bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma fluorination of polystyrene
Authors: Strobel Mark , Thomas Patrick A. , Lyons Christopher S.
Published: April 2003

ESCA and contact‐angle measurements were used to characterize the surfaces of polystyrene films exposed to SF6, CF4, and C2F6 plasmas. SF6 plasmas cause loss of aromaticity in the polystyrene surface region via saturation of the phenyl ring and/or carbon‐bond breakage and subsequent fluorination. C2F6 plasmas graft CFx radicals directly to the polystyrene surface without necessarily destroying the aromaticity of the polymer. CF4 plasmas appear to be intermediate in character between SF6 and C2F6 plasmas.
Polymerization of vinyl monomers by a new oligoperoxide: Oligo(adipoyl‐5‐peroxy‐2,5‐dimethyl n‐hexyl peroxide)
Authors: Hazer Baki
Published: April 2003

A new polymeric initiator, oligo(adipoyl‐5‐peroxy‐2,5‐dimethyl n‐hexyl peroxide), was synthesized by interfacial condensation of adipoyl chloride with 2,5‐dimethyl‐2,5‐dihydroperoxy hexane. This can be used as an initiator to prepare block copolymers by free radical mechanism in a procedure involving several steps, since the colorless, viscous liquid, oligoperoxide, has 8–10 peroxide groups per molecule. The thermal decomposition of this oligoperoxide in benzene solution at 98°C was first order and its half life was 9.75 h. The results of the polymerization kinetics show that this oligoperoxide lies in between of 2,5‐dimethyl‐2,5‐dihydroperoxyhexane and benzoyl peroxide for empirical polymerization rates of styrene and methyl methacrylate at 80°C.
Synthesis and solid state 13C‐NMR studies of some cellulose derivatives
Authors: Pawlowski W. P. , Sankar S. S. , Gilbert R. D. , Fornes R. E.
Published: April 2003

Several cellulose derivatives were synthesized and characterized by IR and 1H‐NMR spectroscopy. The positions of substitution in these derivatives were confirmed using solid state 13C‐NMR spectroscopy techniques.
Polyanhydrides. I. Preparation of high molecular weight polyanhydrides
Authors: Domb A. J. , Langer R.
Published: April 2003

Polyanhydrides composed of the following diacids–sebacic acid, bis(p‐carboxyphenoxy)propane, bis(p‐carboxyphenoxy)hexane, isophthalic acid, 1,4‐phenylene dipropionic acid, and dodecanedioic acid–were synthesized by a melt polycondensation process. Polymers of molecular weight up to 137,010 (weight average) and intrinsic viscosity of 0.92 dL/g were achieved. These high molecular weight polymers were reached by using pure isolated mixed anhydrides of diacids and acetic acid, under optimized reaction conditions (temperature of 180°C for 90 min under vacuum of 10‐4 mm Hg). Polymers of higher molecular weights were synthesized in shorter times by using heterogenic coordination catalysts: cadmium acetate, ZnEt2‐H2O (1:1), barium oxide, calcium oxide, and calcium carbonate. By using these catalysts molecular weights of up to 245,000 were reached in 30 min of reaction. Films made of high molecular weight bis(p‐carboxyphenoxy)propane–sebacic acid copolymers showed tensile strengths of 40–160 kg/cm2; the strength increased as a function of the bis(p‐carboxyphenoxy)propane content and molecular weight.
Synthesis and characterization of N‐phenylated aromatic polyureas from N,N′ ‐dichloroformyl‐p‐dianilinobenzene and N,N′ ‐bistrimethylsilyl‐diamines
Authors: Oishi Yoshiyuki , Padmanaban Munirathina , Kakimoto Masa‐Aki , Imai Yoshio
Published: April 2003

NovelN‐phenylated aromatic polyureas having inherent viscosities of 0.13–0.35 dL/g were synthesized by the solution polycondensation of N,N′‐dichloroformyl‐p‐dianilinobenzene with N,N′‐bistrimethylsilyl derivatives of bis(4‐aminophenyl)ether, piperazine, and p‐dianilinobenzene in sulfolane. Except the polyurea containing piperazine unit, the other polyureas were amorphous and readily soluble in a variety of organic solvents such as tetrahydrofuran. The polyurea derived from p‐dianilinobenzene, which has no vulnerable hydrogen on the urea linkage, did not melt below 350°C and was stable up to 450°C in air.
Copper carboxylate formation in the thermal oxidative degradation of atactic polypropylene on copper oxide films
Authors: Webb John D. , Czanderna A. W. , Pitts J. R.
Published: April 2003

The thermal oxidation of atactic polypropylene on CuO0.67 surfaces in air was studied using IR reflection‐absorption spectroscopy. Degradative losses of primary, secondary, and tertiary alkyl hydrogens were observed. At 60 and 73°C, carboxylic acids are the primary degradation products, while at 85 and 100°C, copper carboxylate formation predominates and CuO0.67 is decomposed. The distinct change in the oxidative mechanisms between 73 and 85°C apparently is related to an irreversible thermal transition in the atactic polypropylene films, which may favor carboxylate production by increasing the permeability of the films to oxygen and water vapor.
Radiation‐induced copolymerization of trioxane: Reactivities of some cyclic ether comonomers
Authors: Sagu M. L. , Bhattacharyya K. K.
Published: April 2003

Copolymerization of trioxane solid state induced by gamma radiation with oxycyclic comonomers such as penta acetyl glucose, tetrahydrofuran, styrene oxide, and 1,3 dioxolane has been reported. The relative yields, properties of the copolymers, and the reactivities of the comonomers are discussed. A mechanism for the reactivity is presented.
Epitaxial polymerization of 1,3‐butadiyne by chemical vapor deposition
Authors: Nakada Mikitoshi , Kobayashi Norihisa , Ohno Hiroyuki , Tsuchida Eishun , Matsuda Hiro , Nakanishi Hachiro , Kato Masao
Published: April 2003

