bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copolymerization of vinyl cyclohexane and α‐methyl vinyl cyclohexane with acrylonitrile
Authors: Kharas G. B. , Kleiner V. I. , Stotskaya L. L. , Krentsel B. A. , Lukina G. G. 
Published: April 2003

AbstractCopolymerization of vinyl cyclohexane and α‐methyl vinyl cyclohexane with acrylonitrile in the presence of a complexing agent AlEtCl2 results in the formation of alternate copolymers. In the copolymerization of vinyl cyclohexane with acrylonitrile the copolymer composition depends on the ratio of acrylonitrile to AlEtCl2. If this ratio is unity, alternating copolymers of the composition 1:1 are formed; with a ratio greater than unity statistical copolymers that contain more than 50% acrylonitrile units are produced. The 1H‐NMR spectroscopy measurements indicate that the interaction between the comonomers and the complexing agent leads to the formation of ternary donor–acceptor complexes of equimolar composition. The equilibrium constants of these complexes at −60°C have been determined. The effects of temperature, nature of solvent and dilution on the yield, and composition of the copolymers of vinyl cyclohexane with acrylonitrile formed have been studied. By lowering the temperature the yield of copolymers increases but their composition remains equimolar. An increase in the polarity of the medium results in an increase in copolymer yield, whereas the yield decreases if the reaction is conducted in a donor‐solvent medium. Dilution of the reaction mixture disrupts the alternation of units in the macrochain of copolymers. The kinetic pecularities of copolymerization have been investigated. The linear dependence of the copolymerization rate on the product of comonomer concentration is observed. The rate of copolymerization is proportional to the square root of the incident light intensity. Various additions of radical type and irradiation accelerate the process of copolymerization. The mechanism of alternating copolymerization of vinyl cyclohexane monomers with acrylonitrile in the presence of AlEtCl2 is discussed in terms of homopolymerization of the comonomer complex.
The preparation of poly(N‐acetyl‐α‐amino acrylic acid) [poly(N‐acetyl dehydroalanine)] and poly(α‐amino acrylic acid) (polydehydroalanine)
Authors: Asquith R. S. , Gardner K. L. , Yeung K. W. 
Published: April 2003

AbstractPoly(N‐acetyl‐α‐amino acrylic acid) was prepared by a free radical polymerization reaction. Mild alkaline hydrolysis of the polymer product yielded a second polymer poly(α‐amino acrylic acid) (polydehydroalanine). Both polymers exhibited certain polyelectrolyte behavior, although the latter did not behave as expected for an amphoteric polyelectrolyte.
Polymerization of methyl methacrylate initiated by Mn(III)–glycerol redox system
Authors: Nayak Padma L. , Samal Rajani K. , Nayak Mohan C. 
Published: April 2003

AbstractThe kinetics of thermal polymerization of methyl methacrylate initiated by the redox system Mn(III)–glycerol was studied in aqueous sulfuric acid in the temperature range of 30–40°C, and the rates of polymerization, Rp, and Mn3+ disappearance, etc., were measured. The effect of certain water‐miscible organic solvents and certain cationic and anionic surfactants on the rates of polymerization has been investigated. A mechanism involving the formation of a complex between Mn3+ and glycerol whose decomposition yields the initiating free radical with the polymerization being terminated by the metal ion has been suggested.
Photopolymerization of methyl methacrylate sensitized by aliphatic ketones
Authors: Lissi E. A. , Encina M. V. , Abarca M. T. 
Published: April 2003

AbstractThe polymerization of methyl methacrylate photosensitized by several alkyl ketones has been investigated. It was found that alkyl ketones can induce the free radical polymerization of the monomer with an efficiency that increases when the triplet lifetime decreases. For ketones of similar triplet lifetime those decomposing predominantly by a type I photocleavage show greater initiation efficiencies than those that react by a type II mechanism. The results obtained show that quenching of the excited ketones by the monomer does not induce polymerization. For ketones bearing γ‐hydrogens the initiation is due to the 1,4‐biradical produced by intramolecular hydrogen abstraction.
The chemistry of THPC–urea polymers and relationship to flame retardance on wool and wool‐polyester blends. I. Chemistry of THPC–urea polymers
Authors: Basch Avraham , Zvilichovsky Bina , Hirshmann Bella , Lewin Menachem 
Published: April 2003

