bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ethylene propylene diene terpolymers produced with a homogeneous and highly active zirconium catalyst
Authors: Kaminsky Walter , Miri Massoud 
Published: April 2003

AbstractEPDM terpolymers with ethylidene norbornene as diene monomer could be prepared by means of a soluble Ziegler catalyst formed from biscyclopentadienyl zirconium dimethyl and methylaluminoxane. The overall activities lie between 100 and 1000 kg EPDM/(molZr h bar), obtainable at zirconium concentrations as low as 5 × 10−7 mol/L. After an induction period (0.5–5 h) the polymerization rates increased and then leveled to a value which was constant for several days. From copolymerization kinetics reactivity ratios r12 = 31.5, r21 = 5 × 10−3, and r13 = 3.1 could be derived, and by 13C‐NMR spectroscopy r12 · r21 = 0.3 was found (1: ethylene, 2: propylene and 3: ethylidene norbornene). The regiospecifity of the catalyst toward propylene leads exclusively to the formation of head‐to‐tail enchainments. The diene polymerizes via vinyl polymerization of the cyclic double bond, and the tendency to branching is low. Molecular weights were estimated between 40,000 and 160,000. The average molecular weight distribution of 1.7 is remarkably narrow. Glass transition temperatures of −60 to −50°C could be observed. The cure behavior and the physical properties of cured samples were also tested.
Polymerization of para‐xylylene derivatives (parylene polymerization). II. Heat effects during deposition of parylene C at different temperatures
Authors: Gazicki M. , Surendran G. , James W. , Yasuda H. 
Published: April 2003

AbstractThermal effects accompanying vacuum deposition of poly(chloro‐para‐xylylene) in the temperature range between −196 and 0°C have been studied using two separate methods. One is based on the recording of the rate of evaporation of liquid nitrogen and it is used for the deposition at −196°C, and the second involves the recording of changes in the substrate temperature and is used for the deposition in the range of −162 to 0°C. These methods enable us to observe two distinct effects: fast (discrete), resulting in the appearance of sharp, exothermic spikes; and slow (continuous), resulting in the shift of the baseline. The shift of the baseline exhibits a well‐defined maximum at about −65°C and this temperature is attributed to the melting point of the monomer. The fast process always occurs below this temperature and is explained as a solid state, chain addition polymerization. The quantification of the heat effect at −196°C strongly suggests that the quinonoid form of the monomer participates in the propagation step of this chain reaction. The fast (solid state) and the continuous modes of polymerization may occur simultaneously in the range of about −140 and −65°C. The frequency of the initiation which is the formation of dimer radical seems to control the occurrence of these two modes of polymerization.
Hydrogen peroxide determination by I.R. specular reflectance spectroscopy during uncatalyzed and copper (oxides)‐catalyzed oxidation of isotactic polypropylene
Authors: Jellinek H. H. G. , Kachi H. , Chodak I. , Czanderna A. W. 
Published: April 2003

AbstractIR specular reflectance spectra with respect to hydrogen peroxide formation during uncatalyzed and Cu (oxide)‐catalyzed oxidation of isotactic Polypropylene films have been measured as function of time and temperature (90–130°C). Energies of activation for the various cases have been obtained. The originally proposed kinetic scheme based on oxygen‐absorption measurements has been modified in order to accommodate the spectroscopical results. The amount of ROOH groups present at any time on the polymer is very small, indicating relatively slow rates of ROOH formation and fast rates of their decomposition. The kinetic scheme fits well the experimental data. However, the reasons for the variations of the relevant energies of activation obtained for the catalyzed oxidation in absence and presence of the main volatile reaction products, H2O and CO2, are not yet understood, i.e., the mechanism needs further investigations.
Cure of epoxy resins with esters of cyanoacetic acid
Authors: Renner Alfred , Moser Roland , Bellus Miriam , Fuhrer Hermann , Spitzer Michaela 
Published: April 2003

