bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Polymerization 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

The 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

Functional 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

The 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

Benzobisthiazole 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

A 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

A 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

The 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

2,2′‐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

Several 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

High‐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

Three 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

The 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

The 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

A 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

A 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

Drastic 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

Radical 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

High‐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.
Polymerization of [o‐(trimethylgermyl)phenyl] acetylene and polymer characterization
Authors: Mizumoto Tomohiro , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

[o‐(Trimethylgermyl)phenyl]acetylene was polymerized in the presence of WCl6, W(CO)6‐hv, etc., to give polymers whose weight‐average molecular weights reached ca. 7.0 X 105 at the highest. When the MoOCl4‐n‐Bu4Sn‐EtOH (1 : 1 : 1) catalyst was used, the polydispersity ratio of the polymer obtained was 1.08, and the number‐average molecular weight increased in direct proportion to monomer conversion; these indicate that this polymerization is a living polymerization. The polymer had the structure  [CHC(C6H4‐o‐GeMe3)]n  and was a dark purple solid (λmax = 551 nm, εmax = 6100 M‐1 cm‐1 in THF) soluble in organic solvents such as toluene and chloroform. The onset temperature of weight loss of the polymer in TGA in air was ca. 230°C, and the glass transition temperature was above 180°C. The Po2 of the present polymer is 105 barrers—larger than the value of natural rubber and fairly close to that of poly(dimethylsiloxane). © 1993 John Wiley & Sons, Inc.
Synthesis of novel organic oligomers containing SiH bonds
Authors: Iwahara T. , Kusakabe M. , Chiba M. , Yonezawa K.
Published: April 2003

Several organic oligomers (Mw = 103–104 order) containing SiH bonds of the general formula 1 have been successfully synthesized by platinum‐catalyzed partial hydrosilylation reaction of an allyloxy (or an allyl carbonate) end‐blocked linear organic oligomer 2 with 2,4,6,8‐tetramethylcyclotetrasiloxane, [CH3(H)SiO]4 (3) (hereafter called hydrocyclotetrasiloxane). 1H‐NMR spectroscopy confirmed the introduction of hydrocyclotetrasiloxane moiety into the oligomers through SiC linkage by hydrosilylation reaction. 13C‐NMR analysis revealed that the cyclic structure of the starting hydrocyclotetrasiloxane 3 was retained intact in product 1. As the precursor for 1, allyloxy (or allyl carbonate) end‐blocked oligomers 2 could be prepared from hydroxyl‐terminated oligomers 4. The storage stability of product 1 was significantly influenced by the platinum catalyst still remaining in it. The poor stability was improved by decreasing the amount of the platinum catalyst and/or by adding coordinating compounds. As a result, an excellent stability of product 1 was obtained. © 1993 John Wiley & Sons, Inc.
Studies on the thermotropic liquid crystalline polycarbonates. III. Synthesis and properties of fully aromatic liquid crystalline polycarbonates
Authors: Sun Shih‐Jien , Chang Teh‐Chou
Published: April 2003

Four series of fully aromatic thermotropic liquid crystalline polycarbonates were prepared by melt polycondensation from various novel phenylene diphenyl dicarbonates with monomers, such as hydroquinone, methylhydroquinone, chlorohydroquinone, resorcinol, bisphenol A, 4,4′‐dihydroxydiphenylsulfone, or phenylhydroquinone, respectively. The thermotropic liquid crystalline properties were studied by polarizing microscope with a heating stage, differential scanning calorimeter (DSC), and wide‐angle x‐ray diffraction (WAXD). It was found that the nonlinearity of the carbonate group was compensated by resorcinol (1,3‐phenylene unit), a bent shape unit. Nematic melts were found for the resulting polycarbonates. © 1993 John Wiley & Sons, Inc.
Regioselective hydrosilations. II. The synthesis of silicon–hydrogen functional compounds
Authors: Crivello J. V. , Bi Daoshen
Published: April 2003

The discovery that the rhodium‐catalyzed hydrosilation of unsaturated epoxides with compounds containing two SiH functional groups proceeds in a discrete, stepwise fashion, has made possible the synthesis of a series of interesting compounds containing both SiH and epoxy groups in the same molecule. These compounds can be used both as an interesting new class of epoxy monomers as well as intermediates for the preparation of a wide variety of novel monomers which incorporate epoxide as well as other types of polymerizable functional groups © 1993 John Wiley & Sons, Inc.
Crosslinking of styrene–butadiene rubber with 1,2‐bis(benzocyclobutenyl)ethane
Authors: Fishback Thomas L. , Farona Michael F.
Published: April 2003

