bluuebunny/crossref_metadata_2025 huggingface dataset:
ESR study of free radicals produced from the reaction of o‐substituted phenyl methacrylates with tert‐butoxy radical
Authors: Yamada Bunichiro , Matsumoto Akikazu , Otsu Takayuki
Published: April 2003

ESR spectra of radicals produced from the reactions of phenyl methacrylate (PMA) and four o‐substituted PMAs, 2,4,6‐trimethyl‐, 2,6‐diisopropyl‐, 2,6‐di‐tert‐butyl‐, and 2,6‐di‐tert‐butyl‐4‐methyl‐PMAs, with tert‐butyoxy radical were measured in 2‐methyltetrahydrofuran over the temperature range of −53 to −15°C. The coupling constants of the β‐methylene protons observed varied with the bulkiness of the o‐substituents, whereas the p‐substitution did not affect the pattern of the spectra. 2,6‐Diisopropyl‐ and 2,4,6‐timethyl‐PMAs, which can form homopolymers, gave 5‐ and 13‐line spectra, respectively. For the radicals from 2,6‐di‐tert‐butyl‐ and 2,6‐di‐tert‐butyl‐4‐methyl‐PMAs, the same 8‐line spectrum was observed, indicating that the coupling constant of one of the β‐methylene protons was too small to detect. Conformations of the radicals were deduced from the coupling constants of the β‐methylene protons. Variation of the ESR spectrum according to the bulkiness of the o‐substituent was interpreted as a consequence of steric interactions between the polymer chain bound to the β carbon and the substituents, and the α‐methyl group.
Effect of active‐group position in polymeric interactions
Authors: Worsfold D. J.
Published: April 2003

The effect of the position of a substituent along a polymer chain on the equilibrium constant in interpolymer interactions has been determined for equilibria involving the substituent. Polymers containing single dimethylamino groups have been equilibrated with coupling bidentate dinitro phenols, and the excluded‐volume effect determined. The magnitude of the hindrance to complex formation was found to be considerably greater for centrally substituted polymers than for end‐substituted polymers. However, for all polymers the measured effect is less than those expected from previous theoretical treatments of interpolymer reactions. Also, the size of the effect is less in the equilibria than found previously for interpolymer reactions. This suggests that the theoretical treatments that deal only with the effect of excluded volume on the transition complex may be oversimplifications.
New polymer synthesis. IX. Synthesis of poly(ether sulfone)s from silylated diphenols or hydroxybenzoic acids
Authors: Kricheldorf Hans R. , Bier Gerhard
Published: April 2003

The condensation polymerizations of bis(4‐flurophenyl) sulfone with the bistrimethylsilyl derivates of bisphenol‐A, 4,4′‐dihydroxydiphenyl sulfone, 1,5′‐dihydroxynaphthalene, 3‐hydroxybenzoic acid, and 4‐hydroxybenzoic acid were investigated. These polycondensations were only successful when potassium or cesium fluoride was used as catalyst. The yields were in the range of 91–98% and the number molecular weights in the range of 2,500–17,500 depending on the reaction conditions. Viscosity and GPC measurements were conducted and glass transitions were determined. Crystallization was never observed.
Free‐radical identification by ESR in polyethylene and nylon
Authors: Igarashi M.
Published: April 2003

Identification of the free radicals in polyethylene and nylon produced by irradiation, grinding, and pulling to fracture was carried out by comparing the experimentally observed spectra with the spectra constructed from theoretical consideration with the aid of a computer. It was demonstrated that the various primary and secondary radicals are produced and formed in the materials depending upon means of degradation, degradation processes, orientation of materials, and conditions of ESR measurement.
Exciplex formation in aromatic copolymers and photoinduced electron transfer from exciplex to acceptor
Authors: Iwai Kaoru , Itoh Yoshihiro , Furue Masaoki , Nozakura Shun‐Ichi
Published: April 2003

The exciplex formation in 9‐vinylphenanthrene‐p‐N,N‐dimethylaminostyrene copolymers, its characteristics, and the electron transfer process in polar solvents were studied. The copolymer exhibited a more intense intramolecular exciplex fluorescence than the low‐molecular‐weight model system, phenanthrene‐N,N‐dimethylaniline, in which the intermolecular exciplex formation occurred. Intensities of the exciplex fluorescence, which were unchanged regardless of the copolymer composition, led us to speculate that the efficient energy migration takes place from an excited phenanthrene unit to an exciplex forming site on the polymer chain. The electron transfer in the copolymer‐p‐dicyanobenzene system was studied in polar media. The formation of p‐dicyanobenzene anion radical was measured by flash photolysis and electron spin resonance (ESR). p‐Dicyanobenzene anion radical was generated by the electron transfer process via exciplex and the direct electron transfer process from the excited phenanthrene unit in the copolymer.
Kinetic and mechanistic studies of the copolymerization of bis‐4‐substituted‐1,2,4‐triazoline‐3,5‐diones with styrenes
Authors: Lai Yu‐C. , Butler G. B.
Published: April 2003

