bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyarylate–polystyrene block copolymer from macro‐azoinitiator: Synthesis and its thermal properties
Authors: Ahn Tae Oan , Kim Jung Ho , Lee Jong Chan , Jeong Han Mo , Park Jong‐Yoon 
Published: April 2003

AbstractA macro‐azoinitiator containing polyarylate segment and azo group was prepared by the solution polycondensation of azobiscyanopentanoyl chloride and hydroxy‐terminated polyarylates having viscosity‐average molecular weights of 6200, 8100, and 12 400. These macro‐azoinitiators were used in the radical polymerization of styrene to synthesize polyarylate‐polystyrene block copolymers. Thermal properties measured by the differential scanning calorimetry indicated the phase separated morphology of the block copolymers except at low molecular weight of the block constituents. © 1993 John Wiley & Sons, Inc.
Synthesis and properties of poly(thioether amide)s from 2,6‐bis(acrylamido)pyridine and dithiols
Authors: Oikawa Eizo , Motomi Kiyoshi , Aoki Toshiki 
Published: April 2003

AbstractPoly(thioether amide)s containing pyridine moieties in their backbone were obtained by the polyaddition of 2,6‐bis(acrylamido)pyridine (2,6‐BAAP), derived from 2,6‐diaminopyridine and acryloyl chloride, with an aromatic or aliphatic dithiol. The influence of various reaction conditions on the polyaddition was investigated in comparison with the polyaddition of 1,3‐bis (acrylamido)benzene (1,3‐BAAB). 2,6‐BAAP gave the polymer even in the absence of any initiator at lower temperatures while 1,3‐BAAB did not, which was attributable principally to intramolecular base catalysis of the pyridine moieties. Basic additives effectively promoted the reaction rate and increased the chain length. Those facts and NMR of the resulting polymers indicated Michael‐type polyaddition. The polymers from 2,6‐BAAP were amorphous and gave transparent and tough films having a high refractive index exceeding 1.7. GPC and DSC characterizations were also made. © 1993 John Wiley & Sons, Inc.
Polymerization of Si‐containing acetylenes. XIV. Polymerization of diphenylacetylenes with bulky silyl groups and polymer properties
Authors: Tsuchihara Kenji , Masuda Toshio , Higashimura Toshinobu 
Published: April 2003

AbstractPolymerization and polymer properties of diphenylacetylenes with bulky silyl groups (SiMe2–i‐Pr, SiMe2–t‐Bu, SiMe2Ph, SiEt3) at para or meta position were studied under comparison with those of the SiMe3 derivatives. The present monomers polymerized in good yields with TaCl5‐cocatalysts to form high molecular‐weight polymers (Mw > 4 × 105). The polymer yields of para‐substituted monomers were similar to that of the SiMe3 derivative, while those of meta substituted monomers were lower than that of m‐SiMe3 derivative. Most of the polymers were totally soluble in common solvents such as toluene and CHCl3, although the polymers with p‐SiMe2–t‐Bu and p‐SiMe2Ph groups were partly insoluble in all solvents. These polymers resembled SiMe3‐containing homologues in the UV‐visible absorption and thermal stability. The oxygen permeability coefficients of these polymers were in the range of 10−9−10−8 cm3 (STP) cm/(cm2·s cm Hg)—lower than those of the corresponding SiMe3‐containing polymers. © 1993 John Wiley & Sons, Inc.
Synthesis and characterization of the ring‐opened copolymers of deltacyclene, 5‐siloxydeltacyclene, and norbornene
Authors: Lautens Mark , Abd‐El‐Aziz Alaa S. , Crudden Cathleen M. 
Published: April 2003

