bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of polyamides by ring‐opening polyaddition of 4,4′‐disubstituted bis(3‐buten‐4‐olide) with aliphatic diamines
Authors: Ueda Mitsuru , Yabuuchi Masahiko , Imai Yoshio
Published: April 2003

An investigation of the reaction of 4‐phenyl‐3‐buten‐4‐olide with benzylamine was conducted as a model for the polymerization, and some ethers and acidic solvents were found to be favorable reaction media for formation of the ring‐opened amide as the sole product. By using m‐cresol as the polymerization medium, linear polyamides having inherent viscosities up to 0.67 were readily prepared by the ring‐opening polyaddition of 4,4′‐oxydi‐p‐phenylenebis(3‐buten‐4‐olide) with aliphatic diamines at room temperature. These polymers were soluble in m‐cresol and gave transparent, flexible films by the solution casting technique. They did not show any melt temperature, and began to decompose at around 200°C, both in air and under nitrogen.
Linear polybenzyls. III. Sterically assisted linear polymerization of 2,5‐dimethylbenzyl chloride and α‐methylbenzyl chloride
Authors: Kuo Jeffrey , Lenz Robert W.
Published: April 2003

The low‐temperature Friedel‐Crafts step‐growth polymerization reactions of 2,5‐dimethylbenzyl chloride with TiCl4—(C2H5)2AlCl catalyst, and of α‐methylbenzyl chloride with AlCl3 catalyst were investigated for the effect of reaction conditions on polymer molecular weight, linearity, glass transition temperature, and crystalline properties. Premature precipitation of highly crystalline poly(2,5‐dimethylbenzyl) prevented the preparation of high molecular weight products from this monomer, while most likely an indanyl‐type termination reaction limited the molecular weight of poly(α‐methylbenzyl). Model reactions indicated that, under proper conditions, the latter could be prepared with 99% para substitution, and these polymers were crystalline.
Factors affecting electrical conductivity of carbon black‐loaded rubber. I. Effect of milling conditions and thermal‐oxidative aging on electrical conductivity of haf carbon black‐loaded styrene–butadiene rubber
Authors: Abdel‐Bary E. M. , Amin M. , Hassan H. H.
Published: April 2003

Styrene–butadiene rubber (SBR‐1502) loaded with 50 phr carbon black (HAF) was prepared. The electrical conductivity of rubber vulcanizates was measured. It was found that milling conditions have a marked effect on the temperature dependence of the electrical conductivity σ(T) of test samples. In this case, the resistivity of prepared samples increases with remilling and has a minimum value on the σ(T) curve. Thermal‐oxidative aging of such vulcanizates decreases the conductivity of the prepared samples.
Photopolymerization of methyl methacrylate with the use of tetrahydrofuran–bromine charge‐transfer complex as the photoinitiator
Authors: Ghosh Premamoy , Banerjee Amar Nath
Published: April 2003

The polymerization of MMA was kinetically studied in the presence of visible light (using a 125‐W high‐pressure mercury vapor lamp with fluorescent coating, without a filter), a THF—bromine charge‐transfer complex being used as the photoinitiator. The initiator exponent was 0.5 in bulk polymerization. The monomer exponent varied from about 1.2 to about 2.5, depending on the nature of the solvent used; the initiator exponent also varied in diluted systems, depending on the nature and proportion of the solvent, the variation being from a value of 0.5 in bulk system to zero or almost zero at about 25% (v/v) solvent concentration. Other kinetic parameters, viz., kp2/kt and the activation energy for polymerization, were determined and are reported. Kinetic and other evidence indicates that the photopolymerization takes place by a radical mechanism and termination is bimolecular in nature in bulk systems; in dilute systems, termination by initiator complex assumes predominance, particularly at high solvent concentrations (≥25% v/v).
Triethylaluminum as a concentration‐dependent coinitiator and chain‐transfer agent of free‐radical polymerization of methyl methacrylate in the presence of benzoquinone
Authors: Grotewold Juan , Hirschler Marcelo M.
Published: April 2003

Yields in methyl methacrylate (MMA) polymerization as a function of triethylaluminum (TEA) concentration have been determined at a constant benzoquinone (BQ) concentration. The polymerization is negligible at [TEA]/[BQ] concentration ratios smaller than 1, but reaches a maximum yield and then decreases for larger TEA concentrations. Molecular weight measurements show a similar trend, although the maximum is shifted with respect to that corresponding to polymer yield. The existence of two reaction mechanisms is shown by rate measurements at constant initial concentrations. One is a fast reaction, over in a few minutes, which accounts for most of the yield after 30 min reaction time. The other is a slower photoinitiated reaction of the products of the fast reaction. The mechanism proposed is based on a chain‐transfer reaction between the inhibitor radical, formed by the addition of the polymer radical (M·) to BQ and TEA, giving a reactive ethyl radical:

The competition between a pair of reactions of TEA and BQ, i.e., a free‐radical reaction corresponding to the conjugate addition and a molecular reaction leading to the BQ reduction product, is held responsible for the observed yield maximum, since the molecular reaction prevails at larger TEA concentrations. The observed drop in the molecular weight is the result of a chain‐transfer reaction on TEA, i.e., the substitution of an ethyl group by the growing polymer radical.
Organometallic polymers. III. Organometallic modifications of diene polymers
Authors: Gal Alon , Cais Michael , Kohn David H.
Published: April 2003