AbstractPolymer formation from THPOH‐urea, THPOH‐dichloropropanol‐urea, and THPC‐urea was studied. Order and rate of urea addition were shown to influence insoluble polymer yields as well as polymer structure. The polymers were characterized by elemental analyses and infrared spectroscopy, and predominant structures proposed. The structures were correlated with thermogravimetric and differential scanning calorimetry data and probable thermal decomposition paths.
Linear dimerization of 1‐phenylbutadiene by acid catalysts
Authors: Higashimura Toshinobu , Hasegawa Hiroshi 
Published: April 2003

AbstractThis article describes the linear dimerization of 1‐phenylbutadiene by three catalysts (CF3SO3H, CH3COCIO4, and BF3OEt2) under a variety of conditions. With CF3SO3H catalyst the unsaturated linear dimer was formed selectively (75–85%) in a high yield by the proper choice of conditions; for example, at 70°C in benzene at low monomer concentrations (0.05–0.10 mole/liter). The dimerization was promoted in less polar solvents, at lower monomer concentrations, and at higher temperatures. In contrast, BF3OET2 gave only high‐molecular‐weight oligomers at 50°C in benzene. The structure of the dimer obtained with CF3SO3H was analyzed by infrared (IR) and 1H‐NMR spectroscopy and was concluded to be
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which may be formed via 3,4‐and 1,4‐addition, respectively. Nuclear magnetic resonance (NMR) spectra also showed that the oligomers produced by BF3OEt2 carry cyclic groups—one at the chain end and the other(s) attached to the main chain. Thus it was revealed that the nature of catalysts could control not only the molecular weight but the structure of oligomerization products.
Mechanism of the NCA polymerization. VI. Investigations on cocatalysts of the base‐initiated NCA polymerization
Authors: Kricheldorf Hans R. 
Published: April 2003

AbstractThe triethylamine‐initiated polymerization of glycine‐NCA [N‐carboxylic acid anhydrides (oxazolidine‐2,5‐diones)], L‐alanine‐NCA, and sarcosine‐NCA, as well as the pyridine‐initiated polymerization of sarcosine‐NCA, were carried out in the presence of potential cocatalysts. The 11 electrophilic reagents tested in this work can be divided into two classes: N‐acyllactams and similar compounds, which are less reactive than the monomers and have no influence on the polymerization; and isocyanates and N‐acyl‐NCAs or ‐NTAs [N‐thiocarboxylic acid anhydrides (thiazolldine‐2,5‐diones)], which are more electrophilic than the monomers and behave as cocatalysts in the case of glycine‐NCA and alanine‐NCA, since their base‐initiated polymerization proceeds via the attack of NCA anions on the electrophilic N‐acyl NCA chain and (“activated monomer mechanism”). In the case of sarcosine‐NCA, however, the propagation involves a nucleophilic chain end (“carbamate mechanism”) and the strong electrophilic reagents behave as inhibitors.
Cyclic acetal‐photosensitized polymerization. VII. Photopolymerization of 2‐vinyl‐4‐hydroxymethyl‐1,3‐dioxolane
Authors: Ouchi Tatsuro , Nakamura Takaki , Yonekura Kuniharu 
Published: April 2003

AbstractIn order to assess the effect of the methylol group at the 4‐position of 1,3‐dioxolane on polymerization, the photopolymerization of 2‐vinyl‐4‐hydroxymethyl‐1,3‐dioxolane (VHDO) was carried out in benzene at 40°C. The reaction scheme of VHDO was considered to be the same as that of 2‐vinyl‐1,3‐dioxolane (VDO). The rate of polymerization and the molecular weight of polymer were small because of the degradative chain transfer by allylidene group. Moreover, the rate of polymerization of VHDO was greater than that of VDO, whereas the molecular weight of polymer of VHDO was less than that of VDO.
Dilute solution properties of methyl methacrylate—acrylonitrile copolymer (MA2)
Authors: Kashyap A. K. , Kalpagam V. 
Published: April 2003