AbstractEsters of cyanoacetic acid are a novel class of epoxy curing agents. The model reaction between ethyl cyanoacetate (ECA) and phenyl glycidylether (PGE) yielded a cyano‐spiro‐dilactone under conditions similar to the resin cure. The structure of the spiro compound resulting from 2 ECA and 2 PGE was elucidated by MS, IR, 1H‐, and 13C‐NMR techniques. Ammonia is split off from 1 ECA and acts in statu nascendi as a satellite hardener. An overall model reaction equation for the cyanoacetyl cure is proposed. The cure of bisphenol A–diglycidylether (BADGE) with ECA and with neopentylglycol‐biscyanoacetate (NPGCA) is described over a wide range of the molar ratio. Clear and tough solids are obtained with a glass transition temperature up to 130°C. Cyanoacetates are latent hardeners requiring a curing initiator. Since N‐4‐chlorophenyl N′‐dimethylurea is a latent initiator, liquid “one‐shot” systems can be formulated that are stable at room temperature and harden quickly above 120°C. Heat aging properties of cured specimens are reported. A series of novel liquid, resinous, and crystalline cyanoacetates and their potential as curing agents are described.
Some studies on plasma‐initiated polymerization of (MMA) and on plasma polymerized (PMMA)
Authors: Demi̇rel G¨︁nay , Akovali Güneri 
Published: April 2003

AbstractMethyl methacrylate was polymerized in the liquid state by plasma initiation. The conversion curves obtained for different polymerization conditions strikingly illustrated the effects of applied vacuum, discharge period, post‐polymerization, time, and temperature on monomer conversion and polymerization rate. The plasma initiated PMMA samples are not as monodisperse, as previously predicted.
Nucleic acid base grafted polyethylenimine. Cytosyl pendant groups: Elucidation of structure with solution spectroscopy
Authors: Chu V. P. , Overberger C. G. 
Published: April 2003

AbstractIn a previous paper, potassium 2‐(cytos‐1‐yl)propanoate was grafted onto polyethylenimine of various molecular weights. These water‐soluble polynucleotide analogs exhibited remarkable properties in their solution ultraviolet spectra. High hypochromicity values of 50% and 54% have been observed in alkaline aqueous solution and 50% trifluoroethanol solution, respectively. Percent hypochromicity value was observed to be directly proportional to percent graft. Red shift and hyperchromicity as a function of pH were observed for both the monomer model and the graft polymers. Light‐scattering experiments on nucleic acid base grafted hydrophilic polymer backbones were carried out. Radius of gyration and second virial coefficient values indicated stiff macromolecules, rodlike in nature. Therapeutic potential of cytosyl grafted polyethylenimine was suggested by the results from continuous mixing experiments with polyinosinic acid and polyguanylic acid. Job plots showed enhanced hypochromicity, whose magnitude was dependent upon the polynucleotide and the base‐base distance.
Plasma‐polymerized organosiloxane membranes prepared by simultaneous doping of I2 molecules and the effect on liquid permeability
Authors: Osada Yoshihito , Takase Mitsuo 
Published: April 2003

AbstractGlow‐discharge plasma polymerization of hexamethylcyclotrisiloxane was carried out on the cellulose acetate substrate in the presence of iodine crystal and the effect of I2 doping on liquid permeability such as water, cyclohexane, alcohol homologues, and a water–alcohol mixture was investigated. It was found that I2‐doped poly(siloxane) (PHMS–I2) membrane exhibited larger water permeability than nondoped (PHMS) membrane with anomalous pressure dependence (fourth power with pressure gradient). The permeability of alcohol homologues of PHMS membrane increased with increasing the molecular size and the hydrophobicity, whereas that of PHMS–I2 membrane decreased significantly. The presence of a small amount of hemoglobin also increased the water permeability of both membranes. From the results of flow tests of various kinds of fluid it was assumed that these membranes permeate the liquid predominantly by solution‐diffusion mechanism.
Synthesis and characterization of polymers derived from 2,5‐dimethoxy‐terephthaldehyde and 2,5‐dimethoxy‐terephthalic acid
Authors: Diaz F. R. , Tagle L. H. , Godoy A. , Hodgson C. , Olivares J. P. 
Published: April 2003

