bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and properties of dimethyl phosphonomethyl methylsiloxane dimethylsiloxane copolymers
Authors: Juengst Clifford D. , Weber William P.
Published: April 2003

Dimethyl phosphonomethylheptamethylcyclotetrasiloxane (II) and 1, 3‐bis(dimethyl phosphonomethyl)tetramethyldisiloxane (III) have been prepared by Arbuzov reaction of trimethyl phosphite with bromomethylheptamethylcyclotetrasiloxane (I) and 1, 3‐bis(bromomethyl)tetramethyldisiloxane, respectively. Dimethyl phosphonomethylmethylsiloxane dimethylsiloxane copolymers have been prepared by acid‐catalyzed ring‐opening polymerization of II with hexamethyldisiloxane (MM) as an end‐capping reagent and by reaction of II with III as an end‐capping reagent. Dimethylsiloxane polymers with dimethyl phosphonomethyldimethylsiloxy end groups have been prepared by acid‐catalyzed polymerization of octamethylcyclotetrasiloxane (D4) and III. Under these conditions hydrolysis of the dimethyl phosphonate ester groups was a problem. On the other hand Arbuzov reaction of trimethyl phosphite with bromomethylmethylsiloxane dimethylsiloxane copolymer gave a dimethyl phosphonomethylmethylsiloxane dimethylsiloxane copolymer with uniform properties. These polymers have been characterized by1H‐,13C‐,29Si‐, and31P‐NMR spectroscopy. Their molecular weight distributions have been determined by gel permeation chromatography (GPC) and their thermal stability measured by TGA.
Cationic grafting from carbon black. VII. Grafting of polyacetals by cationic ring‐opening polymerization of trioxane and 1,3‐dioxolane initiated by CO+ClO4− groups on carbon black
Authors: Tsubokawa Norio
Published: April 2003

The cationic ring‐opening polymerization of trioxane and 1,3‐dioxolane was found to be initiated by CO+CIO4− groups on a carbon black surface, which were introduced by the reaction of COCI groups with AgCIO4. The activation energy of the ring‐opening polymerization of trioxane was estimated to be 15.5 kcal/mol. In the polymerization system, poly(oxymethylene) and poly(1,3‐dioxolane) formed were effectively grafted onto carbon black depending upon the propagation of these polymers from the carbon black surface; for instance, the grafting ratio of poly(oxymethylene) onto carbon black increased with an increase in conversion and went up to about 180%. Although the grafted chain of poly(oxymethylene) was subject to stepwise thermal depolymerization from the chain ends, the thermal stability of poly(oxymethylene)‐grafted carbon black was improved by acetylation of hemiformal end groups. The molecular weight of ungrafted poly(oxymethylene) formed in the polymerization was determined to be 1.8–2.0 × 104. Furthermore, the copolymerization of trioxane with 1,3‐dioxolane, styrene, and other comonomers initiated by CO+CIO4− groups and the thermal stability of these acetal copolymer‐grafted carbon black were investigated.
Polymerization of silylacetylenes by W and Mo catalysts
Authors: Tajima Hiroshi , Masuda Toshio , Higashimura Toshinobu
Published: April 2003

Polymerization of HCCSiMe3 homologues (HCCSiMe2R; R = n‐C6H13, CH2CH2Ph, CH2Ph, Ph, and t‐Bu) was studied by use of W and Mo catalysts. W catalysts provided polymers in good yields from all these monomers. Mo catalysts gave mainly a polymer from HCCSiMe2–t‐Bu, but virturally only cyclotrimers from sterically less croweded monomers (R = n‐C6H13, CH2CH2Ph, CH2Ph, and Ph). Polymers with flexible R groups (n‐C6H13, CH2CH2Ph, and CH2Ph) were totally soluble, their number‐average molecular weights being 7000–18,000. Polymers with inflexible R groups (Ph and t‐Bu) were partly insoluble. Every polymer was a yellow rubber or powder, and had the structure, \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH} = {\rm C}\left( {{\rm SiMe}_{\rm 2} {\rm R}} \right)\rlap{--} ]_n $\end{document}. The results were compared with the polymerization and polymer of HCCSiMe3.
Synthesis and characterization of ABA triblock copolymers containing poly(2,6‐dimethyl‐1,4‐phenylene oxide) as A blocks and tetramethyl bisphenol‐A polysulfone as B blocks
Authors: Tingerthal Jeanne M. , Nava Hildeberto , Percec Virgil
Published: April 2003

α, β‐Bis(hydroxyphenol) tetramethyl bisphenol‐A polysulfone (PSUT) was synthesized by two different methods, one using a strong base, the other using a weak base. The bifunctional polysulfone containing tetramethyl bisphenol‐A chain ends was exploited as a model telechelic that can be used for the preparation of ABA triblock copolymers containing poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) as A segments and PSUT as B segments. PSUT and PPO were incorporated into triblock copolymers by an oxidative coupling copolymerization of PSUT with 2,6‐dimethylphenol or by the redistribution of PPO in the presence of PSUT. The mechanism of block copolymerization is discussed. DSC studies indicate that short immiscible PPO and PSUT segments incorporated into a triblock copolymer do not exhibit phase separation. Polymer blends of the PPO–PSUT–PPO triblock copolymers with PPO homopolymer were analyzed by DSC. Both miscible and phase‐separated blends can be prepared depending on the molecular weight of both PPO homopolymer and of the PPO segment present in the triblock copolymer. Polymer blends of the PPO–PSUT–PPO triblock copolymer with PSUT were miscible at all compositions.
Kinetics of retarded polymerization: Investigation of the retardation of V5+–thiourea initiated polymerization of methyl acrylate by phenol
Authors: Mohanty A. K. , Singh B. C. , Misra M.
Published: April 2003