A process for the chemical modification of polybutadienes and natural rubber by various metallocene compounds is described. Soluble products of up to 43% ferrocene content were obtained. The effect of substrate, metallocene, and reaction conditions on the course and extent of substitution was investigated. The glass transition temperature Tg was found to increase considerably with the degree of substitution, e.g., cis‐polybutadiene substituted with ferrocene (18 mole‐%) has a Tg of 30°C, as compared with −91°C for the unsubstituted polymer.
Photoconductive copolymers containing N‐vinylcarbazole
Authors: Chang Daniel M. , Gromelski S. , Rupp R. , Mulvaney J. E.
Published: April 2003

The synthesis of N‐vinylcarbazole (VCbz) copolymers in which electron‐accepting groups are incorporated into the polymer chain is reported. The acceptors were introduced by appropriate reactions of VCbz–vinyl acetate or VCbz–acryloyl chloride copolymers and consisted of 3,5‐dinitrobenzoyl, 2,4‐dinitrophenyl acrylate, β‐2,4‐dinitrophenoxy propionate, and trichlorobenzoquinone units. The copolymer containing the 3,5‐dinitrobenzoyl units required no chloranil as a dopant to be photoconductive, and in fact showed a slightly improved photoresponse relative to conventional poly VCbz doped with external chloranil.
Copolyesters of glycols and bisphenols: Concurrent reactions of a new preparative process
Authors: Riecke E. E. , Hamb F. L.
Published: April 2003

A mechanism for the preparation of copolyesters from a preformed polyester, diacid, and bisphenol diacetate in the melt phase is described. Utilizing copoly(ethylene:4,4′‐isopropylidenediphenylene 50:50 2‐methylisophthalate) as a model system, the reaction is shown to proceed through simultaneous cleavage of the preformed polyester by diacid, polymerization by condensation of carboxyl and bisphenol acetate groups, and equilibration through polyester cleavage by carboxyl polymer ends. In this model system, the rates of cleavage and polymerization are competitive, which results in a random sequence distribution early in the reaction.
Thiol/ene photocurable polymers
Authors: Morgan C. R. , Magnotta F. , Ketley A. D.
Published: April 2003

The photosensitized crosslinking of polyenes with polythiols has been demonstrated to be a free‐radical chain reaction whose apparent quantum yield is in the range of 2 × 102–4 × 102 mole/einstein. Initiation occurs by abstraction of a hydrogen atom from the thiol group by the excited n,π* triplet of the ketonic photosensitizer. Kinetic studies of model systems have shown that electron‐donating substituents attached or close to the double bond accelerate the thiol addition while electron‐withdrawing groups decrease the rate. With a given olefin, slight differences in reaction rates are observed depending on the structure of the thiol. Mercaptopropionate esters are more reactive than mercaptoacetates which, in turn, are more reactive than alkane thiols. Cure rates for polyene–polythiol systems are in accord with results found for the model systems. Aromatic carbonyl compounds are the most effective sensitizers for this reaction. To a first approximation, the effectiveness of the sensitizer depends only upon the absorbance. No correlation was found between photoactivity and the triplet energies or lifetimes of the sensitizers.
Nuclear magnetic resonance studies on the mechanism of ring opening in ethylene oxide polymerization
Authors: Matsuzaki Kei , Ito Hiroshi
Published: April 2003

In order to obtain quantitative results on the mechanism of ring‐opening polymerization of ethylene oxide, 13C satellite spectra of dideuterioethylene oxides and their polymers prepared by anionic, cationic, and coordination catalysts were measured with deuterium decoupling and analyzed. The ratios of the threo to erythro polymers were same as those of the cis to trans monomers. Therefore, it is concluded that the ring‐opening polymerizations of ethylene oxide proceed almost entirely with inversion of configuration, confirming the results obtained by the analysis of the infrared spectra of the deuterated polymers by Price, Tadokoro and co‐workers.
Anionic polymerization of 2‐vinylpyridine initiated by symmetrical organomagnesium compounds in tetrahydrofuran
Authors: Soum Alain , Fontanille Michel , Sigwalt Pierre
Published: April 2003

Anionic polymerization of 2‐vinylpyridine has been studied, initiated either by dialkyl and diaryl magnesium or by living oligomers in tetrahydrofuran solution at 20°C. Spectrophotometric observations indicate the existence of stable active species with different structures. Kinetic data for propagation and viscosimetric measurements on two‐ended polymers agree with a cyclic structure of living polymers and lead us to the conclusion of the existence of reactive negative “tripleions.”
Synthesis and polymerization of vinylidenesilanes
Authors: Billingham N. C. , Jenkins A. D. , Kronfli E. B. , Walton D. R. M.
Published: April 2003

Monomers corresponding to the general formula CH2 = C(X)SiMe3, where × = C6H5, Br, Cl, or CO2H, have been prepared. None of these substances undergoes homopolymerization by any standard technique but copolymerization with styrene, methyl methacrylate, or acrylonitrile under the influence of free radicals proceeds at a low rate.
Block copolymers of poly(m‐phenylene isophthalamide) and poly(ethylene oxide) or polydimethylsiloxane: Synthesis and general characteristics
Authors: Zdrahala Richard J. , Firer Edward M. , Fellers John F.
Published: April 2003

The syntheses of poly(m‐phenylene isophthalamide‐b‐ethylene oxide) and poly(m‐phenylene isophthalamide‐b‐dimethylsiloxane) are reported. The development of synthesis procedures for (AB)n and predominantly triblock ABA and BAB sequences are discussed. Chemical compositions, dilute solution viscosities, and solubility behavior of these systems are also given some consideration. These considerations include the problems that arise in condensing block segments together when phase separation is occurring and developing control of the synthesis procedure to produce block systems of varying compositions.
Photodegradation of cellulose acetate fibers
Authors: Hon Nyok‐Sai
Published: April 2003

