bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of some new bioactive acrylic esters
Authors: Chengxun Lu , Xinde Feng , Chongqing Wang , Dechang Ll 
Published: April 2003

AbstractFour typical bioactive esters of acrylic monomers, N‐p‐acryloxybenzoyloxysuccinimides, 3‐ac‐ryloxy‐4‐oxo‐3,4‐dihydro‐1,2,3‐benzotriazines, N‐acryloxy‐5‐norbornene‐2,3‐dicarboximides, and I‐p‐acryloxybenzoyloxybenzotriazoles, were Synthesized and polymerized as reactive polymers. Twelve new monomers were prepared by coupling acrylic acid, methacrylic acid, p‐acryloxybenzoic acid, or p‐methacryloxybenzoic acid with four N‐hydroxy compounds such as N‐hydroxysuccinimide (HOSu), 3‐hydroxy‐4‐oxo‐3,4‐dihydro‐1,2,3‐benzotriazine (HOObt), N‐hydroxy‐5‐norbornene‐2,3‐dicarboximide (HONB), and I ‐hydroxybenzotriazole (HOBT) in the presence of dicyclohexylcarbodimide. All monomers polymerized readily in solution with azobisisobutyronitrile (AIBN) as free radical initiator. The resulting reactive polymers with reactive OSu, OObt, ONB, or OBT group on the side chain are equally reactive toward n‐butylamine at room temperature in the formation of corresponding polyacrylamides. Reactive polymers were used to immobilizetrypsin. It has been found that poly(N‐p‐methacryloxybenzoyloxy‐5‐norbornene‐2,3‐dicarboximide)‐trypsin matrix had high activity around three times that of the poly(N‐methacryloxy‐5‐norbornene‐dicarboximide)‐trypsin matrix. It is proposed that this activity may be due to the presence of a long spacer arm with a hydrophobic and rigid benzene ring between the ligand and matrix. The reactive poly(N‐p‐methacryloxybenzoyloxysuccinimide‐p‐methacryloxybenzoic acid) copolymer was used to immobilize the serum protein. This immobilized protein was a hopeful bioactive solid immunoadsorbent.
Solid‐state polymerization of long‐chain vinyl compounds. IV. Effects of chain length on the polymorphic behavior and postpolymerization of n‐alkyl methacrylates
Authors: Shibasaki Yoshio , Fukuda Kiyoshige 
Published: April 2003

AbstractPolymorphic behavior and γ‐ray‐initiated postpolymerization of the even‐numbered long‐chain Methacrylates (C18‐C12) have been investigated. Phase transition behaviors of octadecyl, hexadecyl, tetradecyl, and dodecyl methacrylates are
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respectively, which become simpler with shortening of the chain length. The methacrylate monomers with sufficiently long hydrocarbon chains, such as octadecyl and hexadecyl, can be polymerized rapidly in the α‐form crystal (hexagonal packing) by a fully two‐dimensional mechanism, whereas in the β‐form crystal (triclinic packing), polymerization can hardly occur. In the case of dodecyl methacrylate, however, an accelerated polymerization in the β form occurs after an induction period of several hours and the resultant polymer is gel‐like. This can be interpreted by the propagation reaction across the polymer chain already formed. It has been found that the solid‐state post‐polymerization of n‐alkyl methacrylates is affected by the chain length through the packing mode of the monomer molecules and also by the aggregation state of side chains in the resultant comblike polymer.
Kinetics of polymerization of acrylic acid initiated by Mn3+–isobutyric acid redox system. II
Authors: Elayaperumal P. , Balakrishnan T. , Santappa M. , Lenz R. W. 
Published: April 2003