1,3‐Butadiyne was epitaxially polymerized on the graphite basal plane by chemical vapor deposition to form a homogeneous thin film. The film thickness varied from 100 to 3000 Å depending on the polymerization condition. The films on the graphite showed a variety of interference colors such as blue, purple, or gold depending on the film thickness. Raman spectra revealed that the polymerized film was mainly composed of CCbonds. Electron diffraction pattern and the ESCA spectrum of the film were quite similar to those of graphite, suggesting that butadiyne was polymerized in an epitaxial manner.
Synthesis, separation, and resolution of cis‐ and trans‐3‐ethylproline
Authors: Tiba Omar , Overberger C. G.
Published: April 2003

The synthesis, separation, and optical resolution of cis‐ and trans‐3‐ethylproline are described. Two different approaches were employed: (1) The Michael addition reaction of 2‐pentenal with diethyl‐N‐carbobenzyloxyaminomalonate gave the intermediate 3‐ethyl‐5‐hydroxy‐N‐benzyloxypyrrolidine. Hydrogenolysis of this intermediate followed by acid hydrolysis gave a mixture of cis‐ and trans‐3‐ethylproline. Separation of the isomers was accomplished by selective saponification of N‐(p‐toluenesulfonyl)‐cis‐ and trans‐3‐ethylproline methyl esters using 0.25N methanolic sodium hydroxide. (2) The Michael condensation of diethyl acetamidomalonate with 2‐pentenoic acid ethyl ether produced the intermediate 5,5‐bis(ethoxycarbonyl)‐4‐ethylpyrrolidine. Partial saponification followed by decarboxylation afforded a mixture of cis‐ and trans‐isomers of ethyl‐3‐ethylpyroglutamate. The diastereoisomers were separated using low temperature fractional crystallization. Reduction of these isomers and tosylation in situ afforded the corresponding N‐(p‐toluenesulfonyl)‐cis‐ and trans‐3‐ethylprolinols. Chromic acid oxidation gave N‐(p‐toluenesulfonyl)‐cis‐ and trans‐3‐ethylproline. Reaction of these tosylates with 30% hydrogen bromide in acetic acid gave cis‐ and trans‐3‐ethylproline. Both optically active isomers of D(+)‐and L(‐)‐trans‐3‐ethylproline were successfully resolved using (+)‐dibenzoyl‐D‐tartaric acid and (‐)‐dibenzoyl‐L‐tartaric acid as resolving agents. The absolute configurations of the optically active isomers were determined by circular dichroism spectroscopy.
Characterization of organometallic polymers by 13C‐ and 119Sn‐NMR: Configurational/compositional triads in poly(tri‐n‐butyltin methacrylate/methyl methacrylate)
Authors: Manders William F. , Bellama Jon M. , Johannesen Rolf B. , Parks Edwin J. , Brinckman Frederick E.
Published: April 2003

The 1:1 and 2:1 formulations of the free radical initiated copolymers of methyl methacrylate (MMA) and tri‐n‐butyltin methacrylate (TBTM), and the homopolymer, poly(TBTM), are characterized by 13C‐ and 119C‐NMR structural analyses were performed on the tributyltin‐free hydrolyzate, a copolymer of MMA and methacrcylic acid (MAA). Configurational sequencing at the triad level is performed using the α‐methyl region of the 13C‐NMR spectrum. The probability of isotactic (meso) dyad placement at 80°C in the homopolymer (0.19) is determined to be significantly less than the probabilities observed for the copolymers (0.23–0.24). Random compositional sequencing is established for the copolymers through a comparison of the carbonyl regions of the 13C‐NMR spectra of the hydrolyzates with the carbonyl regions in published spectra of structurally characterized copolymers of MMA and MAA. The 119Sn chemical shift and the tin‐carbon J coupling for the polymers are dependent on the solvent employed. This dependence is attributed to electron donor or acceptor interactions between the solvent and the strong SnO dipole. The tin‐containing copolymers exhibit multiple 119Sn resonances, which appear related to compositional sequencing.
Surface modification. I. Graft polymerization of acrylamide onto low‐density polyethylene by Ce4+‐induced initiation
Authors: Batich Christopher , Yahiaoui Ali
Published: April 2003

Polyacrylamide was grafted onto a hydroxylated LDPE (low‐density polyethylene) surface yielding a highly hydrophilic and stable new surface. LDPE was first oxidized by chromic acid and then reduced with diborane to form a hydroxyl‐rich surface. Polymerization was then initiated by Ce4+/HNO3 solution. X‐ray photoelectron spectroscopy and Fourier transform‐IR/attenuated total reflection were used for elemental analysis and identification of the functional groups introduced.
Application of two‐dimensional NMR techniques for the elucidation of the proton spectrum of the epoxy monomer, diglycidyl ether of bisphenol A
Authors: Jagannathan N. R. , Herring F. G.
Published: April 2003

The application of two‐dimensional Fourier transform NMR spectroscopy to the study of the epoxy resin diglycidyl ether of bisphenol A is discussed. The combination of the homonuclear shift‐correlated and J‐resolved experiments permits the complete elucidation of the proton spectrum of the glycidyl ether moiety.
Polystyrene and polystyrene‐butadiene latexes stabilized by poly(N‐isopropylacrylamide)
Authors: Pelton R. H.
Published: April 2003

Latexes stabilized by poly(N‐isopropylacrylamide) (polyNIPAM) were prepared by polymerizing NIPAM in the presence of polystyrene and polystyrene‐butadiene latex or by styrene emulsion polymerization in the presence of NIPAM. In 0.01 M CaCl2 polyNIPAM stabilized latexes exhibited critical flocculation temperatures in the range 32–35°C, which is approximately equal to the lower critical solution temperature of polyNIPAM in water. Partial substitution of NIPAM with some acrylamide (AM) gave higher flocculation temperatures. Coagulation studies with cleaned latex indicated that the polyNIPAM or polyNIPAM‐co‐AM polymer chains were anchored to the latex particle surfaces.
Studies on graft copolymerization onto cellulose derivatives. XXVII. Photo‐induced graft copolymerization onto nitrocellulose
Authors: Takahashi Akira , Sugahara Yasusato
Published: April 2003

