bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radical block polymerization of vinyl chloride. II. Synthesis and characterization of vinyl chloride block copolymers
Authors: Weinand G. , Smets G. 
Published: April 2003

AbstractPeroxidized polypropylene has been used as a heterofunctional initiator for a two‐step emulsion polymerization of a vinyl monomer (M1) and vinyl chloride with the production of vinyl chloride block copolymers. Styrene, methyl‐, and n‐butyl methacrylate and methyl‐, ethyl‐, n‐butyl‐, and 2‐ethyl‐hexyl acrylate have been used as M1 and polymerized at 30–40°C. In the second step vinyl chloride was polymerized at 50°C. The range of chemical composition of the block copolymers depends on the rate of the first‐step polymerization of M1 and the duration of the second step; e.g., with 2‐ethyl‐hexyl acrylate block copolymers could be obtained with a vinyl chloride content of 25–90%. The block copolymers have been submitted to precipitation fractionation and GPC analysis. Noteworthy is the absence of any significant amount of homopolymers, as well as poly(M1)n as PVC. The absence of homo‐PVC was interpreted by an intra‐ and intermolecular tertiary hydrogen atom transfer from polypropylene residue to growing PVC sequences. The presence of saturated end groups on the PVC chains is responsible for the improved thermal stability of these block polymers, as well as their low rate of dehydrochlorination (180°C). Molecular aggregation in solution has been shown by molecular weight determination in benzene and tetrahydrofuran.
Poly(dimethyl biphenylene)
Authors: Krigbaum W. R. , Krause Kenneth J. 
Published: April 2003

AbstractTwo methods were investigated for the preparation of poly(dimethyl biphenylene) in a search for polymers combining good solubility with sufficiently high chain extension to produce a lyotropic nematic phase. The Ullmann reaction was used to condense 4,4′‐diiodo‐3,3′‐dimethyl biphenyl and the corresponding 2,2′‐dimethyl derivative with copper, and 4,4′‐dibromo‐2,2′‐dimethyl biphenyl was polymerized using the coupling reagent, bis(1,5‐cyclooctadiene)nickel(0), developed by Semmelhack. The Ullmann polymers were completely soluble in CHCl3 but only partially soluble in toluene, whereas earlier work had indicated similar polymers of higher molecular weight to be completely soluble in toluene. All the polymers produced were of low molecular weight and no evidence of the nematic phase was found by polarized light microscopy for CHCl3 solutions over the concentration range 6.8–25% by weight.
The chemistry of THPC–urea polymers and relationship to flame retardance on wool and wool–polyester blends. II. Relative flame‐retardant efficiency on wool, polyester, and wool‐polyester blends
Authors: Basch Avraham , Nachamowitz Benjamin , Hasenfratz Sarah , Lewin Menachem 
Published: April 2003

AbstractOptimum flame retardance in THPC‐urea‐type formulations was achieved by approximately 1—0.9 THPC‐urea mole ratio and slow urea addition. A phosphonium salt structure is more efficient in flame retarding 100% wool and wool‐polyester blends than a phosphine oxide structure. Both structures are equivalent in flame retarding 100% polyester. It is considered probable that a vapor‐phase mechanism is predominant in the phosphorus‐based flame retardancy of wool, whereas a mixed solid‐vapor phase mechanism operates for 100% polyester.
Reaction of poly(vinyl chloride) with superoxide anion
Authors: Osawa Zenjiro , Nakano Hiroko , Mitsui Eiichi , Nakano Minoru 
Published: April 2003

AbstractReaction of poly(vinyl chloride) (PVC) with superoxide anion was carried out in tetrahydrofuran (THF) at 40°C in a nitrogen atmosphere. Remarkable changes in infrared (IR) spectra of the samples treated with superoxide anion were observed in the following regions: ca. 3300, 1680, 1620, and 765 cm−1, which suggested the formation of hydroxyl groups, α,β‐unsaturated ketone groups, and ethylenic structures. Ultraviolet–visible spectra also showed the formation of polyene structures. The content of chlorine in the polymer decreased and that of oxygen increased with reaction time. The reaction mechanism was discussed on the basis of these results.
Functional monomers and polymers. XXXXVI. A copolymerization study of methacryloyl‐type monomers containing nucleic acid bases in chloroform solution
Authors: Akashi M. , Kita Y. , Inaki Y. , Takemoto K. 
Published: April 2003

