bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of polymers with substituted allyl end group using dimer of α‐methylvinyl monomer as addition fragmentation chain transfer agent at high temperatures
Authors: Yamada Bunichiro , Tagashira Shinji , Aoki Shuzo 
Published: April 2003

AbstractThe dimerization of methyl methacrylate, ethyl methacrylate, methacrylonitrile, and α‐methylstyrene to 2‐substituted‐1‐allylic compounds [CH2C(X)CH2C(CH3)2X] (X = COOR, C6H5, or CN), and methyl α‐ethylacrylate to a 3‐substituted‐2‐allylic compound [CH3CHC(COOCH3)CH2C(CH3)(C2H5) COOCH3] was carried out by catalytic chain transfer using benzylbis (dimethylglyoximato) (pyridine) cobalt (III). These dimers were then used as addition‐fragmentation chain transfer agents in the polymerizations of methyl methacrylate and styrene at 800C or above. Cross‐dimers from methacrylic ester‐α‐methylstyrene and methacrylonitrile‐α‐methylstyrene mixtures were similarly prepared. Except for those from methyl α‐ethylacrylate and methacrylonitrile, all the dimers participated in the addition‐fragmentation and the copolymerization to different extents. The dimer of methyl α‐ethylacrylate was actually inactive during the styrene and methyl methacrylate polymerizations. The methacrylonitrile dimer was primarily incorporated in the polymer chain through copolymerization. Among the dimer and the cross‐dimers from α‐methylstyrene with the other monomers, those bearing the α‐methylstyrene moiety in the α‐substituent [CH2C(X)CH2C(CH3)2C6H5, XCOOCH3, COOC2H5, and CN] are noted as highly reactive chain transfer agents. © 1994 John Wiley & Sons, Inc.
Synthesis and photochemical properties of solar energy storage‐exchange polymers containing pendant norbornadiene moieties
Authors: Nishikubo Tadatomi , Kameyama Atsushi , Kishi Katsuhiko , Mochizuki Yasushi 
Published: April 2003

AbstractNew photoresponsive polymers 1–4 containing pendant norbornadiene (NBD) moieties with N,N‐disubstituted amide groups were synthesized with 97, 98, 92, and 94% conversions by the substitution reaction of poly (p‐chloromethyl) styrene] with potassium salts of 3piperidyloxo‐2,5‐NBD‐2‐carboxylic acid, 3‐(NN‐dipropylcarbamoyl) ‐2,5‐NBD‐2‐carboxylic acid, 3‐(N‐methyl‐N‐phenylcarbamoyl)‐2,5‐NBD‐2‐carboxylic acid, and 3‐(N,N‐dipheylcarbmoyl)‐2,5‐NBD‐2‐carboxylic acid, respectively, using tetrabutylammonium bromide as a phase transfer catalyst for all. Polymers 1–4 with N,N‐disubstituted amide groups on the NBD moieties were sensitized by adding appropriate photosensitizers such as Michler's ketone and 4‐ (N,N‐dimethylamino) benzophenone in the film state, although the reactivities of the polymers without photosensitizer were lower than that of our previously reported polymer 5 containing pendant 3‐ (N‐phenylcarbamoyl) ‐2,5‐NBD‐2‐carboxylate moiety. It was also found that the photo‐irradiated retaining polymers 1–4 containing the corresponding QC moieties can be stored about 80–86 kJ/mol of their thermal energy. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of novel organonickel–organosilicon alternating copolymers
Authors: Guo X. Andrew , Hunter Allen D. , Chen Jie 
Published: April 2003