The photodegradation of cellulose acetate fibers by ultraviolet light in vacuo at 77°K and at ambient temperature was studied. Three kinds of light sources with different wavelengths between 2353 and 6000 Å were employed. ESR studies at 77°K show that several kinds of free radicals are produced from cellulose diacetate (CDA) and cellulose triacetate (CTA) fibers when irradiated with light of wavelength shorter than 2800 Å. Among these methyl radicals formed decayed within 210 min at 77°K. When the temperature was raised above 77°K, radical transformation occurred at 87°K and most of the free radicals decayed at 193°K, whereas the cellulosic radicals were stable at this and even at higher temperatures. Ultraviolet spectroscopy studies revealed that the main chromophores are the carbonyl function of the acetyl group and acetal groups in the polymer. The photodegradation of the polymers at ambient temperature resulted in the formation of gaseous products (mainly CO, CO2, and CH4), together with the loss of bound acetic acid content and sample weight. Decreases in viscosity and reduction of tensile strength and elongation were also observed in the irradiated samples, revealing that the overt effects of ultraviolet light on cellulose acetate fibers are interpreted in terms of free‐radical reactions ultimately leading to main‐chain and side‐group scissions, unsaturation, and the formation of small molecule fragments. Among these, main‐chain scission took place predominantly in CDA fiber and side‐group scission in CTA fiber. The mechanism of the fundamental photochemical degradation processes of cellulose acetate fibers is elucidated.
Alternating copolymerization of ethylene oxide and sulfur dioxide
Authors: Soga Kazuo , Hattori Iwakazu , Kinoshita Jiro , Ikeda Sakuji
Published: April 2003

Copolymerization of ethylene oxide (EO) and sulfur dioxide (SO2) was conducted by using a variety of amines as catalyst. Aromatic tertiary amines such as quinoline and pyridine were found to show the best catalytic property of the various amines, and copolymerization was carried out in the temperature range between 0 and 80°C with the use of quinoline. The copolymerization rate was approximately first‐order in quinoline, EO, and also SO2. The copolymer, was always composed of the two monomers: 1:1 ratio, independent of the initial concentration of the monomers. The copolymer obtained was a transparent viscous material which decomposed at 218°C to afford a considerable amount of ethylene sulfite. Spectroscopic analysis of the copolymer combined with the results of elemental analysis indicates the copolymer to have the structure The polymerizability of ethylene sulfite, which might be considered an intermediate compound in the copolymerization, was also examined at 60°C for 4 hr in the presence of quinoline, and it was found that ethylene sulfite could not be polymerized under these conditions.
Synthesis of optically active poly(2‐phenylvinyl alkyl thioethers) and corresponding monomers
Authors: Kurešević V. , Fleš D.
Published: April 2003

Cis‐(S)(+)‐2‐phenylvinyl alkyl thioethers having 1‐methylpropyl (I), 2‐methylbutyl (II), and 3‐methylpentyl as alkyl groups, were prepared by condensation of phenylacetylene with sodium thioalcoholates in the presence of sodium ethoxide. Thioethers I, II, and III did not polymerize with radical initiators but could be polymerized cationicaly with BF3·Et2O or SnCl4 in bulk at room temperature to oligomers with molecular weights about 2000. Specific rotations of polymers were compared with those of phenylethyl alkyl thioethers, and it was found that there was no difference in the rotation of polymers having molecular weights up to 2000 and model compounds.
Initiated oxidation of polyenes formed in the thermal degradation of PVC
Authors: Nagy T. T. , Kelen T. , Turcsányi B. , Tüdös F.
Published: April 2003

Polyenes formed in the thermal degradation of PVC are readily oxidized in the liquid phase in the presence of a radical initiator. In pure oxygen at a constant rate of initiation, different length polyenes are consumed by a first‐order reaction: the rate of consumption is proportional to the polyene length and to the square root of initiator concentration. Applying the relationships given by the theory of chain reactions, we determined the ratio of the rate constant of chain propagation calculated for one double bond k2 to the square root of the chain‐termination rate constant k4. The value obtained, which is relatively high in comparison to other unsaturated hydrocarbons, reflects very well the high reactivity of polyenes of the degraded PVC sample towards oxidation. Intramolecular chain propagation steps are also likely to play a role in the oxidation of polyenes.
Polymerization induced by electron‐beam irradiation of octadecyl methacrylate in the form of a multilayer or monolayer
Authors: Hatada Motoyoshi , Nishii Masanobu
Published: April 2003

In continuation of the previous series of studies, polymerization of octadecyl methacrylate (ODMA) induced by electron beams has been investigated in a form of its multilayer or monolayer in an attempt to prepare a stable thin polymer film having a regular layer structure. ODMA multilayers were prepared by the Langmuir‐Blodgett technique and irradiated with electron beams from a Van de Graaff accelerator. Multiple reflection infrared spectroscopy and x‐ray diffractometry revealed that the ODMA multilayer was polymerized to give a thin polymer film having a regular layered structure when irradiated in nitrogen atmosphere, but no indication of polymerization was observed when irradiated in air. A preliminary study on the ODMA monolayer at a nitrogen–water interface indicated that the monolayer was polymerized.
Dye‐partition method of analysis of end groups in nonpolar polymers re‐examined: Sulfate end groups in persulfate‐initiated polystyrene
Authors: Banthia Ajit K. , Mandal Broja M. , Palit Santi R.
Published: April 2003