AbstractThis article deals with studies of the dilute solution properties of methyl methacrylate‐acrylonitrile (MMA‐AN) copolymer of 0.415 mole fraction (mf) of acrylonitrile composition. Mark—Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2‐butanone (MEK), dimethyl formamide (DMF), and γ‐butyrolactone (γ‐BL). The Mark‐Houwink exponent a in all four solvents at all temperatures is larger than the corresponding values of the parent homopolymers. The solvent power is in the order of DMF < γ–BL < MEK < MeCN; [η] decreases with an increase in temperature, which is behavior characteristic of polymers in good solvent. The unperturbed dimensions (K0) values, obtained by the Stockmayer–Fixman method, are lower than those for the parent homopolymers and depend on solvent as well as temperature. The solute—solvent interaction parameter X1 values are close to 0.5; X1 is independent of temperature. The excess interaction parameter XABvalues are negative. The results for this copolymer system in regard to low second virial coefficient A2, large X1, and high a values suggest that the large extension of these copolymer chains is due to the unusual short‐range interactions.
Alternating polyampholytes prepared by hydrolysis of copolymer of maleic anhydride and N‐vinylsuccinimide
Authors: Furukawa Junji , Kobayashi Eiichi , Doi Toshiki 
Published: April 2003

AbstractAlternating polyampholytes (MA‐VA) containing two acidic groups and one basic group were prepared by the copolymerization of maleic anhydride (M1) and N‐vinylsuccinimide (M2) at 60°C with AIBN as the initiator, followed by acid hydrolysis with 1N hydrochloric acid at 140°C for 24 hr. The monomer reactivity ratios r1 and r2 are 0.025 and 0.06, respectively. The structure of polymers was discussed on the basis of the data of their elementary, infrared (IR), and thermal analyses and the binding ability of heavy metal ion. Polyampholytes were soluble in strong acidic and basic media but were precipitated in the pH range 3–4. An isoelectric point at pH 3 was determined by potentiometric titration and the turbidimetric method. By thermal treatment above 205°C the polyampholyte turned quantitatively into a cyclized lactam. This suggests that the polyampholyte MA–VA has an intramolecular hydrogen bond between the amino and γ‐carboxyl groups. The binding of Cu2+ and Hg2+ by the polyelectrolyte was evaluated by equilibrium dialysis.
Synthesis and properties of alternating copolymers of potential antitumor activity containing 5‐fluorouracil
Authors: Umrigar Pesi P. , Ohashi Shinichi , Butler George B. 
Published: April 2003

Abstract“Pyran” copolymer, the 2:1 regularly alternating cyclocopolymer (DVE—MA) of maleic anhydride (MA) and divinyl ether (DVE), first discovered in 1951, has been investigated extensively, both from the standpoint of its chemical structure and its biological activity. Although certain aspects of its structure remain to be determined, it has been shown to possess a wide spectrum of biological activity. It possesses antitumor activity and has been investigated clinically. During the clinical investigation, it was found to be an interferon inducer. Interferon is a protein which appears to be the body's first line of defense against viral infection. DVE—MA also possesses antiviral, antibacterial, antifungal, antiarthritic, and anticoagulant properties, activates macrophages, inhibits reverse transcriptase, and is capable of elimination of Pu. During the course of investigations in these laboratories, many structural modifications of DVE—MA have been made. Many of these modifications also possess considerable antitumor activity and interferon‐induction capability. Perhaps the most interesting structural modification has been the incorporation of 5‐fluorouracil (5‐FU) into the polymer (NSC 255083). This polymer has shown (T/C)% [= ratio of test (T) to control (C) survival times] = 189 for dose by intraperitoneal injection of 200 mg/kg animal weight in CD2F1 mice (6/6 survivors after fifth day) against P388 lymphocytic leukemia. This article describes the synthesis of both the monomer and copolymer, and a study of the hydrolytic rate of release of 5‐FU from the polymer.
Effect of ferric chloride on acid hydrolysis of viscose rayon
Authors: Shinouda H. G. , Moteleb M. M. Abdel , Kinawi A. 
Published: April 2003

