene–DEF. On the contrary, no polymers were obtained from methyl methacrylate (MMA)–styrene and methacrylonitrile (MAN)–styrene in the presence of ZnCl2 either with carbanions or by electrochemical reduction. Styrene–MAN–ZnCl2 yielded an alternating copolymer with carbanions upon introduction of oxygen.
Pulse radiolysis study on the initial processes of radiation‐induced cationic polymerization of styrene and α‐methylstyrene
Authors: Egusa S. , Tabata Y. , Arai S. , Kira A. , Imamura M.
Published: April 2003

Initial processes of radiation‐induced cationic polymerization of styrene and α‐methylstyrene have been studied by means of microsecond pulse radiolysis. For styrene, absorption bands caused by the monomer cation radical St+• appear at 630 and 350 nm in a mixture of isopentane and n‐butyl chloride at about −165°C. In parallel with the decay of St+•, three absorption bands appear in the near‐infrared (IR) region, and at 600 and 450 nm. The IR and 600 nm bands are assigned to the associated dimer cation radical St2+•, and the 450 nm band to the bonded dimer cation radical St‐St+•. The kinetic behavior of these species shows that reaction of St+• with styrene monomer forms both St2+• and St‐St+•. With the decay of St‐St+•, another absorption band appears at 340 nm, and the lifetime of this band is relatively long. The 340 nm band may be due to carbonium ions of the growing polystyrene. For α‐methylstyrene, the monomer cation radical (at 690 and 350 nm), the associated dimer cation radical (in the near‐IR region and at 620 nm) and the bonded dimer cation radical (at 480 nm) behave in a manner similar to that of the corresponding styrene species. The absorption band caused by carbonium ions of growing poly(α‐methylstyrene) appears at 340 nm.
Polyimides derived from bismethylolimides. I. Polyamide–imides from bismethylolimides and dinitriles
Authors: Kurita Keisuke , Itoh Hiroshi , Iwakura Yoshio
Published: April 2003

New polyamide–imides were synthesized from bismethylolimides and dinitriles. The bismethylolimides, N,N′‐bismethylolpyromellitdiimide and N,N′‐bismethylolbenzophenonete‐tracarboxylic diimide, were prepared by the hydroxymethylation of the corresponding diimides with formaldehyde. The polymerization reaction was carried out in either concentrated sulfuric acid or poly(phosphoric acid), and the former was found to be superior to the latter. The polyamide–imides had inherent viscosities in the 0.08–0.41 dl/g range. Most of these polymers were soluble in m‐cresol and dichloroacetic acid. The thermal stability of the polymers was examined by thermogravimetric analysis, and they were found to start to decompose at 275–350°C in air.
Organometallic compounds as catalysts in the alternating copolymerization of acrylonitirle with butadiene
Authors: Kuran Witold , Florjańczyk Zbigniew
Published: April 2003

The catalytic activity of various organometallic compounds of the Lewis acid type RmMXn(M = Zn, Cd, B, Al; R = CH3,C2H5, i‐C4H9, C6H5CH2, C6H5C2H4; X = Cl, OCH3) in the alternating copolymerization of acrylonitrile with butadiene in bulk and in toluene solution has been studied. The activity of the catalyst was found to depend on its acidity, the strength of its MR bond, and on the type of substituent R. The results obtained have been discussed in terms of the copolymerizability of the acrylonitrile complexed by RmMXn and in terms of the effect of the RmMXn structure on the initiation rate of the copolymerization.
Anionic‐initiated polymerization of β‐nitrostyrenes
Authors: Carter Mary E. , Nash James L. , Drueke Joseph W. , Schwietert James W. , Butler George B.
Published: April 2003

β‐Nitrostyrene and many of its derivatives have been shown to yield high polymers via anionic initiation with alkoxide ions in protic solvents, e.g., alcohols. A study was conducted to determine the effect of certain substituents on the polymerization characteristics of representative monomers of this series and the properties of their polymers. A kinetic study was conducted and the relative rates of propagation were unexpectedly found to correlate well with brown's σ+ values. The rates of initiation of two representative monomers, β‐nitrostyrene and p‐methoxy‐β‐nitrostyrene, with sodium ethoxide were found to be 3.51 and 2.86 liter/mole sec, respectively. The rate of chain transfer in ethanol was studied qualitatively by using gel‐permeation chromatography (GPC) to obtain molecular weight distribution (MWD) curves. The low values of the Mw/Mn ratios indicated little chain transfer in the protic solvent.
Application of mass spectrometry to copolymers of ethylene and propylene oxides. II. Kinetic analysis
Authors: Lee A. K. , Sedgwick R. D.
Published: April 2003