Photo‐induced graft copolymerization was investigated using nitrocellulose having a different nitrogen content, especially by a noncatalytic method. The effects of a sample nitrogen content, reaction temperature, and monomer, sample, solvent and photosensitizer concentrations on the degree of grafting, the grafting efficiency, and the apparent number of grafted chains were examined. Methyl methacrylate (MMA) and methyl acrylate (MA) easily polymerized, but acrylamide (AAm), vinyl acetate (VAc), and styrene (St) scarcely polymerized. The apparent activation energies were 4.1–11.5 kcal/mol, indicating the small value in the high nitrogen content sample. The degree of grafting and the apparent number of grafted chains increased with increasing monomer and sample concentrations. In every case, the grafting efficiency was at a high level, above 90%. The polymerization did not occur without the sample in the same condition. Furthermore, a part of nitro groups split off by the irradiation of light. With respect to these results, the mechanisms of the photo graft copolymerization was discussed.
Study on thermal behavior of thermooxidized poly(vinyl formal)
Authors: Aoki Hiroyuki , Suzuki Tsutomu
Published: April 2003

The thermal behavior of thermooxidized poly(vinyl formal) has been investigated by means of thermogravimetry, derivative thermogravimetry, and differential thermal analysis. As a result, it has been clarified (1) that thermal decomposition is composed of three weight loss processes, (2) that, when investigating the ratic of percentage of weight remaining in each process, the behavior differs for each both before and after the thermooxidizing time of 2–4 h; the second weight loss process caused by formation of crosslinking structure prevails in the initial stage of thermooxidation while the first weight loss process caused by decomposition of various types of thermooxidation products such as unsaturated bonds and crosslinking prevails as the thermooxidation proceeds, and (3) that the volume of carbonaceous residue produced as the thermooxidation advances increases about 4 times. When kinetic parameters have been evaluated by applying the Coasts and Redfern method to each weight loss process, on the other hand, it is concluded (1) that each order of reaction is first and (2) that the value of activation energy in the third process of carbonization and burning reaction is substantially lowered as the process of the thermooxidation advances.
Ethylene–chlorotrifluoroethylene copolymers. II. Effects of structure on resistance to thermal stress cracking
Authors: Reimschuesel H. K. , Marti J. , Murthy N. S.
Published: April 2003

Copolymers of ethylene and chlorotrifluoroethylene that contain small amounts of units derived from perfluorohexylethylene show improved resistance of thermal stress cracking. This is a consequence of effects of these units on structural parameters of both the crystalline and amorphous phases. Those of the crystalline phase entail growth and organization of lamellae, whereas those of the amorphous phase are related to conformation and packing of polymer chains. The crystalline phase consists exclusively of alternately arranged units of ethylene and chlorotrifluoroethylene. The amorphous phase is characterized by chain segments composed of randomly distributed units derived from ethylene, chlorotrifluoroethylene, pairs of these two units, and units derived from perfluorohexylethylene.
Steric hindrance in the amine–epoxide reaction
Authors: Glover Donald J. , Duffy James V. , Hartmann Bruce
Published: April 2003

The effect of steric hindrance on the reaction of silicon‐containing aliphatic amines with phenylglycidyl ether (PGE) has been studied using 13C‐NMR, a technique described by Sojka and Moniz [J. Appl. Polym. Sci., 20, 1977 (1976)]. It was found that steric hindrance produced a large change in the reaction rate of the primary and secondary amine hydrogens, thus leading to a separation of the polymerization and cross‐linking reactions.
Radical reactivity of α‐trifluoromethylstyrene
Authors: Ueda Mitsuru , Ito Hiroshi
Published: April 2003

α‐Trifluoromethylstyrene (TFMST) does not undergo radical homopolymerization with azobis(isobutyronitrile) (AIBN) in bulk at 60°C. Low‐temperature initiation was not effective either. Radical copolymerization of TFMST (M2) with styrene (ST, M1) has yielded monomer reactivity ratios as follows: r1 = 0.60 and r2 = 0.00. It has been found that the cyclohexyl radical generated by reaction of cyclohexylmercuric chloride with sodium borohydride adds to the β‐carbon of TFMST 7.5 times faster than that of ST. Combination of the copolymerization analysis and the “mercury method” has allowed us to estimate Alfrey–Price Q and e parameters for TFMST to be 0.43 and 0.90, respectively. Thus, due to the strongly electron‐withdrawing effect of the trifluoromethyl group, this styrene is highly electron deficient. In spite of the favorable electronic effect, however, the ceiling temperature appears very low, presumably due to the steric hindrance.
Reactions and polymerization of 1‐trityl‐4‐vinylimidazole
Authors: Schiavone R. J. , Overberger C. G.
Published: April 2003

1‐Trityl‐4‐vinylimidazole was prepared by direct tritylation of 4(5)‐vinylimidazole and polymerized using a free radical initiator. Poly(1‐trityl‐4‐vinylimidazole) was hydrolyzed using aqueous acetic acid to give poly[4(5)‐vinylimidazole]. The poly[4(5)‐vinylimidazole], which was obtained from the hydrolysis of poly(1‐trityl‐4‐vinylimidazole), was compared with poly[4(5)‐vinylimidazole] prepared directly from 4(5)‐vinylimidazole for differences in stereochemistry. The stereochemistry of both polymers was found to be similar by high‐resolution NMR. Thus, the trityl does not influence the stereochemistry of poly[4(5)‐vinylimidazole]. The reaction of 1‐trityl‐4‐vinylimidazole with n‐butyllithium gave 2‐lithio‐1‐trityl‐4‐vinylimidazole. This intermediate was used to prepare 2‐substituted 4(5)‐vinylimidazoles, which are new monomers that can be polymerized using free radical initiators.
Laser desorption/fourier transform mass spectra of poly(phenylene sulfide), polyaniline, poly(vinyl phenol), polypyrene, and related oligomers: Evidence for carbon clusters and feasibility of physical dimension measurement
Authors: Brown Charles Eric , Kovacic Peter , Welch Kenneth J. , Cody Robert B. , Hein R. E. , Kinsinger James A.
Published: April 2003