AbstractA comparison between the fine structure of viscose hydrocelluloses prepared by acid hydrolysis of viscose fibers in the absence and presence of ferric chloride is given. The results indicate that ferric chloride has little effect on the change in x‐ray crystallinity indices accompanying acid‐hydrolysis of the fibers. On the other hand, specific volume results show that the inner fine structure of hydrocelluloses prepared by hydrolyzing the fibers with free acid differs from that for hydrocelluloses prepared with an HCl‐FeCl3 reagent.
Vinyl polymerization. 364. Polymerization of methyl methacrylate initiated with benzaldehyde
Authors: Imoto Minoru , Maeda Takamasa , Ouchi Tatsuro 
Published: April 2003

AbstractBenzaldehyde (PhCHO) is found to be able to initiate the radical polymerization of methyl methacrylate (MMA). The rate of polymerization is expressed by the following equation: Rp = const[PhCHO]0.5[MMA]1.5. The overall activation energy is estimated to be 56.3 kJ mole−1. The mechanism of polymerization is discussed.
Homopolymerization of propylene oxide and copolymerization of propylene oxide and carbon dioxide with metal salts of acetic acid
Authors: Soga Kazuo , Uenishi Kazuya , Ikeda Sakuji 
Published: April 2003

AbstractThe homopolymerization of propylene oxide was first conducted at 80°C in the absence of any solvent by using various metal salts of acetic acid and it was found that Mg(OAc)2, Cr(OAc)3, Mn(OAc)2, Co(OAc)2, Ni(OAc)2, Zn(OAc)2, and Sn(OAc)2 were effective for the polymerization. The copolymerization of propylene oxide and carbon dioxide was next examined by using these effective metal salts of acetic acid as catalysts. Most of these were effective also for the copolymerization. The nature of the polymer obtained was strongly dependent on the catalyst used. Co(OAc)2 and Zn(OAc)2 gave an alternate copolymer of propylene oxide and carbon dioxide, Mg(OAc)2, Cr(OAc)3, and Ni(OAc)2 gave a random copolymer, while Sn(OAc)2 gave a homopolymer of propylene oxide. Then the copolymerization of propylene oxide and carbon dioxide was kinetically investigated in some detail by using Co(OAc)2 as a catalyst. On the basis of the results obtained, a plausible mechanism was proposed for both the homopolymerization of propylene oxide and copolymerization of propylene oxide and carbon dioxide.
Isolation of the complex between acrylonitrile and trimethylaluminum
Authors: Koma Yasuo , Koide Naoyuki , Tanaka Akira , Iimura Kazuyoshi , Takeda Masatami 
Published: April 2003

AbstractThe complex of acrylonitrile (AN) with trimethylaluminum (AlMe3) was successfully isolated as a white needlelike crystal with a melting point of 42.5°C. In this article the preparation of the complex is described in detail. Cryoscopic and spectral investigations indicated that the complex is formed by an equimolar ratio of AN and AlMe3. From the measurement of the x‐ray diffraction photograph of the crystal the repeat period was determined to be 9.47 ± 0.05 Å.
Asymmetric induction copolymerization. Cationic copolymerization of l‐menthyl vinyl ether with indene and acenaphthylene
Authors: Kurokawa Masahiro , Yamaguchi Hidemasa , Minoura Yuji 
Published: April 2003