AbstractThe kinetics of redox ‐initiated polymerization of acrylic acid (AA) by the systerm Mn3+‐isobutyric acid (IBA) in sulfuric acid was studied in the temperature range of 35–50°C. The overall rates of polymerization (Rp), disappearance of manganic ion (−Rm), and degree of polymerization (Xn), were measured with variation in [monomer], [Mn3+], [IBA], H+, μ, [Mn2+], and temperature. The polymerization is initiated by the organic free radical that develops from the Mn3+‐isobutyric acid oxidation reaction. Two types of termination reactions, one by the metal ion (Mn3+) and the other by the MN3+‐isobutyric acid complex are proposed to explain the kinetic results. The various rate parameters were evaluated an discussed.
Polymerization and copolymerization of 2‐phthalimidomethyl 1,3‐butadiene. I. Preliminary studies of free radical polymerization and polymerizations initiated by various transition metal allyl complexes
Authors: Borg‐Visse F. , Dawans F. , Maréchal E. 
Published: April 2003

Abstract2‐Phthalimidomethyl 1,3‐butadiene was homopolymerized and copolymerized with butadiene by free radical initiators; r1 and r2 were close to 1. All the attempts to polymerize 2PMB anionically have been unsuccessful. Preliminary studies of various η3‐allylic catalysts showed that η3‐allyl M0(CO)3OOCCF3 initiates the polymerization of butadiene and is not sensitive to N‐methyl phthalimide (NMP); neither does it initiate the copolymerization of butadiene and 2PMB. On the other hand, a catalyst that results from the reaction of allyl trifluoroacetate with nickel tetracarbonyl is efficient for the copolymerization of butadiene and 2PMB. η3‐Allyl nickel trifluoroacetate was prepared in heptane or benzene and used in benzene or methylene chloride. In all cases it initiated the copolymerization of butadiene with 2PMB
Microstructural order in cotton fibers by relative availability of O(3)H: Never‐dried fibers
Authors: Rowland Stanley P. , Wade Clinton P. 
Published: April 2003

AbstractAvailabilities of O(3)H relative to O(2)H (that is, [O(3)H]a/[O(2)H]a) on accessible surfaces of microstructural units of cotton fibers were measured by chemical microstructural analysis (CMA). CMA involves a mild chemical reaction with N,N‐diethylaziridinium chloride, determination of substituent distribution for this product and a corresponding product from decrystallized cellulose, and simple computations. Measurements for fibers in commercial cotton fabric, for field‐dried fibers, and for never‐dried fibers are reported. The [O(3)H]a/[O(2)H]a, an inverse measure of intact O(3)H ·· O(5′) bonds, decreased in the stated order; thus, intact O(3)H ·· O(5′) hydrogen bonding increased in this same order. Results indicate a high degree of order in intramolecular bonding in the never‐dried fiber and an increasing disruption of this bonding as the never‐dried fiber is dried and processed.
Polymerization in lyotropic liquid crystals. I. Change of structure during polymerization
Authors: Thundathil Raju , Stoffer James O. , Friberg Stig E. 
Published: April 2003

AbstractPolymerization was made at 60°C in a lyotropic liquid crystal of sodium undecenoate and water. The liquid crystalline structure prior to polymerization was identified by optical microscopy and low‐angle x‐ray diffraction as an array of hexagonal closely packed cylinders with the hydrophobic part of the soap in the center of the cylinders. During polymerization the structure became isotropic at 60°C. Cooling to 20°C transformed the structure to a lamellar liquid crystal–a reversible transition. The structure of the lamellar phase was interpreted as a polyethylene backbone from which deformed decanoate chains reached toward the aqueous layer. Molecular models showed the model to accept head‐tail, head‐head, and tail‐tail configurations in cis and trans conformations with the exception of the cis tail‐tail configuration.
Polymerization in water‐in‐oil microemulsion systems. I
Authors: Stoffer J. O. , Bone T. 
Published: April 2003