Highly reactive 4‐substituted‐1,2,4‐triazoline‐3,5‐diones (TDs) have been studied extensively as dienophiles, but little work has been done on their role as enophiles and particularly on their use as propagating species in polymerization studies. The copolymerization between bis‐4‐substituted‐1,2,4‐triazoline‐3,5‐diones (bis‐TDs) and styrene has been reported. The purpose of the present work was to synthesize new copolymers derived from a variety of substituted styrenes and bis‐TDs and to study the mechanism and kinetics of this novel polymerization. Three bis‐TDs were prepared: 3,3′‐dimethyl‐4,4′‐bis[3,5‐dioxo‐1,2,4‐triazoline‐4‐yl] biphenyl (8), t‐1,4‐bis[3,5‐dioxo‐1,2,4‐triazoline‐4‐yl] methyl cyclohexane (9), and 4,4′‐bis[3,5‐dioxo‐1,2,4‐triazoline‐4‐yl] phenyl ether (10). Their structures were fully established by spectroscopic studies, elemental analyses, and indirectly, their quantitative ene reactions with 2,3‐dimethyl‐2‐butene. Copolymerization between bis‐TDs and substituted styrenes was carried out in dimethylformamide (DMF), tetrahydrofuran (THF), or dichloroethane (DCE). Polymers formed were characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), gel permeation chromatography (GPC), and viscometry. Molecular weights of polymers range from 5000 to 16,000 in most cases. They were stable up to 250°C and higher. Polymers derived from bis‐TDs and p‐t‐butylstyrene, α‐methylstyrene, p‐nitrostyrene, and p‐acetoxystyrene contained only Diels‐Alder‐ene (DAe) repeating units, whereas those derived from styrene, p‐chlorostyrene, p‐bromostyrene, p‐methylstyrene, p‐methoxystyrene, and 4‐vinylbiphenyl contained both DAe and double Diels‐Alder (dDA) repeating units. A kinetic study of the copolymerization of 4,4′‐bis‐(3,5‐dioxo‐1,2,4‐triazoline‐4‐yl) phenyl ether with α‐methylstyrene, p‐t‐butylstyrene, styrene, p‐chlorostyrene, and p‐nitrostyrene in DCE was carried out; the copolymerization rate constants were 60.9, 49.8, 8.4, 5.5, and 0.8 (1 mol−1s), respectively.
Synthesis and thermal analysis of some oligomeric silicon derivatives of ferrocene
Authors: Asatiani L. P. , El‐Agamey A. A. , Diab M. A.
Published: April 2003

This article reports a study of the catalytic addition reaction of ferrocene containing dihydrosilane to diacetylenic silicon derivatives. A hypothetical structure based on reaction kinetics and spectral data is presented. The oligomers obtained were studied by TG and DTA from ambient temperature to 1000°C in oxygen atmosphere (80 mL/min). The existance of phenyl groups in the structure of the oligomers makes them less stable than those with derivatives.
Synthesis and properties of polythienylenes
Authors: Hotz Charles Z. , Kovacic Peter , Khoury Issam A.
Published: April 2003

Although polymerization of 2,5‐dibromothiophene via coupling of the Grignard reagent with organonickel salts was reported in two earlier communications, a detailed examination of reaction variables was not done. This report provides results from variation in the following: time, amount of magnesium, amount of iodine, dilution, and variation in the halide of the monomer. The highest yield was obtained for reactions with 1:1 molar ratio of monomer to magnesium in more concentrated solutions of tetrahydrofuran for a reaction time of 4 h. For variation in the halogen of the monomer the following yield sequence was obtained: I > Br > Cl. The results are compared with the corresponding benzenoid system investigated by Yamamoto. In addition, polymerization studies were carried out with other brominated thiophene monomers. Use of an organic promoter (cis‐1,4‐dichloro‐2‐butene) in place of a nickel salt proved successful in the generation of poly(2,5‐thienylene).
Head‐to‐head polymers. XXIV. Synthesis of head‐to‐head polyisobutylene by Grignard coupling reaction
Authors: Malanga Michael , Vogl Otto
Published: April 2003

Head‐to‐head polyisobutylene of molecular weight 3000 to 10,000 was prepared in about 30% yield by Grignard coupling polymerization of 2,2,3,3‐tetramethyl‐1,4‐dibromobutane with copper(I) tris(triphenylphosphino)bromide as the catalyst. Head‐to‐head polyisobutylene is crystalline, with a Tm of 187°C and a Tg of 87°C and still has bromine end groups left. The polymers have been characterized by their infrared, 1H‐, and 13C‐NMR spectra and compared to the corresponding head‐to‐tail polymers of similar molecular weight. A substantial portion of the reaction product of the Grignard coupling polymerization is not polymeric but was identified as cyclized product, 1,1,2,2‐tetramethylcyclobutane.
Aqueous polymerization of methyl methacrylate. III
Authors: Shukla J. S. , Tiwari R. K. , Sharma G. K. , Shukla S. K.
Published: April 2003

The aqueous polymerization of methyl methacrylate (MMA) initiated by potassium persulfate (I)‐thiomalic acid (TMA) redox couple has been studied at 30 ± 0.2°C under nitrogen atmosphere. The rate of polymerization is given by

up to 20.0 mmol/L TMA concentration, where x = 0.52 for the I concentration 0.6–10 mmol/L and x = 0.27 for higher I concentrations. The temperature had a marked effect on initial rate and maximum conversion. The overall energy of activation was found to be 11.79 kcal/mol (49.31 kJ/mol). Injection of more initiator (I) at intermediate stages enhanced both the initial rate and maximum conversion. Ag (I) and Fe (III) depressed initial rate as well as maximum conversion, while Cu (II) activated the polymerization. The effect of solvent was also studied.
Thermal conversions of polymers with macroheterocycles in the chain
Authors: Siling S. A. , Gribkova P. N. , Ponomarev I. I. , Balykova T. N. , Vlasova I. V. , Pavlova S.‐S. A. , Korshak V. V. , Vinogradova S. V.
Published: April 2003

Thermal conversion of polyhexazocyclanes and compound modeling the fragments of polymers were explored within 300–600°C under vacuum (10−5 torr) and in water vapor. At temperatures below 450°C, the hydrolytic degradation plays a key role in the thermal degradation of polyhexazocyclanes. At a higher temperature, the homolytic processes prevail, water, strongly retained by the macroheterocycle, is most important in the hydrolysis process. It was shown that the increase in the thermohydrolytic stability of polymers with the system of condensed cycles in the macroheterocycles and that of polyhexazocyclanes modified by polymer analogous conversion at the secondary amino groups of the isoindole cycle was caused by the absence of bound water.
Radical polymerization in the presence of complexing agents. V. Effect of low concentration of ZnCl2 on the radical copolymerization of methyl methacrylate with ethyl acrylate
Authors: Madruga E. L. , Román J. San , Rodriguez M. J.
Published: April 2003