The kinetics and mechanism of the retarding action of phenol on the V5+–thiourea initiated polymerization of methyl acrylate (MA) have been studied within the temperature range of 30–50°C. The effects of retarder (phenol), metal ion (V5+), monomer (MA), sulfuric acid, some organic solvents and inorganic salts on the percentage and rate of polymerization have been studied. The remarkable observation of the present study is the positive intercept obtained from the plot of [M]/Rp vs. 1/[M]. This type of observation is significantly different from previous studies on retarded polymerization. The values of composite rate constants k0kt/kikpkK have been calculated from plots of [M]/Rp vs. 1/[M]. On the basis of experimental findings a reaction mechanism has been suggested, and a suitable rate expression has been proposed and explained.
Polymerization and oxidation of pyrrole by organic electron acceptors
Authors: Kang E. T. , Neoh K. G. , Tan T. C. , Ong Y. K.
Published: April 2003

Simultaneous chemical polymerization and oxidation of pyrrole have been initiated by organic electron acceptors, 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone (DDQ) and tetrachloro‐o‐benzoquinone(chloranil). The polypyrrole (PPY) complexes so produced are semiconductive and granular in nature. For the PPY–DDQ and PPY–chloranil complexes obtained from bulk polymerization, the respective electrical conductivities (σ) are of the order of 10−1 and 10−3 ohm−1 cm−1. However, σ is substantially lower for the complexes prepared in solvent media. Both complexes are relatively stable in the atmosphere. Thin uniform films of the PPY–organic acceptor complexes have also been synthesized on SnO2 electrode by electrochemical polymerization in acetonitrile. The physicochemical properties of the PPY–organic acceptor complexes prepared chemically under the various experimental conditions are examined in detail.
The measurement of ozone permeability in silicone polycarbonate copolymers using 10,10′‐dimethyl‐9,9′‐biacridylidene as an optical probe
Authors: Surgi Marion R. , Hodgeson Jimmie A.
Published: April 2003

The permeability (SD) of ozone in a silicone polycarbonate copolymer has been measured by monitoring the depletion of 10,10′‐dimethyl‐9,9′‐biacridylidene (DBA) impregnated into the polymer. The quantity (2SD)1/2 varies linearly with membrane thickness. Extrapolation of this linear relationship to zero thickness provides a positive y‐intercept that can be taken to be the intrinsic permeability of ozone in the silicone portion of this copolymer [SD = 115 ± 17 × 10−9 (cm3 gas) cm sec−1 cm−2 (cmHg, ΔP)−1]. This result compared favorably with the modeled permeability of ozone in silicone homopolymers [142 ± 15 × 10−9 (cm3 gas) cm sec−1 cm−2 (cmHg, ΔP)−1]. The lower permeability determined for the copolymer, when compared with the modeled value, was attributed to a reduced mobility of the amorphous silicone blocks caused by the presence of the crystalline polycarbonte blocks. The permeability was shown to be independent of ozone concentrations, flow rate, temperature, and humidity over the ranges used in these experiments. This method identifies a technique that may be useful in quantitating the permeability of ozone in packaging materials, tire sidewalls, and industrial polymers.
NMR studies of ionomers. 3. Synthesis and microstructure of poly(ethyl acrylate‐co‐lithium acrylate)
Authors: Simmons Alexandra , Natansohn Almeria , Eisenberg Adi
Published: April 2003

Copolymers of ethyl acrylate (EA) with lithium acrylate (LiA) with relatively low contents of LiA units (up to 30%) were synthesized by alkaline hydrolysis of poly(EA). 13C‐NMR spectra of these copolymers registered in a mixture of deuterated benzene with deuterated methanol (85:15 v/v) presented configurational splittings of the ester methylene, methylene main chain, and ester carbonyl group signals. Assignments of these splittings were made and Bernoulli statistics with a meso probability of 0.48 could fit both poly(EA) and poly(EA‐co‐LiA). Only the CO signal of the copolymer was sensitive to sequence distribution and indicated that the LiA units have a tendency to be isolated on the chain. Two‐dimensional HETCOR pulse sequence helped to assign the main chain proton spectrum.
Spectroscopic study of the complexes of poly(N‐methacryloyl‐L‐asparagine) with palladium (II)
Authors: Lekchiri Abdennbi , Morcellet Joëlle , Morcellet Michel
Published: April 2003

The complexes formed between palladium (II) and a polymeric ligand derived from L‐asparagine, poly(N‐methacryloyl‐L‐asparagine) (PNMAsn) have been investigated by electronic absorption and circular dichroism. N‐isobutyroyl‐L‐asparagine (NIBAsn) was also synthesized and studied with the purpose of comparison with its polymeric analog. NIBAsn gives two complexes: at low pH, an optically active complex between one carboxylate and one secondary amide nitrogen (so‐called 1N complex), and at higher pH, a 2N complex involving the primary and secondary amide group. This complex is also optically active. PNMAsn gives at low pH a 1N complex similar to that of NIBAsn, but at higher pH the 2N complex is formed between two carboxylate groups and two secondary amide groups of two different side chains of the polymer. At very high pH this 2N complex is hydrolyzed, i.e., the carboxylate‐palladium bonds are replaced by hydroxyle‐palladium bonds, and the complex becomes optically inactive.
Potentiometric titration behavior of poly(ethylene glycol methyl ether)‐b‐poly(ethylenimine)
Authors: Overberger C. G. , Peng Lin
Published: April 2003

Poly(ethylene glycol methyl ether)‐b‐poly(ethylenimine hydrochloride) was characterized using potentiometric and viscosimetric titration methods. The average chemical compositions of the polyamine hydrochloride salts estimated by the acid‐base titration,1H‐NMR, and elemental analysis were compared. The apparent dissociation constant, pK, and the inherent viscosity of the polyamine hydrochloride were found to be highly dependent on the degree of neutralization. Very strong coulombic interactions among the charged sites were observed at low pH's for this polymer.
Synthesis and characterization of liquid crystalline poly(N‐acylethyleneimine)s
Authors: Rodriguez‐Parada Jose M. , Percec Virgil
Published: April 2003