1,2‐Bis(benzocyclobutenyl)ethane (BBCB) was used as a thermally activated crosslinking agent in styrene–butadiene rubber (SBR), both in the raw and carbon black‐filled materials. Diels–Alder crosslinking reactions occurred to a significant degree, despite the lack of substituents of opposing electronic effects. The reaction is free of toxic crosslinking promoters and evolved by‐products. Various physical properties such as ultimate elongation, tensile strength, and modulus were measured and compared to those properties of a sulfur‐cured sample of SBR. Linear relationships were found between the amount of BBCB present and the modulus of the materials, as well as the amount of BBCB and solvent uptake in swell tests. © 1993 John Wiley & Sons, Inc.
Synthesis and properties of poly(hydroxyurethane)s
Authors: Kihara Nobuhiro , Endo Takeshi
Published: April 2003

Bis(cyclic Carbonate)s 1 were prepared by the reaction of bis(epoxide)s and atmospheric pressure of CO2 in the presence of sodium iodide and triphenylphosphine as catalysts at 100°C in high yield. Polyaddition of 1 and hexamethylenediamine (2a) or dodecamethylenediamine (2b) in dimethylsulfoxide or N,N‐dimethylacetamide (DMAc) at 70 or 100°C for 24 h afforded corresponding poly(hydroxyurethane)s with M̄n 20,000–30,000. When ethylenediamine (2c) or 1,3‐propanediamine (2d) was used as a diamine, poly(hydroxyurethane)s with lower molecular weight were obtained. The presence of water, methanol, or ethyl acetate in the solvent had little effect on the M̄n of the polymer obtained, because of the high chemoselectivity of the reaction of the five‐membered cyclic carbonate and amine. Polyaddition of bis(cyclic carbonate) bearing ester groups and 2a also afforded the corresponding poly(hydroxyurethane) without aminolysis of the ester groups. Poly(hydroxyurethane) 3 obtained from the bis(cyclic carbonate) derived from bisphenol A was less soluble in organic solvents than model polyurethane 8 having no hydroxy groups obtained from 4,4′‐isopropylidenebis(2‐hydroxyethoxybenzene) and hexamethylene diisocyanate, and was thermally stable as well as 8.3 easily undertook crosslinking at room temperature by the treatment with hexamethylene diisocyanate or aluminium triisopropoxide in DMAc or tetrahydrofuran. The gel crosslinked by aluminium triisopropoxide regenerated the original polymer at room temperature by treatment with 1.5 equiv of 1.2M HCl in N‐methylpyrollidinone for 1 h. © 1993 John Wiley & Sons, Inc.
Synthesis and properties of new polyimides derived from 1,5‐bis(4‐aminophenoxy)naphthalene and aromatic tetracarboxylic dianhydrides
Authors: Yang Chin‐Ping , Chen Wen‐Tung
Published: April 2003

Novel aromatic polyimides containing bis(phenoxy)naphthalene units were synthesized from 1,5‐bis(4‐aminophenoxy)naphthalene (APN) and various aromatic tetracarboxylic dianhydrides by the usual two‐step procedure that included ring‐opening polyaddition in a polar solvent such as N,N‐dimethylacetamide (DMAc) to give poly(amic acid)s, followed by cyclodehydration to polyimides. The poly(amic acid)s had inherent viscosities between 0.72 and 1.94 dL/g, depending on the tetracarboxylic dianhydrides used. Excepting the polyimide IVb obtained from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA), all other polyimides formed brown, flexible, and tough films by casting from the poly(amic acid) solutions. The polyimide synthesized from BPDA was characterized as semicrystalline, whereas the other polyimides showed amorphous patterns as shown by the x‐ray diffraction studies. Tensile strength, initial moduli, and elongation at break of the APN‐based polyimide films ranged from 105–135 MPa, 1.92–2.50 GPa, and 6–7%, respectively. These polyimides had glass transition temperatures between 228 and 317°C. Thermal analyses indicated that these polymers were fairly stable, and the 10% weight loss temperatures by TGA were recorded in the range of 543–574°C in nitrogen and 540–566°C in air atmosphere, respectively. © 1993 John Wiley & Sons, Inc.
Regioselective oxidative polymerization of 1,5‐dihydroxynaphthalene catalyzed by bilirubin oxidase in a water–organic solvent mixed solution
Authors: Wang Lili , Kobatake Eiry , Ikariyama Yoshihito , Aizawa Masuo
Published: April 2003