Abstractl‐Menthyl vinyl ether (l‐MVE) was homopolymerized and copolymerized with the monomers indene (IN) and acenaphthylene (ANp) by BF3OEt2 as a catalyst. The chiral menthyl substituent was cloven from the homopolymers and copolymers using dry‐hydrogen bromide gas. After the removal of optically active menthyl group, poly(vinyl alcohol) (PVA) from l‐MVE homopolymer was optically inactive, and copolymers (VA‐IN, VA‐ANp) from l‐MVE‐IN and l‐MVE‐ANp copolymers were still optically active. Hence, in the case of l‐MVE homopolymer, it was concluded that asymmetric induction in the polymer main chain can only produce pseudoasymmetry. In the case of l‐MVE‐IN and l‐MVE‐ANp copolymers, it was found that asymmetric induction proceeded in the copolymer main chain and was caused by the influence of chiral menthyl group.
Electric conductivity of TCNQ salts of ionene polymers containing triethylenediammonium or 4,4′‐bipyridilium ring
Authors: Kamiya Tamotsu , Goto Kuniyuki , Shinohara Isao 
Published: April 2003

AbstractThe ionene polymers were prepared by the Menshutkin reaction of α,ω‐dibromoalkane (n) with triethylenediamine (TDA) or 4,4′‐bipyridil (BP). Resistivities (p) and activation energies of conduction (Ea) were measured for the polymeric 7,7,8,8‐tetracyanoquinodimethan (TCNQ) salts with these ionenes. The correlation between the chemical structure of the ionenes and the conductivity was discussed. In the TDA,n‐TCNQ complex salts and the BP,n‐TCNQ simple salts the salts of the ionenes containing even numbers of CH2 groups showed higher conductivities than those of the ionenes containing odd numbers of CH2 groups. The conductivities determined by the narrower interval between the N+ cations of the main chains were measured in the simple salts. In the complex salts the conductivities determined by the larger interval were measured. The conformational change of the matrix ionenes affected the arrangement of the TCNQ molecules. The values of p were 79.7 and 12.5 Ω cm, and the values of Ea were 0.122 and 0.063 eV for TDA,4‐TCNQ complex salt and BP,5‐TCNQ complex salt, respectively.
Electric conductivity of polymer composites with 7,7,8,8‐tetracyanoquinodimethan salts
Authors: Mizoguchi Katsuhiro , Kamiya Tamotsu , Tsuchida Eishun , Shinohara Isao 
Published: April 2003

AbstractThe electric properties of polymer composites with highly conductive 7,7,8,8‐tetracyanoquinodimethan (TCNQ) salts such as quinolinium–TCNQ complex salt (), acridinium–TCNQ complex salt (), and N‐methylacridinium–TCNQ complex salt () were studied. Polyacrylonitrile (PAN), poly(N‐vinylcarbazole) (PVK), and poly(4‐vinylpyridine), (P4VP), etc., were chosen as matrix polymers. The resistivity (ρ) of the was 0.37 Ω cm at the content of 20 wt % in the film. When the content of was increased up to 40 wt%, a phase separation of the needle crystals was observed and the ρ value increased. When was dispersed into PAN or PVK, the separation was also observed and the samples showed low conductivity. The uniform films were obtained in the and systems, but the values of ρ were high because of the degradation of the TCNQ salts. Uniform films with the naked eye were obtained in the and systems, and the values of Ω were 0.37, 1.05, and 3.40 Ω cm, respectively. was stable even when dispersed into P4VP. The properties of the composites were influenced by the combination of the TCNQ salts and the polymers. The uniformity and the stability of the composites were necessary to obtain the high conductive composites.
Some aspects of the polymerization of n‐butyl vinyl ether by chromyl chloride
Authors: Biswas Mukul , Kabir G. M. Ahsanul 
Published: April 2003

