bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of soluble polyimides derived from 2′,5′‐bis(3,4‐dicarboxyphenoxy)‐p‐terphenyl dianhydride
Authors: Hsiao Sheng‐Huei , Chung Cheng‐Lin , Lee Mei‐Ling
Published: January 2004

A novel bis(ether anhydride) monomer, 2′,5′‐bis(3,4‐dicarboxyphenoxy)‐p‐terphenyl dianhydride, was synthesized from the nitro displacement of 4‐nitrophthalonitrile by the phenoxide ion of 2′,5′‐dihydroxy‐p‐terphenyl, followed by alkaline hydrolysis of the intermediate bis(ether dinitrile) and cyclodehydration of the resulting bis(ether diacid). A series of new poly(ether imide)s bearing laterally attached p‐terphenyl groups were prepared from the bis(ether anhydride) with various aromatic diamines via a conventional two‐stage process that included ring‐opening polyaddition to form the poly(amic acid)s followed by thermal or chemical imidization to the poly(ether imide)s. The inherent viscosities of the poly(amic acid) precursors were in the range of 0.62–1.26 dL/g. Most of the poly(ether imide)s obtained from both routes were soluble in polar organic solvents, such as N,N‐dimethylacetamide. All the poly(ether imide)s could afford transparent, flexible, and strong films with high tensile strengths. The glass‐transition temperatures of these poly(ether imide)s were recorded as between 214 and 276 °C by DSC. The softening temperatures of all the poly(ether imide) films stayed in the 207–265 °C range according to thermomechanical analysis. For all the polymers significant decomposition did not occur below 500 °C in nitrogen or air atmosphere. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1008–1017, 2004
Controlled, radical reversible addition–fragmentation chain‐transfer polymerization in high‐surfactant‐concentration ionic miniemulsions
Authors: McLeary J. B. , Tonge M. P. , de Wet Roos D. , Sanderson R. D. , Klumperman B.
Published: January 2004

Living free‐radical polymerization of methacrylate and styrenic monomers with ionic surfactants was carried out with reversible addition–fragmentation chain transfer in miniemulsion with different surfactant types and concentrations. The previously reported problem of phase separation was found to be insignificant at higher surfactant concentrations, and control of the molar mass and polydispersity index was superior to that of published miniemulsion systems. Cationic and anionic surfactants were used to examine the validity of the argument that ionic surfactants interfere with transfer agents. Ionic surfactants were suitable for miniemulsion polymerization under certain conditions. The colloidal stability of the miniemulsions was consistent with the predictions of a specific model. The living character of the polymer that comprised the latex material was shown by its transformation into block copolymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 960–974, 2004
Synthesis and characterization of new, soluble polyazomethines bearing fluorene and carbazole units in the backbone and solubility‐improving moieties in the side group
Authors: Kim Hyun‐Chul , Kim Jong‐Seong , Kim Kie‐Soo , Park Hong‐Ki , Baek Sungsik , Ree Moonhor
Published: January 2004

A series of novel, soluble polyazomethines bearing fluorene and carbazole moieties in the main chain and solubility‐improving moieties in the side group (dibutyl, ethylhexyl, thienylethyloxy, furyl, and fluorenyl) were synthesized. Good‐quality films of these polymers were prepared through the conventional solution‐casting and drying processes. Depending on the polymer structure, some polymers showed a glass‐transition temperature (107–167 °C) and others showed a melting temperature (285–341 °C). The temperature of 5% weight loss under nitrogen atmosphere of the polymers ranged from 370 to 464 °C. The results indicated that the side groups incorporated into the polyazomethine structure in this work improved the polymer solubility without sacrificing thermal stability. Depending on the polymer structure, some of the polymers were crystalline whereas others were amorphous. All the polyazomethines were solution‐processable and thermally stable, making them potential candidate materials for applications in microelectronics and aerospace. Moreover, the features in the UV–visible spectra of the polyazomethines were redshifted as compared with those of the monomers from which the polymers were synthesized, indicating that these polymers, if combined with an appropriate doping agent to improve the light‐emitting and conducting abilities, may be good candidate materials for optoelectronic devices. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 825–834, 2004
Polymerization of 1,3‐dienes with functional groups. III. Free‐radical polymerization of N,N‐diethyl‐2‐methylene‐3‐butenamide
Authors: Yaegashi Takayuki , Yodoya Shinya , Nakamura Masahiko , Takeshita Hiroki , Takenaka Katsuhiko , Shiomi Tomoo
Published: January 2004