AbstractThe synthesis and characterization of five novel organonickel‐organosilicon alternating copolymers having the repeating unit C6F4Ni‘PBu3’2C6F4SiR2 [where SiR2 = SiMe2, SiMe‘Hex’, SiPh2, SiMe2OSiMe2, and SiMe2‘CH2’6SiMe2] are reported. The model compounds Ni‘PR3’2‘1,4‐C6F4SiMe3’2‘PR3 = PMePh2 or PBu3’ were prepared via reactions of Ni‘PR3’2‘1,4‐C6F4Li’2 with 2 equiv of SiMe3Cl, and were characterized by conventional analytical and spectroscopic measurements. The Polymers were prepared from the reactions of Ni‘PBu3’2‘1,4‐C6F4Li’2 with 1 equivalent of SiMe2Cl2 ‘polymer 1, Mw = 15,800’, SiMe ‘Hex’ Cl2 ‘polymer 2, Mw = 7300’, SiPh2Cl2 ‘polymer 3, Mw = 8600’, O‘SiMe2Cl’2 ‘polymer 4, Mw = 13,900’ and ‘CH2’6‘SiMe2Cl’2 ‘polymer 5, Mw = 19,700’. The molecular weights for each polymer were fully determined by both GPC and VPO. The multinuclear ‘1H‐, 19F‐, and 31P [1H]’‐NMR, FTIR, and UV‐Visible spectroscopic data for each polymer unambiguously establishes its repeating unit structure. The observations indicate that introduction of the silyl or siloxane units into the organonickel backbones has remarkably decreased the chain rigidity of the organonickel‐organosilicon polymers compared to their rigid rod organonickel analogues ‘i.e., [C6F4Ni‘PR3’2]n’. © 1994 John Wiley & Sons, Inc.
Kinetics for the catalyzed formation of poly(ethylene 2,6‐naphthalate) (PEN) by various metal compounds
Authors: Park Sang Soon , Im Seung Soon , Kim Dong Kook 
Published: April 2003

AbstractThe catalyzed transesterification between dimethyl 2,6‐naphthalate and ethylene glycol and polycondensation of bis (2‐hydroxyethyl) naphthalate have been investigated in the presence of various metal compounds as catalysts. The effect of the nature and concentration of these catalysts on both reactions has been studied. The observed overall rate of the transesterification was third order; first order with respect to dimethyl 2,6‐naphthalate, ethylene glycol, and the catalyst including initial concentration of catalyst, respectively. The decreasing order in catalytic activity on the transesterification was the order of Pb(II) > Zn(II) > Mn(II) > Co(II) > Ti(IV) > Sn(II) > Mg(II) > Ca(II) > Na(I) > Sb(III). And also, the decreasing order in catalytic activity on the polycondensation was found to be Ti(IV) > mixtures of Ti(IV) and Sb(III) > Sn(II) > Sb(III) > Co(II) > Zn(II) > Pb(II) > Mn(II) > Mg(II). © 1994 John Wiley & Sons, Inc.
Polyamides based on diamines and N, N′‐dimethyldiamines derived from biphenol
Authors: McCarthy T. F. , Lenz R. W. , Kantor S. W. 
Published: April 2003

AbstractAromatic‐aliphatic polyamides containing a biphenyl mesogen were prepared by both interfacial and solution polymerization reactions. Substitution of the amide nitrogen with methyl groups yielded polymers with significantly different properties than the unsubstituted polyamides. The methyl‐substituted polyamides had improved thermal stability, significantly lower meltin temperatures, and greater solubility in common solvents. Copolyamides were also synthesized which contained different flexible spacer units that varied in the number of methylene groups. No evidence for the presence of liquid crystalline phases could be obtained in either the unsubstituted polyamides or polyamides containing N‐methylated amide units. © 1994 John Wiley & Sons, Inc.
Synthesis, characterization, and polymerization of propenyl ether analogues
Authors: Crivello J. V. , Carter A. M. , Bratslavsky S. A. 
Published: April 2003

AbstractA series of aromatic monomers bearing cationically polymerizable propenyl groups were prepared and characterized using the readily available starting materials: isoeugenol and o‐allyl phenol. Monomers with both propenyl and vinyl ether functional groups were also synthesized by the reaction of these starting materials with chloroethyl vinyl ether. The reactivity of the resulting monomers in photoinitiated cationic polymerization was studied using differential scanning photocalorimetry and photogel point measurements. Their thermal properties were determined using thermogravimetric analysis. © 1994 John Wiley & Sons, Inc.
Synthesis and characterization of random semi‐flexible thermotropic liquid crystalline poly(ester‐imide)s
Authors: Adduci Jerry M. , Facinelli John V. , Lenz Robert W. 
Published: April 2003

