bluuebunny/crossref_metadata_2025 huggingface dataset:
A reinvestigation of the chemical reactivity of N‐perfluoroacylaziridines
Authors: Demember John R. , Taylor Lloyd D.
Published: April 2003

It has been found that polymerization of perfluoroacylaziridine (1) occurs in the presence of acid. The polymers formed in the presence of acid have much higher uniformity of the unit structure and are of similar molecular weight to those obtained from anionic, or nucleophile‐initiated, polymerization of aziridine (1). The polymers formed from polymerization of aziridine (1) in the presence of acid provide an accessible route to linear unbranched polyethylenimine.
The photo‐ and electroinitiated polymerization of N‐vinyl phthalimide
Authors: Davies D. H. , Phillips D. C. , Smith J. D. B.
Published: April 2003

To elucidate mechanisms in electroinitiated polymerization reactions a comparison was conducted between ultraviolet (UV) photoinitiation and electroinitiation of N‐vinyl phthalimide with zinc chloride as a catalyst. Both methods give low yields of a complex polymer product. A detailed analysis, infrared (IR), gel permeation chromatography (GPC), elemental, and molecular weight, conducted on the polymeric products, indicated that phthalimide ring opening was occurring and that complex mixtures of poly(N‐vinyl phthalimide) derivatives were formed. Both initiation methods gave comparable results, which further indicated mechanistic similarity between photo‐and electroinitiation in these donor–acceptor charge transfer polymerizations.
Synthesis of polyamides by ring‐opening polyaddition of bis‐3,1‐benzoxazin‐4‐ones with aliphatic diamines
Authors: Ueda Mitsuru , Imai Yoshio
Published: April 2003

Open‐chain polyamides with inherent viscosities of 0.1–0.6 were prepared in nearly quantitative yields by the ring‐opening polyaddition of combinations of six bis‐3,1‐benzoxazin‐4‐one monomers and two aliphatic diamines in polar aprotic solvents at 80°C or below. The polymerization carried out in dimethyl sulfoxide at 80°C was best for preparing high‐molecular‐weight polymers. These polyamides were generally soluble in polar aprotic solvents, m‐cresol, and pyridine.
Synthesis of formamidine‐containing polymers from aromatic diamines
Authors: Mathias L. J. , Overberger C. G.
Published: April 2003

Aromatic polymers containing formamidine groups in the polymer backbone were obtained from aromatic diamines in high yields with α,α‐dichloromethyl ether and triethylorthoformate. The latter was the reagent of choice. Soluble, high‐molecular‐weight products were obtained with m‐phenylene diamine and 4,4′ bis(aminophenyl)methane. These polymers were characterized by viscosity, microanalysis, and nuclear magnetic resonance and infrared spectroscopy. Generally, insoluble products were obtained from p‐phenylene diamine and 2,6‐diaminotoluene, although small amounts of dimethylsulfoxide (DMSO)‐soluble fractions could be extracted and examined by NMR spectroscopy. IR analysis of the insoluble fractions confirmed formation of polymers with the formamidine‐containing structures. The synthetic procedures developed here make readily available this new class of aromatic polymers.
Plasma polymerization: An ESCA investigation of polymers synthesized by excitation of inductively coupled RF plasmas in isomeric difluoroethylenes
Authors: Clark D. T. , Shuttleworth D.
Published: April 2003

The polymers produced by glow discharge from three isomeric monomers are examined by ESCA. The polymer produced from 1,1‐difluoroethylene is discussed in some detail and compared with those prepared from the two 1,2‐difluoroethylene isomers. Charge distributions for the neutral molecules and their radical cations are calculated within the INDO SCF MO formalism and a possible reaction scheme that involves fluoroacetylene is outlined.
Pyrolysis of polyisoprenes. I. Differentiation between natural and synthetic cis‐1,4‐polyisoprenes
Authors: Gelling I. R. , Loadman M. J. , Sidek B. D.
Published: April 2003

Two methods of differentiating between natural rubber and synthetic cis‐1,4‐polyisoprenes have been examined. Both techniques depend on the presence of Ziegler‐Natta catalyst residues in the synthetic polymers. The major pyrolysis product of cis‐1,4‐polyisoprenes at 350°C is 1‐methyl‐4‐(1‐methylethenyl)cyclohexene. This can undergo disproportionation to yield 1‐methyl‐4‐(1‐methylethyl)benzene and methyl‐(1‐methylethyl)cyclohexenes. It is this disproportionation reaction, catalyzed by Ziegler‐Natta catalyst residues or by carbon black, that is responsible for the different product ratios obtained on pyrolysis of natural rubber and Ziegler‐Natta catalyzed cis‐1,4‐polyisoprenes. Lithium alkyl‐polymerized polyisoprenes undergo this secondary disproportionation reaction only in the presence of carbon black. Derivative thermogravimetric traces of black‐filled sulfur vulcanizates of natural rubber and synthetic polyisoprenes are significantly different because polymerization catalyst residues promote cyclization of the polymer.
Kinetics of radiation‐induced graft polymerization of styrene onto poly(ethylene oxide)
Authors: Omichi H. , Araki K.
Published: April 2003

The graft polymerization of styrene onto preirradiated poly(ethylene oxide) was studied. From the measurement of swelling of the polymer in various solvents the solubility parameter of poly(ethylene oxide) was estimated as 9.3. The kinetic analysis of the reaction indicated that the graft polymerization was diffusion controlled. Kinetic parameters of the reaction such as \documentclass{article}\pagestyle{empty}\begin{document}$\int_0^t {R_i} dt,k_{p,} k_{tr}$\end{document}, and kt were obtained in poly(ethylene oxide)‐styrene system and compared with those in poly(isobutylene oxide)‐styrene system.
Studies of the polymerization of diallyl compounds. XXII. Polymerization of diallyl oxalate in the evolution of carbon dioxide at elevated temperatures
Authors: Matsumoto Akira , Tamura Ikuo , Yamawaki Masataka , Oiwa Masayoshi
Published: April 2003