Sulfate, sulfonate, and isothiouronium salt end groups in polystyrene prepared by using the initiator systems K2S2O8, Na2SO3/Cu+2/O2, FeCl3/thiourea, respectively, have been estimated by the dye partition (extrapolation) method. It was observed that while the persulfate‐initiated polymers analyzed to contain very low amount of sulfate end groups (about 0.05–0.3 per polymer molecule), the other two initiator systems yield polymers with about 2 salt end groups [SO and SC(N+H2)‐NH2, respectively] per polymer molecule. The low amount of sulfate end group in persulfate‐initiated polystyrene is in conformity of the initiation mechanism recently proposed by Ledwith et al. for persulfate‐initiated emulsion polymerization of styrene. This study supports our earlier finding that polymer polarity does not affect the results of end‐group analysis by the dye‐partition technique, contrary to some recent reports which claimed otherwise.
Studies with model membranes. X. Evaluation of the thermodynamically effective fixed charge density and permselectivity of mercuric and cupric iodide parchment‐supported membranes
Authors: Siddiqi Fasih A. , Beg Mohammad N. , Singh Surendra P.
Published: April 2003

Thermodynamically effective fixed charge densities of mercuric and cupric iodide parchment supported membranes were estimated by methods of Teorell, Meyer, and Sievers; Altug and Hair; and the most recent one of Kobatake and co‐workers based on the thermodynamics of irreversible processes. The two limiting forms of Kobatake's equation for dilute and concentrated ranges gave identical values of charge densities. It is interesting to note that these two values of limiting cases are closer to the Teorell‐Meyer‐Sievers and Altug‐Hair values. The theoretical predictions for membrane potential by the Kobatake equation were borne out quite satisfactorily by experimental results obtained with both the membranes.
A new solvent system for gel‐permeation chromatography of poly(ethylene terephthalate)
Authors: Paschke E. E. , Bidlingmeyer B. A. , Bergmann J. G.
Published: April 2003

A new solvent system comprising a mixture of nitrobenzene and tetrachloroethane has been developed for determining the molecular size distribution of poly(ethylene terephthalate) (PET) by gel‐permeation chromatography (GPC). Unlike hot m‐cresol, which until now has been the standard GPC solvent for PET, the nitrobenzene–tetrachloroethane mixture can be used at room temperature and thus minimizes polymer degradation and distribution equilibration. Results with this new system reveal reproducibly discernible differences between PET samples prepared by melt and solid‐state polymerization, differences not previously noted in GPC reports based on the use of m‐cresol.
ESCA study of polymer surfaces treated by plasma
Authors: Yasuda H. , Marsh H. C. , Brandt E. S. , Reilley C. N.
Published: April 2003

Surfaces of polymers [polyethylene, polystyrene, poly(ethylene terephthalate), poly(oxymethylene), cellulose acetate, polyacrylonitrile, nylon 6, and polytetrafluoroethylene] treated with argon (inert) and nitrogen (reactive) plasma were examined by ESCA (electron spectroscopy for chemical analysis). Argon plasma treatment generally introduces oxygen functionalities into the polymer surface. Nitrogen treatment generally incorporates nitrogen and oxygen functionalities into the treated surface. The extent of oxygen incorporation is typically less than that produced by argon plasma. When nitrogen and oxygen functional groups are already in a polymer structure, the extent of additional incorporation of these two elements as a result of plasma treatment is very much less than with other polymers. Polymers which contain only one of the elements tend to incorporate the other element to much the same degree as polymers without either element initially present.
Polymer radicals trapped in radical‐initiated polytetrafluoroethylene
Authors: Saika A. , Ohya‐Nishiguchi Hiroaki , Satokawa Takaomi , Ohmori Akira
Published: April 2003

The electron spin resonance (ESR) spectra of polymer radicals found to be trapped in polytetrafluoroethylene (PTFE) polymerized with radical initiators were comparatively examined under various conditions and assigned. They are identified as the primary (propagating) radicals RCF2CF2·, which are transformed to primary peroxy radicals RCF2CF2OO· in the atmosphere. Studies of the rates of polymerization and postpolymerization and ESR measurements indicate that the radical content steadily increases during polymerization. The results are discussed in connection with the mechanism of polymerization of tetrafluoroethylene (TFE) and the unusual thermal stability of these radicals in PTFE prepared with initiator.
Acid‐catalyzed hydroxymethylation of benzamide with formaldehyde
Authors: Sato Kenji , Abe Yoshimoto
Published: April 2003

Hydroxymethylation of benzamide with formaldehyde was investigated in the pH regions of 0.6–6.7 by use of the sulfite method. Investigation of the dependence of the second‐order rate constant of the hydroxymethylation k on pH revealed that k decreased with increasing acidity from pH 6.7, became approximately constant at pH 4.5–5.5 (minimum rate), and then increased with increasing acidity. The rate equation showing the pH dependence of k was drawn from the reaction mechanism, and theoretical curves denoting this rate equation and the corresponding observed curves were compared. It was found that the hydroxymethylation is a reaction between a molecule of benzamide and the conjugate acid of formaldehyde (methylol cation) in the region below ca. pH 2.5, and the parallel reaction of a molecule of benzamide with methylol cation and a molecule of formaldehyde (HCHO) in the pH region of 2.5–4.0; in the region of ca. pH 4.5–5.5 the reaction is that between a molecule of benzamide and a molecule of formaldehyde, and the reaction in the pH region 5.5–6.7 is a parallel reaction of a molecule of formaldehyde with the conjugate base and a molecule of benzamide.
Polymerization of phenylacetylenes. VI. Chain‐transfer reaction in the polymerizations of phenylacetylene and styrene by WCl6
Authors: Hasegawa Kan‐Ichi , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