Bilirubin oxidase (EC1.11.1.7) was used to catalyze the oxidative polymerization of 1,5‐dihydroxynaphthalene to its polymer in a mixed solvent composed of dioxane, ethyl acetate, and acetate buffer. In an aqueous solution, the enzymatic oxidative polymerization hardly occurred and resulted in negligible yield mainly due to the poor solubility of 1,5‐dihydroxynaphthalene. In the mixed solvent the conversion proceeded with a yield of ca. 70%. The polymer yield was studied with respect to reaction time and solvent components. Elemental analysis, UV‐visible, fluorescent, and FT‐IR spectroscopic analyses, proton NMR and electrochemical studies, and solubility in various organic solvents revealed that 1,5‐dihydroxynaphthalene is polymerized by the CC coupling. The molecular weight of the polymeric products solubilized with DMF varied from low molecular weight product to high molecular weight polymer. From the chromatographic studies, the organic solvent–insoluble residue was suggested to be highly polymerized material. Based on these findings a possible mechanism for enzymatic polymerization of 1,5‐dihydroxynaphthalene is presented: less stable intermediates produced enzymatically from 1,5‐dihydroxynaphthalene undergo coupling and polymerization to ortho‐1,5‐dihydroxynaphthalene polymer, thereby resulting in a regioselective polymerization of 1,5‐dihydroxynaphthalene. © 1993 John Wiley & Sons, Inc.
Main‐chain, syndioregic, high‐glass transition temperature polymer for nonlinear optics: Synthesis and characterization
Authors: Stenger‐Smith J. D. , Henry R. A. , Hoover J. M. , Lindsay G. A. , Nadler M. P. , Nissan R. A.
Published: April 2003

A new main‐chain syndioregic (head‐to‐head) NLO polymer was synthesized. The glass transition temperature of high molecular weight polymer was found to be 208°C, and the polymer has minimal weight loss at temperatures to at least 250°C owing to the incorporation of hydrogen bonding moieties and rigid bridging groups. The polymer was further characterized using nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). The study of the nonlinear optical properties of this polymer are in progress. © 1993 John Wiley & Sons, Inc.
Calorimetric monitoring of emulsion copolymerization reactions
Authors: Urretabizkaia Agustín , Sudol E. David , El‐Aasser Mohamed S. , Asua Josée M.
Published: April 2003

An approach for monitoring both the overall conversion and the cumulative copolymer composition in emulsion copolymerization systems via calorimetric measurements was developed. The approach was checked by carrying out batch emulsion copolymerizations of methyl methacrylate/n‐butyl acrylate, n‐butyl acrylate/vinyl acetate, and methyl methacrylate/vinyl acetate and comparing calorimetric based estimations with off‐line determinations of both the overall conversion and the cumulative copolymer composition. A good agreement was achieved for most of the cases studied. © 1993 John Wiley & Sons, Inc.
One‐phase supported titanium‐based catalysts for polymerization of ethylene. III. ESR spectra of the ternary system Sio2—R3Al—TiCl4
Authors: Věčorek P. , Šindelář P. , Černošková E. , Holeček J.
Published: April 2003

The ternary catalyst systems based on activated silica, aluminum alkyl, and titanium tetrachloride were polymerized in an ethylene gas‐phase polymerization process, and further studied using ESR spectroscopy. Two types of titanium (III) ESR‐active centers were observed and a linear dependence between the concentration of that characterized by a rhombic anisotropic signal with g1 = 1.962, g2 = 1.945, and g3 = 1.913 values and catalyst productivity was found. © 1993 John Wiley & Sons, Inc.
New polymer syntheses. LXVI. Copolyester of 4‐hydroxybenzoic acid and 3‐(4'‐hydroxyphenoxy)benzoic acid or 4‐(3'‐hydroxyphenoxy)benzoic acid
Authors: Kricheldorf Hans R. , Döring Volker , Schwarz Gert
Published: April 2003

