bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses and reactions of porphyrin and metalloporphyrin polymers
Authors: Kamogawa Hiroyoshi 
Published: April 2003

AbstractVarious porphyrin functions such as protoporphyrin IX and chlorin a as well as metalloporphyrin functions such as Mg(II)– and Cu(II)–chlorophyllin a and Fe(III)– and Co(II)–protoporphyrin IX were incorporated into vinyl polymers by preparation and polymerization of their p‐vinylbenzyl esters. The porphyrin function was also incorporated by reaction of poly‐p‐chloromethylstyrene with porphyrins or metalloporphyrins or by the reaction of p‐aminostyrene polymers with chlorophyll b through Schiff‐base formation. Mg(II)–porphyrin polymers were found to be remarkably effective as catalysts in photoredox systems; porphyrin polymers without central metal atoms were also effective to a lesser extent.
Polymerization of vinyloxyaluminum and formation of syndiotactic poly(vinyl alcohol)
Authors: Nozakura Shun‐Ichi , Kida Sueo 
Published: April 2003

AbstractThe polymerization of diisobutylvinyloxyaluminum, CH2CHOAl(i‐Bu)2, and diethylvinyloxyaluminum, CH2CHOAlEt2, did not take place in the presence of typical radical or cationic initiators. The polymerization was realized at 60°C by the addition of tetrahydrofuran (THF) or tetrahydropyran, no conventional initiator being required. Diethyl ether, glyme, and dioxane were not effective on the polymerization. At Dry Ice–acetone temperature, polymerization did not take place, even in the presence of tetrahydrofuran, but did take place in the presence of both THF and SnCl4. The role of cyclic ethers in the polymerization was studied. Polymers were converted into poly(vinyl alcohol) (PVA) by solvolysis. All the resulting PVA was syndiotactic; particularly polymers obtained at −78°C showed syndiotactivity of 89%, which is the highest value ever reported.
Preparation of poly‐p‐benzenesulfonamide
Authors: Kersting R. James , Hulse George E. 
Published: April 2003

AbstractThe poly‐p‐benzenesulfonamide (PBS) structure has been prepared by the transamidation of N1,N1‐dimethylsufanilamide hydrochloride in a melt reaction at 180°C. The polymeric nature of the product is exhibited by brittle film formation and a glass transition temperature of 180–190°C. Infrared and NMR spectroscopy are consistent with the proposed structure. The number‐average degree of polymerization was measured by NMR. The maximum degree of polymerization was 14. Failure to obtain an optimum molecular weight did not appear to be due to monomer purity. Increasing the reaction temperature from 180 to 220°C led to side reactions giving insoluble and infusible product. PBS underwent thermal decomposition near 310°C. The decomposition temperature is independent of molecular weight.
Stereoregularity and polymerization mechanism of polymethacrylonitriles determined by 13C‐NMR spectroscopy
Authors: Matsuzaki Kei , Kanai Taiichi , Matsumoto Susumu 
Published: April 2003

AbstractCarbon‐13 nuclear magnetic resonance (13C‐NMR) spectra of polymethacrylonitriles prepared under various conditions were measured. In acetone solution, the α‐methyl carbon absorptions were split into triads and partially into pentads, and the methylene carbon absorptions into tetrads. In trifluoroacetic acid solution, the α‐methyl carbon absorptions were split into pentads and the cyano carbon absorptions into triads. The triad, tetrad, and pentad tacticities determined from 13C‐NMR spectra were compared with dyad tacticities determined from proton NMR spectra. The stereoregularity of the polymers which are γ‐ray‐initiated in liquid phase at temperatures near melting point (−35.8°C) and in the solid state differs from that of the polymers radically initiated at −20 to 80°C. The stereoregularity and the conversion suggest the existence of an ionic mechanism in the polymerization at low temperatures.
NMR study of poly‐p‐isopropyl‐α‐methylstyrene
Authors: Leonard J. , Malhotra S. L. 
Published: April 2003

Abstract220 MHz NMR spectra of sample of poly‐p‐isopropyl‐α‐methylstyrene prepared through anionic (A) and cationic (B) polymerizations are studied. Peaks at τ values of 9.07, 9.41, and 9.71 are assigned to isotactic (i), heterotactic (h), and syndiotactic (s) α‐methyl triads, respectively. From the α‐methyl triads and the β‐proton tetrads it is found that polymer A deviates little from Bernoullian statistics and that first‐order Markov configurational statistics applies to polymer B. Isopropyl methine and methyl proton resonances are also analyzed in terms of the configurational statistics of the polymer. Resonances of the phenyl protons are assigned with increasing field to s, h, i meta and ortho protons.
Synthesis of polymers by use of divalent metal salts of monohydroxyethyl phthalate: Metal‐containing isocyanurate‐type crosslinked polyurethanes
Authors: Matsuda Hideaki 
Published: April 2003