AbstractPolyamides were synthesized from 2,5‐dimethoxyterephthaloyl dichloride and diamines. Also, polyimines and polyaldoles were prepared from 2,5‐dimethoxy‐terephthaldehyde with diamines and ketones. The polymers were characterized by elemental analysis and infrared and NMR spectroscopy. Their intrinsic viscosity, glass transition temperature, and thermaldecomposition temperatures were determined.
Polyesters from 2,6‐dihydroxy‐9,10‐dihydro‐9,10‐ethanoanthracene and 2,6‐dihydroxyanthracene
Authors: Frazer A. H. , Anderson B. C. , Fukunaga T. 
Published: April 2003

AbstractHigh molecular weight, film‐forming, amorphous polyesters have been prepared from 2,6‐dilydroxy‐9,10‐dihydro‐9,10‐ethanoanthracene with adipic, sebacic, dodecanoic, isophthalic, 4,4′‐oxybibenzoic, 2,6‐naphthoic, 4,4′‐bibenzoic, and terephthalic acid. Thermal elimination of ethylene from these polymers has yielded the corresponding polyesters from 2,6‐dihydroxyanthracene which were of high molecular weight, film forming, and crystalline.
The polymerization of furfuryl acetate in acetonitrile
Authors: Buchwalter Stephen L. 
Published: April 2003

AbstractThe complex resins derived from furfuryl‐alcohol polymerization are a result of at least four competing reactions. By converting the alcohol to its acetate ester, however, three of these reactions can be eliminated. The simpler polymer derived from furfuryl acetate has been characterized spectroscopically, and an interesting chromophoric side reaction of the polymerization has been identified. The remarkable ability of the polymer to crosslink at room temperature upon precipitation from solution is also of interest.
Carbazole‐substituted dehydroalanine main chain polymers. Synthesis and characterization of poly[methyl 2‐(9‐carbazolyl) acetylaminopropenoate] and poly[2‐(9‐carbazolyl) acetylaminopropenoic acid]
Authors: Arora Kartar S. , Overberger C. G. 
Published: April 2003

AbstractThe preparation and radical‐initiated polymerization of a carbazole‐substituted N‐acylated dehydroalanine, namely, 2‐(9‐carbazolyl)acetylaminopropenoic acid (7) and its methyl ester (6) is reported. The monomers 6 and 7 were prepared by dehydrochlorination of N‐acylated β‐chloroalanine derivatives. The monomer model compounds for the two polymers, namely, 2‐(9‐carbazolyl)acetylamino‐2‐methylpropanoic acid (11) and its methyl ester (10), were also prepared. The polymers and their monomer model compounds were characterized by elemental analysis, IR and 1H‐NMR spectra. The polymers 12 and 13 of different molecular weights could be obtained by changing the monomer‐to‐initiator ratios used in polymerization experiments.
Synthesis and flammability of copoly(isophthalamide)s. II. With pendant phosphorus groups
Authors: Gravalos K. G. 
Published: April 2003

AbstractA series of copoly(isophthalamide)s containing pendant phosphorus, dialkoxyphosphinylphenylene, diphenylphosphinylphenylene, and diphenylphosphinylamino groups were prepared. The introduction of phosphorus groups was performed to a degree of ca. 5–17 mol %. From the limiting oxygen index (LOI) measurements, it was found that the LOI of P‐substituted polyamides increased by ca. 14–40%. From TG and DTG analysis the maximum rate and the percentage of mass loss of the decomposition stages were evaluated. From these measurements the mode of action of phosphorus groups in the solid or gas phase was assessed. In the solid phase, due to crosslinking reactions, a reduction of the maximum rate and the percentage of mass loss in the decomposition stage of main chain amide bonds was observed. In this case the increase of the char yield at 700°C of the P‐substituted polyamides was in the range of 21–36%. © 1993 John Wiley & Sons, Inc.
Radicals in the synthesis of sulphur dioxide‐based copolymers
Authors: Hwang Jimmy S. , Tsonis Christos P. 
Published: April 2003