Reactivity ratios for the free‐radical copolymerization of methyl methacrylate with ethyl acrylate in the presence of low concentrations of ZnCl2 are analyzed at different polymerization temperatures, 35,50, and 65°C. The different tendencies of the two monomers toward the formation of molecular complexes with the metal halide modify the homopropagation and cross‐propagation coefficients and the results obtained seem to indicate a conventional cross‐propagation mechanism in which both free and complexed species of acrylic monomers participate.
Functional monomers and polymers. CVIII. Photodimerization of pendant thymine bases in thymine containing poly‐lysine derivatives
Authors: Suda Yasuo , Inaki Yoshiaki , Takemoto Kiichi
Published: April 2003

The photodimerization reaction of pendant thymine bases in thymine‐containing poly‐lysine derivatives was studied over a wide range in aqueous solution. It was found that the quantum yield of the photodimerization of pendant thymine bases is affected mainly by the conformation of the polymers in solution. The differences in photoreaction behavior were discussed for poly‐D‐, poly‐L‐, and poly‐DL‐lysine derivatives.
The effect of filler shape on the mechanical properties of a reinforced vulcanizate: The SBR‐ground asbestos system
Authors: Papirer Eugène
Published: April 2003

Grinding chrysotile under controlled conditions results in microfibers with the dimensions of carbon black or silica agglomerates used in the reinforcement of rubber. The mechanical properties of SBR reinforced with ground asbestos are similar to those of SBR filled with a silica of equivalent surface area.
The investigation of cancerous human bone (osteoclastoma) by small‐angle X‐ray scattering
Authors: Patel A. , Khanduala B. Ch. , Thakur G. B. , Labischinski H.
Published: April 2003

Small‐angle X‐ray scattering methods were applied to provide a pore analysis of cancerous human bone (osteoclastoma). For experimental measurements of the scattering intensities a small‐angle Kratky camera, equipped with a counterattachment and a programmable step‐scanning device, was used. By applying the theories of Kratky, Porod, Debye, and Bueche, applicable to a densely packed two‐phase system belonging to a general micelle system, macromolecular parameters such as specific inner surface, length of coherence, range of inhomogeneity, void percentage, and transversal lengths l̄1 and l̄2 were evaluated and found to be 4.69 × 10−4 Å−1, 21.39 Å, 18.01 Å, 0.21%, 18.01 Å and 8.53 × 103 Å, respectively. A comparison of these parameters with those of pure human bone revealed a macromolecular dissociation in osteoclastoma.
Radical‐initiated homo‐ and copolymerization of cyanomethyl methacrylate
Authors: Ueda Mitsuru , Suzuki Toshiyuki , Imai Yoshio , Pittman Charles U. , Wallace Easley
Published: April 2003

The kinetics of cyanomethyl methacrylate (CyMA) homopolymerization was investigated in acetonitrile with azobisisobutyronitrile as initiator. The rate of polymerization Rp was expressed by Rp = k[AIBN]0.49[CyMA]1.2 and the overall activation energy was calculated as 72.3 kJ/mol. Kinetic constants for CyMA polymerization were obtained as follows: kp/k = 0.10 L1/2s−1/2; 2fkd = 1.57 × 10−5s−. The relative reactivity ratios of CyMA(M2) copolymerization with styrene (r1 = 0.15, r2 = 0.29) and methyl methacrylate (r1 = 0.43, r2 = 0.75) in acetonitrile were obtained. Applying the Q‐e scheme (in styrene copolymerization) led to Q = 1.64 and e = 0.98. The glass transition temperature Tg of poly(CyMA) was observed to be 91°C by thermomechanical analysis. Thermogravimetry of poly(CyMA) showed a 10% weight loss at 265°C in air.
Photoinitiated polymerization of vinyl monomers by benzophenone t‐butyl peresters
Authors: Abu‐Abdoun Ideisan. I. , Thijs L. , Neckers D. C.
Published: April 2003

Benzophenone peresters undergo efficient photodecomposition when irradiated at 366 nm. This article reports peresters derived from benzophenone p,p′‐dicarboxylic acid 1 which may produce radicals at two different centers in the same molecule. These peresters represent a unique new example of an efficient photoinitiator for acrylate and styrene polymerization.
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Phase‐transfer‐catalyzed free‐radical polymerization: Kinetics of polymerization of methyl methacrylate using ammonium peroxydisulfate/hexadecyl pyridinium chloride in ethyl acetate/water
Authors: Jayakrishnan A. , Shah D. O.
Published: April 2003

The kinetics of phase‐transfer‐catalyzed free‐radical polymerization of methyl methacrylate using the system ammonium peroxydisulfate/hexadecyl pyridinium chloride have been investigated in the temperature range of 50–60°C in ethyl acetate/water two‐phase systems. The superior efficiency of the phase‐transfer‐catalyzed reaction in comparison with polymerization initiated by oil soluble initiators such as 2,2′‐azobisisobutyronitrile and benzoylperoxide has been demonstrated. Rate of polymerization increased with increase in concentration of the quaternary salt but showed a tendency to level off at higher concentrations. Increase in the peroxydisulfate concentration also resulted in an increase in the rate at lower concentrations, but was found to decrease at higher concentrations. The order with respect to the monomer was found to be approximately unity. The title reaction has been found to be not truly phase‐transfer catalyzed in character as claimed by previous workers. A suitable kinetic scheme has been proposed to account for the experimental data and its significance discussed.
Ionic species in irradiated poly(methyl methacrylate). A pulse radiolysis and ESR study
Authors: Tabata M. , Nilsson G. , Lund A. , Sohma J.
Published: April 2003