AbstractDivalent metal salts (I) of monohydroxyethyl phthalate have catalytic activity for polymerization of isocyanate groups. The synthesis of novel metal‐containing isocyanurate‐type crosslinked polyurethanes were investigated by the crosslinking reaction of I in DMF with diisocyanates or urethane prepolymers, that is, diisocyanate adducts of polyethylene glycol. 2,4‐Toluene diisocyanate and diphenylmethane diisocyanate were used as diisocyanates, and DMF was the solvent. The crosslinking reactions were followed by determining the gelation time. Gelation time decreased with increasing temperature. The Ca salt was more effective than the Mg salt in the crosslinking reaction. The yields of resulting metal‐containing three‐dimensional polymers decreased with increasing metal content in the feed. The Ca salt was more easily introduced into the network polymers than the Mg salt was. Decomposition temperatures decreased on introducing metals into the network polymers. Some physical properties of the metal‐containing network polymers are also discussed.
Copolymerization of styrene. V. Copolymerization with α‐cyanocinnamamide
Authors: Liebersohn Aharon , Kohn David H. 
Published: April 2003

AbstractCopolymers of styrene with α‐cyanocinnamamide were prepared by free radical initiation in bulk and in DMF solution and also by thermal initiation in bulk. The copolymerization parameters were determined by the conventional scheme of copolymerization and by an improved scheme taking into account the penultimate unit. Different values of the copolymerization parameters were obtained at the above mentioned different polymerization conditions, indicating the existence of a solvent effect. The influence of the comonomer on some of the basic properties, like intrinsic viscosity, solubility, melting range, and glass transition temperature and on some mechanical and behavior properties of the copolymers was studied in comparison with homopolystyrene.
Solid‐state polymerization of a cyclic diacetylene
Authors: Baughman R. H. , Yee K. C. 
Published: April 2003

AbstractLarge polymeric single crystals of a unique ring‐bridged polymer have been produced by the solid‐state polymerization of a cyclic diacetylene (o,o′‐diacetylenyldiphenyl glutarate). These crystals are of high thermal stability, metallic in appearance with an asbestos‐like texture, infusible, and insoluble. Single‐crystal x‐ray diffraction investigation indicates that the polymer is monoclinic (probable space group C2/c or Cc) with a unit cell containing four monomer units of dimensions α = 20.8 Å, b = 8.0 Å, c = 9.7 Å, and β = 106°. Infrared spectra eliminate the previously suggested possibility that the solid‐state reactivity of the above monomer corresponds to either reaction of the carbonyl function with the acetylenic bond or the cleavage of the ester linkage. Diffraction, dichroism, and Raman spectral studies indicate instead that the reaction proceeds by 1,4‐addition polymerization at the diacetylene group to produce a trans–trans polymer of structure
magnified image
where the curved lines represent the di‐(o‐phenyl)‐glutarate linkages which are on opposite sides of the chain for adjacent monomer units.
Effect of nonelectrostatic interactions on the macromolecular behavior of polyelectrolytes. I. Potentiometric titrations of PLL in water and aqueous–organic mixtures
Authors: Fenyo Jean‐Claude , Beaumais Jacques , Selegny Eric 
Published: April 2003

AbstractThe potentiometric and viscosity behavior of salt‐free solutions of the polycondensate between L‐lysine and 1,3‐benzenedisulfonyl chloride (PLL) and related polyelectrolytes, have been investigated in water and in aqueous–organic mixtures (acetone–water). The effects of counterions and solvent on the pH‐induced conformational transition is related to hydrophobic interactions. The transition from a compact state to a more extended one shifts towards high values of neutralization with increasing length of N‐tetraalkylammonium counterions. Moreover, the above transition gradually disappears as the percentage of acetone in the mixture is increased, which is interpreted as reflecting the breakdown of the compact structure due to hydrophobic interactions stabilized by bulky counterions. A linear decrease in the free energy variation ΔGt° is observed with increasing percentage of acetone up to about 40% of acetone, and a value of 1200 cal/unit is obtained for PLL in water, which is a reasonable value compared to other data for hydrophobic polyelectrolytes.
Effect of nonelectrostatic interactions on the macromolecular behavior of polyelectrolyes. II. Influence of urea and dyes on the viscometric and optical behavior of PLL
Authors: Muller Guy , Fenyo Jean‐Claude , Beaumais Jacques , Selegny Eric 
Published: April 2003