AbstractPhase diagrams for monomer (methyl acrylate containing microemulsions) are shown and described. Polymerizations of a series of microemulsified monomer reveals the expected linear dependence of 1/DS vs. [S]/[M] for pentanol acting as a chain transfer agent and giving a value of 5.1 × 10−4 for Cs. No break in molecular weight behavior was shown as a result of micellization at higher water contents. A comparison of molecular weights obtained by various classical methods (solution, emulsion, bulk) are also given.
Pyrolysis mass spectrometry and gas chromatography of plasma‐polymerized benzene and xylene
Authors: Venugopalan M. , Lin I.‐Sioun , Grenda M. S. 
Published: April 2003

AbstractPyrolysis mass spectra and gas chromatograms of plasma‐polymerized benzene (PPB) and p‐xylene (PPX) have been studied. Both polymers gave mass spectra that indicated the presence of disubstitution in an aromatic ring and of product molecules, such as biphenyl and ethylbenzene, trapped in the polymer matrix. The PPB spectrum showed fragments originating from C6H4n structures and the PPX spectrum fragments originated from CH2C6H4CH2n structures. Both the pyrolysis mass spectrum and chromatogram contained peaks that distinguished PPX from commercial polystyrene samples. A chain mechanism which involves H abstraction reactions under plasma activation is proposed. The highly crosslinked structures of the polymers are attributed to the subsequent addition of free radicals to the double bonds of a fragmented chain formed as a result of the scission of the CC aromatic bond(s).
Functional polymers. VI. Preparation and polymerization of methyl 3‐vinylsalicylate, methyl 3‐vinylacetylsalicylate, 3‐vinylsalicylic acid, and 3‐vinylacetylsalicylic acid
Authors: Iwasaki M. , Tirrell D. , Vogl O. 
Published: April 2003

AbstractThe title compounds were synthesized and their homopolymerizations and copolymerizations with styrene and a number of acrylic monomers were investigated. Methyl 3‐vinylacetylsalicylate was prepared in a five‐step synthesis from 2‐ethylphenol in an overall yield of 40%. Methanolysis of this compound gave methyl 5‐vinylsalicylate in 63% yield. Hydrolysis of methyl 3‐vinylsalicylate gave a nearly quantitative yield of 3‐vinylsalicylic acid which could be acetylated to 3‐vinylacetylsalicyclic acid (3‐vinyl aspirin). 3‐Vinylsalicylic acid derivatives were readily homopolymerized and copolymerized with styrene, methyl methacrylate, and methacrylic acid, and 3‐vinylsalicyclic acid was copolymerized with a number of vinyl and acrylic monomers. Copolymer compositions were determined by examination of 1H‐NMR spectra.
The effect of solvents on the radiation‐induced polymerization of ethyl and isopropyl vinyl ethers
Authors: Hsieh W. C. , Kubota H. , Squire D. R. , Stannett V. 
Published: April 2003

AbstractThe radiation‐induced cationic polymerization of ethyl and isopropyl vinyl ethers was studied in a variety of solvents. The propagation rate constants were estimated and found to vary widely with the nature of the solvent. In particular, a good linear relationship existed between the logarithms of the rate constants and the reciprocal of the dielectric constants. The lowest rates were those of the highest dielectric constant solvents. These results have been interpreted in terms of the Laidler and Eyring theory of ion‐molecule reactions. Isopropyl vinyl ether polymerizes much faster than ethyl vinvl ether, although the rates approach the same value at infinite dielectric constant. In contrast, “free” carbenium ion polymerizations initiated by stable carbenium ion salts in methylene chloride solution had similar values for both monomers. A comparison is made between the rate constants obtained with both methods of initiation.
Cyclization and crosslinking of polybutadiene in solution by electron beam irradiation
Authors: Hayashi Kanae , Tachibana Michinori , Okamura Seizo 
Published: April 2003

AbstractEffects of electron beam irradiation on liquid polybutadiene in n‐hexane solution were studied at −10°C. With irradiation, crosslinking of the polymer and loss of double bond by cyclization took place at the same time. These reactions were retarded by the addition of DPPH or triethylamine which indicated that both radical and cationic mechanisms contributed to this system.
Synthesis of polymer containing lipoic acid as a polymeric reagent for acyl transfer
Authors: Nambu Yoko , Endo Takeshi , Okawara Makoto 
Published: April 2003