Chain‐transfer reactions to alkylbenzenes were investigated in the polymerizations of phenylacetylene and styrene by WCl6 in benzene at 30°C. In the polymerization of phenylacetylene, alkylbenzenes did not work as chain‐transfer agents, and further ethyl iodide was not a terminating agent. These findings suggest that the polymerization of phenylacetylene by WCl6 differs from the conventional cationic or anionic mechanisms. On the other hand, the ability of alkylbenzenes as chain‐transfer agents in the polymerization of styrene by WCl6 increased in the following order: toluene < p‐xylene < m‐xylene < o‐xylene. This order is similar to that in the polymerization by SnCl4. These results indicate that the polymerization of styrene by WCl6 proceeds by a conventional cationic mechanism.
Haloaldehyde polymers, VII. Polymerization of chlorodifluoroacetaldehyde
Authors: Yamada B. , Campbell R. W. , Vogl O.
Published: April 2003

Chlorodifluoroacetaldehyde has been prepared by lithium aluminum hydride reduction of methyl chlorodifluoroacetate. Purified chlorodifluoroacetaldehyde was polymerized to crystalline, insoluble polychlorodifluoroacetaldehyde or to a mixture of amorphous polymer soluble in organic solvents and insoluble polymer, depending on polymerization conditions and type and amount of initiators. The polymer, particularly the soluble fraction, could be end‐capped by acetylation to improve the thermal stability of the initially unstable polymer. The thermal degradation of polymer prepared by various techniques has been studied before and after acetylation and the stability was compared to that of other polyhaloacetaldehydes. Chlorodifluoroacetaldehyde was copolymerized with other haloacetaldehydes and with phenyl isocyanate.
Self‐crosslinkable polymers. IV. Copolymerization of 1‐ethenyl‐4‐(2,3‐epoxy‐1‐propoxy)benzene with vinylpyridines
Authors: Tanaka Yoshio , Minowa Michiko , Kato Masao , Kurihara Yoshie , Sakakibara Yoshiaki
Published: April 2003

Soluble and self‐crosslinkable linear copolymers with pendant epoxy and pyridyl groups were obtained from 1‐ethenyl‐4‐(2,3‐epoxy‐1‐propoxy)benzene (M1) and vinylpyridines (M2) by the action of α,α′‐azobisisobutyronitrile. The monomer reactivity ratios were determined in tetrahydrofuran at 60°C (r1, r2, and vinylpyridine given): 0.467, 0.638, 4‐vinylpyridine; 0.556, 1.25, 2‐vinylpyridine; 0.639, 1.38, 5‐ethyl‐2‐vinylpyridine. The Q and e values for 1‐ethenyl‐4‐(2,3‐epoxy‐1‐propoxy)‐benzene were calculated as 1.3–1.6 and −1.1–−1.3, respectively, with the reported Q–e values for these vinylpyridines. The intrinsic viscosities of the copolymers were found to be 0.15–0.30 in tetrahydrofuran at 30°C and to be dependent on the copolymer composition. The copolymers with these vinylpyridines were amorphous, had no clear melting points, and became insoluble crosslinked polymers under heating without further addition of any curing agents.
Synthesis and properties of copoly(pyromellitimide–benzimidazopiperidone)
Authors: Yang Chin‐Ping
Published: April 2003

Some new polymers and model compounds were obtained from the reaction of N,N‐protected glutamic anhydride with primary amines and the ring‐opening reaction was proved to belong to γ‐orientation. When the primary amine is aromatic ortho‐diamine, it was proved that the reaction route of ring‐closure dehydration of the ring‐opening addition products was through imidazolecarboxylic acid rather than imide amine, and at the last step it becomes imidazopiperidone. The corresponding polymer containing pyromellitdiimide and benzimidazopiperidone in the main chain was synthesized by a three‐step reaction of 2,2′‐pyromellitdiimidodiglutaric anhydride with 3,3′‐diaminobenzidine. In the first step, polyaminoamic acid having pyromellitdiimide ring was prepared in polar solvents. In the second step, the conversion of polyaminoamic acid to the copolyimidoimidazole acid was carried out thermally in solution or solid at 140–200°C. At last, the conversion of copolyimidoimidazole acid to the copolypyromellitimidobenzimidazopiperidone was performed either thermally (300°C) or by chemical means. Infrared spectra and NMR spectra were studied and compared with corresponding model compounds. Form solubility and TG analysis, the polymer belongs to a heat‐resistant polymer.
Synthesis of polybenzimidazoles with sulfonic acid groups
Authors: Uno Keikichi , Niume Kazuma , Iwata Yasuhisa , Toda Fujio , Iwakura Yoshio
Published: April 2003

2‐Sulfoterephthalic acid (STA) and disulfoisophthalic acid (DSIA) were synthesized through the sulfonation and the oxidation of m‐ and p‐xylene. The polycondensation reactions of STA and DSIA with aromatic tetraamines gave polybenzimidazoles which contained one or two sulfonic acid groups for each repeating unit. The polymer obtained was soluble in sulfuric acid, some organic solvents, and aqueous strong alkaline solution. The polymers were stable up to 400°C, but they gave polybenzimidazoles above 400°C by eliminating sulfonic acid groups, instead of ring closure.
Anionic polymerization of ϵ‐caprolactam activated with phosphadiazines
Authors: Shalaby S. W. , Reimschuessel H. K.
Published: April 2003