AbstractBehavior of the free radical copolymerization of N‐β‐methacryloyloxyethyl derivatives of adenine with that of thymine was studied in chloroform solution, taking account of the specific base‐base interaction of these monomers. Hydrogen bonding interaction between such monomers was observed by NMR spectroscopy. The acceleration of copolymerization was found to be greater either at lower monomer concentration or at lower polymerization temperature. When N‐β‐methacryloyloxyethylcarbazole was used as a comonomer, the rate of copolymerization showed a similar trend as in the case of usual free radical copolymerizations. From r1 and r2 values obtained, the copolymerization was found to be alternating, particularly in the case of copolymerization between monomers having complementary nucleic acid bases. The results suggest that the hydrogen bonding interaction between adenine and thymine plays a role in the propagation step.
Cyclopolymerization. VI. Polymerization mechanism of N‐methyl‐N‐allylmethacrylamide at lower temperature
Authors: Kodaira Toshiyuki , Murata Osamu 
Published: April 2003

AbstractMechanistic investigations on the polymerization of N‐methyl‐N‐allylmethacrylamide (MAMA) at lower temperature were carried out based upon the ESR studies of MAMA and its monofunctional counterparts irradiated with 60Co γ rays. Cyclopolymerizability of MAMA was also studied in connection with the hindered rotation about its amide CN bond. The propagating radical observed is only related to the methacryl group but not to the allyl group both in MAMA and its monofunctional counterparts. Polymerization at −78°C yielded a polymer with a lower degree of cyclization(88.8%) as compared with that of polymers formed at higher temperatures (93.5% above 0°C). A structural study revealed that the increment of the unsaturation in the poly‐MAMA obtained at −78°C is due to the allyl group and the content of pendant methacryl group is almost unchanged over the temperature range from −78 to 120°C. These results led to the conclusion that the polymerization of MAMA at −78°C proceeds mainly through the methacryl group, the rate‐determining step is the cyclization reaction, and, in addition, cyclization reaction scarcely occurs when it polymerizes through the allyl group. Since MAMA is frozen into a glassy state, the effect of glass transition temperature (Tg) has been studied and it was suggested that the polymerization of MAMA proceeds only above Tg.
Studies with model membranes. XXII. Evaluation of thermodynamic parameters and testing of theories of membrane and bi‐ionic potential based on nonequilibrium thermodynamics
Authors: Siddiqi Fasih A. , Nasim Beg M. , Prakash Poorna 
Published: April 2003

AbstractThermodynamically effective fixed‐charge density of mercuric phosphate and carbonate parchment‐supported membranes have been evaluated by the most recent method of Nagasawa et al., based on the thermodynamics of irreversible processes and compared with the values obtained by the Kobatake et al. and Teorell—Meyer—Sievers (TMS) methods. Bi‐ionic potential (BIP) has also been measured for these membranes with three pairs of electrolyte solutions: KClNaCl, KClLiCl, and NaClLiCl. Theoretical values of BIP have been calculated by using the membrane potential and BIP theories recently developed by Toyoshima et al., based on nonequilibrium thermodynamics. Various parameters have also been evaluated and it was found that the theoretical equation of BIP is applicable to these parchment‐supported membranes.
Copolymerization of acrylonitrile with 2‐hydroxyalkyl methacrylates
Authors: Bajaj P. , Jain P. C. , Gangopadhyay D. 
Published: April 2003