AbstractA series of novel poly(ester‐imide)s were prepared by the reaction of meta‐ and para‐substituted trimellitimide dicarboxylic diacid chlorides with various diols containing four, five, six, seven, eight, nine, 10, and 12 methylene groups by a solution polymerization technique utilizing refluxing 1,2,4‐trichlorobenzene as a solvent. The poly(ester‐imide)s were characterized by dilute solution viscosity, infrared spectroscopy, differential scanning calorimetry, and polarized light microscopy. The inherent viscosities of the meta‐substituted poly(ester‐imide)s ranged from 0.06 to 0.25 dL/g while those of the para‐substituted poly(ester‐imide)s ranged from 0.10 to 0.65 dL/g and were obviously of higher molecular weight. The meta series were amorphous and showed no mesophase formation. All para‐substituted poly(ester‐imide)s exhibited monotropic mesophase identified as smecticAorder. © 1994 John Wiley & Sons, Inc.
Copolymerization of ethylene and 1‐butene with highly active Ticl4/THF/Mgcl2, Ticl4/THF/Mgcl2/SiO2, and TiCl3.1/3AlCl3 catalysts
Authors: Kim Jae Ha , Jeong Young Tae , Woo Seong Ihl 
Published: April 2003

AbstractHighly active catalysts for copolymerization have been prepared by the precipitation of MgCl2/ToCl4 complex with or without high surface area silica. Copolymerization of ethylene and 1‐butene has been tested by using the prepared catalysts at various concentrations of 1‐butene. The catalytic activities are 20–80 kg/g Ti h. The rate of copolymerization is strongly affected by the addition of 1‐butene. The decay rate of copolymerization is first order with respect to time. Analyses of copolymers with solvent extraction, DSC, IR, XRD, and NMR were performed. Ethylene reactivity ratio (k11) for TiCl4/MgCl2/THF catalyst is calculated to be about 26 by NMR spectrum. © 1994 John Wiley & Sons, Inc.
Synthesis of poly (ether‐sulfone‐amide)s by palladium‐catalyzed polycondensation of aromatic dibromides containing ether sulfone structure, aromatic diamines, and carbon monoxide
Authors: Ueda Mitsuru , Yokoo Takayoshi , Nakamura Takeo 
Published: April 2003

AbstractA general method for the preparation of aromatic poly (ether‐sulfone‐amide)s has been developed. Polymerization is based on the palladium‐catalyzed polycondensation of aromatic dibromides containing ether sulfone structural units, aromatic diamines, and carbon monoxide. Reactions were carried out in N, N‐dimethylacetamide (DMAc) in the presence of palladium catalyst, triphenylphosphine, and 1,8‐diazabicyclo [5,4,0]–7–undecene (DBU), and gave a series of poly (ether‐sulfone‐amide)s with inherent viscosities up to 0.86 dL/g under mild conditions. The polymers were quite soluble in strong acids, dipolar aprotic solvents, and pyridine. Thermogravimetry of the polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 470°C in air. The glass transition temperatures of the polymers were around 230°C, which are higher than those of poly (ether‐sulfone) analogues. These polymers also showed the good tensile strengths and tensile modulus. © 1994 John Wiley & Sons, Inc.
Alkali metal ion conductors based on sulfonated poly(p‐phenylene terephthalamide)
Authors: Foo Conrad , Kwei T. K. , Okamoto Yoshi , McBreen James , Lee H. S. 
Published: April 2003

AbstractTo obtain thermally stable and mechanically strong sodium and lithium conducting polymers, we prepared Na+ and Li+ poly(phenylene terephthalamide sulfonate salts) (MW ∼ 5500). We also synthesized oligo(ethylene oxide) (3, 5, or 7 units of ethylene oxide) substituted ethylene carbonate and poly[oxymethylene‐oligo(oxyethylene)]. These are high boiling point liquids with high dielectric constants as well as metal chelating properties. Polyelectrolyte systems were prepared by mixing Na+ or Li+ poly(phenylene terephthalamide sulfonate) salts with various amounts of modified ethylene carbonate and/or poly[oxymethylene‐oligo(oxyethylene)]. Films (0.1–0.5 mm thick) obtained from the blends were found to have considerable mechanical strength; forming free standing films. The ionic conductivities of the Na+ and Li+ polyelectrolyte systems were 10−6−10−5 S/cm at 25°C. Thermal properties of these blend systems were investigated in detail. © 1994 John Wiley & Sons, Inc.
Study on the thermotropic liquid crystalline polycarbonates. IV. Synthesis and properties of liquid crystalline poly(imide‐carbonate)s
Authors: Sun Shih–Jieh , Chang Teh–Chou 
Published: April 2003