AbstractThe ring‐opening metathesis copolymerizations of deltacyclene, substituted deltacyclene, and norbornene was achieved using RuCl3, ReCl5, and molybdenum alkylidene catalysts. The reaction conditions employed are similar to those used previously in the syntheses of homopolymers. The low conversion copolymerization of deltacyclene and norbornene showed that deltacyclene is more reactive than norbornene by a factor of 2.4. The characterization and physical properties of these copolymers were determined using NMR, GPC, Tg, and viscosity measurements. © 1993 John Wiley & Sons, Inc.
Organized polymerization of functional diblock copolymers possessing central isoprene groups
Authors: Ishizu Koji , Kuwahara Kazuo 
Published: April 2003

AbstractFunctional diblock copolymers possessing central isoprene groups were synthesized by anionic addition in a three‐stage process using styrene, isoprene, and 2‐vinylpyridine monomers. These diblock copolymers formed microphase‐separated structure in the solid state. Where the central isoprene groups are organized regularly at the domain interface of the microphase‐separated structure, this is due to the functional groups being located at the block junction position. Addition‐condensation of diblock copolymer film with sulfur monochloride formed AnBn star block copolymers by organization effects. © 1993 John Wiley & Sons, Inc.
Gamma‐, photo‐, and thermally‐initiated oxidation of isotactic polypropylene
Authors: Lacoste J. , Vaillant D. , Carlsson D. J. 
Published: April 2003

AbstractThe detailed oxidation products have been identified and compared from the γ‐, photo‐, and thermally‐initiated oxidation of unstabilized polypropylene films. Products were identified and quantified by a combination of iodometric analysis and infrared spectroscopy. Spectral resolution was enhanced by derivatization reactions which allow the quantification of primary, secondary, and tertiary hydroperoxide and alcohol groups as well as more reliable analysis of carbonyl species. In contrast to polyethylene oxidation which yields predominantly ketone with lesser amounts of secondary hydroperoxide and carboxylic acid, polypropylene oxidizes to give predominantly tertiary hydroperoxide and lesser quantities of secondary hydroperoxide and ketone. In addition carboxylic acid groups are a minor product except at high degrees of thermal and photoinitiated oxidation. © 1993 John Wiley & Sons, Inc.
Synthesis, processing, and third‐order nonlinear optical properties of benzobisthiazole polymers containing thiophene moieties
Authors: Dotrong M. , Mehta R. , Balchin G. A. , Tomlinson R. C. , Sinsky M. , Lee C. Y.‐C. , Evers R. C. 
Published: April 2003

AbstractBenzobisthiazole polymers containing mono‐, bi‐, and terthiophene moieties were synthesized through polycondensation in polyphosphoric acid of 2,5‐diamino‐1,4‐benzenedithiol dihydrochloride with thiophene‐2,5‐dicarboxylic acid, 2,2′‐bithiophene‐5,5′‐dicarboxylic acid, and 2,2′:5′,2″‐terthlophene‐5,5″‐dicarboxylic acid, or their corresponding diacid chlorides, respectively. Intrinsic viscosities of up to 8.1 dL/g (methanesulfonic acid, 30°C) were recorded. Polymer structures were verified by elemental analysis and spectroscopic comparison of the polymers with appropriate model compounds. Onset of breakdown under thermogravimetric analysis in air occurred in the 460–590°C range with the benzobisthiazole polymers containing a monothiophene linkage being the most stable. Films suitable for third‐order optical susceptibility measurements could be prepared by extrusion techniques from the benzobisthiazole polymer containing a monothiophene linkage. Degenerate four wave mixing measurements on this film yielded a third order optical susceptibility χ(3) of approximately 4.5 × 10−10 esu. © 1993 John Wiley & Sons, Inc.
Block/segmented polymers. A new method of synthesis of copoly(amide‐ester)‐ester polymer
Authors: Bera Sureschandra , Jedlinski Z. 
Published: April 2003