Free‐radical homo‐ and copolymerization behavior of N,N‐diethyl‐2‐methylene‐3‐butenamide (DEA) was investigated. When the monomer was heated in bulk at 60 °C for 25 h without initiator, rubbery, solid gel was formed by the thermal polymerization. No such reaction was observed when the polymerization was carried out in 2 mol/L of benzene solution with with 1 mol % of azobisisobutyronitrile (AIBN) as an initiator. The polymerization rate (Rp) equation was Rp ∝ [DEA]1.1[AIBN]0.51, and the overall activation energy of polymerization was calculated 84.1 kJ/mol. The microstructure of the resulting polymer was exclusively a 1,4‐structure where both 1,4‐E and 1,4‐Z structures were included. From the product analysis of the telomerization with tert‐butylmercaptan as a telogen, the modes of monomer addition were estimated to be both 1,4‐ and 4,1‐addition. The copolymerizations of this monomer with styrene and/or chloroprene as comonomers were also carried out in benzene solution at 60 °C. In the copolymerization with styrene, the monomer reactivity ratios obtained were r1 = 5.83 and r2 = 0.05, and the Q and e values were Q = 8.4 and e = 0.33, respectively. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 999–1007, 2004
Synthesis of four‐armed poly(ε‐caprolactone)‐block‐poly(ethylene oxide) by diethylzinc catalyst
Authors: Deng Mingxiao , Chen Xuesi , Piao Longhai , Zhang Xuefei , Dai Zhongli , Jing Xiabin
Published: January 2004

Biodegradable, amphiphilic, four‐armed poly(ϵ‐caprolactone)‐block‐poly(ethylene oxide) (PCL‐b‐PEO) copolymers were synthesized by ring‐opening polymerization of ethylene oxide in the presence of four‐armed poly(ϵ‐caprolactone) (PCL) with terminal OH groups with diethylzinc (ZnEt2) as a catalyst. The chemical structure of PCL‐b‐PEO copolymer was confirmed by 1H NMR and 13C NMR. The hydroxyl end groups of the four‐armed PCL were successfully substituted by PEO blocks in the copolymer. The monomodal profile of molecular weight distribution by gel permeation chromatography provided further evidence for the four‐armed architecture of the copolymer. Physicochemical properties of the four‐armed block copolymers differed from their starting four‐armed PCL precursor. The melting points were between those of PCL precursor and linear poly(ethylene glycol). The length of the outer PEO blocks exhibited an obvious effect on the crystallizability of the block copolymer. The degree of swelling of the four‐armed block copolymer increased with PEO length and PEO content. The micelle formation of the four‐armed block copolymer was examined by a fluorescent probe technique, and the existence of the critical micelle concentration (cmc) confirmed the amphiphilic nature of the resulting copolymer. The cmc value increased with increasing PEO length. The absolute cmc values were higher than those for linear amphiphilic block copolymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 950–959, 2004
Synthesis and characterization of polyethylene/clay–silica nanocomposites: A montmorillonite/silica‐hybrid‐supported catalyst and in situ polymerization
Authors: Wei Liangming , Tang Tao , Huang Baotong
Published: January 2004

A novel approach to the preparation of polyethylene (PE) nanocomposites, with montmorillonite/silica hybrid (MT‐Si) supported catalyst, was developed. MT‐Si was prepared by depositing silica nanoparticles between galleries of the MT. A common zirconocene catalyst [bis(cyclopentadienyl)zirconium dichloride/methylaluminoxane] was fixed on the MT‐Si surface by a simple method. After ethylene polymerization, two classes of nanofillers (clay layers and silica nanoparticles) were dispersed concurrently in the PE matrix and PE/clay–silica nanocomposites were obtained. Exfoliation of the clay layers and dispersion of the silica nanoparticles were examined with transmission electron microscopy. Physical properties of the nanocomposites were characterized by tensile tests, dynamic mechanical analysis, and DSC. The nanocomposites with a low nanofiller loading (<10 wt %) exhibited good mechanical properties. The nanocomposite powder produced with the supported catalyst had a granular morphology and a high bulk density, typical of a heterogeneous catalyst system. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 941–949, 2004
Synthesis and structural characterization of novel, fluorinated poly(phthalazinone ether)s containing perfluorophenylene moieties
Authors: Lu Zhaoqiang , Cheng Lin , Li Jun , Zhang Kai , Yi Song , Qin Jingui
Published: January 2004