Molecular‐weight distributions derived from mass spectrometric studies of some alkylene oxide copolymers have been used to calculate rate constant ratios for the first eight steps in the polymerization process. Results suggest that there is a significant reduction in reactivity of the growing chains during this initial period.
Copolymérisations radicalaires sous haute pression. Influence de la pression sur les rapports de réactivité
Authors: Jenner Gérard , Aieche Salah
Published: April 2003

The pressure effect upon the reactivity of the radicals in copolymerizations can be important. The present work reports the pressure dependence of the reactivity ratios for some radical copolymerizations involving monomers of various polarities and proposes an interpretation concerning their variations with pressure based upon the Q—e scheme (or Alfrey–Price scheme). The direction as well as the magnitude of the pressure effect can thus be predicted.
Kinetic analysis of photopolymerization reaction of lauryl acrylate with a photoinduced chemical reaction calorimeter
Authors: Ikeda Mitsuru , Teramoto Yoshihiko , Yasutake Masatoshi
Published: April 2003

Calorimetric studies on kinetics of photopolymerization reactions made previously have been limited by the structures of the calorimeters. This report suggests a thermal‐leak type of calorimeter for carrying out kinetic analysis of the photopolymerization reaction. The method was applied to the photopolymerization system consisting of lauryl acrylate and benzoin methyl ether. The results obtained illustrate the utility of this apparatus.
Synthesis of block copolymers containing poly(ferrocenylmethyl methacrylate) units
Authors: Pittman Charles U. , Hirao A.
Published: April 2003

Ferrocenylmethyl methacrylate (FMMA) has been polymerized by using LiAlH4–tetramethyl‐ethylenediamine initiation to form living polymers in high vacuum systems. The addition of methyl methacrylate or acrylonitrile to these living systems gave the block copolymers FMMA‐block MMA and FMMA‐block AN. The anions were not nucleophilic enough to initiate styrene polymerization. Therefore, living polystyrene was prepared (sodium naphthalide initiation in THF at −78°C) and upon FMMA addition, styrene‐block FMMA copolymers were formed. Extraction, precipitation, and gel‐permeation chromatography studies were performed to examine the purity of the block copolymers.
Thermal decomposition of poly(vinylidene chloride) prepared in presence of oxygen
Authors: Roberts D. R. , Gatzke A. L.
Published: April 2003

The thermal decomposition of poly(vinylidene chloride) was studied for samples prepared in the presence of oxygen. The products from both mass and aqueous suspension polymerizations show two modes of thermal decomposition. A rapid initial mode varies in rate and extent with the amount of oxygen present. A slower mode is unaffected by oxygen and in similar in rate to the polymer made in the absence of oxygen. The chief volatile products are phosgene and formaldehyde for the rapid decomposition and hydrogen chloride for the slow decomposition. The rapid decomposition is interpreted to be an unzipping reaction of a vinylidene chloride–oxygen alternating copolymer initiated by homolysis of a peroxide bond. The absence of significant amounts of hydrogen chloride during this stage of decomposition shows that none of the free radicals generated are capable of initiating a chain reaction that would unzip hydrogen chloride from the poly(vinylidene chloride) backbone. The presence of oxygen during the aqueous suspension polymerization correlates with the generation of hydrochloric acid in the aqueous phase. By analogy with the high temperature decomposition, the hydrochloric acid is believed to result primarily from the hydrolysis of phosgene produced by partial decomposition of the polyperoxide. Initiation of the decomposition is believed due to a reaction of the chain propagating radical.
Anionic polymerization with alkaline‐earth counterion. II. Polymerization of styrene initiated by dicarbanionic oligostyrylbarium in THF
Authors: Mathis Claude , François Bernard
Published: April 2003

The propagation kinetics of anionic polymerization of styrene initiated by dicarbanionic oligostyrylbarium (PS=Ba++) in THF are described. The apparent propagation rate constant kp increases drastically with the degree of polymerization (DP) of living chains and tends at 20°C, for the highest molecular weight (DP ≃ 5000), to the value determined for monocarbanionic polystyrylbarium(PS−)2Ba++. At given DP, the propagation step follows usual first‐order kinetics with respect to monomer, and kp is inversely proportional to carbanion concentration; as observed for (PS−)2Ba++. Similar behavior is observed in the temperature range from −60 to +20°C. The activation energy of the propagation is 4–5 kcal/mole (16.7–21 kJ/mole). It is shown that kp may be considered as directly proportional to the dissociation constant Kd of ion pairs (∼S−Ba++−S∼ is considered as an ion pair ∼(SBa)+S−∼). The striking variation of kp with the DP living chains is interpreted in terms of cyclic living chains, in which both carbanionic ends are bound to the same cation. Values of the intramolecular dissociation constant Kd of ion pairs included in such a model are computed as a function of DP, and their variation is found to fit rather well with experimental data.
Synthesis and exchange reactions of some polymeric benzotriazolides
Authors: Ferruti Paolo , Vaccaroni Franco , Tanzi Maria Cristina
Published: April 2003