AbstractTwo series of novel thermotropic liquid crystalline poly(imide‐carbonate)s were prepared by melt polycondensation from various arylene or alkylene bis(phenylcarbonate)s by using N,N′‐bis(hydroxyethyl)pyromellitimide and N,N′‐bis(hydroxypropyl)pyromellitimide as monomers. Thermotropic liquid crystalline properties were characterized by a polarizing microscope with a heating stage and a differential scanning calorimeter (DSC). Nematic melts were found for the synthesized aromatic poly(imide‐carbonate)s. In order to investigate whether the pyromellitimide unit could be used as a mesogenic unit for preparing LC polymers, a series of aliphatic poly(imide‐carbonate)s was prepared in this study. However, no significant LC textures were found under the observation by polarizing microscope. It was suggested that the aspect ratio of the pyromellitimide unit was too short to form liquid crystalline poly(imide‐carbonate)s. In addition, it was interesting that the aliphatic poly(imide‐carbonate)s with a longer spacer (n = 3) in the pyromellitimide unit showed better crystallinity. Thermostabilities of all synthesized poly(imide‐carbonate)s were measured by thermogravimetric analysis (TGA). © 1994 John Wiley & Sons, Inc.
Synthesis of polytitanosiloxanes and their transformation to SiO2–TiO2 ceramic fibers
Authors: Gunji Takahiro , Sopyan Iis , Abe Yoshimoto 
Published: April 2003

AbstractA one‐pot synthesis of polytitanosiloxanes (PTS) and its transformation to SiO2–TiO2 ceramic fibers were investigated. PTS was prepared by the hydrolysis of tetraethoxysilane followed by the reaction with bis(2,4‐pentanedionato)titanium diisopropoxide in methanol in 33–95 SiO2 mol %. PTS was considered to be a ladder‐ or sheet‐type polymer consisting of SiOSi and SiOTi linkages as a main chain with pendant hydroxyl and 2,4‐pentanedionato groups. SiO–TiO ceramic fibers were prepared by the pyrolysis of SiO2–TiO2 precursor fibers, which were prepared by the dry spinning of PTS followed by steam treatment. The tensile strength was 610 MPa for the SiO2–TiO2 fibers (SiO2/TiO2 = 20) after the pyrolysis at 7000C. © 1994 John Wiley & Sons, Inc.
The interaction of poly(methacrylate) radicals with diphenyldiacetylenes
Authors: Canizal Gerardo , Burillo Guillermina , Muñoz Eduardo , Gleason Roberto , Ogawa Takeshi 
Published: April 2003

AbstractThe free radical polymerization of methyl methacrylate (MMA) in the presence of p,p′‐ disubstituted diphenylbutadiynes was studied. Both the rate and degree of polymerization are somewhat lowered by the presence of the diynes, but the propagating radicals were stabilized giving clear ESR signals of the interacted polyMMA radicals at the polymerization temperature of 70°C. The magnitude of the interaction depended on the electron density of the diynes; in the cases of diphenylbutadiyne and dimethoxycarbonyldiphenylbutadiyne, the intoraction was more enhanced showing ESR signals with smaller spectra widths and increasing the number of radicals with the polymerization time, while in the cases of electron donor‐substituted diynes the interaction was weaker and the radical concentration remained constant during the polymerization. These systems are considered to be examples of the stabilization of transient radicals by the direct interaction of radicals with additives without formation or breaking of chemical bonds. No diacetylenic group was found in the polyMMA obtained. © 1994 John Wiley & Sons, Inc.
A novel catalyst system for the production of polyacetylene and of blends of polyacetylene with some silicon‐containing polymers
Authors: Graczyk Tomasz , Harrod John F. 
Published: April 2003