AbstractThe effect of urea and of dyes on the viscometric behavior of aqueous solutions of PLL has been investigated. The compact structure, which is characteristic of PLL in pure water, is found to disappear progressively as the amount of urea is increased. This is interpreted as due to the destruction in such media of nonelectrostatic interactions responsible for the stabilization of the compact structure of PLL in pure water. In 8M urea, the macromolecular behavior of PLL during the ionization is dependent only on the repulsive interactions between the charged groups. The extension of PLL is then practically independent of the nature of counterions, contrary to what was observed in pure water. In the presence of dye (acridine orange), the compact form of PLL is stabilized, and the dye is found to bind for the two structures of PLL. The analogy between the behavior of Bu4N+ and that of dye is in agreement with the fact the Bu4N+ leads to a stabilization of the compact structure by way of specific interactions between N‐tetraalkylammonium counterions and the PLL chain through the structure of water. The hydrodynamic behavior of PLL is in good agreement with data obtained from potentiometric and optical activity measurements.
Melting behavior of highly stretched isotactic polypropylene film
Authors: Tanaka Hiroshi , Takagi Nobuyuki , Okajima Saburo 
Published: April 2003

AbstractIsotactic polypropylene film was stretched in poly(ethylene glycol) at 140°C and its melting behavior was investigated by using a differential scanning calorimeter (DSC‐1B). The shape of the melting curve depends largely on the stretching ratio, v. A sample stretched to moderate extension (1 < v < 3.5–4) has only a single melting peak (163°C) in the thermogram. When the sample is stretched beyond v = 3.5–4, the thermogram becomes more and more complex with increase of v, and some peaks appear when stretched to 10 < v < 13. The lowest peak which is considered to be the melting peak of the intermolecular crystals produced by the unfolding of chain molecules in the lamellae develops gradually with increase of v. In the thermogram for v = 18 the lowest temperature peak is most pronounced, in contrast to the highest temperature peak which decreases markedly in intensity. The phenomenon shows that large amounts of lamellar crystals are converted to intermolecular crystals in this region. On further stretching (v > 20) a very sharp high temperature peak appears, whose half‐width is about 1°C. Qualitatively similar results were obtained for the samples stretched in poly(ethylene glycol) at 150°C and in air at 140 and 150°C.
Effect of oxygen on the polymerization of vinyl chloride. II. Polymer properties
Authors: Garton A. , George M. H. 
Published: April 2003

AbstractThe bulk and suspension polymerizations of vinyl chloride have been carried out in the presence of small known amounts of added oxygen at 54°C in the presence of peroxide initiators. The concentrations of oxygen were in the range 0–1240 ppm for 1‐gal bulk polymerization systems and 0–400 ppm for 15‐gal suspension polymerization systems. The thermal stabilities of the polymers prepared in the presence of oxygen were lower than those prepared under corresponding oxygen‐free conditions. The average molecular weights of bulk polymers isolated at relatively low conversions were reduced in the presence of oxygen, and the infrared spectra of the polymers were altered. The significance of the decreased thermal stabilities of the polymers prepared in the presence of oxygen is discussed briefly in relation to the possible sites of initiation of dehydrochlorination.
Vinylhydroquinone. III. Copolymerization of vinylhydroquinone and vinyl monomers by tri‐n‐butylborane
Authors: Iwabuchi S. , Kojima K. , Nakahira T. , Ueda M. , Kobayashi M. , Iwakura M. 
Published: April 2003

AbstractThe copolymerization of vinylhydroquinone (VHQ) and vinyl monomers, e.g., methyl methacrylate (MMA), 4‐vinyl‐pyridine (4VP), acrylamide (AA), and vinyl acetate (VAc), by tri‐n‐butylborane (TBB) was investigated in cyclohexanone at 30°C under nitrogen. VHQ is assumed to copolymerize with MMA, 4VP, and AA by vinyl polymerization. The following monomer reactivity ratios were obtained (VHQ = M2): for MMA/VHQ/TBB, r1 = 0.62, r2 = 0.17; for 4VP/VHQ/TBB, r1 = 0.57, r2 = 0.05; for AA/VHQ/TBB, r1 = 0.35, r2 = 0.08. The Q and e values of VHQ were estimated on the basis of these reactivity ratios as Q = 1.4 and e = −;1.1, which are similar to those of styrene. This suggests that VHQ behaves like styrene rather than as an inhibitor in the TBB‐initiated copolymerization. No homopolymerization was observed either under nitrogen or in the presence of oxygen. The reaction mechanism is discussed.
Ester phenyl‐as‐triazine and ester phenylquinoxaline polymers
Authors: Hergenrother Paul M. 
Published: April 2003