The polymerization of diallyl oxalate was conducted in the presence of radical initiators at a high temperature range of 80–180°C; a large decrease in degree of polymerization, an increase in residual unsaturation of the resulting polymer, and the evolution of carbon dioxide were observed with the elevation of temperature. These findings were reasonably interpreted by considering the dismutation of the uncyclized growing radical to yield the allyl radical, carbon dioxide, and polymer carrying a terminal double bond. The kinetics of the polymerization of diallyl oxalate in the evolution of carbon dioxide at elevated temperatures were also discussed in detail.
Monomer‐isomerization polymerization. XIX. Monomer‐isomerization copolymerizations of methylbutenes and 2‐butene with Ziegler‐Natta catalyst
Authors: Endo Kiyoshi , Otsu Takayuki
Published: April 2003

The copolymerization of 3‐methyl‐1‐butene (3M1B), 2‐methyl‐2‐butene (2M2B), or 2‐methyl‐1‐butene (2M1B) with trans‐2‐butene (2B) was attempted in the presence of a Ziegler‐Natta catalyst. It was found the 3M1B underwent monomer‐isomerization copolymerization with 2B to give a copolymer consisting of both 3M1B and 1‐butene (1B) units, with an infrared (IR) spectrum in good agreement with that obtained from the copolymerization of 3M1B with 1B under similar conditions. When the apparent copolymerization parameters obtained by a TiCl3–(C2H5)3Al catalyst were compared, the apparent reactivity of 3M1B observed in the 3M1B‐2B system was much higher than that in the 3M1B‐1B system. However, 2M2B and 2M1B did not undergo monomer‐isomerization copolymerization with 2B, and only the homopolymer of 1B was obtained under similar conditions.
Synthesis of wholly aromatic polysulfonamides from aromatic disulfonyl chlorides and aromatic diamines
Authors: Imai Yoshio , Ueda Mitsuru , Iizawa Takashi
Published: April 2003

Wholly aromatic polysulfonamides of high molecular weight were prepared by the solution poly‐condensation of aromatic disulfonyl chlorides with aromatic diamines in tetramethylene sulfone and substituted pyridines as the acid acceptor. Polysulfonamides with inherent viscosities as high as 1.2 were readily obtained by initiating polycondensation at a temperature of 5–10°C to control the side reactions. The polycondensation was fairly fast and was completed in 10 min at 60°C. All the aromatic polysulfonamides dissolved in a wide range of solvents, including acetone and tetrahydrofuran. These polymers were less thermally stable than the corresponding aromatic polyamides.
Fluorination of polyhydrofluoroethylenes. II. Formation of perfluoroalkyl carboxylic acids on the surface region of poly(vinylidene fluoride) film by oxyfluorination, fluorination, and hydrolysis
Authors: Shinohara Haruka
Published: April 2003

Oxyfluorination and postfluorination behaviors of poly(vinylidene fluoride) films, as well as hydrolysis of the films treated so far, have been studied by infrared (IR) spectrometry. By exposing the polymer film to a mixture of oxygen and fluorine at about 90°C acyl fluoride groups attendant on the scission of the polymer chains were formed. The oxyfluorinated molecules could be further perfluorinated with fluorine alone at about 90°C, leaving many of the acyl fluoride groups. When the properly oxyfluorinated and postfluorinated film was further treated with a hot 6M sodium hydroxide solution the opaque layer of perfluoroalkyl sodium carboxylate of high molecular weight was formed on the surface of the film, to about 3 μm in thickness, which behaved as a cation exchanger. This new type of cation exchanger of perfluoroalkyl carboxylic acid was significantly more acidic than the usual methacrylic acid exchanger. It was able to adsorb the sodium ions from a neutral sodium chloride solution up to about 70% of the exchange capacity and to keep the ions stable while washing them with water, though it could be regenerated to the hydrogen form with a dilute acetic acid solution. The nature of the new ion exchanger has been examined in some detail by IR spectrometry with Li+, Na+, and Cs+ ions.
Polysalt complexes of poly(vinylbenzo‐18‐crown‐6) and of poly(crown acrylate)s with polyanions
Authors: Varma A. J. , Majewicz T. , Smid J.
Published: April 2003

Macrocyclic polyether or crown ether ester derivatives of acrylic and methacrylic acid were synthesized and polymerized. The cation binding properties of the polymers determined by extraction of picrate salts were similar to those obtained for poly(crown ether)s derived from styrene. In the presence of a crown‐complexable cation both polymers form insoluble polysalt complexes with sodium carboxymethylcellulose, potassium poly(styrene sulfonate), and potassium polyacrylate. The extent of precipitation depends on the type and concentration of cation as well as on the ratio polyanion to poly(crown ether). The precipitate appears to have an equal number of positive and negative charges. An insoluble hydrogen‐bonded complex is formed in the absence of salt when poly(vinylbenzo‐18‐crown‐6) and poly(acrylic acid) are mixed in 0.01M HCl. Organic solutes bound to the poly(crown ether)s, which occur in an aqueous mixture of poly(vinylbenzo‐18‐crown‐6) and picrate anions, are precipitated with the poly(crown ether) when the polysalt complex is formed.
Polymerization of vinylpyridinium salts. III. Further studies on the interfacial and isotropic polymerization of 4‐vinyl‐N‐methylpyridinium methylsulfate
Authors: Paleos C. M. , Evagelatos G. P. , Dais Photis , Kipouros G.
Published: April 2003