Copolyesters of 4‐hydroxybenzoic acid (HBA) and 3‐(4'‐hydroxyphenoxy)benzoic acid were prepared by two different procedures. Either the acetyl derivatives were polycondensed in bulk at temperatures up to 300°C or they were polycondensed in an inert reactions medium (Marlotherm‐S) at 340°C. Two analogous series of copolyesters were synthesized from 4‐acetoxybenzoic acid (4‐HBA) and 4‐(3'‐acetoxyphenoxy)benzoic acid. The copolyesters were characterized by elemental analyses, inherent viscosities, 1H‐ and 13C‐NMR spectroscopy, WAXS and DSC measurements, and by optical microscopy. All copolyesters synthesized in solution were highly crystalline materials which were neither meltable nor soluble. Part of the copolyesters prepared by polycondensation in bulk were semi‐crystalline, meltable, and soluble. The copolyester derived from 3‐(4'‐hydroxyphenoxy)benzoic acid proved to be thermotropic forming a nematic melt, whereas the isomeric copolyesters of 4‐(3'‐hydroxyphenoxy)benzoic acid only formed isotropic melts. © 1993 John Wiley & Sons, Inc.
Mechanisms and kinetics of polymerization of thermoplastic polyimides. II. Study of “bridged” dianhydride/aromatic amine systems
Authors: Grenier‐Loustalot Marie‐Florence , Joubert Fréderic , Grenier Philippe
Published: April 2003

The aim of the present work was to identify and follow the main and side reactions involved in the ring dehydration of amic acid prepared from “bridged” dianhydrides whose central substituent is an electron acceptor or donor, and an aromatic diamine. Several isomeric structures may appear as a result of the opening reactivity and selectivity of anhydride groups towards the aromatic amine. Reaction mechanisms and kinetics were thus studied in solvent phase with HPLC and 13C‐NMR and in solid molten phase by FTIR and solid 13C‐NMR. The experimental conditions (liquid and solid) and the structure of the products (type of central substituent) affecting the mechanisms and kinetics of the reactions were noted. © 1993 John Wiley & Sons, Inc.
γ‐poly(glutamic acid) as an initiator of cationic polymerization of N‐vinylcarbazole and N‐vinyl‐2‐pyrrolidone
Authors: Tsubokawa Norio , Inagaki Masatoshi , Kubota Hidetoshi , Endo Takeshi
Published: April 2003

The cationic polymerization of vinyl monomers initiated by biosynthesized γ‐poly(glutamic acid) (γ‐PGA) powder surface was carried out in a heterogeneous system. It was found that the polymerization of N‐vinylcarbazole (NVC) and N‐vinyl‐2‐pyrrolidone (NVPD) is initiated by γ‐PGA powder. The grafting of polymers onto γ‐PGA surface was scarcely observed. The apparent activation energy of the polymerization of NVC and NVPD was estimated to be 20.2 and 24.8 kJ/mol, respectively. The polymerization was totally inhibited by the addition of triethylamine and pyridine, but not hydroquinone. The polymerization rate in nitrobenzene was larger than that in toluene. These results indicated the cationic nature of the polymerization. γ‐PGA treated with KOH did not show the initiating activity of the polymerization. Therefore, carboxyl groups on γ‐PGA powder surface play an important role in the initiation of the polymerization. It may be suggested that the polymerization is initiated by proton addition to monomer from carboxyl groups on γ‐PGA powder surface and the propagation proceeds with carboxylate anion on the surface as counter ion. © 1993 John Wiley & Sons, Inc.
Polymerization of monoisocyanates by the Pruitt–Baggett adduct
Authors: Yilmaz Osman , Usanmaz Ali , Alyürük Kemal
Published: April 2003

n‐Butyl isocyanate (nBIC) was polymerized in bulk by the Pruitt–Baggett adduct (PBA) at −23, 0.0, and 25.0°C. Polymerization was accompanied by trimerization to the cyclicisocyanurates at all temperatures. Spectroscopic evidences supported the nylon‐1 structure for both trimer and polymer. The polymer/trimer ratio and the molecular weight of produced polymers were found to increase with decreasing temperature. The Pruitt–Baggett catalyst (PBC), which is the reaction product of (PBA + H2O) system, also polymerized nBIC, but with a relatively slower rate. In aromatic and etheric solutions, nBIC was only trimerized by PBA. Copolymerization of nBIC with propylene oxide by PBA and PBC failed. Some selected monoisocyanates were also polymerized by PBA. © 1993 John Wiley & Sons, Inc.
Thermoplastic and thermoset main chain liquid crystal polymers prepared from biphenyl mesogen
Authors: Su W‐F. A.
Published: April 2003