The synthesis of three cyclic imino ethers containing mesogenic groups attached to the heterocyclic unit through flexible spacers is described. Cationic ring‐opening isomerization polymerization of two of them, i.e., 2‐[4‐(4‐methoxy‐4′‐biphenyloxy)butyl]‐2‐oxazoline (MeOBiph‐4‐Oxz) and 2‐[6‐(4‐methoxy‐4′‐biphenyloxy)hexyl]‐2‐oxazoline (MeOBiPh‐6‐Oxz) provided thermotropic liquid crystalline (LC) poly(N‐acylethyleneimine)s, whereas the polymerization of 2‐[4‐(4‐phenylphenoxy)butyl]‐2‐oxazoline (BiPh‐4‐Oxz) led to a crystalline polymer.
Preparation and characterization of macroporous polystyrene resins containing ethynyl groups and transition metal acetylide complexes
Authors: Yamaguchi H. , Shinohara K. , Sonogashira K. , Yamaguchi K.
Published: April 2003

Ethynylated polystyrene resins were prepared as functionalized polymer supports by the iodination reaction of macroporous polystyrene resins and reacted with transition metal diethynyl complex (Mt = Ni) and metal halides (Mt = Rh, Pd, and Pt) in a basic solvent using cuprous iodide as a catalyst to obtain macroporous polystyrene resins containing organotransition metals. The distribution of the metal acetylide complexes in the modified macroporous resins was determined by an electron probe microanalyzer. A gradient in the transition metal distribution was observed in any case of the modified resins. The stability of the organotransition metal complexes in the polymer matrix could be compared with a low molecular weight analogous complex quantitatively.
Preparation and properties of some cardopolyamides containing phenoxathiin‐10,10‐dioxide and phenoxaphosphine units
Authors: Reddy T. Ashok , Srinivasan M.
Published: April 2003

Several new cardopolyamides containing phenoxathiin‐10,10‐dioxide and phenoxaphosphine units were prepared by condensing 3,3‐bis(4‐aminophenyl)‐phthalide (PDA), 9,9‐bis(4‐aminophenyl) fluorene (FDA), and 9,9‐bis(4‐aminophenyl)‐10‐anthrone (ADA) with 2,8‐dichloroformylphenoxathiin‐10,10‐dioxide (PDC) and 2,8‐dichloroformyl‐10‐phenylphenoxaphosphine‐10‐oxide (PPDC) in DMAc. A low temperature solution polycondensation technique was employed throughout. The cardopolymides were obtained in 80–92% yield and showed inherent viscosities in the range 0.41–0.6 dL/g. All the polymers were characterized by IR spectra, density, solubility, crystallinity, and thermal analysis.
Polytetrafluoroethylene–iron oxide composite. Interactions with acrylic acid and vinyl acetate
Authors: De Barros Glaucione Gomes , Galembeck Fernando
Published: April 2003

Iron oxide finely dispersed on polytetrafluoroethylene (PTFE) affects the behavior of this polymer with regard to acrylic acid and vinyl acetate sorption. Acrylic acid photopolymerization and grafting onto x‐ray preirradiated PTFE are also affected. Infrared, Mossbauer, and ESR spectroscopies show that PTFE‐embedded iron oxide is not transformed to iron acrylate, although it is converted to iron acetate by exposure to acetic acid. X‐ray‐induced polytetra‐fluoroethylene free radicals are longer lived in the polymer‐oxide composite than in plain polytetrafluoroethylene.
Synthesis of the aldehyde of oligomeric polyoxyethylene
Authors: Paley M. Steven , Harris J. Milton
Published: April 2003

Conjugates of polyoxyethylene with proteins and surfaces are of much importance in various biotechnical applications. Consequently, methods for preparing the aldehyde of POE are of interest because of the potential ready attachment of this compound to proteins and aminated surfaces by reductive amination. In this work we describe the results of attempts to prepare an oligomeric POE aldehyde by six routes, two of which proved to be effective. Two previously published routes, manganese‐oxide and DMSO/Ac2O oxidation were ineffective. The aldehyde was shown to be unstable in the presence of base and thus of little use for reductive amination. On the other hand, the benzaldehyde derivative, which we also synthesized, is stable, easy to prepare, and undergoes ready reductive amination.
Degradation and stabilization of high molecular weight polyethylene in solution
Authors: Chirinos‐Padrón Alfonso J. , Azócar José , Mun̄oz‐Escalona A. , Fuentes Alberto M.
Published: April 2003

The changes in the molar mass of high molecular weight polyethylene, in o‐dichlorobenzene, with time are examined using viscometry. The results show that the molar mass decreases with time and that the observed decay can be satisfactorily explained by a simple degradation model. Commercial antioxidants can inhibit the degradation process if the appropriate concentration is chosen. Thus, at very low concentrations a polynuclear phenol shows good antioxidant behavior but this decreases with an increase in concentration due to direct oxidation of the inhibitor. Conversely, zinc dimethyldithiocarbamate shows the best stabilizing activity which increases with concentration. The results are explained on the basis of the established mechanistic action of these compounds and show that viscometry is not an accurate method for measuring the molar mass of high molecular weight polyethylene samples unless the appropriate conditions are chosen. Even with the best inhibitor, some degradation is still observed.
Curing studies of a polyimide precursor. II. Polyamic acid
Authors: Brekner Michael‐Joachim , Feger Claudius
Published: April 2003

The cure of pyromellitic dianhydride–oxydianiline polyamic acid is compared with that of a model compound, diphenylcarbamido–dicarboxy–benzene, both having been synthesized in 1‐methyl‐2‐pyrrolidinone (NMP). Laser interferometry and thermogravimetric analysis showed that, analog to the diamic acid model compound, the polyamic acid forms complexes with NMP (repeat unit/NMP: 1/4 and 1/2). Thermal stability of these complexes was found to be similar to the ones of the diamic acid model compound as revealed by comparison of decomplexation temperature–heating rate curves. Activation energies of the decomplexation processes for the diamic acid are given. Anhydride formation, a reaction found in the cure of the model compound to compete with imidization, takes place also during the polyamic acid cure at fairly low temperatures. The molecular weight drop due to chain scission resulting from anhydride formation was followed by viscometry.
Polypyrazoles from aromatic dipropynones and aromatic dihydrazines
Authors: Connell J. W. , Bass R. G. , Sinsky M. S. , Waldbauer R. O. , Hergenrother P. M.
Published: April 2003