AbstractThe radical copolymerization of acrylonitrile with 2‐hydroxyethyl‐ (HEMA) and 2‐hydroxypropyl‐methacrylate (HPMA) has been studied in two media: dimethylformamide (DMF) and dimethylsulfoxide (DMSO), at 60°C. Copolymer composition was determined from the hydroxyl content and reactivity ratios were calculated by the Kelen‐Tüdös method. The values of r1 and r2 computed by the integrated and the Kelen‐Tüdös methods have been compared. A strong influence of the solvent on the reactivity ratios, particularly on r2 (HEMA or HPMA), has been observed. The copolymers prepared in DMSO are richer in hydroxyalkyl acrylates than those prepared in DMF. This effect may be attributed to preferential monomer solvation and the stability of the growing radicals. The influence of hydroxyalkyl acrylate comonomer on the properties of acrylonitrile copolymers (intrinsic viscosity and thermal behavior) are also discussed.
ESCA applied to polymers. XXII. An investigation of sample charging phenomena for polymeric films on gold
Authors: Clark D. T. , Dilks A. , Thomas H. R. , Shuttleworth D. 
Published: April 2003

AbstractSample charging phenomena arising in the ESCA experiment have been investigated for gold and polymer films of known thickness ranging from 5 Å to 20 μ deposited on gold either insulated from or in electrical contact with the spectrometer. Charging induced by a monochromatic x‐ray source is typically an order of magnitude greater than that induced by a nonmonochromatized source and exhibits a marked time dependence. A novel source of secondary electrons which employs a low‐power, low‐pressure mercury lamp external to the spectrometer source chamber as an alternative to an electron flood gun is described, and the charging and biasing characteristics of polymer films as a function of film thickness are discussed and demonstrated to provide an extra informational dimension for the study of polymeric materials.
Syntheses and reactions of functional polymers. XCVII. Chemical activation and functionalization of poly(γ‐methyl‐L‐glutamate)
Authors: Kudo Akira , Endo Takeshi , Tosabayashi Yoshihiro , Okawara Makoto 
Published: April 2003

AbstractTo enhance its solubility in common solvents poly(γ‐methyl‐L‐glutamate) (PMG) was transesterificated with ethylene chlorohydrin, ethylene cyanohydrin, and β,β,β‐trichloroethanol, respectively. The aminolyses of the resulting polymers proceeded easily in pendant ester groups to give the corresponding amides in reasonable yields without main chain fission. By these procedures the incorporation of functional groups such as azide, amino acid, and thiol into PMG is successfully performed.
Coordination reaction of cobaloxime with 4‐vinylpyridine‐styrene copolymer
Authors: Terada Ei‐Ichi , Nishikawa Hiroshi , Cho Jinshū , Tsuchida Eishun 
Published: April 2003

AbstractThe equilibrium constants of the coordination reaction of chlorodimethylformamide·cobaloxime with 4‐vinylpyridine–styrene copolymers (PPS) were determined. The constants for PPS, which contain 20–50% 4‐vinylpyridine (4VP) unit, measured about 1.3 × 105 liter/mole larger than those in the pyridine system (6.8 × 104 liter/mole). When the polymer ligand is 4VP homopolymer or contains less than 20% 4VP unit, K values are lower. The rate constants (kf) of the coordination reactions of the cobaloxime with polymer ligands were also measured in dimethylformamide (DMF) and benzene. In DMF kf decreased with an increase in 4VP unit content of the polymer ligand; in benzene it was increased by the 4VP fraction. These results can be explained by the variation in conformation of the polymer chain in each solvent. The effect of the polymer chain on complexation was discussed on the basis of the kinetic data.
Polymerization of coordinated monomers. XIV. Systematic deviations from alternating regulation in copolymerization of methyl methacrylate with styrene in the presence of metal halides
Authors: Hirai Hidefumi , Tanabe Tsuneaki , Koinuma Hideomi 
Published: April 2003