Main chain liquid crystal thermoplastic polyesters and thermosetting epoxy resins were prepared using biphenyl mesogens. The melting points of the polyesters were effectively decreased by incorporating flexible methylene spacers into the polymer main chain. The liquid crystal epoxy resins exhibit high glass transition temperature, low thermal expansion coefficients, high dielectric strengths, and low dielectric loss. They are suitable for the preparation of self‐reinforcing molecular composites. © 1993 John Wiley & Sons, Inc.
Physicochemical and catalytic investigations of grafted poly(tetrafluoroethylene) complexed with some transition metal nitrates
Authors: El‐Sawy Naeem M. , Fagal Gehan A. , El‐Shobaky Gamil A.
Published: April 2003

Radiation‐induced graft polymerization of methacrylic acid into poly(tetrafluoroethylene) by the mutual irradiation technique has been studied. The obtained hydrophilic solids were treated with solutions containing calculated amounts of iron, cobalt, nickel, or copper nitrates. The amounts of these transition metal nitrates were fixed at 16 wt%, expressed as metal oxide. IR, XRD, TG, and catalysis of CO oxidation reaction by O2 have been carried out on the various prepared solids. The results obtained revealed that most of iron and copper species were contributed in complex formation of the polymeric material via carboxylic groups while some of the cobalt and nickel were involved in the complex formation and the rest remained as separate phases. The thermal treatment either in air at 400°C or in vacuo at 240°C led to degradation of the treated grafted polymeric material with subsequent formation of poly(methacrylic acid) together with Co3O4 (poorly crystalline phase) and NiO (having moderate crystallinity) and minute amounts of Fe2O3 and CuO (undetected by XRD). The PTFE‐g‐PMAAc treated with the different transition metal nitrates and subjected to heating under vacuum at 240°C exhibited different catalytic activities that vary in the order: Co > Ni > Cu ≫ Fe. The catalytic activity was mainly dependent on the produced amount of free oxide and their degree of division. © 1993 John Wiley & Sons, Inc.
Optically clear simulataneous interpenetrating polymer networks based on poly(ethylene glycol) diacrylate and epoxy. II. Kinetic study
Authors: Lin Mu‐Shih , Jeng Kuen‐Tay , Huang Kun‐Yui , Shih Yen‐Fong
Published: April 2003

Simultaneous interpenetrating polymer networks (SINs) based on diglycidyl ether of bis‐phenol A (DGEBA) and poly(ethylene glycol) diacrylate (PEGDA) in weight ratios of 100/0, 50/50, and 0/100 were blended and cured simultaneously by using benzoyl peroxide (BPO) and m‐xylenediamine (MXDA) as curing agents. A kinetic study during SIN formation was carried out at 45, 55, 63, and 70°C. Concentration changes for both the epoxide and CC bond were monitored with FTIR. A rate expression for DGEBA cure kinetics was established with a model reaction of phenyl glycidyl ether (PGE) and benzylamine. Experimental results revealed that lower rate constants and higher activation energy for the SIN were found, compared with those for the constituent DGEBA and PEGDA network formation. A model of network interlock was proposed to account for this phenomenon. During simultaneous cure of DGEBA and PEGDA, the interlock (mutual entanglement) between DGEBA and PEGDA networks provided a sterically hindered environment, which subsequently increased the activation energy and reduced cure rates for both DGEBA and PEGDA. © 1993 John Wiley & Sons, Inc.
Regiodefined substituted poly(2,5‐thienylene)s
Authors: Gallazzi M. C. , Castellani L. , Marin R. A. , Zerbi G.
Published: April 2003

The polymerization of 3,3″‐dialkylterthiophenes overcomes the lack of regiospecificity associated (to some extent) with all the polymerization methods in use, thus allowing the preparation of perfectly regioregular polymers endowed with enhanced electrical and optical properties. Moreover, the larger spacing of the alkyl chains achieved with the insertion of an unsubstituted thiophene unit confers to such regioregular polymers an extraordinary doping stability. Two regiochemically defined alkoxy‐substituted terthiophenes were also polymerized and the effects of the effects of the presence and position of the alkoxy group on the polymerization reaction and on the polymer properties are discussed. © 1993 John Wiley & Sons, Inc.
Tetrahydrofuran and 3,3‐bis(chloromethyl) oxetane triblock copolymers synthesized by two‐end living cationic polymerization
Authors: Hsiue Ging‐Ho , Liu Ying‐Ling , Chiu Yie‐Shun
Published: April 2003