AbstractLipoic acid was immobilized on crosslinked polystyrene beads to generate a polymeric reagent. The acyl transfer reaction of the p‐nitrobenzoyl group from the polymer‐bound lipoic acid to cyclohexylamine was investigated spectrophotometrically and was compared with a monomeric model compound. The acceleration effect of silver ion on the acyl transfer reaction also was studied.
Polymers containing crown ethers: Polyureas from diisocyanates and 1,10‐diaza‐18‐crown‐6
Authors: Mathias Lon J. , Al‐Jumah Kusay 
Published: April 2003

AbstractA new class of polyureas are reported which contain a crown ether analog in the backbone. Synthesis involves condensation of 1,10‐diaza‐4,7,13,16‐tetraoxacyclooctadecane with either 2,4‐toluene diisocyanate or hexamethylene diisocyanate in dichloromethane. The former gives tough, flexible polymers and the latter tacky, hygroscopic products. The infrared (IR) and proton nuclear magnetic resonance (NMR) spectra of these materials are given along with those of the polyurea from piperazine and hexamethylene diisocyanate. The carbon NMR chemical shifts and spin‐lattice relaxation times are also reported. Comparison is made with monomer, other crown ethers, polyoxyethylene, and a model compound prepared from the diaza monomer and phenylisocyanate. The T1 values indicate a greater degree of backbone and macrocycle flexibility for the hexamethylene‐containing polyurea than for the toluene analog.
Kinetic studies of rigid copolymers containing 3,3′‐substituted biphenyls and vinylimidazole
Authors: Hayama Shigeru , Takeishi Makoto , Niino Shogo , Okamura Toshiaki 
Published: April 2003

AbstractKinetic studies were investigated with rigid copolymers composed of vinylimidazole (VIm) and 3,3′‐substituted biphenyls. For neutral substrates, two different kinetic figures were observed by the influence of 3,3′‐substituents. The second‐order rate constants kinetically determined were largely enhanced by the reduction of ethanol content less than 30 vol % in contrast to the rapid decrease in viscosities of catalyst solutions. A parameter concerning the polymer conformation and the effect of hydrophobic interaction was obtained using a relationship between the kinetic constants with ethanol content. Maximum kinetic effect of electrostatic interaction appeared at about 50 mole % VIm content by attracting cationic substrates towards the COO− group of the polymer catalyst. This maximum rate profile was nearly coincident with a curve derived by calculating the sequence distribution of the (VImCOOH) linkage unit.
Thermal properties of wholly aromatic polyamides
Authors: Chaudhuri Ajit K. , Min B. Y. , Pearce Eli M. 
Published: April 2003

AbstractVarious wholly aromatic polyamides based on m‐and p‐phenylene diamines and isophthaloyl and terephthaloyl chloride have been synthesized and their thermal properties and oxygen index values have been studied. The effect of different substituents on the aromatic ring of the diamine have been explored by comparing their differential thermal analysis (DTA) and thermogravimetric analysis (TGA) behavior, their relative char yields at 700°C, and their oxygen indices. The Cl, NO2, and OH substituted polyamides have been found to produce the highest char yields. The high char yields are probably associated with crosslinking occurring at high temperatures. Attempts at correlating char yield with oxygen index indicated enhancement for the chlorosubstituted aramids.
Ampholytic polystyrene ionomers from cationic–anionic monomer pairs
Authors: Salamone J. C. , Tsai C. C. , Olson A. P. , Watterson A. C. 
Published: April 2003

AbstractThe preparation of a new form of ionomer is described. This class of material is based on the polymerization of a neutral monomer with a small amount of a cationic–anionic monomer pair. The resulting ionomers are ampholytic in character and contain no inorganic ions. In this investigation, the polymerization of styrene with 3‐methacrylamidopropyldimethylammonium and trimethylammonium 2‐acrylamido‐2‐methylpropanesulfonate in a variety of solvents is described.
Magnetic circular dichroism studies of aromatic polymers
Authors: Kaye H. , Hwang J. S. 
Published: April 2003