AbstractA new method of preparation of segmented copolymer amide‐ester type is described here starting from two oligomers, one hard crystallizable (A) having a glass transition temperature (Tg) above room temperature and the other soft, amorphous (B) having Tg well below room temperature. A, an oligo amide‐ester terminated with hydroxyl groups has been synthesized from bis(hydroxy acylo amide) alkane, a reaction product of a lactone and diamine and dicarboxylic acid. B, an oligoester hydroxyl terminated was synthesized by the conventional method. The two oligomers A and B were transesterified removing diol as by‐product to obtain segmented (amide‐ester)‐ester copolymer. The polymer showed mostly two Tgs one at −40 to −50°C and other at +40 to +50°C; and one melting temperature 200°C. Maxm inherent viscosity was recorded at 1.75 dL/gm. © 1993 John Wiley & Sons, Inc.
Sequential analysis of polyesters by stepwise chemical degradation: Application to oligo and poly(alkylene terephthalate)s
Authors: Rossbach Volker , Schmitz Franz P. , Windeln Johannes 
Published: April 2003

AbstractA specifically tailored reagent was used to label the hydroxyl end groups of poly(ethylene/butylene terephthalate), which is synthesized by transesterification of the corresponding homopolymers. The terminal monomeric unit was then eliminated, together with the attached label, as a low molecular‐weight cyclic compound. Specially synthesized reference compounds containing ethylene terephthalate and butylene terephthalate units enabled the terminal monomeric unit to be identified as butylene terephthalate, although the copolymer showed an otherwise random distribution. Despite the practical and theoretical reasons that restrict this sequential degradation to the last monomeric unit for polymers, the principle can be used in a wider range of applications if combined with selective degradation and separation by means of HPLC, which results in chemically uniform oligomers. The ultimate and penultimate monomeric units of ethylene/butylene terephthalate type oligomers can be identified using the cyclodegradation procedure described here. © 1993 John Wiley & Sons, Inc.
Polymerization of 4‐phenyl‐1‐butyne catalyzed by metathesis and Ziegler–Natta catalysts
Authors: Oh Se‐Young , Oguri Fumiteru , Akagi Kazuo , Shirakawa Hideki 
Published: April 2003

AbstractThe polymerization of 4‐phenyl‐1‐butyne was carried out using metathesis and Ziegler‐Natta catalysts. Especially, the Fe(acac)3‐AlEt3 catalyst with toluene as a solvent produced an extremely high molecular weight polymer of Mw ≈ 106. Solubility of the polymers at room temperature in organic solvents such as benzene, toluene, dichloromethane, chloroform, and THF was excellent despite their high molecular weights. It has been indicated that the polymer prepared by the Fe(acac)3‐AlEt3 catalyst is of cis form with a high stereoregularity. © 1993 John Wiley & Sons, Inc.
Study of bulk chain coupling reactions. I. Reaction between bisoxazolones and amine‐terminated polyamide 12
Authors: Acevedo Margarita , Fradet Alain 
Published: April 2003

Abstract2,2′‐Bis(4,4‐dimethyl‐5(4H)‐oxazolone) (B3) and 2,2′‐(1,2‐ethylene)‐bis(4,4‐dimethyl‐5(4H)oxazolone) (B4) have been reacted in the bulk with α, ω‐diamino polyamide‐12 (PA12) of M̄n = 1000. The reactions have been studied by SEC, and 1H‐ and 13C‐NMR and resulting polymers characterized by DSC and TGA. The chain coupling reaction is fast and gives high molar mass polymers within 10 min at 200°C with B4 while some side reactions occur with B3 leading to polymers of lower molar mass. The crystallinity of resulting polymers is lower than that of starting oligomer. However, the thermal stability is higher. Model reactions using B3 or B4 and hexamethylene diamine or 1‐dodecanamine have been carried out and studied. An intramolecular cyclodehydration giving 2‐imidazolin‐5‐ones takes place during the reactions. Higher cyclization extent is found in the presence of amino group excess. 2‐Imidazolin‐5‐one heterocyclic structures are also observed in the chains of the polymers obtained from PA12 and B3 or B4. © 1993 John Wiley & Sons, Inc.
New fluorescence probes for monitoring the kinetics of laser‐initiated polymerization
Authors: Paczkowski Jerzy , Neckers D. C. 
Published: April 2003