In the present study the polymerization of 4‐vinyl‐N‐methylpyridinium methylsulfate at liquid–liquid interfaces is investigated. Various experimental procedures that may favor the interfacial mode of polymerization over the isotropic one are discussed. The effectiveness of the methods was evaluated by physical characterization studies and particularly polymer tacticity. This last property is directly associated with the achieved organization of the monomers at interfaces. 13C‐NMR technique was used for tacticity determination. According to tacticity, random polymers are primarily obtained that result from an isotropic polymerization in the aqueous phase, where the monomer is extremely soluble. The small predominance of the syndiotactic triad over the isotactic one is explained by the occurrence of an interfacial polymerization induced by the orientation of the monomers. A polymerization model is proposed that justifies the stereospecificity modification of polymerization.
Kinetics of radiation‐induced graft copolymerization of styrene with ethyl acrylate
Authors: Omichi H. , Araki K.
Published: April 2003

The radiation‐induced graft copolymerization of styrene with ethyl acrylate onto preirradiated polyethylene powder was carried out at 20°C. The grafting yield decreased in the following order: ethyl acrylate ≫ styrene > styrene–ethyl acrylate mixture. On the other hand, the amount of absorption of liquid monomers in polyethylene powder decreased as follows: styrene > styrene–ethyl acrylate mixture > ethyl acrylate. By kinetic analysis of the grafting yield and amount of absorption of monomers it was elucidated that the value Kp/Kt in an ethyl acrylate system (7.7 × 10−2) was much larger than those in styrene–ethyl acrylate systems and in a styrene system (ca. 1.0 × 10−2).
Vinylhydroquinone. V. Tri‐n‐butylborane‐initiated copolymerization of maleic anhydride and redox property of copolymers
Authors: Iwabuchi Susumu , Watanabe Yasaku , Nakahira Takayuki , Kojima Kuniharau
Published: April 2003

Tri‐n‐butylborane (TBB) was found to be capable of initiating the copolymerization of vinylhydroquinone (VHQ) with maleic anhydride (MAn) and diethyl fumarate (DEF) in cyclohexanone at 30°C under nitrogen. Redox potentials of the VHQ–MAn copolymer obtained were examined. These results, along with spectroscopic data, indicate that the copolymers are of a highly alternating character.
Metallo esters. VII. Stabilizing effect of sodium tert‐butoxide on the growth center in the anionic polymerization of methacrylic esters
Authors: Lochmann L. , Kolařík J. , Doskočilová D. , Vozka S. , Trekoval J.
Published: April 2003

The growth center in the anionic polymerization of methacrylic esters is stabilized with alkaline alkoxides, sodium tert‐butoxide in particular. The lifetime of the growth center was investigated in the polymerization of methyl methacrylate by evaluating yield and molecular weight distribution of the polymer formed when the monomer was added in two doses. The average lifetime of the original growth center stabilized by sodium tert‐butoxide at 20°C under the given conditions was longer than several minutes. The stabilization of the growth center was also used in the stepwise copolymerization of n‐butyl methacrylate and methyl methacrylate. The copolymer thus obtained in high yield was characterized as a block copolymer on the basis of its solubility, nuclear magnetic resonance (NMR) spectra, and measurements of the complex shear modulus.
Graft copolymers of nucleic acid bases on polyethyleneimine: Interaction of the polymers
Authors: Overberger C. G. , Inaki Yoshiaki , Nambu Yoko
Published: April 2003

Interactions of the graft copolymers of nucleic acid bases on polyethyleneimine with polynucleotides were studied. The backbone of the polymer is linear or branched polyethyleneimine. The nucleic acid bases are adenine and thymine. The polynucleotides used were polyadenylic acid (poly‐A) and polyuridylic acid (poly‐U). Interactions between these polymers were measured by ultraviolet (UV) absorption and the results were compared with the vinyl‐type nucleic acid model polymer.
Anionic polymerization. VI. Effect of polar modifiers on alkylsodium and alkylpotassium polymerization of butadiene
Authors: Halasa Adel Farhan , Cheng Tai Chun , Hall James E.
Published: April 2003

It was found that N,N,N′,N′‐tetramethylethylene diamine and hexamethyl phosphorus triamide minimize chain transfer reactions in the polymerization of 1,3‐butadiene in hydrocarbon solvent with alkylsodium or alkylpotassium initiators. The polymers obtained with alkylsodium initiators had a high molecular weight and high vinyl content at 90–95% conversion. The molecular weight of the polybutadiene made by alkylsodium and alkylpotassium initiators was dependent on the polymerization temperatures and modifier ratios, but the vinyl contents were independent of the modifier ratios. Vinyl contents of alkylpotassium‐initiated polymers showed a slight dependency on polymerization temperature; the vinyl contents of alkylsodium‐initiated polymers were independent of temperature. Addition of lithium tert‐butoxide and potassium tert‐amylate to these initiators in the presence of the modifiers affected the molecular weight but not the microstructure.
Radiation‐induced copolymerization of methyl trifluoroacrylate with ethylene
Authors: Matsuda Osamu , Watanabe Terutaka , Tabata Yoneho , Machi Sueo
Published: April 2003

Copolymerization of methyl trifluoroacrylate (MTFA) with ethylene in bulk was induced by γ irradiation. The copolymerization was observed to proceed in the liquid monomer mixture of MTFA and ethylene at 25°C with the dose rates ranging from 5.0 × 104 to 1.0 × 106 rad/hr. A wide range of the initial monomer composition gives an almost equimolar and alternating copolymer. The highest polymerization rate was observed at the equimolar monomer composition. The dose rate exponent of the polymerization rate is unity. The reactivity ratios of r1 (MTFA) and r2 (ethylene) were determined to be 0.034 and 0.14, respectively.
Effect of solvent on the termination rate constant in initial stages of free radical polymerization
Authors: Mahabadi Hadi Kh. , Rudin Alfred
Published: April 2003