Laser desorption/Fourier transform mass spectra of poly(phenylene sulfide), polyaniline, poly(vinyl phenol), polypyrene, poly(p‐phenylene), poly(1‐methyl‐2,5‐pyrrolylene), poly(1‐phenyl‐2,5‐pyrrolylene), and poly(2,5‐thienylene) are compared. Poly(phenylene sulfide) fragments at CS bonds during analysis, but rearrangement is minor. Evidence is found for dibenzothiophene moieties within the polymer chains. Unambiguous determination of the structure of polyaniline is not possible. Rearrangement appears to accompany chain scission. Completely aromatic polymers do not undergo similar reactions during analysis. Species with more carbons than can be accounted for by an integer multiple of six‐membered rings arise from side reactions during dehydrocoupling of aromatic monomers. Carbon clusters, which are observed in the spectra of some aromatic polymers, appear to arise from laser volatilization and multiphoton ionization of large polynuclear components that are formed during synthesis. Negative ions of about 40–120 carbons and positive ions with about 120–400 atoms are detected. The results also suggest that the physical dimensions of some polymer molecules might be measured by Fourier transform mass spectrometry.
Synthesis of poly(1,3,4‐oxadiazole)s by direct polycondensation of dicarboxylic acids with hydrazine sulfate using phosphorus pentoxide/methanesulfonic acid as condensing agent and solvent
Authors: Ueda Mitsuru , Sugita Hiroya
Published: April 2003

A convenient method for the synthesis of poly(1,3,4‐oxadiazole)s of high molecular weights has been developed. These polymers were prepared readily by the direct polycondensation of dicarboxylic acids with hydrazine sulfate (1) using phosphorus pentoxide/methanesulfonic acid (PPMA) as both a condensing agent and solvent. Polycondensation of aliphatic dicarboxylic acids with 1 proceeded even at room temperature and produced poly(1,3,4‐oxadiazole)s with inherent viscosities up to 1.4 dL/g. The synthesis of aromatic poly(1,3,4‐oxadiazole)s from aromatic dicarboxylic acids containing phenyl ether structures was carried out by a one‐pot procedure because the preactivation of dicarboxylic acids was required. The synthesis of 2,5‐disubstituted‐1,3,4‐oxadiazoles by the reaction of carboxylic acids with 1 in PPMA was studied to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(1,3,4‐oxadiazole)s showed 10% weight loss both in air and in nitrogen at 440–490°C.
Formation and reaction of polyenesulfonic acid. I. Reaction of polyethylene films with SO3
Authors: Ihata Jyoji
Published: April 2003

The surface of polyethylene (PE) film was sulfonated by reaction with gaseous SO3. The structure of the sulfonated PE films was determined on the basis of spectroscopic data such as IR, UV, and resonance Raman spectra. It was confirmed that a PE film and SO3 gave unsaturated sulfonic acids and that, as the reaction proceeded, the elimination of sulfurous acids took place to form sulfonic acids having highly conjugated CC unsaturated bonds.
Formation and reaction of polyenesulfonic acid. II. Photoreaction of polyenesulfonic acids
Authors: Ihata Jyoji
Published: April 2003

Conjugated polyenesulfonic acids were found to be sensitive not only to UV but also to visible light, affording stable radical species. The photoreaction included the cleavage of CS bonds to eliminate sulfonic acid groups.
Formation and reaction of polyenesulfonic acid. III. Preparation and photoreaction of 1,3,5‐hexatriene‐1,6‐disulfonic acid
Authors: Ihata Jyoji
Published: April 2003

As a model for the reaction between polyethylene films and gaseous SO3, n‐hexane was allowed to react with gaseous SO3 to give 1,3,5‐hexatriene‐1,6‐disulfonic acid (HTDS), which was isolated from the reaction products by column chromatography. Furthermore, it was found that an aqueous solution of HTDS‐Na was sensitive to UV, which eliminated one of the sulfonic acid groups by a radical mechanism. sulfonic acids having less than three conjugated double bonds were not sensitive to UV.
Synthetic study of aromatic polybenzoxazinone derived from methylene‐4,4′‐diaminodiphenyl‐3,3′‐dicarboxylic acid
Authors: Padma S. , Mahadevan V. , Srinivasan M.
Published: April 2003

Polybenzoxazinones were prepared in two successive steps from methylene‐4,4′‐diaminodiphenyl‐3,3′‐dicarboxylic acid and azodicarbonyl chloride in 40–60% yield. These polymers were characterized by molecular weight and IR and NMR spectra. Their physical properties like solubility, viscosity, and thermal stability were also studied in detail.
Grafting onto carbon black by the reaction of reactive carbon black having masked isocyanate or acyl azide group with functional polymers
Authors: Tsubokawa Norio , Kobayashi Kazuhisa , Sone Yasuo
Published: April 2003

Although isocyanate group (NCO) introduced onto carbon black surface was inactivated rapidly upon storage, it could be stabilized by masking the NCO group with active hydrogen compounds such as acetylacetone, diethyl malonate, and sodium hydrogensulfite. Upon heating these carbon blacks having masked NCO group at 150°C, the NCO group was regenerated on carbon black by the decomposition of the masked NCO group. On the other hand, acyl azide (CON3) group introduced onto carbon black was stable at below 20°C, but readily decomposed to NCO group by heating. By means of the reaction of NCO group on carbon black with functional polymers having hydroxyl, amino, and carboxyl group, these polymers were effectively grafted onto carbon black surface. When carbon black having CON3 group was used as reactive carbon black, the grafting ratio of diol‐type polyethylene glycol (Mn = 8.2 × 103), polyethyleneimine (Mn = 2.0 × 104), polyvinyl alcohol (Mn = 2.2 × 104), and bifunctional carboxyl‐terminated polystyrene (Mn = 1.1 × 105) was determined to be 29.7, 81.7, 32.2, and 50.4%, respectively. The number of grafted polymer chain decreases with an increase in molecular weight of the polymers, because the shielding effect of NCO group by grafted polymer chain is enhanced with an increase in molecular weight of the polymer.
Chemistry of epoxide–polycarbonate copolymer networks
Authors: Yu Yunzhao , Bell J. P.
Published: April 2003