AbstractSeveral new fluorescence probes useful for following photopolymerization have been characterized. Among these are probes which can be used in rapidly gelling monomer mixtures and for photochemical polymerization initiated by very high laser powers. Systems which can be used with polyolacrylates and either with visible initiators or with UV initiators are reported. © 1993 John Wiley & Sons, Inc.
High‐resolution solid‐state 19F‐NMR spectroscopy of the sorption and diffusion of fluorine‐containing aromatic molecules in polymeric media
Authors: Toscano Paul J. , Waechter John , Schermerhorn E. James , Zhou Peiguang , Frisch Harry L. 
Published: April 2003

AbstractHigh‐resolution 19F solid‐state NMR spectroscopy was employed to study the sorption properties of hexafluorobenzene (HFB) and 3,5‐bis (trifluoromethyl) aniline (TFMA) in polystyrene (PS) and butyl rubber (BR). The NMR spectra indicate that the penetrants undergo dual‐mode sorption in the glassy polymer (PS), but are highly mobile in the rubbery polymer (BR). In addition, the NMR method was utilized in the experimental determination of diffusion coefficients for the HFB/PS, TFMA/PS, and HFB/BR systems through desorption studies. The diffusion results for the TFMA/PS case agree very well with those previously obtained via resonance nuclear reaction analysis. © 1993 John Wiley & Sons, Inc.
Studies on the thermotropic liquid‐crystalline polymer. VIII. Synthesis and properties of fully aromatic poly(ester)s and poly(amide‐ester)s containing p‐phenylene diacrylic group
Authors: Li Chien‐Hui , Hsu Keh‐Ying , Chang Teh‐Chou 
Published: April 2003

AbstractThree series of polymers containing p‐phenylene diacrylic group were prepared by direct polycondensation in the presence of diphenylchlorophosphate and pyridine. Series I was prepared from p‐phenylene bis(acrylic acid) with various hydroquinones. Series II was prepared from p‐phenylene bis (β‐cyano acrylic acid) with methylhydroquinone. Series III was prepared from 3‐methyl‐4‐aminophenol with p‐phenylene bis(acrylic acid) or p‐phenylene bis(β‐cyano acrylic acid), respectively. The phase behavior of these polymers was studied by differential scanning calorimetry (DSC), optical polarizing microscopy equipped with a heating stage, and wide‐angle x‐ray diffraction (WAXD). It was found that these polymers, except IIIb, exhibit thermotropic liquid‐crystalline properties and show threaded or Schlieren texture under the optical polarizing microscopic observation. Furthermore, the melting temperatures of these polymers were decreased in the range of 254–354°C by incorporating with p‐phenylene diacrylic group into the main chain. © 1993 John Wiley & Sons, Inc.
Alginate polyelectrolyte ionotropic gels. XVIII. Oxidation of alginate polysaccharide by potassium permanganate in alkaline solutions: Kinetics of decomposition of intermediate complex
Authors: Hassan Refat M. 
Published: April 2003

AbstractThe kinetics of decomposition of [Alg · Mn VIO42−] intermediate complex have been investigated spectrophotometrically at a constant ionic strength of 0.5 mol dm−3. The decomposition reaction was found to be first‐order in the intermediate concentration. The results showed that the rate of reaction was base‐catalyzed. The kinetic parameters have been evaluated and found to be ΔS‡ = −103.88±6.18 J mol−1 K−1, ΔH‡ = 51.61 ± 1.02 kJ mol−1, and ΔG‡ = 82.57 ± 2.86 kJ mol−1, respectively. A reaction mechanism consistent with the results is discussed. © 1993 John Wiley & Sons, Inc.
Infrared spectroscopy studies of the cyclic anhydride as the intermediate for the ester crosslinking of cotton cellulose by polycarboxylic acids. I. Identification of the cyclic anhydride intermediate
Authors: Yang Charles Q. 
Published: April 2003