The effect of solvent on the termination rate constant Kt, in the initial stages of free radical polymerizations has been estimated by considering its effect on the viscosity of the medium and on the overall dimensions of the macroradicals. The expression derived predicts that Kt is inversely proportional to the viscosity of the reaction medium, η0, and that Kt, increases as the overall dimensions of the radicals decrease in poorer solvents. The effect of solvent on the η0Kt, product depends on the average size and concentration of polymer in the system. For relatively high concentrations of high‐molecular‐weight polymers η0Kt can be greater in a better solvent than in a poorer solvent. This trend would be reversed for low concentrations and/or low polymer molecular weights. Good agreement has been found between experimental and estimated values of η0Kt.
Synthesis of polyacylsulfonamide‐amides by ring‐opening polyaddition of N,N′‐arylenedisulfonylbissuccinimides with diamines
Authors: Imai Yoshio , Ueda Mitsuru , Okuyama Kazuo
Published: April 2003

Ring‐opening polyaddition of N,N′‐arylenedisulfonylbissuccinimides with both aliphatic and aromatic diamines in N‐methyl‐2‐pyrrolidone at room temperature afforded polyacylsulfonamide‐amides having inherent viscosities in the range of 0.2–0.4 in excellent yields. The polymers revealed acidic nature and were readily soluble in both polar aprotic solvents and basic media. They melted at a temperature below 200°C and began to decompose at around 250°C in nitrogen.
Binding the hydrophobic fluorescent probe, 2‐p‐toluidinylnaphthalene‐6‐sulfonate, by polycations that contain apolar pendant groups: Equilibrium dialysis and fluorescence measurements
Authors: Takagishi Toru , Naoi Yozo , Kuroki Nobuhiko
Published: April 2003

The thermodynamic parameters for the interaction of the hydrophobic fluorescent probe, 2‐p‐toluidinylnaphthalene‐6‐sulfonate (TNS), and polycations that contain a piperidinium cation and various nonpolar pendant groups were calculated. Binding is exothermic and involves a positive entropy gain. The contribution of the entropy term to the free energy change tends to increase with increasing hydrophobicity of the polymers. The intensity of the fluorescence of TNS is enhanced when the probe binds to the polycations. The nature and phenomena of hydrophobic fluorescent probe binding with the polymers are discussed.
Pyrolysis/chemical ionization mass spectrometry of polymers
Authors: Shimizu Yukio , Munson Burnaby
Published: April 2003

Pyrolysis/mass spectrometric studies have been made on polystyrene, poly(vinyl chloride), and poly(methyl methacrylate) with electron ionization (EI) and chemical ionization (CI) mass spectrometry and a variable temperature probe for direct insertion into the source of the mass spectrometer. Similar results obtained with EI and CI mass spectrometry are in agreement with previous experiments. Advantages of the simplification of spectra in the CI made, as well as the advantages of using both techniques for identification of pyrolysis products, are discussed.
A new route for synthesis of oligomeric polyurethanes. Alternating copolymerization of carbon dioxide and aziridines
Authors: Kuran W. , Rokicki A. , Romanowska D.
Published: April 2003

Carbon dioxide was copolymerized with 2‐methylaziridine and 1‐phenethylaziridine in the presence of organozinc coordination catalysts. Fully alternating copolymers–polyurethanes were obtained. Relations between reaction conditions and polymer yield are given. On the basis of these results a probable scheme of the copolymerization reaction is proposed.
Changes in row structure of extruded polyethylene film in grafting with styrene. II. Copolymer morphology
Authors: Ungar G. , Dlugosz J.
Published: April 2003

The morphology of extruded high‐density polyethylene film grafted with styrene was studied by transmission electron microscopy of thin stained sections. Near the film surface grafted polystyrene was confined to amorphous layers between lamellar crystals of polyethylene. In the film interior separate polystyrene domains were also formed and became predominant in grafting in diluted styrene. The deciding factor for the location of grafted polystyrene is the chain length because only long chains can coalesce in large separate zones. The polystyrene zones expand by cracking the stacks of lamellae along the lamellar normals. Straightening of the twisted crystalline lamellae of polyethylene occurred in grafting. “Bubbles” of styrene homopolymer were formed under conditions of high monomer concentration. The effect of staining the graft by the Kanig method2 was also discussed.
Copolymérisations de l'acrylonitrile. XII. Phénomènes de solvatation préférentielle et effet de conversion dans la copolymérisation (acrylonitrile–styrène)
Authors: Pichot C. , Guyot A. , Strazielle C.
Published: April 2003

Kinetic deviations with the conversion observed in free‐radical‐initiated [acrylonitrile (A)–styrene (S)] copolymerization carried out in DMF solution have been interpreted in terms of preferential solvation of the polymer by one of the monomers or the solvent. First it is well established that the initial styrene content of the PAS copolymer increases if a slight amount of polymer is introduced before the beginning of polymerization. Next the preferential solvation has been studied and characterized in various solvents (toluene or DMF) from the results of differential refractometry at dialysis equilibrium of the ternary solution (solvent–monomer–polymer) versus its solvent mixture. It was found that the most polar monomer, acrylonitrile, is already adsorbed by the polymer, mostly in copolymerizations carried out in DMF, from initially rich acrylonitrile mixtures. It is suggested that this phenomenon implies a heterogeneous repartition of the monomer mixture in the solution, which may affect the kinetic copolymerization when the conversion increases.
Solid‐state polymerization of long‐chain vinyl compounds. I. Effect of molecular arrangement on polymerizability of octadecyl methacrylate
Authors: Shibasaki Yoshio , Nakahara Hiroo , Fukuda Kiyoshige
Published: April 2003