AbstractMethyl methacrylate (MMA) and styrene (St) copolymerize in the presence of zinc chloride at 3°C under photoirradiation. The contents of methyl methacrylate in the copolymers obtained at a [ZnCl2]/[MMA] molar ratio of 0.4 are systematically larger than 53 mole %, which is the limiting value at a small feed ratio of methyl methacrylate. The resulting copolymers are confirmed as the sole products and not the mixtures by thin layer chromatography. The effect of dilution of the monomer feed mixture with toluene on copolymer composition suggests that it depends chiefly on the feed concentration of styrene and hardly at all on monomer feed ratios. Copolymerizations are also conducted in the presence of stannic chloride at −17°C under photoirradiation and in the presence of ethylaluminium sesquichloride at 0°C with spontaneous initiation. The contents of methyl methacrylate in both copolymers obtained at feed ratios lower than 60 mole % almost correspond to the 1:1 alternating copolymer and increase systematically with higher feed ratios. The systematic deviations of copolymer composition obtained in the presence of metal halides are reasonably interpreted by the participation of the binary molecular complex composed of metal halide and methyl methacrylate in the polymerization of the ternary molecular complex composed of metal halide, methyl methacrylate, and styrene.
Radical cyclocopolymerization of divinyl ether and maleic anhydride. A 13C‐NMR study of the polymer structure
Authors: Kunitake Toyoki , Tsukino Mitsuo 
Published: April 2003

AbstractThe structure of the 1:2 copolymer of divinyl ether and maleic anhydride was investigated by 13C‐NMR spectroscopy. The polymer contains the bicyclic unit composed of one molecule of each monomer and the maleic anhydride unit. The carbon chemical shift for these units was calculated on the basis of the chemical shift of many model compounds. The major peaks of the cyclopolymer prepared in chloroform were consistent with the presence of the symmetrical bicyclic unit with cis junction and the trans monocyclic anhydride unit. The carbonyl carbon spectrum for the copolymer obtained in a mixed solvent of acetone and CS2 suggested the predominant formation of the unsymmetrical bicyclic unit. The polymerization process was discussed on the basis of these results.
Dye‐sensitized photoinitiated cationic polymerization. The system: Perylene–triarylsulfonium salts
Authors: Crivello J. V. , Lam J. H. W. 
Published: April 2003

AbstractPerylene has been found to photosensitize the photolysis of triarylsulfonium salts at wavelengths from 390 to 475 nm. Using perylene in combination with various triarylsulfonium salt photoinitiators, the photoinduced cationic polymerizations of cyclohexene oxide and 2‐chloroethyl vinyl ether have been demonstrated using light of these wavelengths.
Low‐temperature modification of dienic polymers via the “Ene” reaction with 4‐substituted‐1,2,4‐triazoline‐3,5‐diones
Authors: Butler George B. , Williams A. Grady 
Published: April 2003

Abstract4‐Substituted‐1,2,4‐triazoline‐3,5‐diones have been used to synthesize a series of new polydienes by the “ene” reaction at ambient temperatures. The extent of chemical conversion can be varied widely and up to 93% of the diene‐repeating units of the parent polymer chain undergo reaction. Yields of the new polymers based on the reactant range from 90 to 95% at room temperature; their physical properties range from secondary crosslinking effects or elasticity at low degrees of conversion to rigid, amorphous polymers with high softening points at high degrees of conversion. The new polymers show a predictable correlation between the extent of conversion and the softening point. A similar correlation exists between the polarity of the new polymers and the extent of conversion. Polydienes with conversions to the extent of 45% or greater are soluble in aqueous solutions of sodium hydroxide and those with conversions of 60% or greater are soluble in aqueous sodium bicarbonate. Thus, in general, the new polymers (1) have higher Tg, (2) become increasingly polar, hence are soluble in polar solvents, and (3) possess a reasonably acidic proton, hence form salts. Bistriazolinediones result in room temperature crosslinking. A kinetic study with model compounds suggests that the rate of the reaction can be varied, depending on the electronic nature of the 4‐substituent.
Monomer‐isomerization polymerization. XVII. Monomer‐isomerizations copolymerizations of 2‐butene with 3‐heptenes and 4‐methyl‐2‐pentenes with Ziegler‐Natta catalyst
Authors: Otsu Takayuki , Endo Kiyoshi , Yousufzai A. H. K. 
Published: April 2003