Diepoxides and in‐chain carbonate groups react readily in the presence of quarternary ammonium salts, although reaction is not observed without this catalyst. Two moles of epoxide react with each mole of carbonate. When diepoxides and polycarbonates are reacted, a three‐dimensional network of chains crosslinked with carbonate groups is produced; the crosslink density is controlled by adjusting the epoxy/carbonate ratio. Tertiary amines and alkoxides also catalyze the epoxy/carbonate reaction, but these have the undesirable attribute of promoting epoxy polymerization. The presence of oligocarbonates accelerates the epoxy–amine reaction.
Nonclassical urea oligomers. IX. Photo‐reducing nature of binuclear copper complexes of noncyclic pendant‐type urea oligomers
Authors: Araki Takeo , Kubo Yasuo , Hino Atsushi , Yasuda Yohko , Kamachi Mikiharu
Published: April 2003

The octameric oligomers of 1‐(N‐substituted‐carbamoyl)‐aziridine, i.e., N‐ureanized‐oligo‐ethylenimines, form Cu(II) complexes. When the N‐substituents are phenyl(1, 3), methyl(2), and p‐tolyl(4) groups, the main portions of the Cu(II)‐complexes are binuclear. The binuclear oligomer–Cu(II) complexes showed characteristic properties of photo‐reduction of Cu(II) species, giving rise to stable yellow Cu(I) species. The ease of photo reduction strongly depends on the oligomer structures, especially on the nature of the pendant‐urea groups, i.e., 4 > 1,3 > 2. In the series of aromatic type urea‐oligomers, highly stable photo‐radicals were observed in ESR. By using an optically active oligomer (3) the molecular requirements for these characteristic properties were investigated with circular dichroism and cyclic voltammometry. And one of the plausible structures was deduced as the model of binuclear Cu(II) sites surrounded by oligomeric environments.
Telechelic sulfate ionomers. I. Preparation and solution and thermal properties
Authors: Hegedus R. D. , Lenz R. W.
Published: April 2003

New telechelic ionomers with zinc and sodium sulfate salt terminal groups on hydrogenated polybutadiene (HPB) backbones (I) were prepared from hydroxyl‐terminated hydrogenated polybutadiene (HTHPB) of three different molecular weights (1350, 2100, and 3200 g/mol). Quantitative acid‐base titration, elemental analysis, and NMR spectroscopy were used to verify the structure, and further characterization included differential scanning calorimetry (DSC) and solution viscometry. The DSC results indicated that the ionomers are free of impurities within the limit of the resolution of the method. Glass transition temperatures determined by DSC indicated that the elevation in glass transition temperature by ionic crosslinking was most strongly dependent on the molecular weight of the backbone of the telechelic ionomer. The solution viscometry results showed that the sulfation reaction did not cause either covalent crosslinking or chain scission. Furthermore, the solubility characteristics of the sulfate‐terminated hydrogenated polybutadiene (STHPB) oligomers were shifted towards a preference for polar solvents by the presence of salt groups. The lower molecular weight ionomers of the series showed polyelectrolyte‐like extension at very dilute concentrations in polar solvents. The onset of polymer gelation in hexane was observed for the ionomers which had the highest molecular weight backbones.
Synthesis of functionalized linear poly(divinylbenzene). III. Synthesis of polymeric delocalized carbanion of poly(divinylbenzene) and its reactions
Authors: Aoshima Sadahito , Higashimura Toshinobu
Published: April 2003

A polymeric delocalized carbanion of poly(divinylbenzene) [poly(DVB)] (2) was obtained by the proton abstraction with alkyllithium from the acidic methine moieties (HA) of linear poly(DVB) (1), which was prepared by the polymerization of DVB initiated by acetyl perchlorate. The formation of polyanion 2 was confirmed by UV–visible spectroscopy (λmax = 630 nm) and the reaction with methyl iodide to give methylated poly(DVB). Delocalized polyanion 2 reacted with various electrophilic reagents in THF at 60°C, to yield poly(DVB) derivatives having pendant trimethylsilyl, vinyl, vinyloxyl, hydroxyl, and carboxyl groups. Proton abstraction with base and subsequent reactions with electrophiles were also studied with the linear unsaturated dimer of styrene (1,3‐diphenyl‐1‐butene), as a model for poly(DVB) 1.
Chemical modification of polynorbornene. I. Sulfonation in dilute solution
Authors: Planche J. P. , Revillon A. , Guyot A.
Published: April 2003

The sulfonation of dilute solutions of polynorbornene (PN) in CCl4 has been carried out using SO3–triethylphosphate complexes of various stoichiometries dissolved in dichloroethane (DCE) or trifluoro‐trichloro‐ethane (TTE). This leads to an electrophilic substitution, with very few side reactions, yielding high sulfonation ratios (ca. 85%). The initial reaction is first order in both reactants (PN and SO3) and has an activation energy of 17.5 kJ mol−1. The reaction becomes diffusion‐controlled after ca. 30 min at room temperature due to the precipitation of the partially sulfonated polymer. The initial rate is almost independent of the isomeric structure (cis or trans) and the molecular weight of the polymer, as well as on the stoichiometry of the SO3–TEP complex; it is higher when TTE is used as solvent. The final sulfonation ratio is strongly dependent on the concentration of SO3 and seems to be controlled by the conditions of diffusion inside the precipitated solid.
Radiation‐induced copolymerization of hydrophilic monomers: Synthesis and thermal properties
Authors: Ramakrishna M. S. , Deshpande D. D. , Babu G. N.
Published: April 2003