AbstractFree radicals generated from a number of olefinic, acetylenic, and vinyl monomers in the presence of sulphur dioxide and tert‐butyl hydroperoxide were investigated. In all reaction systems a sulphonyl propagating radical first appears which depropagates into the corresponding carbon radical at higher temperatures. The sulphonyl radicals were observed between −119 and −44°C, whereas the carbon radicals were observed from −63 to −1°C. The order of decreasing reactivity of the reaction system was: 3‐hexyne > 1‐heptene > methyl acrylate > acrylonitrile > 1‐heptyne. © 1993 John Wiley & Sons, Inc.
Studies on thermotropic liquid crystalline polymer. XI. Effect of amide group on thermotropic liquid crystalline polymer properties
Authors: Chang Teh‐Chou , Li Chien‐Hui 
Published: April 2003

AbstractA series of poly(azomethine)s containing amide, ether, or ester groups was prepared by the condensation of dialdehydes with various diamines. The thermotropic liquid crystalline properties were examined by DSC and microscopic observations. The effects of the number and position of amide groups, which are attached to the rigid segment, on the thermotropic liquid crystalline properties of the homo‐and copoly(amide‐azomethine‐ether)s were also investigated in this study. The copolymerization took place by changing the amount of amide group to obtain copoly(amide‐azomethine) (P13 and P14) which exhibit thermotropic liquid crystalline properties. The poly(azomethine)s containing ether or ester groups also exhibited thermotropic liquid crystalline properties. © 1993 John Wiley & Sons, Inc.
Polyesters, polycarbonate, and polyurethanes from a novel monomer: α,α,α′,α′‐tetramethyl‐1,4‐tetrafluorobenzenedimethanol
Authors: Guo X. Andrew , Hunter Allen D. 
Published: April 2003

AbstractThe novel diol monomer, α,α,α′,α′‐tetramethyl‐1,4‐tetrafluorobenzenedimethanol, has been synthesized by a convenient route which involves the addition of acetone to 1,4‐dilithiotetrafluorobenzene and can be purified by washing with hexanes. It does not directly undergo condensation polymerizations with diacid chlorides. Its disodium salt, prepared by its reaction with sodium hydride, similarly fails to undergo such polymerizations readily. However, the dilithium salt, prepared in situ by the reaction of the title diol with 2 equiv of n‐butyllithium in tetrahydrofuran, is suitable for the preparation of various classes of condensation polymers. Four polyesters and one polycarbonate derived from the reactions of the dilithium salt of the diol with adipoly dichloride, sebacoyl dichloride, isophthaloyl dichloride, terephthaloyl dichloride, and phosgene and two polyurethanes derived from its reactions with tolylene‐2,4‐diisocyanate and methylene‐di‐1,4‐phenyl diisocyanate were prepared. Each was fully characterized by GPC, NMR, IR, and UV‐visible spectroscopies, and the results of these studies are reported herein. © 1993 John Wiley & Sons, Inc.
Preparation of high molecular weight polyhydrazides from hydrazine monohydrochloride using phenylphosphonic dichloride and phosphorus compounds as additives
Authors: Higashi Fukuji , Lee Yen‐Nen 
Published: April 2003