Phenylphosphonyl‐N,N′‐biscaprolactam (I) and phenylphosphonyl‐N,N′‐bis(3,5‐dimethylpyrazole) (II) were synthesized and found to be very efficient activators for the anionic polymerization of caprolactam when used in combination with strong bases such as sodium caprolactam. Polymers obtained in the presence of I and II had generally higher molecular weights and were less sensitive to thermal degradation upon molding than those whose preparation entailed the use of N‐acetyl‐caprolactam (III) as an activator. Thermal behavior and tensile properties indicated that the structure of these polyamides differs from that encountered in nylon 6 prepared with conventional anionic catalyst systems.
Syntheses and reactions of functional polymers. XCIII. Syntheses of polymers containing the N‐(4‐hydroxy‐3‐nitrophenyl)succinimide structure in the chain and the use of these activated polymer esters of N‐blocked amino acids or peptides
Authors: Teramoto Takero , Narita Mitsuaki , Okawara Makoto
Published: April 2003

Polymers containing the N‐(4‐hydroxy‐3‐nitrophenyl)succinimide residue were designed in order to achieve acyl activation of a reacting carboxylic acid in the solid phase. These polymers were prepared through the following three routes: (a) styrene was allowed to copolymerize with N‐(4‐hydroxy‐3‐nitrophenyl)‐ or N‐(4‐acetoxy‐3‐nitrophenyl)maleimide, (b) styrene was copolymerized with N‐(4‐acetoxyphenyl)maleimide in the presence of divinylbenzene (DVB), and the copolymer obtained was hydrolyzed and nitrated, (c) a copolymer of maleic anhydride and styrene was reacted with p‐aminophenol, followed by nitration. The polymers prepared by routes b and c were converted to the activated polymer esters of N‐blocked amino acids and peptides by using dicyclohexylcarbodiimide (DCC). The acylated polymers thus obtained were treated with amino acid esters and found to give peptides quantitatively without racemization.
Thermal decomposition and volatilization of poly(α‐olefins)
Authors: Seeger Michael , Gritter Roy J.
Published: April 2003

The thermal decomposition of normal alkanes and linear poly(α‐olefins) was found to occur predominately by random scissions, followed by volatilization into an open system. To show these processes the fragment distribution from high molecular weight linear polyethylene (fragments to C55), n‐alkanes, polypropylene, and polyisobutylene (fragments to C60) are reported and discussed in depth. Based on the results, a mechanism of random scissions followed by volatilization is postulated for polyethylene and n‐alkanes as well as for polyisobutylene and polypropylene. Polystyrene is shown not to follow the same mechanism, for little evidence for fragments above trimers was found. In addition, temperature rise–time measurements at the pyrolyzer probe are reported and explained.
Analysis of plasma‐polymerized hydrocarbons by pyrolysis/gas chromatography
Authors: Seeger M. , Gritter R. J. , Tibbitt J. M. , Shen M. , Bell A. T.
Published: April 2003

Plasma‐polymerized oils, films and powders obtained from ethylene, acetylene, butadiene, and benzene were characterized by flash pyrolysis and gas chromatography (P/GC). None of the pyrograms resembled those of commercial polyethylene, polybutadiene, or polystyrene. Each of the plasma‐polymer pyrograms did exhibit essentially the same fragments up to C8, albeit in a different distribution, indicating that all samples are structurally similar. Analysis of the P/GC data shows these materials to contain a random arrangement of side chains, crosslinks, double bonds, and aromatic structures. Changes in the fragment distribution were obvious when the sample was a powder, solid film, or oily film produced from the same monomer. It was shown that powder products generally have a higher concentration of branches and/or crosslinks than the oil or film products. There are also differences in the pyrograms of products of the same form derived from dissimilar monomers. The results obtained from P/GC generally support those derived from infrared or NMR measurements performed earlier.
Preparation and photolysis of poly‐p‐ethylacrylophenone and poly‐p‐chloroacrylophenone and their copolymers with styrene and methyl methacrylate
Authors: Lukáč I. , Pilka J. , Kulíčková M. , Hrdlovič P.
Published: April 2003

Poly‐p‐ethylacrylophenone (PPEtAP) and poly‐p‐chloroacrylophenone (PPClAP) and their copolymers with styrene (PEtAP/S) and (PClAP/S) and with methyl methacrylate (PEtAP/MMA) and (PClAP/MMA) were prepared. Quantum yields of main‐chain scissions at 366 nm at room temperature in benzene solution are of the same order as those of the unsubstituted polyacrylophenone and its copolymers. Substitution with chlorine and ethyl group in the para position compared to the unsubstituted polyacrylophenone and its copolymers leads to an increase of the lifetime for the n–π* excited triplet state, as is evident from the measured quenching constants of photolysis. The low‐temperature emission spectra of the copolymers are similar to the spectra of the model compounds in a polymer film. For the homopolymer, however, the character of the emission spectrum changes considerably.
Mechanism of coating by electropolymerization on metal cathodes from zinc chloride solutions of acrylamide
Authors: Collins George L. , Thomas Norman W.
Published: April 2003

Electrocoating by polymerization of aqueous zinc chloride solutions of acrylamide and methylenebisacrylamide has been reexamined. The original investigators of this system proposed a mechanism in which the initiation was formed by electrochemical reduction of a zinc complex of molecular oxygen. That mechanism is not compatible with the present findings that polymerization occurs when oxygen is excluded by nitrogen bubbling. Evidence is presented for the intervention of a zinc complex with monomer. The pH dependence of electrocoating indicates that the species involved is ZnOH+. Failure to achieve coating in acidic solutions of monomers in the absence of zinc points to a multisite attchment of the metal species to monomer in a ring structure. The interpretation is consistent with the observed electropolymerization of N,N‐dimethylacrylamide and with the correlation of electropolymerizability with shifts detected in laser Raman spectra of selected acrylic monomers.
Polymerization of diallyl phthalate in solution by γ‐radiation
Authors: Divakar R. S. , Rao K. N.
Published: April 2003