The radiation‐induced bulk copolymerization of 2‐hydroxyethyl methacrylate (HEMA), 2‐hydroxypropyl methacrylate (HPMA), and N‐vinyl‐2‐pyrrolidone (NVP) with methacrylic acid (MAA) was studied by using 60Co γ‐radiation at a dose rate of 0.16 ± 0.02 M rads/h. The copolymer composition was estimated from the carboxylic acid content and the reactivity ratios were determined by Kelen–Tüdós. In all the systems MAA was found to be the most reactive. The copolymers were characterized by intrinsic viscosity measurements in dimethyl formamide (DMF) at 30 ± 0.1°C. The thermal behavior of the copolymers was evaluated.
The initiation of vinyl polymerization by tetrakis (trialkyl‐phosphite) nickel (o) derivatives
Authors: Hargreaves Keith
Published: April 2003

The study of the polymerization of vinyl monomers initiated by zero‐valent nickel phosphite derivatives in the presence of organic halides has been extended to tetrakis (triethylphosphite) nickel (o) and tetrakis (tri 2‐chloroethylphosphite) nickel (o). A kinetic study with methyl methacrylate and carbon tetrachloride shows that the polymerization proceeds by a free radical process and that the mechanism of initiation resembles that previously reported for the corresponding triphenylphosphite and carbonyl derivatives. The primary process which becomes rate determining at sufficiently high carbon tetrachloride concentration is the nonreversible SN1 scission of an alkylphosphite ligand. These alkylphosphite initiators are considerably more active than the corresponding carbonyl derivatives, but are less active than the corresponding triphenyl‐phosphite derivative. The difference in activities between the aryl and alkylphosphite derivatives has been accounted for by differences in steric over‐crowding of these molecules.
γ‐Irradiation of Nylon 6
Authors: Gupta Mool C. , Pandey Rajbahadur R.
Published: April 2003

Viscosity, Infra‐red, NMR spectral measurement technique, density measurement, and electrical conductivity were used to study the changes that occured during γ‐radiolysis of Nylon 6. It was observed that it undergoes chain scission and crosslinking, but chain scission predominates over crosslinking in air irradiation. From melting temperature, density measurement, and the use of the Flory equation the enthalpy of fusion of Nylon 6 is 11.86 and 13.84 kJ/mol in an inert atmosphere and in air irradiation, respectively. The indirect effective band gap decreases and electrical conductivity increases when Nylon 6 is irradiated with γ‐rays.
Synthesis, microstructure, and copolymerization studies of 2‐chloroethyl α‐chloroacrylate
Authors: Pathak Chandrashekhar P. , Patni Mahendra J. , Babu Gaddam N.
Published: April 2003

Poly(2‐chloroethyl α‐chloroacrylate) was synthesized by radical initiation, and its microstructure was evaluated using carbon‐13 NMR. Methyl methacrylate (M1) and 2‐chloroethyl α‐chloroacrylate (M2) were copolymerized in toluene at 55°C using azobisisobutyronitrile as initiator. The reactivity ratios are 0.37 ± 0.28 and 1.21 ± 2.26, The thermal properties of these copolymers have also been reported.
Kinetics and mechanism of the benzoin isobutyl ether photoinitiated polymerization of styrene
Authors: Lipscomb N. Thornton , Tarshiani Yassin
Published: April 2003

The kinetics of the photopolymerization of styrene in bulk and in dilute systems in the presence of benzoin isobutyl ether as photoinitiator have been examined. The values of the intensity exponent, calculated at different temperatures or at different styrene concentrations, and the monomer exponent, calculated at various intensities, showed significant departure from those predicted by the ideal kinetic scheme, particularly at high intensity, at low temperature, or at low styrene concentrations. Low molecular weight polymer was the dominant product when high light intensity or low polymerization temperature was used. As the temperature was raised, however, or as the intensity was reduced, a high molecular weight polymer became progressively more important. Kinetic and molecular weight data suggest that at low temperature, high intensity, and/or at low monomer concentration, the benzoyl radical is the dominant initiating species; and the benzyl ether radical was consumed mainly in the termination step. At low intensity, high temperature and/or high monomer concentration, however, it appears that both benzoyl and benzyl ether radicals initiated polymerization.
XPS analysis of NH3 plasma‐treated polystyrene films utilizing gas phase chemical modification
Authors: Nakayama Youichi , Takahagi Takayuki , Soeda Fusami , Hatada Kenji , Nagaoka Shoji , Suzuki Jirou , Ishitani Akira
Published: April 2003

Gas phase chemical modification (GCM) is found to be more preferable as a pretreatment for the XPS surface analysis of polymer materials than the conventional liquid phase treatment because it can circumvent problems such as solvent contamination and swelling. We have tried the quantification of the surface composition successfully by estimating the yield of the reaction from model samples. GCM was then applied to correlate the surface composition of NH3 plasma‐treated polystyrene films with their cell‐affinity. The amount of primary‐amine and that of carboxylic acid were directly determined by GCM. Although the amount of primary‐amine, 15–20% of total nitrogen, did not depend on the treatment intensity, the total amine content for the treated samples increased with the plasma treatment intensity. The quantity of carboxylic acid generated was found to be very small. All treated samples had better cell‐affinity than the control. The sample N2 (of medium treatment) showed the best cell‐affinity. The most strongly treated sample N3, with larger amine content than N2, showed worse cell‐affinity because of the interference by the sputtered SiO2 on the surface.
Studies on some radical transfer reactions by entrapping the radicals as polymer end groups. II. Reactions of ȮH radicals with amino acids
Authors: Pramanick Dinabandhu , Sarkar Jyotish , Bhattacharyya Ramanath
Published: April 2003