Two types of polypyrazoles, unsubstituted and phenylated, were prepared by a novel synthetic route involving the cyclopolycondensation of aromatic dihydrazines and aromatic dipropynones. The polymers had inherent viscosities as high as 1.05 dL/g and were soluble in N, N‐dimethylacetamide, chloroform (phenylated polypyrazoles only), and sulfuric acid. The polymers exhibited glass transition temperatures ranging from 202 to 266°C and polymer decomposition temperatures (10% weight loss) as measured by thermogravimetric analysis of 400–500°C in air and 465–512°C in nitrogen. The synthesis and characterization of several polypyrazoles are discussed.
Phthalonitrile‐based conductive polymer
Authors: Keller Teddy M.
Published: April 2003

An aromatic, diether‐linked phthalonitrile resin, prepared from 4,4′‐bis(3,4‐dicyanophenoxy)biphenyl, can be converted into an environmentally stable, highly conductive material by thermal means. The conductivity of the pyrolyzed polymer can be varied and controlled as a function of both the pyrolytic temperature and annealing time. This allows the generation of a range of electrical behavior from an insulator to semiconductor and approaching metallic regions.
Synthesis of aromatic polyethers containing 2,6(7)‐dihydroxy [1,3,5(6),7(8)‐tetramethylanthracene] units
Authors: Percec Virgil , Tingerthal Jeanne Marie
Published: April 2003

Friedel–Crafts copolymerization of 4,4′ bis(2,6‐dimethylphenoxy‐4‐Phenyl)sulfone with methylene chloride used both as comonomer and solvent leads to linear and soluble aromatic polyethers containing 2,6(7)‐dihydroxy[1,3,5(6),7(8)‐tetramethylanthracene] units. The polymerization proceeds by multiple electrophilic substitutions that lead first to diphenylmethane and then to dihydroanthrylene units, followed by dihydrogenation.
Binding of methyl orange and its homologs by powdered nylon 612: Peculiar temperature dependence on the binding
Authors: Takagishi Toru , Shibano Michihiro , Lim Yong Jin
Published: April 2003

The ability of powdered Nylon 612 to bind methyl orange, ethyl orange, propyl orange, and butyl orange was investigated at 5, 15, 25 and 35°C in an aqueous solution. The amount of binding of the dye is much higher with this polyamide than with powdered Nylon 66 reported previously,1 although the former polymer has fewer amide end groups. The Van't Hoff plots of the first binding constant for the binding of butyl orange and propyl orange by powdered Nylon 612 exhibit a bell‐shaped curve, whereas the plots for methyl orange and ethyl orange do not. Maximal binding occurs at approximately 15°C for propyl orange and at about 25°C for butyl orange. This is the first instance where the peculiar temperature dependence of the binding constant has been found in the binding of propyl orange, whose hydrophobicity is less than that of butyl orange. These tendencies can be accounted for in terms of increased hydrophobic of butyl orange. These tendencies can be accounted for in terms of increased hydrophobic domains in powdered Nylon 612 and enhanced hydrophobic contributions in the binding process.
A polymer thin‐film technique to study the micromorphology of core/shell latexes
Authors: Shaffer O. L. , Dimonie V. L. , El‐Aasser M. S. , Vanderhoff J. W.
Published: April 2003

A series of poly(styrene)/poly(styrene‐co‐acrylonitrile) core‐shell latexes were synthesized by seeded emulsion polymerization. The dried latex was dissolved in toluene and then cast on the surface of water to form a very thin film (60–90 nm). Phase separation in the thin film was studied by transmission electron microscopy (TEM). Electron micrographs of these thin films yielded fine structure and interesting morphology that was unattainable by ultramicrotoming of the corresponding compression‐molded specimens. Glass transition temperatures and percent grafted polystyrene were correlated with the TEM results. As grafting increases, mixing of the two phases improves, with the resulting Tg value being between the two Tg's of poly(styrene) and poly(styrene‐co‐acrylonitrile).
Effect of crystallinity and flexibility on the photodegradation of polyurethanes
Authors: Hoyle Charles E. , Kim Kyu‐Jun
Published: April 2003

Using fluorescence spectroscopy and gel content measurement, the photolysis of simple polyurethanes based on methylene 4,4′‐diphenyldiisocyanate (MDI) is shown to depend on both the flexibility and crystallinity of the polymer. Polyurethane films based on MDI and 1,12‐dodecanediol (MDI‐12) can be either annealed or quenched to yield a semicrystalline (as measured by DSC and X‐ray diffraction) or amorphous film, respectively. In the case of the quenched (amorphous) film, photolysis yields an ortho photo‐Fries product whereas the annealed (semicrystalline) film does not. Similarly, for a given photolysis time the annealed film generates a lower extent of crosslinked gel. In addition, photolysis of amorphous polyurethane films derived from MDI and ethylene oxide oligomers shows that for relatively inflexible polymers with only three ethylene oxide segments, little or no ortho photo‐Fries rearrangement products are generated upon photolysis. In contrast, photolysis of more flexible polyurethane films with approximately 13 ethylene oxide linkages yields the ortho photo‐Fries product. Apparently, for aromatic diisocyanate based polyurethanes, the extent and mechanism of degradation is directly dependent on the crystallinity and main‐chain flexibility of the polymer.
Synthesis of tailor‐made copolymers containing 1,3‐benzodioxole systems for selective flocculation of minerals
Authors: Bertini V. , Pocci M. , Picci N. , Lucchesini F. , Falbo A. , De Munno A.
Published: April 2003

A general simplified model of the morphology of a polymeric flocculant based on only three types of chemical functions, that must be present in the polymer, is described and used for the preparation of tailor‐made selective flocculants for titanium minerals through the radical copolymerization of five new vinyl monomers (I–V) containing the 1,3‐benzodioxole system, with 4‐vinylpyridine, acrylic, methacrylic, and 4‐vinylbenzoic acids.
Selective vinyl cationic polymerization of monomers with two cationically polymerizable groups. III. 2‐vinyloxyethyl glycidyl ether: An epoxy‐functionalized vinyl ether
Authors: Sawamoto Mitsuo , Takeuchi Etsu , Hashimoto Tamotsu , Higashimura Toshinobu
Published: April 2003