The polymerization of diallyl phthalate has been studied in two solvents, benzene (GRadical = 0.7) and chloroform (GR = 11.2), γ‐radiation being used to investigate the effect of the solvent on the rates of polymerization and also chain transfer to the solvent. Kinetic analysis shows that in benzene solution the initiating species come almost exclusively from the monomer, but in chloroform they arise only from the solvent. The latter was further confirmed from the chlorine analysis of the polymer wherein chloroform appears to have telomerized with diallyl phthalate. In neither of the solvents was high molecular weight polymer obtained. The kp/kt1/2 for the polymerization of DAP was found to be 3.3 × 10−4 and 1.17 × 10−3 in benzene and chloroform solutions, respectively. The chain‐transfer constant CS was 11.25 × 10−3 and 9.75 × 10−3 for benzene and chloroform, respectively.
Polymérisation anionique amorcée par les composés lamellaires du graphite et du lithium
Authors: Merle G. , Pascault J. P. , Pham Q. T. , Pillot C. , Salle R. , Golé J. , Rashkov I. , Panayotov I. , Guérard D. , Hérold A.
Published: April 2003

In the present work, we use the binary insertion compound LiC12 to polymerize styrene, methyl methacrylate, butadiene, isoprene, and to copolymerize isoprene and styrene in various hydrocarbon solvents (aromatics and aliphatic) and etheral solvents. We show that the styrene polymerization in aromatic solvents gives better yields than in the etheral solvents, the polymer being atactic. Methyl methacrylate does not polymerize in toluene but does so completely in DME. More generally, the yields of polymerization are better with KC37 than with LiC12 because of the different capacities of the monomer to get into the carbon layers. The polymerization of dienes with LiC12 shows that the microstructures of the polymer obtained in π‐or n‐donor solvents are similar to the ones obtained by homogenous polymerization with Li cation in such solvents. However, for isoprene in cyclohexane, the results are different. The isoprene styrene copolymers are statistical ones and the mean length of styrene blocks is less than 5. The monomer interaction with the insertion compound and the growing chain geometry between the carbon layers are the facts which control either the stereospecificity of the polymerization or the selectivity of the copolymerization.
Metal‐containing crosslinked polyester resins by combined polyesterification and polymerization of curable mixtures based on divalent metal salts of mono(hydroxyethyl)phthalate
Authors: Matsuda Hideaki
Published: April 2003

Preparations of metal‐containing crosslinked polyester resins based on divalent metal salts of mono(hydroxyethyl)phthalate were investigated by the cure, by combined polyesterification and polymerization, of curable mixtures prepared from above metal salts, maleic anhydride, glycidyl methacrylate, and methyl methacrylate. The curable mixtures containing Ca showed lower viscosity than those containing Mg. They were subjected to curing reactions in the presence of peroxide and under photoirradiation, respectively. In the cure, polyesterification and polymerization proceeded simultaneously smoothly, giving metal‐containing cured resins. Generally, the peroxide‐cured resins showed better physical properties than the photo‐cured resins. Especially, the former resins with high metal content showed high compressive strength and Rockwell hardness. Further, resistance to chemical attack and boiling water and thermal behavior are also discussed.
Toxic gas evolution from polymers: Evolution of hydrogen cyanide from polyurethanes
Authors: Jellinek H. H. G. , Takada K.
Published: April 2003

The thermal oxidative degradation of two aromatic and one segmented polyurethane has been studied, with special emphasis on HCN evolution over a range of temperatures and oxygen concentrations. A tentative mechanism for HCN formation has been presented. Other gaseous products were ascertained by chromatography. Infrared spectra during degradation were measured, and the extent of crosslinking was also determined. It is shown that HCN evolution can be inhibited by copper or its oxide.
Semiconducting organic polymer from polyacrylamide–Cu++ chelate and iodine
Authors: Higashi Fukuji , Cho Chong Su , Kakinoki Hideo , Sumita Osao
Published: April 2003

Semiconducting organic polymer was obtained by the modification of polyacrylamide (PAAm)–Cu++ chelate with iodine in acetone. Favorable conditions for preparing the chelate effective for the conduction were investigated. Surface resistivities were affected by the amounts of cupric salts and iodine, satisfactory results being given by about 25 wt % of the salts based on PAAm and more than 1 wt % of iodine on the chelate. The conductivity was also varied with the degree of neutralization of the chelate in solution, and optimal values were obtained by addition of about an equimolar amount of potassium hydroxide to cupric salts. Effective structures of the polymer chelate in solution were assumed on the basis of the visible and the NMR spectra and potentiometric titration.
Anionic polymerization initiators containing protected functional groups. II
Authors: Schulz D. N. , Halasa A. F.
Published: April 2003

An organolithium reagent substituted with a primary amine‐protecting group [i.e.,N(TMS)2] has been prepared and used to polymerize 1,3‐butadiene and isoprene. A method is described for converting the resultingN(TMS)2‐containing polydienes intoNH2‐containing polymers. Both N(TMS)2‐ and NH2‐terminated polydienes have been characterized with regard to microstructure, Mn, and Mw/Mn data, as well as qualitative and quantitative end‐group analyses. The described preparative procedures represent a convenient route to the elusive primary amine‐terminated polydienes.
Polymerization of acetylenic derivatives. XXX. Isomers of polyphenylacetylene
Authors: Simionescu C. I. , Percec V. , Dumitrescu Svetlana
Published: April 2003