AbstractSignificantly high molecular weight poly(isophthalic dihydrazide) of inherent viscosity up to 1.6 (DMSO) was prepared by the reaction of isophthalic acid and hydrazine monohydrochloride using phenylphosphonic dichloride in the presence of phosphorus compounds such as phosphine oxides. The phosphorus compounds used as additives were assumed to be involved in the reaction through a complexation with the monohydrochloride, enhancing the reactivity of the hydrazine. It was attempted to prepare copoly(hydrazide‐amides) with different monomer sequences by changing the relative reactivity between diamines and the hydrazine using the phosphorus compounds. The copoly(hydrazide‐amide)s were studied in terms of the dehydration reaction of hydrazide groups into 1,3,4‐oxadiazole groups. © 1993 John Wiley & Sons, Inc.
Polymeric complexed membranes used as oxygen carrier: Axial and in‐plane ligand effects
Authors: Hsiue Ging‐Ho , Yang Jen‐Ming 
Published: April 2003

AbstractThe complex formation reaction of modified styrene–butadiene–styrene block copolymer (SBS‐g‐VP and ESBS) with cobalt Schiff base (CoS) in chloroform solution is studied. The coordination number and formation constant are determined by the Miller method. The polymeric complexed membranes (SBS‐g‐VP–CoS and ESBS–CoS and ESBS–CoS) are made by solution casting method. The kinetics of oxygen binding to polymeric complexed membranes (SBS‐g‐VP–CoS and ESBS–CoS) is studied and the equilibrium, association, and dissociation constants are determined. The effects of polymeric axial ligand and of the equatorial chelate group are discussed. © 1993 John Wiley & Sons, Inc.
Propenyl ethers. I. The synthesis of propenyl ether monomers
Authors: Crivello J. V. , Jo K. D. 
Published: April 2003

AbstractA variety of mono‐, di‐, and multifunctional propenyl ethers were readily prepared in high yields by the condensation of alcohols with allyl halides followed by the base or transition metal‐catalyzed rearrangement of the corresponding allyl ethers. Their straightforward synthesis and high reactivity in cationic UV curing make these monomers highly attractive for a variety of applications. The successful photopolymerization of these monomers has required the synthesis of specially tailored onium salt photoinitiators. © 1993 John Wiley & Sons, Inc.
Synthesis and radical polymerization of vinyl monomers having oxazolidone moiety
Authors: Atobe Ichiro , Takata Toshikazu , Endo Takeshi 
Published: April 2003

AbstractOxazolidone group‐containing vinyl monomers, 4‐(2‐oxo‐3‐oxazolidinyl)methylstyrene (OS) and 4‐[2‐(2‐oxo‐3‐oxazolidinyl)ethoxy]methylstyrene (OES), were synthesized and their polymerization and copolymerization behaviors with styrene (St), p‐methoxystyrene (PMS), and m‐hydroxystyrene (MHS) were investigated. OS was prepared in 70% yield by the reaction of 2‐oxazolidone with p‐chloromethylstyrene in the presence of sodium hydride. OES was obtained by the similar reaction of p‐chloromethylstyrene with N‐hydroxyethyl‐2‐oxazolidone which was prepared by the reaction of 2‐oxazolidone with ethylenecarbonate. Homopolymerization of OS and OES afforded mainly gelled polymers, but also soluble polymers on high dilution. In the copolymerization with styrene derivatives, an alternating nature was suggested from the copolymerization parameters obtained by either the nonlinear least‐squares analysis method or the Fineman–Ross method. The alternating copolymerizability decreased in the following order: MHS > PMS > St. Q−e values of OS and OES were calculated and demonstrated that OS and OES behaved as stronger electron‐accepting monomers in the copolymerization with MHS than in those with St and PMS. The copolymerization behavior of OS (OES) with MHS was compared with those of 4‐(2‐oxo‐1‐pyrrolidinyl)methylstyrene (PS) and 4‐[2‐(2‐oxo‐1‐pyrrolidinyl)ethoxy]methylstyrene (PES). From an IR study examining the shift of carbonyl absorption by addition of MHS, the interaction which contributed to the increase of the alternating copolymerizability in the copolymerization of OS (OES) with MHS was concluded to be based on hydrogen bonding. © 1993 John Wiley & Sons, Inc.
Molecular design of three‐dimensional artificial extracellular matrix: Photosensitive polymers containing cell adhesive peptide
Authors: Moghaddam Minoo Jalili , Matsuda Takehisa 
Published: April 2003