γ‐Ray‐initiated postpolymerization of octadecyl methacrylate in polymorphic crystals and melt has been investigated to clarify the effect of molecular arrangement of the monomer on polymerizability. From thermal, x‐ray, and infrared (IR) analyses this long‐chain monomer exhibited three crystalline modifications that we refer to as α‐, sub‐α, and β‐forms. The β‐form (mp 28.7–29.7°C), which is obtainable from solution, is a stable state with triclinic chain packing. The α‐form (mp 19.5–20.0°C), which is obtained first from the melt but transforms into β‐form on storing, is a metastable state with hexagonal chain packing. The sub‐α‐form appears transiently in α→β transition. The polymerizability of octadecyl methacrylate in the β‐form is extremely low, whereas the α‐form can polymerize easily and the initial polymerization rate, saturated conversion, and polymer molecular weights increase with temperature. Polymerizability in the molten state at fairly high temperature is rather low, however. Thus maximum polymerizability is obtained just above the melting point of α‐form. It has been found that particular orientation and suitable packing mode with some freedom of rotational motion of the monomer molecules in layered structure accelerate the polymerization reaction.
Thermal decomposition of flame retardants: Mixtures of chlorinated polymers with Sb2O3 and (BiO)2CO3
Authors: Ballistreri A. , Foti S. , Montaudo G. , Pappalardo S. , Scamporrino E.
Published: April 2003

The thermal decomposition products that evolve from mixtures of poly(vinyl chloride) (PVC), poly(vinylidene chloride) (PVC2), and chlorinated paraffin (CP) with Sb2O3 and (BiO)2CO3, respectively, have been analyzed by a method of direct pyrolysis in the ion source of a mass spectrometer. This method allowed us to detect volatile products with masses as high as 226 (SbCl3), 314 (BiCl3), 484 (Sb4), 580 (Sb4O6), and 836 (Bi4). Except for SbCl3, this is the first direct evidence of the presence of these species in the gas phase. The volatilization rate profiles of these species versus the pyrolysis temperature have been also determined. Our data confirm that the effectiveness of the title mixtures as flame‐retardant agents depends on the transport of volatile metal products in the flame and provide direct evidence of the presence of metallic Sb and Bi below the polymer ignition temperatures.
Synthesis of hydroxyl‐containing polyamides by ring‐opening polyaddition of 3,3′‐disubstituted bis‐β‐propiolactone with diamines
Authors: Ueda Mitsuru , Takahashi Masayoshi , Imai Yoshio
Published: April 2003

A new bis‐β‐lactone monomer, 3,3′‐p‐phenylenebis(2,2‐dichloro‐β‐propiolactone), was synthesized by the cycloaddition of dichloroketene with terephthalaldehyde. Hydroxyl‐containing polyamides with inherent viscosities as high as 1.1 were prepared by the ring‐opening polyaddition of the bis‐β‐lactone with various diamines in tetrahydrofuran at room temperature. They were readily soluble in a wide range of solvents, which included tetrahydrofuran and acetone. The polymers melted and decomposed at temperatures around 200°C.
Multichain copoly(α‐amino acid). III. Multichain copoly(α‐amino acid) prepared by the reaction of copoly(L‐lysine γ‐methyl‐L‐glutamate) with N‐carboxy anhydride of β‐benzyl L‐aspartate
Authors: Sakamoto Munenori , Kuroyanagi Yoshimitsu
Published: April 2003

Graft copolymerization of N‐carboxy anhydride of β‐benzyl‐L‐aspartate onto copoly(L‐lysine γ‐methyl‐L‐glutamate) was carried out in N,N‐dimethylformaide which contained 3 v/v% of dimethyl sulfoxide to obtain multi‐Nε‐poly(β‐benzyl‐L‐aspartyl)copoly(L‐lysine γ‐methyl‐L gluta mate). The degree of polymerization of the branch chain attained was much influenced by the interval of the grafting sites of the copoly(L‐lysine γ‐methyl‐L‐glutamate). The solvent‐induced two‐step conformational transition of the multichain copoly(α‐amino acid) was observed in the chloroform‐dichloroacetic acid system at 25°C by the ORD technique. The stability of the α‐helical conformation of the backbone polymer chain was decreased by the presence of poly(β‐benzyl‐L‐aspartyl) branch chains that could form unstable α‐helical conformations of opposite spirals.
The structure of chlorinated poly(vinyl chloride). VI. Comparison of the chlorination of poly(vinyl chloride) and β,β‐d2‐poly(vinyl chloride) with 1H‐NMR and 13C‐NMR spectroscopy
Authors: Lukáš R. , Kolínský M. , Doskočilová D.
Published: April 2003

Samples of chlorinated poly(vinyl chloride) (CPVC) and chlorinated β,β‐dideuterated poly(vinyl chloride) (β,β‐d2‐CPVC) were prepared under identical reaction conditions. The microstructure of CPVC and β,β‐d2‐(CPVC) was characterized by a combination of 1H‐NMR, 13C‐NMR spectroscopy, and analytically determined chlorine content. A difference was observed in the reaction rates of chlorination of PVC and β,β‐d2‐PVC, and, in their thermal chlorination in solution, also in the structure of the chlorinated products. It was proved that in the chlorination of β,β‐d2‐PVC a new chlorine atom can also enter the originalCHCl group. The results are discussed from the standpoint of the chlorination mechanism.
Photobleaching of chemically degraded poly(vinyl chloride)
Authors: Owen Eryl D. , Read Roger L.
Published: April 2003