Cationic polymerization of 2‐vinyloxyethyl glycidyl ether (VEGE), a vinyl ether with an epoxy group, was conducted with various initiators in CH2Cl2 in the temperature range from +15 to −78°C, and the possibility of its selective vinyl polymerization was investigated. BF3OEt2 polymerized both vinyl and epoxy groups of VEGE to yield polymers partially insoluble in organic solvents. HI/I2, iodine, and CF3SO3H gave soluble, low‐molecular‐weight oligomers with epoxy pendants. 1H‐NMR structural analysis of the oligomeric products showed that the epoxy/vinyl ratio of the pendants decreases in the order: 100% epoxy ∼ CF3SO3H > HI/I2 ∼ I2 ≫ BF3OEt2. Although HI/I2 or iodine mainly polymerized the vinyl group, the reaction of the vinyl ether‐type growing end with an epoxy group of VEGE took place during the polymerization, so that the monomer conversion leveled off at about 40%.
Studies in the formation of poly(oxazolidones). II. Selectivity of catalysts and kinetics in the synthesis of 2‐oxazolidone from butyl isocyanate and phenylglycidyl ether
Authors: Šehović Hajrija , Sendijarević Aiśa , Sendijarević Vahid , Frisch Kurt C.
Published: April 2003

The reaction of butyl isocyanate with phenylglycidyl ether was selected as a model reaction for the synthesis of aliphatic isocyanate‐based poly(2‐oxazolidones). The selectivity of different metal halides and aluminum trichloride/triphenylphosphine oxide (AlCl3 TPPO) and aluminum hexamethylphosphoramide (AlCl3 HMPA) complexes were investigated for oxazolidone formation. Both FTIR and mass spectrographic methods were employed for characterization of the reaction products. The kinetics of the model reaction was studied using AlCl3 TPPO in o‐dichlorobenzene at 120 and 140°C.
Preparation and properties of fluorine‐containing polyarylates from tetrafluoroisophthaloyl chloride and bisphenols
Authors: Kakimoto Masa‐Aki , Harada Shigeyuki , Oishi Yoshiyuki , Imai Yoshio
Published: April 2003

Fluorine‐containing polyarylates having inherent viscosities of 0.2–0.8 dL/g were prepared from tetrafluoroisophthaloyl chloride and various bisphenols by low temperature solution polycondensation in chloroform with triethylamine or by two‐phase polycondensation in a dichloromethane‐water or nitrobenzene‐water system with benzyltriethylammonium chloride as the phase transfer catalyst. These polyarylates were amorphous and were readily soluble in various solvents, including chloroform and N‐methyl‐2‐pyrrolidone. The glass transition temperature of the polymer derived from 2,2‐bis(4‐hydroxyphenyl) propane was 150°C. These polyarylates started to lose weight around 350°C in an air or nitrogen atmosphere.
Polymerization systems driven by aromatization energy: Anionic polymerization of 4‐allylidene‐2,6‐dimethyl‐2,5‐cyclohexadien‐1‐one and spiro[2,5]octadienone derivatives
Authors: Cho Iwhan , Kim Won‐Tai
Published: April 2003

To investigate the polymerization systems driven by aromatization energy, 4‐allylidene‐2,6‐dimethyl‐2,5‐cyclohexadien‐1‐one (Ia), 5,7‐dimethyl‐1‐vinylspiro[2,5]octa‐4,7‐dien‐6‐one (Ib), 4,7‐dimethyl‐1‐vinylspiro[2,5]octa‐4,7‐dien‐6‐one [Ic], 2‐vinyl‐2′‐methylspiro[cyclopropane‐1,4′‐(1′‐naphthalenone)] (Id), and 2‐phenyl‐2′‐methylspiro[cyclopropane‐1,4′‐(1′‐naphthalenone)] (Ie) were prepared and polymerized with sodium cyanide in N,N‐dimethylformamide. Monomer Ia was highly polymerizable even at −65°C. Monomers Ib–Ie also polymerized well, giving powdery polymers that were soluble in common solvents. All the polymerizations took place through the aromatization of the cyclohexadienone ring, suggesting that the aromatization energy is the driving force for the polymerization of these monomers.
Synthesis of new polydimethylsiloxane‐polyamide copolymers from phenylene‐bis‐5‐oxazolones and aminopropyl‐terminated polydimethylsiloxane oligomers
Authors: Policastro Peter P. , Hernandez Pamela K.
Published: April 2003

Alternating polydimethylsiloxane‐polyamide block copolymers were prepared in dichloromethane or chloroform solution at room temperature from 3‐amino‐n‐propyl‐terminated polydimethylsiloxane oligomers and 2,2′‐p‐phenylenebis(4,4‐dimethyl‐5‐oxazolone). Solution and thermal properties of the polymers were characterized.
Selective vinyl cationic polymerization of monomers with two cationically polymerizable groups. II. p‐vinylphenyl glycidyl ether: An epoxy‐functionalized styrene
Authors: Hashimoto Tamotsu , Sawamoto Mitsuo , Higashimura Toshinobu
Published: April 2003

p‐Vinylphenyl glycidyl ether (VPGE), a styrene derivative with an epoxy pendant, was polymerized by various cationic initiators, and its selective vinyl polymerization was investigated at low temperatures below −15°C. BF3OEt2 (a metal halide) and CF3SO3H (a strong protonic acid) polymerized both vinyl and epoxy groups of VPGE, and produced cross‐linked insoluble polymers. The HI/I2 initiating system and iodine, in contrast, polymerized its vinyl group in polar solvents (CH2Cl2 and nitroethane) highly selectively in the temperature range of −15 to −40°C to give soluble polymers with a polystyrene backbone and epoxy pendants; however, under these conditions, 10–15% of the epoxy groups of the polymers were consumed during the polymerization by the reaction with the growing species. The polymerization by HI/I2 in CH2CI2 involved a long‐lived propagating species, as indicated by a progressive increase in the molecular weight (M̄n) of the polymers with monomer conversion and their fairly narrow molecular weight distributions (M̄w/M̄n ∼ 1.6). The differences between the polymerizations of VPGE and p‐isopropenylphenyl glycidyl ether, an α‐methylstyrene‐type counterpart of VPGE, were also discussed with an emphasis on the effects of the α‐methyl group in the latter monomer.
Polyelectrolytes containing dihydronicotinamide. III. Fluorescence quenching by nicotinamide‐containing polymers in aqueous solution
Authors: Itoh Yoshihiro , Abe Koji , Senoh Saburo
Published: April 2003