Abstract2‐Butene(2B) copolymerizes with 3‐heptene(3H) and 4‐methyl‐2‐pentene(4M2P) by a monomer‐isomerization copolymerization mechanism in the presence of TiCl3–(C2H5)3Al catalyst at 80°C to yield the copolymers of 1‐olefin units. By comparison, the copolymerization of 1‐butene(1B) with 4‐methyl‐1‐pentene(4M1P) was also carried out under similar conditions. The composition of the copolymers obtained from these copolymerizations was determined from the ratios of optical densities D723/D1380 and D1170/D1380 in their infrared (IR) spectra. The apparent monomer reactivity ratios for the monomer‐isomerization copolymerization of 2B with 3H and 4M2P, in which the concentration of olefin monomer in the feed was used as 2‐olefin, were determined as follows: cis‐2B(M1)/3H(M2); r1 = 4.00, r2 = 0.20: trans‐2B(M1)/3H; r1 = 3.50, r2 = 0.20; 4M2P(M1)‐trans‐2B(M2): r1 = 0.05, r2 = 9.0. These results indicate that the isomerization of 2‐olefins to 1‐olefins was important to monomer‐isomerization copolymerization.
Photolytic behavior of copolyamides from adipic and truxillic acids
Authors: Caccamese S. , Maravigna P. , Montaudo G. , Recca A. , Scamporrino E. 
Published: April 2003

AbstractThe synthesis of copolyamides from adipic and truxillic acids with piperazine was undertaken to include photoreactive units in aliphatic polyamides and to throw light on the factors that control the photolytic rates and photochromic behavior of these materials. The results indicate that the introduction of variable amounts of truxillic units (photodegradable) induces a measurable increment in the photolytic rate of the aliphatic polyamide. Moreover, it has been found that the addition of strong acids induces a higher photolytic cleavage of the polyamides, which may allow a further reduction in the amount of truxillic units in the copolyamides.
Stereochemistry in cationic polymerization of alkenyl ethers. II. Formation of poly(ß‐substituted vinyl ether)s with erythro‐meso structures
Authors: Hirokawa Yoshitsugu , Higashimura Toshinobu , Matsuzaki Kei , Uryu Toshiyuki 
Published: April 2003

AbstractThe formation of polymers with erythro‐meso structures, which could not be obtained from propenyl ethers with BF3O(C2H5)2, was studied by 13C‐NMR spectroscopy on poly(ß‐substituted vinyl ether)s obtained under a variety of conditions of polymerization. It was established that poly(cis‐ethyl propenyl ether) obtained with Al2(SO4)3–H2SO4 complex in toluene at 0°C was a highly stereoregular polymer with an erythro‐meso structure. Cis‐2‐chlorovinyl ethyl ether and cis‐methyl and ethyl butenyl ethers also yielded polymers with erythro‐meso structures under the same conditions. In addition, with BF3O(C2H5)2 at −78°C these three cis isomers produced amorphous polymers with threo‐meso, racemic, and, in a few cases, erythro‐meso structures, whereas cis‐ethyl propenyl ether produced polymers with only threo‐meso and racemic structures by the same catalyst. On the other hand, all trans isomers produced stereoregular polymers with threo‐meso structures with BF3O(C2H5)2 at −78°C, regardless of their ß‐substituents; no erythro‐meso structures were found in the polymers obtained.
Polymerization of t‐butyl thiirane. III. Temperature effect on the stereoelective polymerization
Authors: Dumas Philippe , Spassky Nicolas , Sigwalt Pierre 
Published: April 2003