AbstractA photodimerizable monomer, methacrylic acid‐(7‐coumaroxy) ethyl ester, was synthesized and was copolymerized with a hydrophilic monomer (N,N‐dimethylacrylamide) to obtain a water‐soluble photosensitive polymer. Irradiation of the copolymer film and aqueous solution with a high‐pressure mercury lamp resulted in highly hydrated gel. The gel yield was enhanced with the content of the photodimerizable group in the copolymer and the irradiation time. The degree of swelling of the gels decreased concomitantly. Incorporation of the well‐known cell adhesive peptidyl ligand Arg‐Gly‐Asp‐Ser(RGDS) into photosensitive copolymers attained a biologically active hydrophilic gel matrix upon UV light irradiation. Irradiation of a buffer solution of the latter copolymer premixed with smooth muscle cells entrapped the cells throughout the gel matrix. This indicates that the designed polymer and the resulting cell‐incorporated hydrogel are biomimic to an extracellular matrix and to the media of the vascular wall, respectively. © 1993 John Wiley & Sons, Inc.
Synthesis of α,ω‐arylamine functionalized poly(dimethylsiloxane)s
Authors: Babu J. Ramesh , Sinai‐Zingde G. , Riffle J. S. 
Published: April 2003

AbstractThis research has focused on the development of telechelic, aromatic amine functional, poly(dimethylsiloxane) oligomers without any aliphatic components in the polymer backbone. The intent is to produce flexible oligomers with enhanced thermal stability for incorporation into materials which will be processed at elevated temperatures. The poly(dimethylsiloxane)s have been synthesized using living polymerization of hexamethylcyclotrisiloxane with protected aniline derivatives as initiators and termination reagents for the reactions. Low molecular weight oligomers prepared using the living polymerization method can be easily converted to a range of higher, controlled molecular weight materials in redistribution reactions. A basic tetramethylammonium siloxanolate catalyst in conjunction with octamethylcyclotetrasiloxane has been used for the equilibration procedure. © 1993 John Wiley & Sons, Inc.
Syntheses, structural characterizations, and thermal resistances of new epoxy–imide polymers
Authors: Shau Min‐Da , Chin Wei‐Kuo 
Published: April 2003

AbstractA new type of imide–epoxy resin in which imide compounds were grafted on the main chain of the epoxy was synthesized. The imide compounds used were mono (aminophthalimide)s. The structures of imide monomers and imide–epoxy polymers were confirmed by spectra characterizations of IR, 1H‐, and 13C‐NMR. The thermal resistances and solubilities of synthesized imide–epoxy were also studied. © 1993 John Wiley & Sons, Inc.
Dual‐phase solid polymer electrolytes prepared from styrene–butadiene copolymer latices
Authors: Ichino Toshihiro , Matsumoto Morihiko , Rutt J. Steven , Nishi Shiro 
Published: April 2003

AbstractA new dual‐phase solid polymer electrolyte system has been proposed. In this system, a network of ion pathways is formed in a low‐polarity, host polymer matrix. A series of electrolytes were prepared from styrene‐butadiene copolymer latices with dissolved lithium salts. Polymer films were formed from these latices, and then impregnated with γ‐butyrolactone (γ‐BL) or γ‐butyrolactone/dimethoxyethane mixture (γ‐BL/DME), giving latex polymer electrolytes. The ionic conductivity of the polymer electrolyte system increased with increasing solvent content, although a distinct percolation threshold was not measured. Ionic conductivity also increased with the use of DME cosolvent, with the highest conductivity being 1.4 × 10−4S/cm. Complex impedance diagrams are discussed. The diagrams show significant deviations from the ideal. TEM/SEM observations are consistent with the desired dual‐phase morphology. © 1993 John Wiley & Sons, Inc.