AbstractA series of new high molecular weight soluble ester phenyl‐as‐triazine and ester phenyl‐quinoxaline polymers were prepared by solution cyclopolycondensation of oxalamidrazone or 3,3′‐diaminobenzidine, respectively, with various bis(benzilyl)esters. Ester groups are incorporated within the backbone of the polymer chain and also as pendant groups on the heterocyclic ring. By TGA in air, initial weight losses for the all‐aromatic polyester phenyl‐as‐triazines and polyester phenylquinoxalines began at ca. 350 and 400°C, respectively. Films of ester phenyl‐as‐triazine and ester phenylquinoxaline polymers exhibited good thermo‐oxidative stability after aging in circulating air at 232 and 288°C, respectively. Two phenylquinoxaline model compounds were also prepared.
Stereoregularity of polystyrene‐β,β‐d2
Authors: Matsuzaki Kei , Uryu Toshiyuki , Osada Kiyoshi , Kawamura Tokiji 
Published: April 2003

AbstractThe 100‐MHz methine proton spectra of polystyrene‐β,β‐d2 obtained by radical and cationic initiators consisted of four peaks at 2.35, 2.25, 2.17, and 2.03 ppm, the proportion of which changed with polymerization conditions such as catalyst, solvent, and temperature. The spectrum was interpreted in terms of pentad sequences assuming Bernoullian statistics and the stereoregularity was determined. Polystyrene‐β,β‐d2 prepared by radical initiators had a syndiotactic‐rich configuration, independent of polymerization temperature. Polymers obtained by cationic initiators had lower racemic dyads. Cationic polymerization in toluene at 0°C gave a polymer of an almost random configuration. It was revealed that nondeuterated polystyrene of a random configuration can be distinguished from syndiotactic‐rich polystyrene as well as the isotactic polymer by 100 MHz NMR spectroscopy.
Synthesis and properties of poly(2,5‐ethylene benzimidazole)
Authors: Shalaby S. W. , Lapinski R. L. , Turi E. A. 
Published: April 2003

AbstractMethyl β‐(3,4‐diaminophenyl)propionate, its hydrochloride, and β‐(3,4‐diaminophenyl)propionic acid were prepared and their structures were established. The effect of temperature, time, and pressure on the polymerization of these compounds and the molecular weight and structure of the resulting polymers were examined. Thin films of different polymer samples were prepared by compression molding, and their infrared spectra were used to study their structures. Samples of poly(2,5‐ethylene benzimidazole) formed under typical polymerization conditions were shown by differential scanning calorimetry and x‐ray techniques to be amorphous, and the glass transition temperature ranged between 201 and 240°C. The polymers were shown by thermogravimetric analysis to have good thermal stability, and 29–34% of the original weights remained after heating to 1000°C in nitrogen.
Pyrolysis of poly(vinyl chloride)
Authors: Chang E. P. , Salovey R. 
Published: April 2003

AbstractA pyrolysis–gas chromatography–mass spectrometric technique has been developed to study the thermal degradation of poly(vinyl chlorides) polymerized at different temperatures. Hydrogen chloride and benzene evolution during successive stages of pyrolysis have been quantitatively determined and correlated to the tacticity and molecular weight of the polymer. It was found that lowering the temperature of polymerization and molecular weight depresses benzene evolution and increases char weight but does not affect the HCl yield. It is suggested that the syndiotactic trans microstructure favored at low temperature of polymerization yields polyenes which cannot cyclize to form benzene. As the molecular weight decreases, the increase in number of vinyl chain ends facilitates pyrolytic crosslinking and char formation.
Novel polyviologens: Photochromic redox polymers with film‐forming properties
Authors: Simon Myron S. , Moore Phylis T. 
Published: April 2003