Cis‐transoidal (orange, soluble, and of low crystallinity) and cis‐cisoidal (red, insoluble, and highly crystalline) polyphenylacetylenes (PPA) were prepared by Ziegler‐Natta catalysts and trans‐cisoidal (yellow, soluble, and amorphous) polyphenylacetylenes were prepared by using phosphine complexes, TiCl4 and by thermal initiation. The cis‐transoidal and cis‐cisoidal structures isomerize thermally in the solid state above 100°C. In solution the cis‐transoidal structure isomerizes above 80°C. The polymers obtained by thermal isomerization are soluble, amorphous, and have a trans‐cisoidal structure. At temperatures higher than 120°C the cis–trans isomerization is accompanied by cyclization and by scission of the polymer chain. A method was developed for determination of cis content of cis‐transoidal and cis‐cisoidal polyphenylacetylenes.
Photophysical properties of poly‐2‐phenyl‐5‐(p‐vinyl)‐phenyloxazole
Authors: McInally I. , Soutar I. , Steedman W.
Published: April 2003

2‐Phenyl‐5‐(p‐vinyl)phenyloxazole (POS) has been synthesized. Copolymers of POS with styrene and the homopolymer poly–POS have been prepared. The polymers have been characterized through measurements of fluorescence decay times (using synchrotron radiation for excitation) and examination of excimer formation in the homopolymer. Fluorescence decay times of 0.6(±0.4) nsec and 9 (±0.2) nsec have been recorded at 298°K in toluene solution for monomer and excimer, respectively. Poly‐POS exhibits excimer formation characterized by an activation energy of 5.9(±0.5) kJ/mole and a binding energy of 17.0(±1.0) kJ/mole.
Suspension polymerization of vinyl chloride initiated by in situ generated diisobutyryl peroxide
Authors: Barter James A. , Kellar David E.
Published: April 2003

It was found that diacyl peroxides can be formed in situ in a polymerization medium by the reaction of an acid anhydride with hydrogen peroxide. For the specific application to aqueous vinyl chloride polymerization, an initiator system based on the base‐catalyzed reaction of isobutyric anhydride with hydrogen peroxide to produce diisobutyryl peroxide gave very good results. In contrast, the acid chloride was completely ineffective as a peroxide precursor in this reaction. Studies pointing to diisobutyryl peroxide as the initiating species; investigations of reactant stoichiometry; and comparison of the in situ system with preformed diisobutyryl peroxide were conducted. It was shown that this system makes possible the polymerization of vinyl chloride at 30°C at rates comparable to those obtained with dialkyl peroxydicarbonates at 50°C, thus demonstrating the ability of this system to initiate vinyl chloride polymerization at low temperature. The rates of vinyl chloride polymerization with the use of different concentrations of in situ diisobutyryl peroxide at 30, 40, and 50°C were determined. Similarly, polymerization rates with the use of combinations of in situ diisobutyryl peroxide and n‐propyl peroxydicarbonate were determined. The data obtained demonstrate rapid initiation of the polymerization reaction and a reduction in polymerization time made possible by this dual initiator system. These results were verified in pilot‐plant and commercial‐scale PVC polymerizations.
Polymerization of acrylonitrile initiated by thiourea–chromium(VI) redox system
Authors: Nayak Padma L. , Samal Rajani K.
Published: April 2003

The kinetics of polymerization of acrylonitrile initiated by Cr(VI)–thiourea and Cr(VI)–ethylene thiourea have been studied at 35, 40, and 45°C in nitrogen. The rates of polymerization and of disappearance of Cr(VI) were measured. Chromic acid alone did not initiate the polymerization under deaerated and undeaerated conditions. On the basis of the experimental observation of the dependence of the rate of polymerization Rp, the rate of Cr(VI) disappearance, –Rm, etc., on various variables, a suitable kinetic scheme was proposed and various rate and energy parameters were evaluated.
Photoinitiation and electroinitiation in the polymerization of 2‐vinylnaphthalene
Authors: Davies D. H. , Phillips D. C. , Smith J. D. B.
Published: April 2003

The zinc chloride‐catalyzed polymerization of 2‐vinylnaphthalene (VN) with both photoinitiation and electronitiation methods was examined. Good yields were obtained with both methods, the electroinitiated process being somewhat faster. The mechanism for polymerization initiation was investigated through a detailed comparison of the kinetics. Both initiation methods show a similar response to increasing input energy and to change in salt to monomer mole ratio. Both methods indicate formation of a ZnCl2–(2‐VN)2 complex as intermediate with the formation of the species being rate‐determining. These results, together with other similar investigations, are then used to deduce a mechanism that involves the formation of an electronically excited donor–acceptor complex. It is argued that in certain salt‐stabilized, electron‐delocalized, aromatic systems, such excitation is possible in electroinitiation.
Photoreversible reactions of polymers containing cinnamylideneacetate derivatives and the model compounds
Authors: Tanaka Hideaki , Honda Koichi
Published: April 2003

Photoreversible reactions of 1,4‐butanediol dicinnamylideneacetate(BCA) and its photocyclized compound (BCD), the model compounds for poly(vinyl cinnamylideneacetate), were studied. They exhibited an excellent photoreversibility in a rigid medium at 77°K. The quantum yield of dimerization in the rigid medium is much larger than that in the solution and approximately equal to that in polymer film. Poly(vinyl esters) of substituted cinnamylideneacetic acids also showed photoreversibility to various extents, depending on the substituent. Poly(vinyl α‐cyanocinnamylideneacetate) showed the best photoreversibility among the series, reflecting the least amount of side reaction upon the photodimerization.