AbstractDimethyltitanocene, in conjunction with a wide variety of compounds containing SiH bonds, is an excellent catalyst for the polymerization of acetylene to give free standing films. Polymerizations of acetylene in a variety of siloxane and silane matrices using this catalyst system are described. The polyacetylenes produced with a [(MeSiHO)3(Me2Si)17]n random copolymer showed very similar properties to those previously produced by Naarman et al. with a Shirakawa‐type catalyst in a polydimethylsiloxane matrix. Ring, or chain, poly(methylhydrosiloxanes) with higher proportions of (MeSiHO) undergo redistribution in the course of acetylene polymerization to give polyacetylene embedded in an insoluble polysiloxane glass. Polyacetylene produced in a poly(phenylsilane) matrix yielded a 2‐component material from which the polysilane could not be solvent extracted. The electrical conductivity of iodine doped samples of this material is somewhat lower than that of the pure polyacetylene, but its mechanical properties and its resistance to degradative oxidation are superior to those of either of the pure component polymers. © 1994 John Wiley & Sons, Inc.
Temperature dependence of the interaction between water and sodium polymethacrylate in water–methanol mixture
Authors: Kim Hyun Gi , Jhon Mu Shik 
Published: April 2003

AbstractThe information for the interaction between water molecules and a polyelectrolyte was obtained from 23Na‐NMR studies for sodium polymethacrylate in water‐methanol mixtures. The chemical shift and the line width of the 23Na nucleus give the information on the immediate magnetic environment and the motion of the nucleus, respectively. The change of the chemical shift for 23Na nucleus is investigated by decreasing the temperature and changing the mol fraction of water in the solvent. According to these results, the hydrogen bonding of water molecules and polyanions becomes weaker as the temperature of the system decreases, but the interaction increases when the temperature is below the freezing point for water in this system. This effect, due to the change of temperature, becomes higher as the water mol fraction increases in the solvent. © 1995 John Wiley & Sons, Inc.
Synthesis of cross‐conjugated polyketones by the crossed‐aldol condensation of cyclic ketones with aromatic dialdehydes
Authors: Hudson Lilith Gentles , Stevens Malcolm P. 
Published: April 2003

AbstractInsoluble cross‐conjugated polyketones were prepared from terephthalaldehyde and a variety of cycloaliphatic ketones by the crossed‐aldol condensation. Elemental analyses and infrared spectra suggest that the polymeric aldol intermediates were not completely dehydrated. Evidence is also presented that suggests conjugate addition of the base to the α,β‐unsaturated ketone may occur. Soluble cross‐conjugated polyketones were prepared from terephthalaldehyde and 2‐indanone, which contains no beta hydrogens, and from cycloaliphatic ketones and 1,2‐bis(4‐formylphenoxy)ethane, a dialdehyde containing isolated aldehyde groups. It is proposed, therefore, that the lack of solubility in the terephthalaldehyde‐based polyketones arises from crosslinking via enolate anions formed at the beta position of the cyclic ketones, which are delocalized through the carbonyl groups of neighboring backbone repeating units. © 1995 John Wiley & Sons, Inc.
Reactivity ratios and microstructure determination of vinyl acetate–alkyl acrylate copolymers by NMR spectroscopy
Authors: Brar A. S. , Charan Shiv 
Published: April 2003

Abstract(Vinyl acetate)/(ethyl acrylate) (V/E) and (vinyl acetate)/(butyl acrylate) (V/B) copolymers were prepared by free radical solution polymerization. 1H‐NMR spectra of copolymers were used for calculation of copolymer composition. The copolymer composition data were used for determining reactivity ratios for the copolymerization of vinyl acetate with ethyl acrylate and butyl acrylate by Kelen‐Tudos (KT) and nonlinear Error in Variables methods (EVM). The reactivity ratios obtained are rv = 0.03 ± 0.03, rE = 4.68 ± 1.70 (KT method); rv = 0.03 ± 0.01, rE = 4.60 ± 0.65 (EV method) for (V/E) copolymers and rv − 0.03 ± 0.01, rB − 6.67 ± 2.17 (KT method); rv = 0.03 ± 0.01, rB = 7.43 ± 0.71 (EV method) for (V/B) copolymers. Microstructure was obtained in terms of the distribution of V‐ and E‐centered triads and V‐ and B‐centered triads for (V/E) and (V/B) copolymers respectively. Homonuclear 1H 2D‐COSY NMR spectra were also recorded to ascertain the existence of coupling between protons in (V/E) as well as (V/B) copolymers. © 1995 John Wiley & Sons, Inc.
119Sn‐NMR evidence for 2,1‐initiation in the anionic polymerization of butadiene with trialkyltin lithium
Authors: Hergenrother William L. , Doshak John M. , Brumbaugh Dennis R. , Bethea Tristram W. , Oziomek James 
Published: April 2003