The benzotriazolides of N‐methacryloylglycine, N‐methacrylolyl‐ε‐aminocaproic acid, and 4‐methacryloxybenzoic acid, have been prepared and polymerized. The exchange reactions of the resulting polymers with amines, alcohols, and phenol have been studied.
Cationic polymerization of dimethyl‐1,3‐butadienes
Authors: Hasegawa Kan‐Ichi , Asami Ryuzo
Published: April 2003

The cationic polymerizations of dimethyl‐1,3‐butadienes with various catalysts in methylene chloride and toluene have been investigated. The activity of catalysts decreased in the order WCl6 > AcClO4 > SnCl4·TCA > BF3OEt2. The homopolymerization rate of dimethyl‐1,3‐butadienes with WCl6, AcClO4, and SnCl4·TCA decreased in the order 1,3‐dimethyl‐1,3‐butadiene > 2,3‐dimethyl‐1,3‐butadiene > 1,2‐dimethyl‐1,3‐butadiene > 2,4‐hexadiene. The polymers prepared with WCl6, SnCl4.TCA, and BF3OEt2 were rubberlike polymers or white powders, whereas those prepared with AcClO4 were oily oligomers. The 1,4‐propagation increased in the order 1,2‐dimethyl‐1,3‐butadiene < 1,3‐dimethyl‐1,3‐butadiene < 2,3‐dimethyl‐1,3‐butadiene < 2,4‐hexadiene. This order may indicate that the steric effect of methyl group determine primarily the microstructure of the polymer. The relative reactivity of dimethyl‐1,3‐butadienes toward a styryl cation decreased in the order 1,3‐dimethyl‐1,3‐butadiene > 1,2‐dimethyl‐1,3‐butadiene > 2,3‐dimethyl‐1,3‐butadiene > 2,4‐hexadiene. This order may be explained in terms of the stability of the resulting allylic cation.
Alkaline hydrolysis of cured phenol–formaldehyde resins at high temperatures
Authors: Summers R. M.
Published: April 2003

Hydrolysis of cured phenolic resin, either straight or oil‐ or epoxy‐modified, in dilute caustic at 280–320°C, gives novolac resins in 70–80% recovery. Infrared analysis indicates these novolacs have the same composition as conventional novolacs made by the acid‐catalyzed phenol–formaldehyde condensation. Like the conventional novolacs, these recovered resins are soluble in oxygen‐containing solvents and form crosslinked infusible thermoset materials when heated with 10% hexamethylenetetramine. Molecular weights of the recovered novolacs, determined by high‐pressure liquid chromatography, are dependent on both time and temperature of the hydrolysis. The weight‐average molecular weight varied from 270 to 770. The Lowry index values indicate that the molecular weight distribution is narrower for the recovered novolacs than that normally obtained for conventional novolacs. The recovered novolacs have higher melting temperatures than the corresponding commercial novolacs. This is believed to be due to the lower free phenol content of the recovered novolacs.
Estimation of monomer reactivity ratios by nonlinear least‐squares procedure with consideration of the weight of experimental data
Authors: Yamada Bunichiro , Itahashi Masaki , Otsu Takayuki
Published: April 2003

To obtain the optimum values of the monomer reactivity ratios for the copolymerization systems with largely different reactivities between both monomers, a nonlinear least‐squares procedure which took into account the weights of experimental data, was proposed and discussed. The weights of the data were treated for the errors arisen from the amounts of monomers charged, the densities of monomers, the weights of copolymer formed, and the composition of copolymer. The least‐squares procedure with the consideration of the weights was applicable to both differentiated equation and integrated equation derived by Lewis and Mayo. This procedure was applied to radical copolymerizations of α‐substituted crotonic esters with styrene, and reasonable monomer reactivity ratios were obtained. It was noted that errors from the copolymer composition were more important than those from the other factors and that the use of the integrated equation was recommended even when the copolymers were isolated at low conversions.
Preparation of (AB)n‐type block copolymers by use of polyazoesters
Authors: Walz R. , Heitz W.
Published: April 2003

Polyesters of the formula, [(OR)nOCOC(CH3)2NNC(CH3)2CO]m, where (OR)n are poly(ethylene oxide), Poly(propylene oxide), or PTHF units, were used to prepare block copolymers with styrene. Ester and ether groups were cleaved with HI, NaOCH3, and diisobutylaluminum hydride. The resulting polystyrene is telechelic with two COOH and OH groups, respectively. The number of styrene blocks per polymer molecule is 3–4.
Bisorthoesters as polymer intermediates. I. Synthesis of bisorthoesters
Authors: Dudgeon C. D. , Vogl O.
Published: April 2003