AbstractThe mechanism of esterification of cotton cellulose by a polycarboxylic acid was investigated using Fourier transform infrared spectroscopy (FT‐IR). The infrared spectroscopic data indicate that a polycarboxylic acid esterifies with cotton cellulose through the formation of an acid anhydride intermediate. A five‐member cyclic anhydride intermediate was identified in the cotton fabric treated with poly(maleic acid). The five‐member cyclic anhydride is a reactive intermediate and readily esterifies when reaction sites are available. We also found that those polycarboxylic acids, which form five‐member cyclic anhydride intermediates, crosslink cotton cellulose more effectively than those polycarboxylic acids which form six‐member cyclic anhydride intermediates. © 1993 John Wiley & Sons, Inc.
Absorbable biopolymers derived from dimer fatty acids
Authors: Domb Abraham J. , Maniar Manoj 
Published: April 2003

AbstractA new class of aliphatic copolyanhydrides was synthesized from nonlinear hydrophobic dimers (FAD) of erucic acid and sebacic acid which possessed the desired physico‐chemical and mechanical properties for use as a carrier for drugs. The polymers were synthesized by melt condensation to yield film‐forming polymers with molecular weights of 250,000. The copolymer composition was determined by 1H‐NMR and gravimetric methods. In vitro degradation studies showed that these polymers degrade following a first‐order kinetics with a rapid degradation in the first 10 days leaving a residue which is mostly the FAD comonomer. The drug release from the polymer also followed a first‐order kinetics which correlates with the degradation process of the polymer. Drugs like carboplatin, methotrexate, tetracycline, and gentamicin were released in vitro for over 2 weeks and in some cases over 6 weeks. In vivo biocompatibility tests in rats and rabbits in the brain, muscle, and subcutaneously, demonstrated their toxicological inertness and biodegradability. The 1 : 1 copolymer of FAD : SA was selected as a carrier for various applications including a gentamicin‐releasing implant which is now undergoing human clinical trials for the treatment of osteomyelitis. © 1993 John Wiley & Sons, Inc.
Chemical modification of butyl rubber. I. Synthesis and properties of poly(ethylene oxide)‐grafted butyl rubber
Authors: Yamashita Shinzo , Kodama Kazutoshi , Ikeda Yuko , Kohjiya Shinzo 
Published: April 2003

AbstractA new amphiphilic polymer, i.e., poly(ethylene oxide) (PEO)‐grafted butyl rubber (IIR‐g‐PEO), was synthesized by chemical modification of chlorinated butyl rubber (CIIR). This synthesis was based on the reaction between chlorine in CIIR and potassium salt of polyethylene glycol monomethyl ether (PEGM). PEGM's with molecular weights of 750 and 2000 were used. The maximum grafting percent of the resulted copolymers after the purification was ca. 45%, regardless of the molecular weight of PEGM. The microphase separated structure was observed in the films of IIR‐g‐PEOs. IIR‐g‐PEO, whose PEO molecular weight was 2000 and whose PEO content was 23.8 wt %, swelled 3.1% in water, and it was six times larger than the swelling of CIIR. The hydrophilicity of grafted polymers depended on the molecular weight of PEO side chains and PEO content. Even when the PEO contents were same in the polymers which were grafted PEGM‐750 and PEGM‐2000, their swellings in organic solvents were not equal. It was due to the difference of the microphase‐separated structures of the grafted polymers. IIR‐g‐PEO, whose PEO molecular weight was 750 and whose PEO content was 10.3 wt %, swelled 1.5% in water, but showed an excellent emulsifying ability, where an oil‐in‐water‐type emulsion was formed. © 1993 John Wiley & Sons, Inc.
X‐ray microtomography studies of nascent polyolefin particles polymerized over magnesium chloride‐supported catalysts
Authors: Ferrero M. A. , Sommer R. , Spanne P. , Jones K. W. , Conner W. Curtis 
Published: April 2003