AbstractLow molecular weight polybutadienes and styrene butadiene copolymers were anionically prepared with trialkyltin lithium initiator and end‐capped with either hydrogen or a trialkyltin group. These polymers were prepared with a variety of microstructures. Analysis by 119Sn‐NMR and comparison to model compounds showed no cis‐1,4‐initiation of the butadiene. The initiation sites found were trans‐1,4‐ and both 2,1‐ and 1,2‐additions of the tin‐lithium bound to a 1,3‐butadiene. At low levels of added polar modifier, the 2,1‐addition predominated. The 119Sn‐NMR spectra allowed the assignment of the sequence distribution associated with the nearest eight main chain carbon atoms (2‐4 monomer units) adjacent to the tin end groups. No initiation could be detected involving the styrene comonomer, but incorporation of styrene was detected as the first or second unit after initiation. The reaction of the allyl‐tin end groups of these polymers with 1,2‐napthoquinone was followed by NMR and was used to assign the peaks associated with 1,2‐addition of the trialkyltin lithium to 1,3‐butadiene. © 1995 John Wiley & Sons, Inc.
Poly(p‐Phenylenebenzobisoxazole) fiber with polyphenylene sulfide pendent groups
Authors: So Ying‐Hung , Bell Bruce , Heeschen Jerry P. , Nyquist Richard A. , Murlick Cheryl L. 
Published: April 2003

AbstractPoly(p‐phenylenebenzobisoxazole) (PBO) fiber with polyphenylene sulfide (PPS) pendent groups was made to improve PBO fiber compressive strength by crosslinking. PPS moieties allowed the polymeric network to crosslink at heat‐treatment temperatures at which PBO does not thermally degrade. PBO‐PPS fiber heat‐treated for 30 s at 600°C did not dissolve or break up in methanesulfonic acid. Compressive strength of crosslinked fiber was about 20% better than that of unmodified PBO fiber. In another experiment, 10 mol % of 2,5‐diphenylsulfideterephthalic acid was incorporated into PBO fiber. The side chain of one phenyl sulfide unit was too short to enhance crosslinking, and the fiber had about the same compressive strength as unmodified PBO fiber. © 1995 John Wiley & Sons, Inc.
Synthesis and characterization of segmented liquid crystal poly(azoxy polyester‐co‐polyoxypropylene)
Authors: Huang Jaine‐Ming , Kuo Jen‐Feng , Chen Chuh‐Yung 
Published: April 2003

AbstractIn this study a series of a segmented copolyester, poly(4,4′‐dioxy‐2,2′‐dimethyl‐azoxybenzene dodecanedioyl) (PMABD)‐co‐polyoxypropylene 400 (POP), was prepared. The chain length of PMABD studied (n) was varied from 7.8‐18.2, and that of POP was unchanged. The intrinsic viscosity of the segmented copolyesters was 1.04‐1.30, and the number average molecular weight obtained was 2.53 × 104−3.49 × 104 g/mol. The mesophase texture and thermal properties of the segmented copolyesters were measured as functions of n. It was found that the insert of flexible POP between those liquid crystalline domains of PMABD did affect thermotropic properties of PMABD. As the n value was 9.0 and 7.8 (or 7.4 and 8.6% by weight POP) the texture appeared as cholesteric‐like oily streaks. The effect could not be attained by simply copolymerizing a mesogenic moiety with a pair of spacers of different lengths. The fluidity and domain structure of the flexible dodecanedioyl‐POP‐dodcanedioyl segments are taken into account for the obtained results. © 1995 John Wiley & Sons, Inc.