Derivatives of three types of bisorthoesters, hexaalkyl orthoisophthalates, hexaalkyl orthoterephthalates, and hexaethyl orthooxalate, were synthesized. The orthoesters of isophthalic and terephthalic acid were prepared from α, α, α, α′, α′, α′ ‐hexachloro‐m‐xylene or hexachloro‐p‐xylene, respectively. It was found more advantageous to prepare initially the hexamethyl orthoesters by reacting the hexachloro compounds with sodium methoxide in methanol either at the boiling point of methanol or under pressure at temperatures up to 200°C. Transesterification with higher alcohols, for example, ethanol or propanol, with the aid of molecular sieves gave the higher bisorthoesters in high yield and high purity. Attempts to synthesize orthoisophthalates and orthoterephthalates of higher alcohols directly from the hexachloroxylenes and alkoxides of higher alcohols gave only low yields of impure products. The Pinner synthesis of the bisorthoesters from the corresponding dinitriles was also ineffective. The ease of purification of hexa‐n‐propyl orthoisophthalate and orthoterephthalate makes these orthoesters the favored candidates for use in polymer syntheses. Hexaethyl orthooxalate was prepared in a three‐step synthesis from triethyl orthoformate by a convenient, but low yield reaction. All bisorthoesters were purified to give compounds which were monomer grade materials free of normal esters.
Synthesis and properties of polymeric azine and thiazine dyes
Authors: Shigehara Kiyotaka , Matsunaga Haruo , Tsuchida Eishun
Published: April 2003

Some polymeric azine or thiazine dyes were prepared by radical polymerization of dye monomers or by polymer reactions between dyes and suitable prepolymers, and their photoredox reactivities were studied. The thionine polymers containing labile OH groups exhibited photochromism and thermochromism, which were extremely sensitive to the moisture content of the polymer film. The reversibility of the photochromism and thermochromism increased with the water content in the film. The water‐soluble polymeric dyes were photobleached under the influence of suitable reducing agents. The degree of photobleaching was smaller than for the monomeric systems except for the dye polymers containing OH groups, probably because of the large steric hindrance of the polymers.
Catalysis by polymer complexes. VIII. Enhanced nucleophilic reactivity of hydroxamate anions bound to quaternized polyethylenimines and related compounds
Authors: Okahata Yoshio , Kunitake Toyoki
Published: April 2003

Water‐soluble polyethylenimine derivatives composed only of the tertiary amine and quaternary ammonium groups were prepared by methylation and quaternization of commercial polyethylenimine. The reaction of the hydrophobic hydroxamate anion and p‐nitrophenyl acetate (aqueous solution, 30°C) was more than 100 times accelerated by the polyethylenimine partly quaternized by stearyl bromide. The polymers quaternized by less hydrophobic groups or by the stearyl and methyl groups were much less effective. The former polymer also accelerated decomposition of the acetyl hydroxamate up to 25 times. The rate‐enhancing effect of these polyethylenimine derivatives appeared to be produced by the general, hydrophobic microenvironment without regard to the peculiar structural characteristics of polyethylenimine. The effect of fully quaternized triethylenetetramine was similarly studied.
Catalysis of hydrolysis of a schiff base by a carboxyl‐containing poly(ethylenimine) derivative
Authors: Suh Junghun , Klotz Irving M.
Published: April 2003

Hydrolysis of 3‐methyl‐2‐cyclohexenylidene laurylamine (I) in the presence and absence of laurylsuccinoylpoly(ethylenimine) has been studied. Water attack on the conjugate acid of I in the polymer environment is about 102 times faster than in bulk medium. To achieve the same rate in bulk media by general base catalysis, about 70 M acetate or cacodylate would be needed. This indicates that the reactivity of the carboxylate attached to the polymer is substantially enhanced by the polymer environment.
Synthesis and properties of polymers containing sprio(indoline‐isoxazoline)
Authors: Watarai Syu , Katsuyama Harumi , Umehara Akira , Sato Hideo
Published: April 2003

Polymers containing spiro(indoline‐isoxazoline) nuclei were prepared by 1,3‐dipolar cycloaddition reactions of N,N′‐alkylene‐bis‐3,3‐dimethyl‐2‐methyleneindolines with bis‐hydroxamic chlorides. Irradiation of the polymers with UV in solution resulted in novel skeletal rearrangements and resulted in polymers containing benzo‐1,5‐diazocine‐2‐one nuclei. Photoconductivities of the polymers were also studied.