The reaction of ȮH radicals with a number of aliphatic amino acids has been studied by entrapping the resultant radicals as end groups of poly(methyl methacrylate) that have been detected and estimated by the sensitive dye partition technique. The rate constants of the reaction (in mol−1 L S−1) of 7 amino acids at 25°C and at pH 1.00 have been determined as 8.33 × 108 for glycine, 2.56 × 109 for β‐alanine, 2.01 × 109 for β‐alanine, 3.99 × 109 for 4‐amino butyric acid, 7.56 × 109 for (1+) valine, 1.42 × 1010 for (1−) leucine, and 5.98 × 1010 for 6‐amino caproic acid. Glycine, α‐alanine, β‐alanine, and 4‐amino butyric acid produced radicals that underwent deamination and incorporated only carboxyl‐bearing end groups in the polymer. The other amino acids, leucine, valine, and 6‐amino caproic acid, produced at least two types of radicals, radicals that underwent deamination and those that remained intact, and incorporated in the polymer both carboxyl‐ and amine‐bearing end groups but in different amounts. The latter type of radicals were about 29% from 6‐amino caproic acid, 23% from leucine, and 18% from valine. The change of pH from 0.80 to 2.72 did not produce any significant change in the end group profile of the polymer obtained, indicating no appreciable change in the rate of the reaction of ȮH radicals with the simplest amino acid glycine in the pH range studied.
Synthesis, physical, and thermal properties of linear poly(dialkoxyphosphinyl‐s‐triazine)s
Authors: Mikroyannidis John A.
Published: April 2003

A novel class of linear poly(dialkoxyphosphinyl‐s‐triazine)s were prepared by interfacial or solution polycondensation reactions of various diamines such as ethylenediamine, hexamethy‐lenediamine or bis(4‐aminocyclohexyl)methane with 2‐dialkoxyphosphinyl‐4,6‐dichloro‐s‐triazines. The latter were synthesized by reacting cyanuric chloride with an equimolar amount of trialkyl phosphite. The phosphorous‐containing polymers were characterized by inherent viscosity measurements as well as by infrared (IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy. The thermal properties of polymers were investigated by differential thermal analysis (DTA) and thermogravimetric analysis (TGA). Pyrolysis of all polymers was exothermic. Polymers were stable up to 150–200°C both in nitrogen and air atmosphere. They afforded 16–42% char yield at 700°C under anaerobic conditions.
Redox polymerization of methyl acrylate in absence and in presence of some inorganic silicon compounds
Authors: Badran A. S. , Abd‐El‐Hakim A. A. , Moustafa A. B. , El‐Ghaffar M. A. Abd
Published: April 2003

The polymerization of methyl acrylate in water using ammonium, potassium, and sodium persulphates with sodium bisulphite as redox initiation system was studied. It has been found that ammonium persulphate had the least activity on the rate of polymerization and resulted in the formation of the highest viscosity average molecular weights for the obtained polymers. The rate of polymerization was found to increase with sodium bisulphite concentration in the redox system, but the viscosity average molecular weights were found to decrease with the increase of sodium bisulphite concentration. Addition of some inorganic silicon compounds (containing the same weight equivalent of SiO2) resulted in increasing the rate of polymerization and decreasing the induction period. The average molecular weights obtained in presence of china clay were found to be the highest and those obtained in presence of talc were the least.
Comparison of methods of calculation of 13C‐NMR chemical shifts of diene polymers with applications to isomerized natural rubber
Authors: Bradbury J. H. , Elix J. A. , Perera M. C. S.
Published: April 2003

Natural rubber was isomerized by two methods that involved either dehydrobromination of hydrobrominated natural rubber or heating natural rubber with butadiene sulfone. The 13C‐NMR spectra of the methylene region of isomerized natural rubber was interpreted in terms of dyad arrangements for which assignments were made by calculating chemical shifts according to three different published methods. One method [Gronski, Murayama, Cantow, and Miyamoto, Polymer, 17, 358 (1976)] gave the best overall agreement with the experimental chemical shifts; another [Sato, Ono, and Tanaka, Polymer, 18, 580 (1977)] was better for C‐1 and C‐3 methylene carbon atoms; and still another [Khatchaturov, Dolinsky, Prozenko, Abramenko, and Kormer, Polymer 18, 871 (1977)] gave results which deviated considerably from the other methods. From 13C‐NMR intensity measurements it was shown that the elimination of HBr from hydrobrominated natural rubber occurred by a random process. Contrary to literature reports, it was found that the sulphur dioxide catalyzed isomerization of natural rubber was accompanied by a significant amount of double bond migration; a possible reaction scheme was proposed.
Polymerization of oxiranes by polymeric organoantimony oxides
Authors: Nomura Ryoki , Wada Yasunori , Matsuda Haruo
Published: April 2003

Polymeric arylantimony(V) oxides [poly(ArSbO2), Ar = phenyl, p‐chlorophenyl (CPh), and p‐methylphenyl (Tol)] were employed as catalysts for the polymerization of oxirane [ethylene oxide (EO)] and also substituted oxiranes [propylene oxide (PO), 1,2‐butylene oxide (BO), and epichlorohydrin (ECH)]. The polymerization of EO by ArSbO2s proceeded 3–60 times faster than that by the other organoantimony and ‐tin compounds such as triphenylstibine oxide (Ph3SbO) and arenestannoic acids (ArSnO2H), respectively. Apparent activation energy for the polymerization of EO was estimated as 13.7, 13.3, and 13.6 kcal/mol for PhSbO2, TolSbO2, and CPhSbO2, respectively. The results of the polymerization as well as 1H‐, 13C‐, and 17O‐NMR spectroscopy suggested that the polymerization was initiated by ArSbO2 or Ar2Sb2O4 fragments, which was derived from a nucleophilc solvation of the polymeric ArSbO2 by oxiranes in situ.
Furanized rubber studied by NMR spectroscopy
Authors: Perera M. C. S. , Elix J. A. , Bradbury J. H.
Published: April 2003

The double bonds of natural rubber latex (stabilized by a nonionic surfactant) were reacted with an approximately equimolar amount of performic acid at room temperature with a limited amount of formic acid present. Product analysis by 1H‐NMR during the course of the reaction showed that 69–90% epoxidation occurred before the advent of ring opening and ring expansion to produce furanized rubber; hence the rate of epoxidation was greater than the rate of furanization. Indeed, at lower concentrations of formic acid and rubber latex, epoxidation occurred to 90% and furanization was prevented; it was subsequently brought about by the addition of a catalytic amount of orthophosphoric acid. Increased formic acid concentration caused early coagulation of the modified rubber latex. By 1H‐ and 13C‐NMR, it was found that the furanized rubber probably consisted of tetrahydrofuran rings linked together by CC bonds at positions adjacent to the hetero atom and contained a terminal hydroxy group. The number average sequence length was 2–9, but only the sample with an average sequence length of 9 was effective as a cation binder.
Functional polymers. XLVIII. Polymerization of ω‐alkenoate derivatives
Authors: Purgett Mark D. , Vogl Otto
Published: April 2003