Charge‐transfer (CT) interaction of N‐benzyl‐1,4‐dihydronicotinamide (BNAH) and poly(sodium styrene‐p‐sulfonate) containing 6 mol % of BNAH groups (PNAH) with several types of nicotinamide‐containing polyelectrolytes in aqueous solution was investigated by fluorescence quenching. The experimental data were analyzed in terms of a kinetic model including both static and dynamic quenching. Hydrophobic association of BNAH with the polymers led to more effective quenching than the monomer [N‐benzylnicotinamide (BNA)] system. Electrostatic attraction of PNAH and BNA also resulted in the remarkably large value of apparent quenching constant (K′ = 1.4 × 104M−1). Further, the fluorescence of PNAH was quenched far more effectively by poly[N‐(p‐vinylbenzyl)nicotinamide] (PBNA) and poly(acrylamide)s containing nicotinamide (NA) groups (PAm) due to the formation of a polyelectrolyte complex (PEC). In this case, the K′ value depended on the BNA content in the copolymer, suggesting the structural matching effect of the interacting pair on the intermacromolecular interaction.
Magnesium chloride supported high‐mileage catalysts for olefin polymerizations. XVIII. Effect of hydrogen and lewis bases
Authors: Chien James C. W. , Hu Youliang
Published: April 2003

Hydrogen has been found earlier to increase the initial rate of polymerization by MgCl2/EB/PC/AlEt3/TiCl4‐AlEt3/MPT, CW‐catalyst (+Bi, +Be) (EB, ethyl benzoate; PC, p‐cresol; MPT, methyl‐p‐toluate), but decays more rapidly as compared to polymerizations in the absence of H2. In this study the effect of H2 was studied when either the internal Lewis base, EB Bi, or the external Lewis base, MPT Be, or both are deleted from the CW‐catalyst. H2 does not affect the stereospecificity of all the catalysts, but causes a slight increase of polymer yield, whereas the yield is virtually unchanged by H2 for the catalysts activated with Be. Unlike the catalyst (+Bi, +Be) where H2 increases active site concentrations [Ti*] about threefold, it affects [Ti*] negligibly when Be is absent. The rate constants of propagation is about the same with or without H2 for the CW‐catalyst (+Bi, –Be) or (–Bi, –Be); the same statement can be said about the rate constant of chain transfer with AlEt3 or with H2. Hydrogen increases the rate of catalyst site deactivation for the various catalysts in the order of(+Bi, +Be) > (–Bi, –Be) > (+Bi, –Be).
Syntheses and crosslinking reactions of self‐curable copolymers containing pendant cyclic iminoethers and carboxylic acid groups
Authors: Nishikubo Tadatomi , Iizawa Takashi , Takahashi Makoto , Tokairin Atushi
Published: April 2003

Soluble copolymers containing both pendant cyclic iminoethers such as 4,4‐dimethyl‐2‐oxazoline or 4,4,6‐trimethyl‐4H‐dihydro‐1,3‐oxazine and carboxylic acid were successfully synthesized by radical copolymerizations of 4,4‐dimethyl‐2‐vinyl‐2‐oxazoline, 4,4‐dimethyl‐2‐isopropenyl‐2‐oxazoline, or 4,4,6‐trimethyl‐2‐vinyl‐4H‐dihydro‐1,3‐oxazine with methacrylic acid and styrene, methyl methacrylate, or ethyl acrylate using AIBN as an initiator in benzene or DMF at 60 or 80°C. The crosslinking reaction of the copolymers obtained did not occur by heating at 70°C. However, these copolymers quantitatively produced gel products by heating at 130°C. The rate of crosslinking reaction of the copolymer increased with increasing pendant cyclic iminoether and carboxylic acid groups. The rate of crosslinking was also affected by the molecular motion of the polymer chain.

Our results show that the copolymers of more sterically hindered 2‐vinyl‐2‐oxazolines are more stable and so they can be crosslinked in a controlled manner and at higher temperatures than the previously studied polyoxaziline system.
Polymerization and conformational studies of poly(trans‐3‐ethyl‐D and L‐proline)
Authors: Tiba Omar , Overberger C. G.
Published: April 2003

Poly(L‐trans‐3‐ethylproline), L‐PT3EP, and poly(D‐trans‐3‐ethylproline), D‐PT3EP, were prepared by ring opening polymerization of the corresponding N‐carboxyanhydrides (NCA) using triethylamine as an initiator. Using circular dichroism spectroscopy, it was shown that the incorporation of an ethyl group at the 3 position of the pyrrolidine ring caused a noticeable change in the conformational behavior of the polymer in solution. The ethyl group limited to some extent rotation of the polymer chain around the CCO bond and prevented the mutarotation between the two forms found in poly‐L‐proline polymers.
Poly(α‐amino acid)‐immobilized polymer adsorbents for optical resolution. IV. Elucidation of chiral recognition mechanism of poly(N5‐benzyl‐L‐glutamine)‐immobilized resin
Authors: Kiniwa Hideaki , Doi Yuka , Nishikaji Takashi , Ogata Naoya
Published: April 2003

Various investigations have been carried out in order to further elucidate the chiral recognition mechanism of immobilized poly(N5‐benzyl‐L‐glutamine) (PBLGN) for optical resolution. The shape and dimension of the chiral recognition site are determined by resolution of hydantoin derivatives, with substituents of varied bulkiness at the chiral center. The site of the hydrogen bonding association of the enantiomers responsible for chiral recognition is also elucidated. Several adsorbents with electron‐donating/withdrawing substituents incorporated into the PBLGN side chain phenyl are synthesized and evaluated for the resolution of (RS)‐5‐isopropylhydantoin in order to elucidate the association site of PBLGN. Based on the experimental evidences obtained, a most plausible mechanism of chiral recognition is proposed. Additionally, adsorbents with several other poly(α‐amino acid)s are also synthesized, and the effect of poly(α‐amino acid) side chain length is discussed.
Synthesis and esterolytic reactions of linear and cross‐linked asymmetric imidazole‐containing polymers
Authors: Tomono T. , Schiavone R. J. , Overberger C. G.
Published: April 2003