Poly(methyl methacrylate) free of initiators was synthesized by γ‐irradiation and cast into transparent films. The samples were investigated by ns pulse radiolysis at various temperatures, and by ESR spectroscopy after γ irradiation at 77°K. Short‐lived transients with optical absorptions at 440 and 725 nm were observed. The 440 nm absorption has been ascribed to the cation and the 725 nm absorption (εG = 3000 M−1 cm−1 (100 eV)−1, τ1/2 = 190 ns at −13°C, Ea = 6.5 kcal/mol) to the anion. These assignments are based on ESR data of samples of poly(methyl methacrylate) and pivalic acid methyl ester deuterated at the ester deuterated at the ester and α‐methyl groups, respectively, and subjected to thermal annealing and photobleaching. The anion decomposes on photobleaching by loss of the ester ·CH3 radical, and the cation is proposed to decay by loss of the ·CH3 radical from the α‐methyl group. The thermal decay of the anion is discussed.
Termination in radical copolymerization: Correlation of experimental data
Authors: Procházka Ondřej , Kratochvíl Pavel
Published: April 2003

Various termination models in the radical copolymerization are compared on the basis of available experimental data for the dependence of the initial rate of copolymerization on the composition of the monomer mixture. A diffusion‐controlled model seems to be more adequate for the majority of reported data than a chemically controlled one. The potential effect of activity coefficients in calculations of the initial rate of copolymerization is discussed.
The skewness of polymer molecular weight distributions
Authors: Chen Show‐An , Hu Hsing‐Chung
Published: April 2003

A new parameter α3 for characterization of the skewness of a polymer's molecular weight distribution (MWD) based on the statistics is introduced. For α3 > 0, the skewness is positive, characterizing the MWD with a tail at higher‐MW side. For α3 = 0, the MWD is symmetric. For α3 < 0, the skewness is negative, characterizing the MWD with a tail at the lower‐MW side. A relationship between α3 and the first four (from zeroth to third) moments of the MWD is developed which allows calculation of the skewness without detailed calculation of the MWD. An example of polymerization of styrene with n‐butyllithium is given to demonstrate the characteristics of α3.
Effect of Rh(III) and Ru(II) complexes in the polymerization of vinyl monomers initiated by charge transfer mechanism
Authors: Dass N. N. , Sen S. R.
Published: April 2003

The initiation of polymerization of vinyl monomers such as methyl methacrylate (MMA) and methyl acrylate (MA) by a charge transfer complex formed between n‐butylamine(nBA) and carbon tetrachloride (CCl4) in dimethylsulfoxide (DMSO) at 30°C is slow. The effect of the dimethylsulfoxide complexes of Rh(III) and Ru(II) on the polymerization of MMA and MA in the presence of nBA, and CCl4 in DMSO has been studied. The rate of polymerization and percent conversion of the MMA and MA at 30°C are evaluated at the critical concentration of the metal complexes. At the critical range of the metal complex concentrations, both Rp, and percent conversion of MMA and MA were found to be highest. However, above and below the critical concentrations, Rp and percent conversion of the monomers were found to decrease. A suitable mechanism for the polymerization has been proposed.
Syntheses and polymerizations of some vinyl monomers containing nitro‐ or fluorophthalimides
Authors: Overberger C. G. , Shalati Mohamad D.
Published: April 2003

4‐Nitro‐N‐vinylphthalimide (4) was synthesized by two different procedures. Compound4was not polymerizable or copolymerizable by AIBN. Poly(N‐vinylphthalimide) (17) was prepared and partially nitrated at 10–25°C.N,N′‐(1,2‐Ethanediyl)bis(4‐nitrophthalimide) (15) andN,N′‐(1,3‐propanediyl)bis(4‐nitrophthalimide) (16) were prepared by the condensation of the corresponding diamine with phthalic anhydride followed by nitration of the condensation products. 4‐Nitrophthalic anhydride was prepared by the hydrolysis of15. Four styrene‐substituted phthalimide monomers were synthesized. These includeN‐(4‐vinylphenyl)phthalimide (25a),N‐(4‐vinylphenyl)‐3‐fluorophthalimide (25b),N‐(4‐vinylphenyl)‐3‐nitrophthalimide (25c), andN‐(4‐vinylphenyl)‐4‐nitrophthalimide (25d). Monomers25aand25bwere polymerized by freeradical initiator (AIBN), whereas monomers25cand25dwere not polymerizable or copolymerizable by AIBN due to a strong inhibitive effect exerted by the nitrophthalimide group. Monomers25cand25dwere cationically polymerized (BF3·OEt2). Monomer25band styrene were copolymerized and their reactivity ratios werer1= 1.7 andr2= 0.55, respectively. The prepared polymers are useful as backbone polymers for grafting living anionic polymers.
Electron–proton and electron–methyl exchanges in pyrolysis of polyacetylene and polymethylacetylene
Authors: Fan J. L. , Chien James C. W.
Published: April 2003

Pyrolysis of polyacetylene is marked by high yields of proton‐enriched products methane, ethane, ethylene, propane, polypylene, butadiene, cyclopentadiene, 1,3‐pentadiene, and toluene in total amounts exceeding benzene. The activation energies for their formation are low. Polyacetylene doped with AsF5 and iodine produced these products in even higher yields of two to 17 times of undoped polymers. The dominant mechanism is thought to be random‐chain scission followed by electron–proton exchange reactions. Polymethylacetylene is thermally less stable than polyacetylene. Pyrolysis gave mesitylene as the expected main product. However, as in the case of polyacetylene, large amounts of proton‐enriched products were formed with moderate activation energies. (The yields of methane, propylene, and propane are nearly the same in the pyrolysis of polymethylacetylene as compared to that of polyacetylene at 923°K referenced to mesitylene and benzene, respectively.) By analogy, mechanisms involving both electron‐proton and electron–methyl exchange reactions were proposed to account for the formation of all the pyrolyzates of polymethylacetylene. These reactions, not observed in the pyrolysis of polypropylene and polyisoprene, are attributable to the conjugated backbone permitting facile migrations of electrons, protons, and methyl groups.
Thermal oxidation of polyacetylene
Authors: Will Fritz G. , McKee Douglas W.
Published: April 2003