Esters of ω‐alkenoic acids have been homopolymerized with transition metal initiating systems. The key to the successful polymerization was the complexation of the monomer prior to its addition to the initiating system. Titanium trichloride, aluminum activated, was found to be best as the transition metal part of the initiator systems, with diethyl‐, or better, diisobutylaluminum chloride as the reducing agents andn‐hexane or toluene as the solvents. Best results for polymerizations were obtained with 2,6‐dimethylphenyl esters of the functional α‐olefin monomers; however, other phenyl esters also polymerized well. Attempts to polymerize methyl 10‐undecenoate gave the corresponding polymer in only low yields. Polymers of the 2,6‐dimethylphenyl esters, obtained in high molecular weight, were characterized. Polymers were also obtained from 2,6‐dimethylphenyl 7‐octenoate, but not from ω‐alkenoates with less than three methylene units between the ester group and the terminal olefin group.

Poly(2,6‐dimethylphenyl 10‐undecenoate) was hydrolyzed in an aqueous sodium hydroxide/1,4‐dioxane solution to poly(sodium 10‐undecenoate) that in turn was neutralized with acetic acid to poly(10‐undecenoic acid).
29Si nuclear magnetic resonance of dimethyl and phenylmethyl containing polysilanes
Authors: Wolff Andrew R. , Nozue Ikuo , Maxka Jim , West Robert
Published: April 2003

The 29Si‐NMR spectra are reported for poly(methylphenylsilylene), 1, poly(1,1,2‐trimethyl‐2‐phenyldisilene) 2, two samples of poly(dimethylsilylene‐co‐phenylmethylsilylene), 3a and 3b, and poly(phenylmethylsilylene‐co‐n‐hexylmethylsilylene), 4. The spectra of 3a, 3b, and 4 indicate that these polymers contain blocklike regions with considerable segregation of RMeSi and PhMeSi groups. The spectrum of 2 shows no evidence for stereospecific polymerization. The preparation of 2 from 1,1,2‐trimethyl‐2‐phenyldichlorosilane is also described.
29Si nuclear magnetic resonance of dialkylpolysilanes
Authors: Wolff Andrew R. , Maxka Jim , West Robert
Published: April 2003

The silicon‐29 nuclear magnetic resonance spectra of a number of dialky‐ and alkylmethylpoly‐silanes are reported. Polysilanes composed of asymmetrically substituted silylenes (i.e., alkylmethylsilylenes) exhibited very broad resonance lines attributed to diastereomeric chemical shifts of stereogenic silylenes alpha and beta to the observed nucles Symmetrically substituted polysilanes showed a single narrow peak. The 29Si chemical shifts for these polysilanes decrease with increasing steric bulk of the substituents, varying inversely with the electronic excitation energy.
Functional polymers and sequential copolymers by phase transfer catalysis. XXVIII. Synthesis and characterization of alternating block copolymers and polyformals of polyisobutylene and aromatic polyether sulfone
Authors: Percec Virgil , Auman Brian C. , Nava Hildeberto , Kennedy Joseph P.
Published: April 2003

Alternating—i.e., ‐(A‐B)n‐ type—block copolymers of polyisobutylene (PIB) and aromatic polyether sulfone (PSU) have been prepared by phase transfer catalyzed Williamson polyetherification of α,ω‐di(phenol)PIB with α,ω‐di(chloroallyl)‐ or ‐(bromobenzyl)PSU. Block copolymers of the two prepolymers were also synthesized by the phase transfer catalyzed polyetherification of methylene chloride with α,ω‐di(phenol)PIB and α,ω‐di(phenol)PSU (bisphenol‐A‐terminated PSU). This method leads to ‐[(A)x‐(B)y]n‐ block copolymers with formal linkages between segments. At sufficiently high segment lengths, both types of block copolymers exhibit two distinct Tgs, indicating phase separation into rubbery PIB and glassy PSU domains.
A study of polypyrrole synthesized with oxidative transition metal ions
Authors: Chao Taina H. , March Juan
Published: April 2003

Polypyrrole powder and films were chemically synthesized by the reaction of AgNO3, FeCl3, Fe(NO3)3, Cu(NO3)2, or Cu(NO3)2‐AlCl3 with pyrrole in an aqueous solution or a water—toluene two‐phase system. Products were characterized by elemental analysis, IR, scanning electron microscopy with energy dispersive x‐ray analysis (SEM with EDAX), and conductivity measurements. The polypyrrole synthesized from pyrrole with FeCl3 had a composition of C4.00H3.05N0.99Cl0.25. The pressed powder had a conductivity of 2.7 × 10−2 S/cm and the film 2.8 S/cm. All the other metal salts produced films that had the same organic backbone, morphology, and conductivity as the polymer synthesized using Fe(III) salts, regardless of the considerable differences in the reduction potentials of the metal ions. The nature of the anions of the transition metal salts had no effect on the reaction. Anions, however, were retained as the counterions of the cationic polypyrrole backbone and could be easily exchanged with other anions.
Structure characteristics of halouracils containing chiral centers and their polymers with polyethylenimine
Authors: Ye Dakeng , Overberger C. G.
Published: April 2003

Uracil esters and acids containing both a chiral center and a halogen atom at the 5‐position (fluoro, chloro and bromo) were preapred. The esters of these species were then grafted onto polyethylenimine via an amide bond. The precise nature of this bond was examined using 1H, 13C, 19F, and 13C‐1H coupled spectroscopies. The results show that the polymers obtained under our experimental conditions possess both covalent and ionic bonds at the grafting position.