AbstractSeveral novel polyamides containing the N,N′‐dialkyl‐4,4′‐dipyridinium (“viologen”) system were made by interfacial condensation of N,N′‐bis(aminoalkyl)‐4,4,‐dipyridinium salts with di‐, tri‐, or tetrafunctional acid chlorides. These materials are useful redox polymers which turn deeply colored when reduced chemically or electrically, or when exposed to light.
Block and graft copolymers by selective cationic initiation. II. Synthesis and characterization of styrene‐isobutylene block copolymers by use of chlorobrominated alkanes
Authors: Kennedy Joseph P. , Melby Earl G. 
Published: April 2003

AbstractThe synthesis and characterization of a new block copolymer, poly(styrene‐b‐isobutylene) (PSt‐b‐PIB), is described. The synthesis involves the initiation of an isobutylene polymerization by a polystyrene molecule containing a terminal tertiary bromine (PSt‐Br), in conjunction with diethylaluminum chloride coinitiator. The species PSt‐Br is in turn synthesized by initiating the polymerization of styrene selectively by the tertiary chlorine of the 2‐bromo‐6‐chloro‐2,6‐dimethylheptane/Et3Al initiator system in the absence of chain transfer. The conditions conducive for selective initiation by tertiary chlorine have been worked out. The pure block copolymer, PSt‐b‐PIB, is obtained by selective extraction and some of its properties were determined, e.g., solubility and film behavior, Tg, and intrinsic viscosity versus temperature. The intrinsic viscosity (in toluene) exhibits a maximum and a minimum in the temperature range from 15 to 55°C.
Synthesis and characterization of optically active poly(2‐phenylvinyl alkyl ethers) and corresponding monomers
Authors: Vuković R. , Fleš D. 
Published: April 2003

Abstractcis‐(S) (+)‐2‐phenylvinyl alkyl ethers having as alkyl groups 1‐methylpropyl (I), 2‐methylbutyl (II), and 3‐methylpentyl (III) were synthesized by condensation of phenylacetylene with the corresponding sodium alcoholates. Polymerization of monomers was performed cationically with BF3 · Et2O or SnCl4 in toluene or CH2Cl2. Specific rotations of polymers were compared with those of low molecular weight model compounds prepared by hydrogenation of monomers, and it was concluded that the difference in the rotation of poly I and model compound ([α]D 19.3° and 5.68°, respectively) and poly II and model compound ([α]D 11.4° and 3.00°, respectively) can be attributed to the asymmetric induction at carbon atoms of the principal polymer chain.
Spontaneous polymerization of the nitroethylene–isobutyl vinyl ether system
Authors: Kushibiki Nobuo , Irie Masahiro , Hayashi Koichiro 
Published: April 2003

AbstractInitiation and propagation mechanisms of the spontaneous polymerization of the system nitroethylene–isobutyl vinyl ether were studied. An equimolar mixture of these two monomers gives white precipitates below room temperature, though they react explosively to give viscous products at higher temperature. The precipitate was found to be composed of a polynitroethylene and a cycloadduct of these two monomers. The isolated cycloadduct product is so reactive that it not only polymerizes itself spontaneously but also initiates the polymerization of nitroethylene. The polymerization of the cycloadduct was revealed to proceed without termination to produce an alternate copolymer of these two monomers. These results indicate that the explosive spontaneous polymerization of this system consists of three elementary reaction processes; (1) cycloaddition reaction between two monomers, (2) anionic polymerization of nitroethylene induced by the cycloadduct, and (3) the living ring‐opening polymerization of the cyclo‐adduct.
Potential energy calculations of ethylene–butadiene copolymers
Authors: Cernia E. , Conte G. , D'ilario L. , Pavel N. V. , Giglio E. 
Published: April 2003

AbstractThe copolymer ethylene–butadiene (PEBU) was investigated by van der Waals potential energy calculations as a function of four internal rotation angles. The butadiene/ethylene molar ratio was assumed to be very small, no greater than 0.25. The energy values corresponding to the fully extended chain of PEBU and polyethylene (PE) are nearly equal, so that the replacement of a H2CCH2 unit with the trans HCCH group (TDB) in PE crystals can be considered feasible, as found by x‐ray diffraction measurements. The three deepest minima of the van der Wals energy correspond to folded chains, with the double bonds lying in the fold parts. Similar calculations carried out on a PE chain point out that TDB behaves as fold‐supporting. The two energetically more favorable conformations of PEBU reproduce rather well the (110) and (200) folds in PE crystals. The path of the (110) → (200) transition does not appear to be hindered by a large potential barrier. If the HCCH group is in the cis conformation, no stable folded chain can be obtained by means of only four intramolecular degrees of freedom. On the basis of these results it is reasonable to suppose that many TDB's could be located on the surface of PEBU single crystals.