Dilute (0.23%) tetrahydrofuran solutions of chemically degraded poly(vinyl chloride) were irradiated with monochromatic light (307,320, or 354 nm) after being degassed or saturated with oxygen. The rates of the resulting photobleaching reactions of the polyene sequences present depended in a complex way on the wavelength of the light used and on the presence or absence of oxygen. During 307‐nm irradiation an initial fast decrease in absorbance at 307 nm, which proceeded with a rapidly decreasing quantum yield and which was unaffected by oxygen, was followed by a slower reaction with constant quantum yield that was strongly inhibited by oxygen. The same general trend was observed for solutions irradiated with 320‐ or 354‐nm light but in each case the rates of changes in absorbance at wavelengths other than those irradiated were complex. A mechanism that involves intra‐ and intermolecular reactions of the polyenes is suggested to explain the observed effects.
Cationic polymerizations by aromatic initiating systems. II. Correlation between cationic model and polymerization reactions with the p‐CH3C6H4CH2Cl/Et3Al system
Authors: Reibel Leonard , Kennedy Joseph P. , Chung David Y. L.
Published: April 2003

Model experiments and subsequent polymerization runs have been carried out to elucidate the mechanism of cationic olefin polymerizations initiated by aromatic carbenium ions. Thus, the p‐methylbenzylation of 2,4,4‐trimethyl‐1‐pentene, a nonpolymerizable model olefin for isobutylene, was investigated by using the p‐CH3C6H4CH2Cl/Et3Al initiating system and CH2Cl2 solvent under various conditions. All the important organic reaction products were identified and most of them, quantitatively determined. Analysis of the nature of the products and their distributions gave important mechanistic information about the chemistry of elementary events and their relative rates; for example, hydridation and ethylation by the Et3AlCl⊖ counteranion of various cations occurs and these processes mimic termination in carbocationic polymerizations. Hydridation and ethylation are much faster than proton elimination (chain transfer in polymerization) and experimental conditions (e.g., Al/Cl ratio and temperature) influence the relative rates of these processes. According to model experiments, the p‐CH3C6H4CH2Cl/Et3Al system may initiate olefin (isobutylene) polymerization; chain transfer to monomer should be relatively unimportant, but rapid hydridation or ethylation should reduce the kinetic chain and give low conversions. Predictions derived from model experiments were substantiated by polymerizations with isobutylene and the aromatic initiating system.
Polymerization photosensitized by carbonyl compounds
Authors: Lissi E. A. , Encina M. V.
Published: April 2003

The polymerization of methyl methacrylate and styrene photosensitized by acetone, aldehydes, ethyl pyruvate, 2,3‐butanedione, and 2,3‐pentanedione has been investigated and the effect of several additives (carbon tetrachloride, cumene, diethyl amine, triethyl amine, 2‐pentanol, and tetrahydrofuran) on initiation efficiency has been evaluated. The initiation efficiency of a given system depends on several factors, the most important of which are the relative rates of quenching by the monomers and the additives and type of product obtained.
Organosilane polymers. I. Poly(dimethylsilylene)
Authors: Wesson J. P. , Williams T. C.
Published: April 2003

Poly(dimethylsilylene) higher polymers prepared by alkali metal coupling of purified dimethyldichlorosilane were found to be high melting, largely crystalline polymers, soluble in solvents at temperatures above 200°C.
N‐(monohalogenphenyl) maleimides and their copolymers with styrene and butadiene
Authors: Bezděk M. , Hrabák F.
Published: April 2003

N‐(Monohalogenphenyl)maleamic acids (I) and N‐(monohalogenphenyl) maleimides (II) which contained bromide or chlorine atoms in the 2‐, 3‐, or 4‐position of the phenyl ring and their respective isoimides (III) were prepared. The radical copolymerization of Pairs II + styrene and II + butadiene in benzene solution initiated with 2,2′‐azobisisobutyronitrile at 50°C was used to determine the monomer reactivity ratios of II. Their values, which are close to zero, indicated an alternating addition of the two monomers on the polymer radical. The thermal stability of the copolymers was characterized by thermogravimetric analysis; their flammability was determined by the method of limiting oxygen index. The copolymerizability of III with styrene and isobutylene was verified at 30°C.
Influence of tertiary aromatic diamines on the n‐buLi‐initiated polymerization of isoprene in hexane solution
Authors: Cheminat A. , Friedmann G. , Brini M.
Published: April 2003

The influence of three aromatic tertiary diamines, bis(4‐dimethylamino phenyl) methane (DMAPM), N,N,N′,N′‐tetramethyl‐p‐phenylenediamine (p‐TMPDA), and N,N,N′,N′‐tetramethyl‐o‐phenylenediamine (o‐TMPDA), on the kinetics of polymerization of isoprene in hexane solution, with n‐BuLi as initiator, was studied for different values of ratio r = [amine]/[n‐BuLi]. It is shown that added amine increases initiation rate according to its complexing ability (DMAPM < p‐TMPDA « o‐TMPDA); this result is explained by the formation of complexes between amine A and n‐BuLi, (n‐BuLi, A)x, where x = 6, 4, and 1 for the three amines, respectively. The propagation rate and the structure of polyisoprene are modified with o‐TMPDA only; the decrease in propagation rate and the increase in 3,4 units in the polymer obtained when r increases are assigned to the formation of solvated ion pairs PI−Li+, o‐TMPDA.
Synthesis of polysulfonamides from aromatic disulfonyl bromides and diamines
Authors: Imai Yoshio , Ueda Mitsuru , Iizawa Takashi , Kudo Shuichi
Published: April 2003