Triblock copolymers based on tetrahydrofuran (THF) and 3,3‐bis(chloromethyl) oxetane (BCMO), BCMO‐block‐THF‐block‐BCMO and poly(BCMO‐co‐THF)‐THF‐(BCMO‐co‐THF), have been synthesized by two‐end living cationic polymerization with a bifunctional initiator, trifluoromethanesulfonic anhydride [(CF3SO2)2O]. The polymers are obtained by using the two end propagating species of poly(THF) to initiate the sequential BCMO polymerization. The resulting polymers are characterized by infrared (IR), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC), confirming that the polymers are ABA‐type block copolymers. The identities of the molecular weights predetermined and which determined by GPC show the success of predetermining molecular weights of the polymers and preparing well‐defined polymers. The narrow polydispersities, 1.1–1.3, indicate that the chains are propagating by a living mechanism. © 1993 John Wiley & Sons, Inc.
Melt polymerization of hexachlorocyclotriphosphazene in the presence of organotin (IV) compounds
Authors: Cho Yangha , Sohn Youn Soo , Jun Moo‐Jin
Published: April 2003

The melt polymerization of hexachlorocyclotriphosphazene to poly(dichlorophosphazene) has been studied in the presence of organotin (IV) compounds. Unlike other typical Lewis acids, diethyltin (IV) chloride, Et2SnCl2, has shown to be an inhibitor for the thermal polymerization of the trimer, raising the activation energy to 70 kcal/mol. Diethyltin(IV) chloride remarkably delayed the rate of polymerization and efficiently inhibited the crosslinking reaction, thus leading to an improvement in the yield of the linear polymer without sacrifice to its molecular weight. © 1993 John Wiley & Sons, Inc.
Synthesis and copolymerization behavior of methacrylate dimers
Authors: Abbey K. J. , Trumbo D. L. , Carlson G. M. , Masola M. J. , Zander R. A.
Published: April 2003

Methacrylic ester‐based dimers and oligomers were synthesized using a metal‐based catalytic chain transfer agent. Conditions were employed which maximized the yield of unsaturated dimers, and the copolymerization behavior of these dimers was investigated. The molecular weight and polymer yield were found to decrease with increasing dimer concentration in the copolymerization feeds. © 1993 John Wiley & Sons, Inc.
Characterization of polymer molecular weight distributions by ratios of molecular weight averages
Authors: Pyun Chong Wha
Published: April 2003

The molecular weight (MW) distribution of a polymer is characterized by a hierarchy of average MWs and their appropriate combinations. For example, the ratio of the weight‐average to the number‐average MW is the most frequently used measure of the polydispersity of a polymer. As is well known the lower bound to this ratio is unity, and it has been shown that the upper bound is (m + 1)2/4m, where m = Mmax/Mmin is the ratio of the highest to the lowest MW of the MW species present in a given polymer. This upper bound corresponds to an extremely bimodal MW distribution of one half weight fraction with Mmin and the other half with Mmax. The behavior of the upper bound for two special unimodal distributions is investigated: one is the triangular distribution, the other the quadrilateral. The results suggest that the upper bound for all possible unimodal distributions is considerably less than the corresponding general case, especially for large values of m. For example, the maximum ratios for the quadrilateral distribution and the general upper bound are 1.04 and 1.125 for m = 2; 1.43 and 3.205 for m = 10; 2.56 and 25.5 for m = 100; 3.99 and 250.5 for m = 1000, respectively.
A dielectric study of poly(ethylene‐co‐vinylacetate)–poly(vinyl chloride) blends. I. Miscibility and phase behavior
Authors: Rellick G. S. , Runt J.
Published: April 2003

Measurements of the complex permittivity were used to study miscibility and phase behavior in blends of poly(vinyl chloride) (PVC) with two random ethylene—vinyl acetate (EVA) copolymers containing 45 and 70 wt % of vinyl acetate. The dielectric β relaxation of the pure polymers and blends was followed as a function of temperature and frequency for different blend compositions and thermal treatments. Blends of EVA 70/PVC were found to be miscible for compositions of about 25% EVA 70 and higher. Blends of lower EVA 70 content showed evidence of two‐phase behavior. EVA 45/PVC blends were found to be miscible only at the composition extremes; at intermediate compositions these blends were two‐phase, partially miscible. Both blend systems showed lower critical solution temperature behavior. Phase separation studies revealed that in the EVA 45/PVC blends, PVC was capable of diffusing into the higher Tg phase at temperatures below the Tg of the upper phase. In the blends, ion transport losses were significant above the loss peak temperatures, and in the two‐phase systems, often obscured the upper temperature loss process. It was shown possible, however, to correct the loss curves for this transport contribution.