The thermal oxidation of undoped trans‐polyacetylene powder in dry air has been studied and the principal features of the mechanism have been developed. Thermogravimetric and differential thermal analysis reveal an exothermic process that first leads to a weight increase, followed by precipitous weight loss above 240°C due to formation of volatile oxidation products. Isothermal weight gain studies between 25 and 142°C show first‐order kinetics below 90°C with a rate constant of 3.10−7 s−1 at 25°C and an apparent activation energy of 16 kcal/mol. A weight gain of more than 40% has been observed at 25°C after 2000 h of exposure to air. A change in first‐order kinetics occurs at temperatures above 90°C. Identification of solid oxidation products with photoacoustic infrared spectroscopy reveals that oxygen intercalates into the polymer structure in large concentrations, similar to other electron acceptors. However, oxidative attack on the polymer backbone occurs simultaneously. At elevated temperatures or for long‐term oxygen exposure, the concentration of dopant oxygen decreases, probably by intramolecular regrouping of hydrogen atoms, resulting in the formation of hydroxyl groups and enhanced polymer degradation. This mechanism is consistent with the finding of others that the conductivity of polyacetylene upon oxygen exposure increases initially before decreasing significantly with continued exposure, especially at elevated temperatures.
Reactive oligomers. II. Polymerization of glycol bis(allyl phthalate)s and glycol bis(allyl succinate)s
Authors: Matsumoto Akira , Kukimoto Yutaka , Aoki Kazuhiro , Oiwa Masayoshi
Published: April 2003

Seven glycol bis(allyl phthalate)s (GBAP) and four glycol bis(allyl succinate)s (GBASu) as reactive oligomers were prepared and their polymerization behaviors were investigated in detail in terms of cyclopolymerization and gelation as compared with diallyl dicarboxylates. Thus, the rates of polymerization of GBAPs were reduced compared to diallyl phthalate, being attributed to the steric effect on the intermolecular propagation of the uncyclized radical, whereas those of GBASus were enhanced as a consequence of intermolecular association by dipole–dipole interaction in polar GBASu monomers. Cyclization was enhanced in the following order: diallyl aliphatic dicarboxylates series < GBASu series < GBAP series. Gelation was discussed according to Gordon's theory; the actual gel‐point conversions increased with an increase in the molecular weight of monomers, although the discrepancy between actual and theoretical gel‐point conversion inversely tended to be decreased. The decreased delay in gelation with an increase of the molecular weight of monomers is ascribed to the reduction of excluded volume effects on crosslinking.
Synthesis and reactivity of aromatic aldehyde functions based on crosslinked polystyrene
Authors: Geckeler K. , Zheng H. , Bayer E.
Published: April 2003

Crosslinked polystyrene‐containing chloromethyl groups were transformed into an aldehyde‐containing arylether polymer by an one‐step reaction with 4‐hydroxybenzaldehyde. Further modification of the aldehydic derivative of polystyrene by reaction with hydroxylamine proved the chemical availability of the polymer‐bound aldehyde functions and also good conversions for the product. In contrast, 2,4‐dinitrophenylhydrazine did not react under comparable conditions but after swelling in dioxan. It could be shown that swelling is a prerequisite for this reaction. The aldehyde function of the polymer was oxidized to the carboxylic acid using crown ether‐solubilized potassium permanganate. The carboxylic acid was converted to the carboxylic acid chloride by reaction with thionyl chloride. Finally, kinetic aspects of the reaction of chloromethyl polystyrene and 4‐hydroxybenzaldehyde have been investigated and discussed.
Plasma polymerization. XI. A comparison of the plasma polymerization of the isomeric perfluorinated diazines
Authors: Clark D. T. , Abu‐shbak M. M.
Published: April 2003

Plasma polymers synthesized by inductively coupled RF techniques have been investigated as a function of operating parameters for the isomeric perfluorinated diazines (pyrazine, pyrimidine, and pyridazine). A combination of ESCA and microanalytical studies shows that plasma polymers are produced by rearrangement mechanisms: the C/F and C/N stoichiometric ratios are similar to those of the starting monomers over a range of operating parameters. A comparison of rates of formation of plasma polymer films reveals distinctive differences between the isomeric diazines that suggest that equilibration of valence isomers occurs on a substantially slower time scale than for isomeric fluorinated benzenes5–9 which, in general, polymerize at essentially the same rates. In contrast to the remarkably low critical surface tension of plasma polymers based on perfluorobenzenes (ca. 20 dynes cm−2), the plasma polymer films from the perfluorinated diazines which are initially hydrophobic become hydrophilic in contact with water droplets. This is attributed to the hydrolytic instability of films associated with the labilizing influence of nitrogen on nucleophilic displacement of fluoride which is a feature of the chemistry of monomers.
Photoinitation of cationic polymerization. II. Laser flash photolysis of diphenyliodonium salts
Authors: Pappas S. Peter , Pappas Betty C. , Gatechair Leslie R. , Schnabel Wolfram
Published: April 2003

Laser flash photolysis of diphenyliodonium salts produces phenyliodinium radical cation (PhI+·), which was also generated independently by flash‐induced electron transfer from iodobenzene to a phenanthrolinium salt. Apparent second‐order rate constants were determined for reaction of the transient (PhI+·) with nucleophiles, including iodobenzene and cyclohexene oxide. Quantum yields of formation of acid from stationary photolysis of diphenyliodonium hexafluoroarsenate were found to be significantly higher than yields of iodobenzene. These results may be explained by facile reaction of PhI+· with PhI to yield a new iodonium salt together with a proton. High reactivity of PhI+· with cyclohexene oxide suggests that the transient may directly initiate cationic polymerization of epoxides.
Solvent effects on radical homo‐ and copolymerizations of methacryloyl fluroride
Authors: Ueda Mitsuru , Kumakura Toshihisa , Imai Yoshio , Pittman Charles U. , Wallace Easley
Published: April 2003