Asymmetric linear and cross‐linked imidazole‐containing polymers were prepared from 1‐[2(S)‐methylbutyl]‐4‐vinylimidazole and 1‐[2(S)‐methylbutyl]‐5‐vinylimidazole. The esterolytic reactions of these linear and cross‐linked asymmetric polymers with the enantiomeric substrates (R)‐ and (S)‐4‐(3‐methylpentadecanoyl)‐3‐nitrobenzoic acid, (R)‐ and (S)‐S, were studied by measuring the pseudo‐first order kinetics of the solvolysis of these enantiomeric substrates in the presence of these asymmetric polymers. The linear homopolymers and copolymers of 1‐[2(S)‐methylbutyl]‐4‐ and 5‐vinylimidazole showed hydrophobic and electrostatic effects in the solvolysis of the enantiomeric substrates with these linear asymmetric polymers. Cross‐links were introduced into these asymmetric polymers to increase the rigidity and reduce the number of conformations available to the polymer. The reduced conformational mobility was expected to enhance any enantioselectivity in the solvolysis of the enantiomeric substrates with these polymers. Using these cross‐linked polymers, hydrophobic interactions were observed in the solvolysis of a series of substrates with increasing alkyl chain length. Also, on changing the polarity of the solvent, a bell‐shaped rate profile was observed in the solvolysis of the long chain substrate S. This effect was attributed to a combination of the coiling of the cross‐linked polymer chains and hydrophobic interactions with the substrate on changing solvent polarity. Even with the increased rigidity of these cross‐linked polymers, no significant enantioselectivity in the solvolysis of the enantiomeric substrates was observed. So, neither the linear nor the cross‐linked asymmetric polyvinylimidazoles showed enantioselectivity in the solvolysis of these enantiomeric substrates. In this case, the hydrophobic interactions and the reduced conformational mobility through crosslinking were not strong enough to bring about enantioselectivity in the solvolysis of these enantiomeric substrates.
Synthesis and characterization of polyesters containing heterocyclic thiaxanthone units
Authors: Reddy T. Ashok , Srinivasan M.
Published: April 2003

Several polyesters containing thiaxanthone rings were prepared from 2,7‐dichloroformylthiaxanthone‐5,5′‐dioxide (IVa), 2,8‐dichloroformylthiaxanthone‐5,5′‐dioxide (IVb), and bisphenols by solution polycondensation. The 2,8‐diethoxycarbonylthiaxanthone‐5,5′‐dioxide (V) was prepared and characterized by spectral methods to confirm the formation of 2,8‐thiaxanthonedicarboxylic acid‐5,5′‐dioxide (IVb). Prior to polymer synthesis two model compounds,2,7‐diphenoxycarbonylthiaxanthone‐5,5′‐dioxide (MDE‐1) and 2,8‐diphenoxycarbonylthiaxanthone‐5,5′‐dioxide (MDE‐2), were synthesized and characterized by spectral methods. The polyesters were obtained in 62–78% yield and had inherent viscosities in the range 0.42–0.90 dL/g. The effect of thiaxanthone rings on solubility, crystallinity, and thermal stability of the polyesters are also discussed. The polyesters have decomposition temperatures in the range 372–438°C.
Ion conductivity of poly(ethylene oxide)‐based polyurethane networks containing alkali metal salts
Authors: Tada Hiroaki , Fujino Kozo , Kawahara Hideo
Published: April 2003

Ion conductivity of poly(ethylene oxide) (PEO)‐based polyurethane networks containing alkali metal salts has been investigated. Consequently, it has been revealed that the conductivity is dependent on the following parameters: lattice energy of the alkali metal salt, concentration of alkali metal salt, and the cross‐linking density of the network polymer (which is a function both of the amount of cross‐linking agent and the molecular weight of PEO). Under optimal conditions, the conductivity at ambient temperature corresponded to 2.51 × 10−5 Scm−1, which is greater than that of a typical alkali metal‐PEO system by a factor of about 102 to 103. Moreover, from the standpoint of the application to electrochromic displays (ECD), tensile bond strength between the polymer electrolytes and tungsten trioxide (WO3), which is the most promising electrochromic material, has been evaluated. The bonding strength of the bond of WO3 with the present electrolyte has been found to be much larger than that of the alkali metal‐PEO system.
Functional monomers and polymers. CXLVII. Inclusion compounds of poly(1,3‐butadiyne) in deoxycholic acid and apocholic acid canals: Synthesis and characterization
Authors: Tsutsumi Hiromori , Miyata Mikiji , Takemoto Kiichi
Published: April 2003

The inclusion polymerization of 1,3‐butadiyne was studied at different temperatures using deoxycholic acid and apocholic acid as the host molecules. The polymers that resulted consist of predominantly 1,4‐structure rather than 1,2 or acene structure as confirmed by both IR and Raman spectroscopies. The poly(1,3‐butadiyne)s were found to possess unique optical properties and high electric conductivity as compared with those prepared by the usual polymerization methods.
Polymerization of isobutylene by the adamantane bromide–diethylaluminum chloride catalyst system
Authors: Kuntz Irving , Cheng Doris M. , Dekmezian A. H. , Hsu Chang S.
Published: April 2003

Isobutylene has been polymerized in a continuous stirred tank reactor using a catalyst system comprised of 1‐bromoadamantane and diethylaluminum chloride. The polymerization was carried out in hexane solvent at −15 to −27°C and gave 100% conversion to polyisobutylene (PIB) of 1000–3000 Mw. The results of pyrolysis–gas chromatography–mass spectrometry analyses are consistent with a mechanism involving the formation of the adamantyl cabocation and its addition to an isobutylene molecule to initiate polymerization. 13C‐NMR analyses show that the PIB products contain R2CCR2 and R2CCHR olefin types. Information on the nature of these olefins and the route to their formation has been developed.
Esterification reactions on syndiotactic poly(methallylalcohol). IV. Homo‐ and copolymers of N‐protected methallyl‐(L)‐histidinate
Authors: Frey W. , Dernst C. , Klesper E.
Published: April 2003