AbstractThe rate of n‐butyl vinyl ether polymerization by chromyl chloride is first order in [catalyst] and second order in [monomer]. Added H2O (after a certain concentration) and HCl increase the rate, thiophene retards the rate, while pyridine inhibits the rate. DP is independent of [chromyl chloride] and increases with increasing [monomer] up to 1M, thereafter becoming independent of it. Both rate and DP increase over the range 10−32°C and decrease at higher temperatures.
Nonclassical urea oligomers. IV. Polymerization of (S)‐1‐(N‐phenyl‐carbamoyl)‐2‐methylaziridine. A synthesis of optically active crystalline oligomer with narrow molecular weight distribution
Authors: Araki Takeo , Nagata Koichi , Tsukube Hiroshi 
Published: April 2003

AbstractIn the presence of Et2SO4, (S)‐1‐(N‐phenyl‐carbamoyl)‐2‐methylaziridine gave an oligomer with a structure of [CH2CHCH3N(CONHPh)]n. The oligomer has optically active isotactic configuration and narrow molecular weight distribution (DP ca. 8). The net polymerization behavior of the monomer and chemical property, such as absorptivity of Et2SO4, of the oligomer are analogous to the case of 1‐(N‐phenyl‐carbamoyl)‐aziridine. The ring opening occurs with retention of the configuration at the asymmetric carbon atom and the oligomer can be crystallized at around 90°C.
Thermal degradation of poly(vinyl chloride): effect of oxygen on the thermal degradation of poly(vinyl chloride)
Authors: Gupta V. P. , St. Pierre L. E. 
Published: April 2003

AbstractOn the basis of the simultaneously measured free radical generation and HCl evolution a mechanism accounting for the effect of the oxygen on the degradation of poly(vinyl chloride) (PVC) is proposed. The mechanism is based on the reaction of oxygen with radicals generated in PVC to form unstable peroxy radicals. In addition, it is proposed that oxygen reacts directly with conjugated polyenes to form peroxy linkage.
Photoinduced ionic polymerization. VII. Cationic polymerization of cyclohexene oxide in solid state
Authors: Irie Masahiro , Sasaoka Senzo , Yamamoto Yukio , Hayashi Koichiro 
Published: April 2003

AbstractPhotopolymerization of cyclohexene oxide in the presence of electron acceptors was studied in a bulk system (in liquid as well as in solid states). The polymerization was proved to proceed by a cationic mechanism in both states by the effect of inhibitors. In a liquid phase the light intensity dependence of the rate of polymerization and the molecular weight distribution showed a contribution of a free ionic polymerization. Any discontinuous phenomenon in the rate as well as in the molecular weight was not discerned between liquid(above −36°C) and plastic crystal (between −36 and −81°C) phases. A quantum yield of monomer consumption as high as 8 × 103 was observed in the plastic crystal phase. Below −81°C in the normal crystal phase the rate as well as the molecular weight was remarkably suppressed.
Neighboring effect of the sodium carboxylate group on the saponification of diallyl phthalate prepolymer
Authors: Imai Itsuro , Matsumoto Akira , Oiwa Masayoshi 
Published: April 2003

AbstractThe neighboring effect of sodium carboxylate groups on the saponification of diallyl phthalate prepolymer was investigated in detail in dioxane solutions that contained various amounts of water at 50°C by using different types of model compound; this procedure is also compared with the neighboring effect of hydroxyl groups.
The reaction of diphenyl carbonate with amines and its application to polymer synthesis
Authors: Yamazaki Noboru , Iguchi Tadao , Higashi Fukuji 
Published: April 2003

AbstractSelective formation of biscarbamates from diphenyl carbonate (DPC) and diamines and the preparation of polyurethanes from the carbamates and diols under mild conditions were studied. The reaction of DPC and diamines was significantly affected by catalysts, biscarbamates being exclusively prepared in high yields in the presence of 2‐hydroxypyridine. The polycondensation reaction of the biscarbamates with diols was facilitated by catalysts such as metal salts; among the catalysts examined magnesium chloride in pyridine gave the best results. Metal chlorides in pyridine also promoted the reaction of DPC with aromatic amines to give the corresponding ureas, and the direct synthesis of polyureas was achieved by the polycondensation of DPC with diamines in the presence of the chloride.