The effect of solvent in homo‐ and copolymerizations of methacryloyl fluoride (MAF) was investigated in various aromatic solvents. In these solvents, there is a significant effect on the rate of polymerization, on the tacticity of the resulting poly(methacryloyl fluoride), and on the copolymerization of MAF with methyl methacrylate (MMA). The equilibrium constants between MAF and aromatic solvents were determined from NMR spectroscopic measurements. These results indicated that the solvent effect on the MAF polymerization stems from changes in reactivity of MAF induced by the strong MAF–solvent interaction as well as stabilization of the MAF radical by solvents. Copolymerization of MAF with both p‐methoxystyrene (MSt) and p‐nitrostyrene (NSt) was also studied.
Monte carlo study of star‐branched polymers on the tetrahedral lattice. II. Statistical thermodynamics of single macromolecules
Authors: Sikorski Andrzej , Koliński Andrzej
Published: April 2003

The thermodynamical properties of the star‐branched polymers on the tetrahedral lattice are studied taking into account nearest‐neighbor interactions. The excess free energy and energy and heat capacities are computed for wide ranges of chain lengths, reduced potential ϵ/kT, and number of branches. A significant influence of the degree of branching on long‐range interactions in the polymer random coil is observed. The possibilities of phase transitions in both linear and branched systems are discussed on the basis of the Monte Carlo data.
Photoinduced swelling control of amphiphilic azoaromatic polymer membrane
Authors: Ishihara Kazuhiko , Hamada Naoshi , Kato Shinji , Shinohara Isao
Published: April 2003

To control the swelling of polymer membrane by photoirradiation amphiphilic azoaromatic polymer membranes were prepared and a photoinduced change in the swelling degree of water was investigated. The azobenzene moiety in the side chain of the polymer was isomerized from trans form to cis form by ultraviolet (UV) irradiation and reverse isomerization was found by visible light irradiation. The swelling degree of the polymer membrane for water in the dark was decreased by UV radiation, and when visible light irradiation was carried out in the polymer membrane the degree of swelling recovered to the original level. The swelling degree decreased with an increase in the mole fraction of the azobenzene moiety in the dark and under UV irradiation. The deswelling degree of the polymer membrane by UV irradiation also decreased with an increase in the mole fraction of the azobenzene moiety. This reversible change in the swelling degree was considered to be caused by the photoisomerization of the azobenzene moiety in the polymer membrane.
Organosilane polymers: Formable copolymers containing dimethylsilylene units
Authors: Zhang Xing‐Hua , West Robert
Published: April 2003

Formable silane copolymers that contain dimethylsilylene units were synthesized and characterized. These polymers have high molecular weights and appreciable solubility in common solvents, can be molded or cast into films or drawn into fibers, and are photoactive.
Property relationships in dimer acid‐modified copolyesters of poly(1,4‐cyclohexylene dimethylene terephthalate) and poly(1,4‐cyclohexylene dimethylene 1,4‐cyclohexane dicarboxylate)
Authors: Fagerburg David R.
Published: April 2003

Dimer acid (D) modified copolyesters based on 1,4‐cyclohexane dimethanol (CHDM) and either terephthalic acid (T) or trans‐1,4‐cyclohexane dicarboxylic acid (C) were examined. Both series produced clear, flexible materials with physical properties changing regularly with changing modifier levels. Yield stress, elongation at break, and Young's modulus showed linear correlations of log property versus volume fraction of CHDM‐D segments in accord with the logarithmic rule of mixtures. Annealing the CHDM‐T‐based copolyesters caused little or no change in properties. Annealing the CHDM‐C‐based copolyesters gave similar results except for a large decrease in the modulus—the higher the dimer acid level, the larger the decrease in modulus. The density measurements, the x‐ray pattern, and the dynamic mechanical analysis at 110 Hz before and after the annealing treatment supported the hypothesis that the modulus decrease resulted from domain perfection in the copolyester induced by the annealing process. Transmission electron‐microscope examination of osmium tetroxide‐stained films supported this hypothesis, although initial results were not repeatable.
On the reaction of linear and crosslinked polystyrene with 1,4‐bis(chloromethoxy)butane
Authors: Carpov Adrian , Luca Cornelia , Bărboiu Virgil
Published: April 2003

The chlorometylation of linear and crosslinked polystyrene with 1,4‐bis(chloromethoxy) butane was studied, and the behavior of 1,4‐bis(chloromethoxy)butane in the presence of chloromethylation catalysts was also established by 1H‐NMR spectroscopy.
Polyaromatic ether‐ketone sulfonamides prepared from polydiphenyl ether‐ketones by chlorosulfonation and treatment with secondary amines
Authors: Lee Jasun , Marvel C. S.
Published: April 2003

Polyaromatic ether‐ketone sulfonamides with potentially open structures of interest for membranes were prepared from polyaromatic ether‐ketones by sulfonation with chlorosulfonic acid, followed by amination with various amines. Various degrees of substitution were achieved by controlling the reaction conditions of sulfonation. These polymers are soluble in solvents like dimethylformamide, dimethylacetamide, and chloroform and can be cast into transparent films.
Organic solid photochromism by photoreduction mechanism: Viologen embedded in solid polar aprotic polymer matrix
Authors: Kamogawa Hiroyoshi , Masui Toshiaki , Amemiya Suguru
Published: April 2003

Reversible photocolor developments of viologens embedded in poly(N‐vinyl‐2‐pyrrolidone) films, a typical polar aprotic solid matrix, were found to be affected by the kinds of viologen cation as well as the paired anion. The color developments in the corresponding low‐molecular‐weight solvents are connected closely to the solubility of viologens in these solvents; viologens are highly sensitive in the polar aprotic solvents in which they have poor solubilities, such as N‐methyl‐2‐pyrrolidone and hexamethyl phosphoric triamide. These facts confirm the color‐development mechanism consistings of electron transfer to the photoexcited viologen cation from the paired anion in polar aprotic solid matrices such as poly(N‐vinyl‐2‐pyrrolidone).
Solid‐state polymerization of butadienes. Polymerization of salts of 6‐amino‐2,4‐trans,trans‐hexadienoic acid
Authors: Tieke Bernd
Published: April 2003