Syndiotactic poly(methylallylalcohol) is fully esterified with Nα‐protected (L)‐histidine by carbodiimide in pyridine to yield the corresponding homopolymers, i.e., Nα‐protected 2‐methylallyl‐(L)‐histidinate monomer units and unreacted 2‐methylallyl alcohol units are obtained, which in a second exhaustive esterification step are reacted with Nα‐(benzyloxycarbonyl)‐(L)‐aspartic acid anhydride. The resulting copolymers consist of Nα‐protected 2‐methylallyl‐(L)‐histidinate and 2‐methylally‐Nα‐(benzyloxycarbonyl)‐(L)‐hydrogen‐α‐aspartate monomer units. They are polyampholytes containing both imidazole and carboxyl groups. The structure, including composition of the copolymers, is determined by 1H‐ and 13C‐NMR, while water solubility and apparent pKaa values are investigated by potentiometry.
A few characterization studies on some poly(methyl aryloxymethacrylates)
Authors: Devarajan R. , Balakrishnan T. , Santappa M.
Published: April 2003

High polydispersity values obtained for the molecular weights, as determined by light scattering, osmometry, and GPC, of polymers prepared by different methods from the monomers recently synthesised indicate the presence of large quantities of low molecular weight species besides the high molecular weight species besides the high molecular weight species. Intrinsic viscosity data were used to evaluate Mark–Houwink constants K and “a” for this new series of monomers. DSC analyses show that the polymers have low Tg. X‐ray diffraction studies made on the fibers show a high percentage of crystallinity in poly(methyl α‐phenoxymethacrylate).
Methanol transport in PMMA: The effect of mechanical deformation
Authors: Harmon Julie P. , Lee Sanboh , Li J. C. M.
Published: April 2003

The effect of cold work on the transport of liquid methanol in crosslinked PMMA disks has been determined at temperatures from 35–56°C. Deformed samples absorb at fast rates with kinetics that approach those of Fickian diffusion. Undeformed samples sorb at lower rates and the kinetics tend toward those of Case II transport. Shape recovery accompanied swelling in deformed samples. Samples saturated with methanol were desorbed in cyclohexanol. Resorption of desorbed samples showed fast rates for both deformed and undeformed samples and matched those of the absorption cycle in deformed samples. An analogy is made between the microstructure due to cold work and due to swelling.
Modification of olefin polymerization catalysts. I. Mechanism of the interaction between AIEt3 and silyl ethers
Authors: Vähäsarja Eila , Pakkanen Tuula T. , Pakkanen Tapani A. , Iiskola Eero , Sormunen Pekka
Published: April 2003

The interaction between AlEt3 and silyl ethers, PhnSi(OMe)4‐n (n = 0–3), was followed by 13C‐ and 29Si‐NMR techniques in conditions close to those typical for an olefin polymerization reaction with supported Ziegler–Natta catalysts (A1Et3:silyl ether ratios from 1 to 10, temperature range 25–75°C). A1Et3 and silyl ethers form instantaneously at ambient temperature a donor‐acceptor complex, which is stable at a 1:1 molar ratio. In the presence of excess A1Et3 the complex decomposes via a mechanism consisting, in the case of PhSi(OMe)3, of five consecutive steps: alternating complexation and ether reductions with the formation of alkylated silyl ethers, Ph(Et)nSi(OMe)3‐n (n = 1,2), and dialkyl‐aluminum alkoxides, (Et2A1OMe3)n (n = 2,3). The rate of decomposition was enhanced by the increasing number of methoxy groups present in the silyl ether, heating, or a high A1Et3:silyl ether ratio. The decomposition was not inhibited by the presence of 1‐hexene.
Electrophilic substitution of organosilicon compounds. II. Synthesis of allyl‐terminated polyisobutylenes by quantitative allylation of tert‐chloro‐polyisobutylenes with allyltrimethylsilane
Authors: Wilczek Lech , Kennedy Joseph P.
Published: April 2003

Essentially quantitative allylation of linear and three‐arm star tert‐chloro capped polyisobutylenes [tCl–PIB–Clt and PIB(Clt)3] has been achieved by the use of allyltrimethylsilane (AllylSiMe3) and Friedel–Crafts acids. Quantitative allylation occurs under suitable conditions, e.g., slight molar excess of TiCl4 and AllySiMe3 polar media, −70°C. These conditions have been developed from quantitative model allylation experiments using 2,4,4‐trimethyl‐2‐chloropentane. Essentially quantitative allylation occurs with long‐chain or “once fired” tert‐chloro‐end groups. Complete allylation can also be effected in a “one‐pot two‐step” synthesis, i.e., by first preparing the tert‐chloro‐ended PIB by the inifer method and without isolating the product, completing the synthesis by allylation in the same reactor. Extensive but not quantitative allylation can also be obtained in situ, i. e., during polymerization, by the use of the AllylSiMe3/cumyl chloride/BCI3/isobutylene combination. While allylation proceeds with great ease under the mildest conditions, e.g., −70°C, vinylation with vinyltrimethylsilane could not be achieved even under more forcing conditions.
Macromonomers from vinyl and cyclic monomers prepared by initiation with stable carbenium salts
Authors: Velichkova R. S. , Toncheva V. D. , Panayotov I. M.
Published: April 2003

The initiation of polymerization of α‐methylstyrene and p‐methoxystyrene with 9‐anthranylmethyl salts proceeds by hydride transfer from the monomer to the initiator. As a result, macromonomers with a double bond as head group are formed. These products polymerize and copolymerize by radical and ionic mechanism leading to graft and block copolymers. Styrene and α‐caprolactone polymerize with the same initiator by cationation of the monomer. In this case each macromonomer contains one photoreactive anthranylmethyl group which may photodimerize. As a result copolymers of the type AA or AB are produced.