Solution polycondensations of aromatic disulfonyl bromides with diamines in tetramethylene sulfone at room temperature by the use of organic or inorganic acid acceptors yielded polysulfonamides with moderately high molecular weights. Preferred acid acceptors were 2‐methylpyridine and propylene oxide and lead oxide. The high activity of lead oxide was discussed in relation to the principle of hard and soft acid and bases.
Polyamides of 2,5‐bis(amino methyl) 1,4‐dioxane and dicarboxylic acids
Authors: Akkapeddi Murali K.
Published: April 2003

Novel polyamides of 2,5‐bis(amino methyl) 1,4‐dioxane (cis/trans‐BAMD) with adipic/sebacic acids and of 2,5‐bis(carboxy methyl)/2,5‐bis(carboxy) 1,4‐dioxane with 1,6‐hexane diamine have been prepared. Because of the slightly higher conformational flexibility of the 1,4‐dioxane ring in comparison with that of the cyclohexane ring, the BAMD polyamides have lower Tg and Tm than the corresponding 1,4‐bis(amino methyl) cyclohexane (BAMC) polyamides. The symmetry of the trans‐dioxane moiety permits high crystallinity in the trans‐BAMD polymers. The crystallinity Tg and Tm of the trans polymers are decreased with the incorporation of the cis‐dioxane moiety which lacks a plane of symmetry. Because of the hydrophilic nature of the dioxane ring, t‐BAMD‐6 has good moisture‐regain properties, yet is melt processable (Tm = 292°C).
Particle nucleation in emulsion polymerization. III. Nucleation in systems with anionic emulsifier investigated by seeded and unseeded polymerization
Authors: Hansen F. K. , Ugelstad J.
Published: April 2003

Studies of seeded and unseeded polymerization of styrene using sodium dodecylsulfate as emulsifier have been carried out in order to investigate the mechanism of particle nucleation in such systems and to test the theory presented in Part I of this series. The rate of capture of water‐soluble oligomeric radicals was considered to be governed by absorption of oligomers with chain length one less than the critical chain length. It was concluded that the micelles became the dominating loci for particle nucleation above CMC for the emulsifier. A complete nonsteady‐state model for particle initiation above CMC which takes into account radical desorption and reabsorption has been developed. It was indicated that, even for styrene, desorption of radicals may play a role in controlling the radical and particle number of interval I under certain conditions. The model also showed that the efficiencies of particles in absorbing radicals could be calculated from physical parameters, such as diffusion constants and surface charge densities, which are available for the system.
Phase separation in the interpenetrating polymeric network on the basis of polyurethane and polyurethane acrylates
Authors: Shilov V. V. , Lipatov Yu. S. , Karabanova L. V. , Sergeeva L. M.
Published: April 2003

Interpenetrating polymer networks (IPN) of polyurethane and polyurethane acrylate were obtained. A small‐angle x‐ray scattering technique was used to study the character of the microheterogeneities in IPN and their variation with composition. It was shown that IPN formation is accompanied by phase separation of constituent components. On the basis of experimental data, which involved the mean square of fluctuations of electron densities in IPN, scattering intensity extrapolated to the zero angle, thickness of the transition layer between two phases, degrees of component segregation and diffuseness of phase boundary, degree of miscibility of components on the molecular level, specific inner surface, and the extent of the heterogeneous regions and their mean radius were determined. Parameters that characterize the intensity of microphase separation are dependent on composition: at a higher content of PUA the segregation degree is higher than that of low content. The dimensions of the heterogeneous regions, which extend from one network to the matrix of the other, depend on the composition of IPN and changes most sharply in the range of mean composition due to phase inversion. Thickness of the transition layer ranges from 20 to 40 Å.
Epoxy resins. II. The preparation, characterization, and curing of epoxy resins and their copolymers
Authors: Lin S. C. , Pearce E. M.
Published: April 2003

A polymer with high aromatic ring content in the chain backbone usually has high heat and flame resistance. Three diglycidyl ethers of epoxy resins were prepared from bisphenol A (DGEBA), phenolphthalein (DGEPP), and 9,9‐bis(4‐hydroxyphenyl)fluorene (DGEBF) in a study of the relation between the cured polymer structure and properties. The epoxy resin prepared from phenolphthalein was separated by liquid chromatography and three fractions were obtained. The fractions had a basic structure of 3,3‐disubstituted phthalide and differed only in molecular weight. The DGEPP resin changed color from yellow to red after mixing with trimethoxyboroxine (TMB), the curing agent, and to orange after completing the curing cycle. To prepare a highly crosslinked material with good thermal stability, TMB with three active Lewis sites in a molecule was used as the curing agent. The reactivity of the three different resins toward TMB, measured by differential scanning calorimetry (DSC), was DGEBA > DGEBF > DGEPP. For the same curing conditions the order of crosslink density was DGEBA > DGEPP > DGEBF. To modify the flammability of DGEBA, the conventional epoxy resin, it was copolymerized with DGEPP and DGEBF, the higher‐performance epoxy resins. The glass transition temperatures of poly(DGEBA‐co‐DGEPP) and poly(DGEBA‐co‐DGEBF) systems deviated from this relationship. The DGEBF copolymers showed an increased char residue (40 wt % at 700°C) at 20 mole % of DGEBF. This deviation may be due to the lower crosslinking density of this system.
Hydrophobic interactions in the binding of polyvinylpyrrolidone
Authors: Maruthamuthu Meenakshi , Sobhana Meenakshi
Published: April 2003

A spectrophotometric method was used for the quantitative determination of binding in the poly‐vinylpyrrolidone–rose bengal system. Binding of tiron, another anionic dye, onto polyvinylpyrrolidone was investigated by equilibrium dialysis. Comparison of binding constants of the two systems indicated the importance of hydrophobic interactions in binding. Because rose bengal can serve as a fluorescent probe, a fluorimetric method was also used and the increase in fluorescence confirmed the significance of hydrophobic interactions in the binding of the dye onto the polymer.
Polymerizations of substituted cyclopropanes. I. Radical polymerization of 1,1‐disubstituted 2‐vinylcyclopropanes
Authors: Cho Iwhan , Ahn Kwang‐Duk
Published: April 2003