AbstractThe magnetic circular dichroism (MCD) spectra of syndiotactic and isotactic polymers which contain aromatic chromophores have been found to be sensitive to configurational and conformational differences. For isotactic polymers it was determined that as the aromatic ring moved farther from the main chain the ration of B terms of the polymers to those of their model compounds reached a minimum but increased significantly when the aromatic ring was separated from the main chain by four atoms. This enhancement of MCD is believed to be caused by the alignment of the more flexible side chains which would allow the interaction of the aromatic rings with neighboring groups and could result in a favorable mixing of the ester electronic transition with the aromatic 1A1g−1B2u transition. This effect was not felt to any great extent by the syndiotactic polymers because the necessary nearest‐neighbor interaction was sterically unfavorable. The ratio of the B terms of isotactic poly(phenyl methacrylate) to its model compound decreased as the polymer coil expanded, whereas it increased for the syndiotactic polymer. This effect reflects the different changes that the side chain interaction and orientations undergo in these polymers during coil expansion. The MCD ratios for iso‐ and syndiotactic poly(phenylethyl methacrylate) were not so sensitive during coil expansion. The ratio of the dipole strengths of the polymers and model compounds paralleled the MCD results, but the ultraviolet (UV) technique was less sensitive than MCD to subtle conformational differences. Poly(benzyl methacrylate) and benzyl pivalate were unsuitable systems for studying the MCD effect because the B terms of these materials approached zero.
Polyenaminoesters from α,α′‐bis(carbomethoxy)diacetylbenzenes and phenylene diamines
Authors: Moore J. A. , Mitchell T. D. 
Published: April 2003

AbstractPolyenaminoesters are prepared by condensation of α,α′‐bis(carbomethoxy)diacetylbenzenes with phenylene diamines in the presence of N,N‐dimethylaniline hydrochloride. Thermogravimetric analysis allowed the determination of the optimum temperature at which to conduct cyclization of the polymers to form thermally stable polypyridoquinolones. The structures of the polymers were assigned by spectroscopic comparisons with appropriate model compounds.
Polymer syntheses via aromatic nitro displacement reaction
Authors: Takekoshi T. , Wirth J. G. , Heath D. R. , Kochanowski J. E. , Manello J. S. , Webber M. J. 
Published: April 2003

AbstractNucleophilic displacement of activated aromatic nitro groups with aryloxy anion is a versatile and useful reaction for the synthesis of aromatic ethers. Preparation of various aromatic monomers and polymers containing ether linkages is described.
Configurational rules governing the stereochemical control of chiral initiators in ring‐opening polymerizations of heterocyclic monomers
Authors: Spassky Nicolas , Leborgne Alain , Momtaz Ardèchir , Sepulchre Maurice 
Published: April 2003

AbstractConfiguration rules were established for the polymerization of cyclic monomers with chiral initiators. The latter recognize in the monomer an asymmetric carbon of homochiral configuration. The chirality of the initiator is defined by the “local” asymmetry of the ligand and by the overall asymmetry of the particular arrangement of catalytic aggregates. Two types of process called “homosteric” and “antisteric,” which apply to the polymerization of resolvable monomers and achiral monomers of meso structure, are defined. These configurational rules have a general character and are verified in many examples of differently substituted three‐ or four‐membered cyclic monomers (oxiranes, thiiranes, β‐lactones). Stereoelective polymerization appears to be an original method for the determination of the absolute configuration of some monomers of unknown chirality.
Effect of metal oxides on the evolution of aromatic hydrocarbons in the thermal decomposition of PVC
Authors: Ballistreri Alberto , Foti Salvatore , Maravigna Pietro , Montaudo Giorgio , Scamporrino Emilio 
Published: April 2003