The polymerization of 6‐amino‐2,4‐trans,trans‐hexadienoic acid and various of its salts was studied in the solid state. Crystals of the hydrochloride and organic inorganic double halides with cadmium chloride, manganese (II) chloride, and iron(II) chloride were found to polymerize rapidly upon UV or γ irradiation. An erythro‐diisotactic polymer is obtained in the form of extended chain crystals. The polymer behaves as an amphoteric polyelectrolyte. The kinetics and the mechanism of the polymerization as well as morphological changes during the solid state reaction are discussed.
Interaction between poly(N‐vinylpyrrolidone) and poly(acrylic acid)s: Influence of hydrogen and cupric ions on the adduct formation
Authors: Subramanian R. , Natarajan P.
Published: April 2003

Interpolymer adduct formation between poly(N‐vinylpyrrolidone) (PVP) and poly(methacrylic acid) (PMAA) is mainly due to hydrogen bonding. It is found that the interpolymer adduct formation is enhanced in the presence of Cu(II). A simple turbidity measurement making use of a spectrophotofluorometer is described for the study of the interpolymer adduct formation. Enhanced adduct formation in the presence of Cu(II) is described by the empirical relation d[PAd]/D[PVP] = k × 104α[Cu(II)]α, where PAd represents the interpolymer adduct and α and k are constants. Similar results have been obtained in the case of interpolymer adduct formation between poly(acrylic acid) (PAA) and PVP. In the above expression α signifies the influence of chelation on Cu(II)–PAA/PMAA–PVP‐type complex formation and k is the extent of PVP–PAA/PMAA interaction. The enhancement of adduct formation in the presence of Cu(II) is more in PAA than in PMAA. Turbidity and viscosity measurements further indicate that the influence of Cu(II) on interpolymer adduct formation between PVP and PMAA or PAA is more in the case of PAA than PMAA, as PAA is a better chelating ligand. But the extent of adduct formation is more in the case of PMAA in the absence of Cu(II) ions due to hydrophobic interactions exerted by methyl groups.
Mechanisms of polymer‐supported catalysis. 5. Solvation of quaternary onium ions in polystyrene gels by 13C‐NMR spectroscopy
Authors: Ford Warren T.
Published: April 2003

13C‐NMR linewidths and spin‐lattice relaxation times have been determined for soluble and crosslinked polystyrenes containing quaternary phosphonium and ammonium ions. Solubilities and NMR linewidths show that the solvating abilities toward tri‐n‐butylphosphonium ions are CDCl3 > CH3OH > D2O > benzene, toluene, toward the trimethylammonium ions, CH3OH > CDCl3 > D2O > toluene, and toward the nonpolar polymer backbone, CDCl3, benzene > toluene > CH3OH > D2O.
Infrared study on the interaction of poly(vinyl chloride) and ketones. I. PVC‐MEK film system
Authors: Monteiro Elisabeth E. C. , Mano Eloisa B.
Published: April 2003

In a previous article we presented preliminary information on IR spectrometric evidence for the interaction between poly(vinyl chloride) and ketones by using films with residual solvent as samples for spectrometry. This article reports detailed information on PVC–MEK film systems as compared to model compounds. The results indicate that there are “specific” interactions which were observed by a frequency shift of the carbonyl absorption of the ketone and changes on intensities of the CCl vibrational modes of the polymer, which are similar to the effects observed for nonpolymeric systems.
Kinetic study of preirradiation grafting of acrylic acid onto poly(tetrafluoroethylene–perfluorovinyl ether) copolymer
Authors: Hegazy El‐Sayed A. , El‐Assy Nasef B. , Rabie Abdel‐Gawad M. , Ishigaki Isao , Okamoto Jiro
Published: April 2003

A kinetic study has been made on the preirradiation grafting of acrylic acid (AAc) onto poly(tetrafluoroethylene–perfluorovinyl ether) (PFA) film. The effect of grafting conditions was investigated. The dependences of the grafting rate on preirradiation dose and monomer concentration was found to be of the order of 0.5 and 1.3, respectively. The final degree of grafting was found to increase with dose and monomer concentration. However, it decreases as the grafting temperature increase. The overall activation energy for the graft polymerization was calculated from Arrhenius plots to be 5.6 kcal/mol. The activation energy for this grafting system was found to be independent of preirradiation dose used in the range from 10 to 100 kGy. The relationship between the grafting rate and film thickness gave a negative first‐order dependence. The results suggest that the grafting proceeds by radical mechanism with bimolecular termination of growing chain radicals. It was reasonable concluded that this grafting proceeds from the surface to the center of film with progressive monomer diffusion through the grafted layer which swells in the monomer solution.
Structure and immunological properties of polyacrolein formed by means of ionizing radiation and base catalysis
Authors: Rembaum A. , Chang M. , Richards G. , Li M.
Published: April 2003

The kinetics of the formation of polyacrolein microspheres by ionizing radiation (polymer I) were investigated. Their structure and reactivity were compared with polyacrolein microspheres prepared by base catalysis (polymer II). The study of Fourier infrared (IR) spectra of polymers I and II showed structural differences. The reaction of polyacrolein spheres with m‐aminophenol indicated the presence of conjugated groups. The reaction of antibodies with polyacrolein spheres was investigated as a function of pH and the number of reactive aldehyde groups was determined by nitrogen analysis of polyacrolein‐hydroxylamine adducts. Intensely fluorescent polyacrolein microspheres obtained by Co‐γ‐irradiation in sizes of 100 Å–4 μm have already found applications as immunoreagents for cell labeling and separation.
Reversible protection of oligomeric ethylene glycols by bis (2,4‐dinitrophenylation) and basic ethanolysis
Authors: Warshawsky Abraham , Shoef Nurit
Published: April 2003