Diethyl 2‐vinylcyclopropane‐1,1‐dicarboxylate (Ia), 2‐vinylcyclopropane‐1,1‐dicarbonitrile (Ib), ethyl 1‐cyano‐2‐vinylcyclopropanecarboxylate (Ic), and 1,1‐diphenyl‐2‐vinylcyclopropane (Id) were radically homo‐ and copolymerized. Ia, Ib, and Ic polymerized cleanly in 1,5‐type ring‐opening fashion to yield polymers of high molecular weight. Id failed to homopolymerize but copolymerized with common monomers which included maleic anhydride. Infrared (IR) spectra indicated that the double bonds of the polymer chains were in trans form. All polymers were soluble in solvents and solution‐cast films were clear and flexible, showing Tg values in the 25–40°C range. Model reactions of those monomers with benzenethiol also indicated predominant 1,5‐addition reactions. From the results of our investigation it was concluded that the driving force for the facile radical 1,5‐polymerization of Ia, Ib, and Ic was the stabilization of growing radicals by two substituents.
Chain transfer in vinylpyridine polymerizations
Authors: Howard G. J. , Lai Siu‐Hung
Published: April 2003

Transfer constants to monomer at 55°C have been measured in 2 and 4‐vinylpyridine radical polymerizations. In addition, the transfer constants to ethanol, octan‐1‐ol, toluene, benzyl alcohol, chloroform, and nitroethane have been measured. These values, which increase in the order above, show no significant variation between the two isomeric monomers.
Monomer dependence of radiation graft polymerization. V. Poly(ethylene‐g‐4‐vinylpyridine)
Authors: Odian George , Derman Arif
Published: April 2003

The radiation‐initiated graft polymerization of 4‐vinylpyridine to high‐density polyethylene has been studied under diffusion‐free conditions by the mutual irradiation technique. The reaction rate is 1/2 order in radiation intensity over the range 0.00076–0.011 Mrad/hr. The reaction rate is first order in monomer at 0.00076 Mrad/hr, over the complete range of monomer concentrations; at 0.021 Mrad/hr, up to 60 vol % monomer; and at 0.21 Mrad/hr, up to 50 vol % monomer.
Copolymerization of vinyl acetate with a homologous series of vinyl esters: A comparative study of vinyl acetate–vinyl ester and ethylene–vinyl ester copolymerization
Authors: van der Meer R. , German A. L.
Published: April 2003

The effect of the alkyl group on the relative reactivity of a homologous series of vinyl esters (M2) has been studied with vinyl acetate (M1) as reference monomer andtert‐butyl alcohol as solvent at 62°C and 35 kg/cm2. The description of the relative reactivities of the vinyl esters toward the vinyl acetate (VAc) macroradical in terms of the Taft relation is analogous to our previous findings in a similar study with ethylene (Eth) as reference radical. This implies that chiefly polar factors affect the relative reactivity, whereas from vinyl pivalate (VPV) on steric hindrance impairs the addition rate. The constancy of ther2values, also found in the series with Eth (M1) as reference monomer (viz.,r2= 1.50), appears to exist in the present investigation (r2= 1.04) but does not hold for the VAc–VPV combination. This can be interpreted in terms of steric hindrance. A combination of kinetic results indicates sterically hindered additions in all those reactions in the system Eth–VAc–VPV that involve at least one VPV unit as macroradical or monomer (except for the addition of Eth to a VPV macroradical). The monomer reactivity ratios that pertain to the Eth–VAc–vinyl ester systems are discussed in terms of theQ–escheme and the product relation postulated by Ham. The Ham relation does not hold for the latter systems.
Grafting vinyl monomers onto wool fibers. III. Graft copolymerization of methyl methacrylate onto wool using hexavalent chromium ion
Authors: Nayak Padma L. , Lenka Subasini , Pati Nrusingha C.
Published: April 2003

The use of hexavalent chromium to initiate graft copolymerization of methyl methacrylate onto wool fibers has been investigated. The rate of grafting was determined by varying monomer, chromium(VI), temperature, acidity of the medium, nature of wool, reaction medium, and redox system. The graft yield increases with increasing monomer concentration up to 0.65M, and, with further increase of monomer the graft yield decreases. The graft yield increases with increasing chromium(VI) concentration. The grafting is considerably influenced by chemical modification of wool prior to grafting. The effect of certain inorganic salt and anionic surfactant on the rate of grafting has been investigated. The graft yield is influenced by thiourea concentration; it decreases with increasing thiourea concentration.
Studies of the polymerization of diallyl compounds. XXVIII. Copolymerization of monoallyl phthalate with allyl benzoate and diallyl phthalate
Authors: Imai Itsuro , Matsumoto Akira , Oiwa Masayoshi
Published: April 2003

The bulk copolymerizations of monoallyl phthalate (MAP) with allyl benzoate (ABz) and diallyl phthalate (DAP) were conducted in the presence of benzoyl peroxide as an initiator at 70°C; copolymers containing allyl alcohol unit were obtained. The copolymer composition was reasonably interpreted in terms of polymerization kinetics, including the partial elimination of phthalic anhydride (PhA) from the MAP growing chain end in its propagation reaction with another monomer. Kinetics of the copolymerization of DAP with MAP were also discussed in detail, and the gel point was additionally evaluated. DAP–MAP copolymer was homogeneously reacted with zinc acetate to produce the polymer gel carrying ionic crosslinkages.