AbstractThe thermal decomposition of poly(vinyl chloride) (PVC) mixed with several metal oxides was investigated by direct pyrolysis in a mass spectrometer (MS) and flash pyrolysis–gas chromatography. Our results show that the thermal decomposition of PVC occurs in two stages. Unsubstituted aromatic hydrocarbons (benzene, naphthalene, and anthracene) are evolved mainly in the first stage, alkyl‐aromatics (e.g., toluene) in the second. Although the addition of some metal oxides results in an overall suppression of aromatic hydrocarbons, the unsubstituted aromatics are much more suppressed with respect to alkyl‐aromatics. Furthermore, the formation of ZnCl2 and SnCl4 was revealed by the mass spectra of PVC–metal oxide pyrolysates. This suggests that, at least in these two cases, metal chlorides are responsible for aromatic hydrocarbon suppression. With this information a detailed reaction mechanism could be formulated for the thermal degradation of PVC.
Some contributions to the characterization of active sites in Mg‐supported Ziegler–Natta catalysts
Authors: Simon A. , Gröbler A. 
Published: April 2003

AbstractThe contribution of different MgO supports to the coordination polymerization of ethylene was studied by x‐ray diffractometry and infrared (IR) and electron spin resonance (ESR) spectroscopy of the supports and their products after treatment with TiCl4. It was concluded that TiCl4 was bonded on the surface OH groups of MgO mainly in inactive form, whereas the majority of the active sites was associated with the coordinatively unsaturated O2− ions.
A microcalorimetric study of complex formation between alkaline sodium tartrate and iron(III)
Authors: Dale Bruce E. , Tsao George T. 
Published: April 2003

AbstractThe structure of the cellulose solvent ferric sodium tartrate (FeTNa) was studied using a sensitive adiabatic calorimeter. FeTNa was found to be a typical transition metal complex in which three tartrate ligands add in a stepwise fashion to iron. The structure of FeTNa first proposed by Franke is thus confirmed. The equilibrium constant for the addition of the third tartrate ligand to iron is approximately 100, a value typical of those for other cellulose‐dissolving metal complexes. There is no calorimetric evidence for addition of more than three tartrate molecules to iron. The increase in molar heats of reaction with increasing ionic strength is consistent with dilute electrolyte solution theory. Based on these data, the probable reaction between FeTNa and cellulose has been postulated.
Fillers in polypropylene. II
Authors: Hancock M. , Tremayne P. , Rosevear J. 
Published: April 2003

AbstractPart I showed that significant differences exist between calcium carbonate and silicate minerals when incorporated into polypropylene (three grades). It showed further that an ultrafine calcium carbonate, when coated with stearic acid, gives significantly better impact properties to the composite than a coated ground whiting but with no significant effect on its tensile properties. This article examines the effect of particle size and surface coating of chalk‐based calcium carbonate on the physical properties of GWE 21 Propathene homopolymer. The effect of variation in filler level was also investigated.
Synthesis of novel poly(xylylenyl benzimidazole)s
Authors: Ibrahim A. Mahammad , Mahadevan V. , Srinavasan M. 
Published: April 2003

AbstractNovel poly(xylylenyl benzimidazole)s (PXBI) with methyl substituents on the xylylene units were synthesized by high‐temperature polycondensation techniques. Two different tetraamine hydrochlorides were condensed independently with 2,5‐dimethyl‐1,4‐benzene diacetic acid and 2,4‐dimethyl‐1,5‐benzene diacetic acid in polyphosphoric acid (PPA) to yield different poly(xylylenyl benzimidazole)s. Their syntheses, characterization, and properties such as density, viscosity, solubility, crystallinity, and thermal stability were described. Two model benzimidazoles (MBI) were also synthesized from o‐phenylene diamine (OPDA) and the above two diacetic acids to confirm the formation of polymers from the tetraamines. The polymers thus obtained had high intrinsic viscosities in the range of 0.67‐0.94 dl/g and were stable up to 450°C.