Bis‐(2,4‐dinitrophenyl)glycols are stable in the presence of triethylamine but undergo ethanolysis in the presence of hydroxide ions. The quantitative removal of the DNP blocking group allows an integrated scheme to pure glycols from commercially available polyethylene glycol mixtures

Mixtures of ethylene glycol oligomers are obtained by anionic polymerization of ethylene oxide. See, for example, G. O. Curme and F. Johnston, Glycols, Reinhold, New York, 1953. They are commercially available (as PEG‐200, PEG‐400, etc., to indicate the average molecular weight of the major components).

by bis‐dinitrophenylation, chromatographic separation, and end‐group removal, using high performance liquid chromatography (HPLC) of the bis‐(2,4‐dinitrophenyl)glycols for purity monitoring. A facile synthetic method for the production of penta‐to dodecaglycols in a mixed, aqueous, dioxane solvent system, with fair yields, is also described. The bis‐(2,4‐dintrophenyl) protection of glycols is a reversible reaction that can be used as (1) a preparative method for pure glycols from readily available commercial polyethylene glycol mixtures; (2) a highly sensitive and accurate analytical method

A. Warshawsky, A. Tishbee, and N. Shoef, J. Liq. Chromatogr., submitted for publication.

coupled with HPLC.
Microstructures of polybutadienes prepared by anionic polymerization in polar solvents. Ion‐pair and solvent effects
Authors: Bywater S. , Firat Y. , Black P. E.
Published: April 2003

The microstructure of polybutadiene produced by anionic initiation in diethyl ether and tetrahydrofuran with counterions Li+, Na+ and K+ was determined by 1H‐ and 13C‐NMR. Ionization suppressing salts were added in tetrahydrofuran to ensure that only the ion‐pair reaction was studied. Results are compared with older published data. In general, the 1,4 content of the polymer increases with increasing counterion size but varies somewhat with solvent with a given counterion. The cis component of the 1,4 structures changes with temperature and counterion. It is suggested that this change reflects the proportion of cis and trans centers that carry the reaction.
Polymer‐bound flavins. I. Influence of polarity of the polymer chain on properties of bound flavin
Authors: Bootsma Jan P. C. , Challa Ger , Müller Franz
Published: April 2003

The preparation of flavin‐containing, water‐soluble terpolymers with varying contents of quaternary ammonium and neutral monomer units is described. The composition of the polymer, that is, the polarity of the polymer chain, affects the UV/VIS absorbance spectrum of the bound flavin moiety by influencing the flavin‐solvent interaction. Aerobic oxidation of 1‐benzyl‐1,4‐dihydronicotinamide (BNAH) is accelerated as much as 17‐fold by polymer‐bound flavins, compared with free flavin. Depending on the ratio of polar/nonpolar groups in the flavin polymer and the 2‐propanol content of the aqueous reaction medium (pseudo) first‐order or Michaelis‐Menten type kinetics were observed as a function of substrate concentration. The influence of the polymer composition on flavin/BNAH complex formation (Km−1) and rate‐limiting hydride transfer step (k2) is discussed. Accumulation of the substrate in the polymer domain due to apolar interactions is one of the major factors that determine the observed rate enhancements.
Poly[(3‐hydroxypropyl) oxirane] and poly[(4‐hydroxybutyl)oxirane]: New hydrophilic polyether elastomers
Authors: Shih Jenn S. , Tirrell David A.
Published: April 2003

Preparations of poly[(3‐hydroxypropyl)oxirane] and poly[(4‐hydroxybutyl)oxirane] are described. Three routes to poly[(3‐hydroxypropyl)oxirane] are discussed, each of which involves the methanolysis of a polymeric ester. (3‐Acetoxypropyl)oxirane, [3‐(m‐chlorobenzoyloxy)propyl]oxirane, and (3‐chloropropyl)oxirane were polymerized using the AIEt3/H2O/AcAc initiator system. Poly[(3‐acetoxypropyl)oxirane] and poly{[3‐(m‐chlorobenzoyloxy)propyl]oxirane} were converted directly to poly[(3‐hydroxypropyl)oxirane] by methanolysis, the former under either acidic or basic conditions only. Poly[(3‐chloropropyl)oxirane] was first converted to poly[(3‐benzoyloxypropyl)oxirane] by treatment with tetrabutylammonium benzoate; subsequent basic methanolysis then afforded poly[(3‐hydroxypropyl)oxirane]. Poly[(3‐hydroxypropyl)oxirane] is a colorless elastomer which can be cast into tough, clear films from water or methanol. Poly[(4‐hydroxybutyl)oxirane] was prepared from poly[(4‐chlorobutyl)oxirane] by benzoyloxylation and subsequent methanolysis. Poly[(4‐hydroxybutyl)oxirane] is insoluble in water, but is hydrophilic and can be cast into tough films from methanol or dimethylsulfoxide.
Anionic polymerization of lactones initiated by alkali graphitides. III. Polymerization of δ‐valerolactone initiated by KC24
Authors: Rashkov Iliya Bl. , Gitsov Ivan
Published: April 2003

The anionic polymerization of δ‐valerolactone initiated by KC24 in xylene or tetrahydrofuran was investigated. The influence of the polymerization conditions on the amount and composition of the oligomers fraction and high polymers formed was tested. Experiments were done with a potassium mirror and benzophenone‐potassium as initiators of the polymerization to check the influence of the layered structure of the initiator. It was found that the amount of the oligomers formed under comparable conditions increases in the order KC24 (9%), potassium mirror (22%), benzophenone‐potassium (56%). The highest yields of poly(δ‐valerolactone) (over 90%) and highest intrinsic viscosities (1.0 dL/g and more) were achieved by the KC24‐initiated polymerizations in xylene.