AbstractThe effect of temperature on stereoelective polymerization of t‐butyl thiirane was studied. Although the overall kinetic scheme was not modified by a change of temperature, a strong effect on the stereoelectivity ratio was observed. Very high optical yields were obtained for polymerizations run below 0°C. On the other hand, at temperatures higher than 120°C, the stereoelection is inversed; i.e., the opposite enantiomer is chosen. The stereoselectivity ratio varies with temperature according to an Arrhenius relationship.
Thermotropic liquid crystalline polymers. II. Polymers with amino acid fragments in the side chains
Authors: Shibaev V. P. , Tal'roze R. V. , Karakhanova F. I. , Platé N. A. 
Published: April 2003

AbstractThe comblike polymers, poly(Nε‐methacryloyl‐Nα‐acyl) derivatives of L‐lysine, which contain amino acid fragments and long sequences of methylene groups in the side chain, were synthesized. This article, which is based on x‐ray data, differential thermal analysis, and optical microscopy, describes the structure of these polymers and their properties. It also shows that the combination of anisodiametric side groups with a “rigid” matrix of main chains leads to a liquid crystalline structure of examined polymers.
Ferrocene‐containing polymers. II. Radiation‐induced copolymerizations of ferrocenylmethyl methacrylate with styrene, methyl methacrylate, and ethyl acrylate
Authors: Tsubakiyama Kyoji , Matsuo Togoro , Sasaki Takashi , Yoshida Kenzo , Araki Kunio 
Published: April 2003

AbstractFerrocenylmethyl methacrylate (FMMA) was copolymerized with styrene (St), methyl methacrylate (MMA), and ethyl acrylate (EA) in benzene solution at 25°C by γ radiation. The reactions proceeded by a free radical mechanism, and monomer reactivity ratios were derived by the Tidwell–Mortimer method for St(M1)–FMMA(M2), r1 = 0.35 and r2 = 0.46; for MMA(M1–FMMA)(M2), r1 = 0.85 and r2 = 1.36; for EA(M1)–FMMA(M2), r1 = 0.36 and r2 = 3.03. The Q and e values of FMMA determined from copolymerization with St were 0.97 and 0.55, respectively. Terpolymerization of a MMA–FMMA–EA system based on the Alfrey–Goldfinger equations was studied. This is a typical terpolymerization system in which reactivities of the monomers obey the Q–e scheme. Comparing the results obtained here with those previously reported for other monomers, we concluded that FMMA is one of the most highly reactive monomers among alkyl methacrylates.
Polymerization of aromatic nuclei. XIX. Polymerization of thiophene by aluminum chloride
Authors: Kovacic Peter , McFarland Kathryn N. 
Published: April 2003

AbstractThiophene was polymerized in high yield on exposure to aluminum chloride in solvent under mild conditions. Experimental evidence [IR, NMR, UV, and mass spectra, elemental analyses, reductive desulfurization, and comparison with the literature trimer of thiophene (prepared with phosphoric acid)] suggests the following structure:
magnified image
From gel permeation chromatography an average weight of 1290 was obtained, which corresponded to the presence of 15 rings; the highest‐molecular‐weight chains contained about 192 rings. Mechanistically, participation of cationic intermediates is proposed. Apparently chain extension can occur by various routes, including participation of neutral oligomer molecules.
Synthesis of polyamides from active 2‐benzothiazolyl diesters and diamines under mild conditions
Authors: Ueda Mitsuru , Sato Akira , Imai Yoshio 
Published: April 2003

Abstract2‐Benzothiazolyl benzoate as a model compound was successfully synthesized from the benzoylation of 2‐benzothiazolone under kinetically controlled conditions. The aminolysis of 2‐benzothiazolyl benzoate afforded excellent yields of N‐substituted benzamides at room temperature in a short reaction time. Solution polycondensations of new active diesters, di‐2‐benzothiazolyl isophthalate and di‐2‐benzothiazolyl terephthalate, with aliphatic and aromatic diamines, took place rapidly even at room temperature and yielded polyamides with high molecular weight. The high reactivity of 2‐benzothiazolyl benzoate was discussed in relation to intramolecular general base catalysis and the tautomeric effect of the benzothiazolone moiety.