AbstractDrastic changes occur during the initial stages of the α‐olefin polymerization over heterogeneous catalysts. Fragmentation of the support takes place as polymer is formed at the active sites within the voids of the support/catalyst. Magnesium chloride‐supported titanium catalyst/polymer particles have been analyzed employing high‐resolution computed microtomography (CMT) using synchrotron radiation at Brookhaven National Laboratory. The changes in morphology, the spatial distribution of the support/catalyst fragments, porosity, and polymer distribution in single growing polypropylene and polyethylene particles have been studied. These studies documented considerable macroporosity ( > 2 μm in size) within the growing catalyst/support/polymer particles. The largest pores may be due to agglomeration of smaller subparticles. Our results confirm that the initial fragmentation of the support proceeds readily and uniformly to yield a multi‐grain growth of subparticle agglomerates. The support/catalyst fragments appear to be distributed relatively uniformly within the growing polymer particle. The surface of the subparticle agglomerates is accessible through the void‐space between growing catalyst/particle grains. This may facilitate monomer transport to the activate sites through the polymer/catalyst particles. © 1993 John Wiley & Sons, Inc.
Radical polymerization and copolymerization reactivities of fumarates bearing different alkyl ester groups
Authors: Otsu Takayuki , Shiraishi Kohei , Matsumoto Akikazu 
Published: April 2003

AbstractRadical polymerization of fumarates bearing different alkyl ester groups (DRF) on the same molecules was investigated. In bulk polymerization of DRF at 60°C initiated with 2,2′‐azobis(isobutyronitrile), it was confirmed that the polymerization reactivity depended on the structures of both alkyl ester groups. The introduction of bulky alkyl groups increased the polymerization rate and molecular weight of the polymer because of retardation of bimolecular termination rates. The effect of the ester substituents on the termination was examined by electron spin resonance spectroscopy. The copolymerization reactivities of DRF with styrene were also investigated. © 1993 John Wiley & Sons, Inc.
Comonomer effects with high‐activity titanium‐ and vanadium‐based catalysts for ethylene polymerization
Authors: Karol Frederick J. , Kao Sun‐Chueh , Cann Kevin J. 
Published: April 2003

AbstractHigh‐activity titanium‐ and vanadium‐based catalysts for ethylene polymerization frequently show an increase in reaction rate in the presence of an α‐olefin. The magnitude of this increase depends on the specific α‐olefin. The results show propylene > 1‐butene > 1‐hexene in increasing initial reaction rates. Addition of certain electron‐donor compounds to these catalysts can lower the magnitude of the comonomer effect and, in some cases, totally eliminate such an effect. Among the classes of electron‐donor compounds examined were ether‐alcohols, ether‐esters, amino‐alcohols, alkoxysilanes, siloxanes, and phosphine oxides. Reaction kinetics show that the presence of a comonomer can influence the kinetic order of the reaction. These results can be interpreted using a mechanistic model involving two vacant coordination positions at the active sites. In this model electron donors and comonomers are viewed as Lewis‐base ligands which influence features of chain propagation and chain termination. As Lewis‐base ligands, the comonomers can also increase the number of active sites available for polymerization. Catalyst deactivation following the initial comonomer rate increase is believed to be caused by reaction with the Lewis bases (α‐olefin included) in the system and by possible reduction in the oxidation state of the metal centers. The most acidic metal centers activated by the comonomer are most reactive to Lewis bases and deactivate most rapidly. Veratrole (1,2‐dimethoxybenzene) can be employed as a probe for estimating the number of bis‐vacant coordination sites in vanadium‐based catalysts. Addition of low levels of veratrole led to significant deactivation of the vanadium‐based catalyst. © 1993 John Wiley & Sons, Inc.