The synthesis and structural characterization of a series of novel, fluorinated poly(phthalazinone ether)s containing perfluorophenylene moieties are described. The monomers, 4‐(4′‐hydroxyaryl)phthalazin‐1(2H)‐ones (2a–2d), were conveniently and efficiently synthesized from phenols and phthalic anhydride in two steps via 2‐(4′‐hydroxybenzoyl)benzoic acids, which were first obtained by the Friedel–Crafts reaction in good yields and with high stereoselectivity and were then converted into 2a–2d by fusion with hydrazine. All the polymers were prepared by nucleophilic aromatic substitution (SNAr) polycondensation between the compounds perfluorobiphenyl and 4‐(4′‐hydroxyaryl)phthalazin‐1(2H)‐ones (2a‐2d). The resulting fluorinated polymers were readily soluble in common organic solvents (e.g., CHCl3, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, N‐methylpyrrolidone, etc.) at room temperature. Their weight‐average molecular weights and the polydispersities ranged from (7.96–18.25) × 103 to 1.31–2.71, respectively. Their glass‐transition temperatures varied from 213 to 263 °C. They were all stable up to 390 °C both in air and in argon. The 5% weight‐loss temperatures of these polymers in air and argon ranged from 393–487 to 437–509 °C, respectively. Wide‐angle X‐ray diffraction studies indicated they were all amorphous and could be attributed to the presence of kink nonplanar moiety, phenyl phthalazinone along the polymer backbone. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 925–932, 2004
Generation of highly stable amidate anion in anionic polymerization of 3‐(triethylsilyl)propyl isocyanate
Authors: Ahn Jun‐Hwan , Lee Choon‐Hwa , Shin Yeong‐Deuk , Lee Jae‐Suk
Published: January 2004

To study living anionic polymerization, 3‐(triethylsilyl)propyl isocyanate (TEtSPI) monomer was synthesized by hydrosilylation of allylamine with triethylsilane and treatment of the resulting amine with triphosgene. The polymerization of TEtSPI was performed with sodium naphthalenide (Na‐Naph) as an initiator and in the absence and presence of sodium tetraphenylborate (NaBPh4) as an additive in tetrahydrofuran (THF) at −78 and at −98 °C. A highly stabilized amidate anion for living polymerization of isocyanates was generated for the first time with the combined effect of the bulky substituent and the shielding action of the additive NaBPh4, extending the living character at least up to 120 min at −98 °C. Even the anion could exist at −78 °C for 10 min. A block copolymer, poly(n‐hexyl isocyanate)‐b‐poly[(3‐triethylsilyl)propyl isocyanate]‐b‐poly(n‐hexyl isocyanate), was synthesized with quantitative yields and controlled molecular weights via living anionic polymerization in THF at −78 °C for TEtSPI and −98 °C for n‐hexyl isocyanate, respectively, with Na‐Naph with three times of NaBPh4 as a common ion salt. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 933–940, 2004
Polymer–silicate nanocomposites produced by in situ atom transfer radical polymerization
Authors: Zhao Hanying , Argoti S. Dayana , Farrell Brendan P. , Shipp Devon A.
Published: January 2004

Polymer–silicate nanocomposites were synthesized with atom transfer radical polymerization (ATRP). An ATRP initiator, consisting of a quaternary ammonium salt moiety and a 2‐bromo‐2‐methyl propionate moiety, was intercalated into the interlayer spacings of the layered silicate. Subsequent ATRP of styrene, methyl methacrylate, or n‐butyl acrylate with Cu(I)X/N,N‐bis(2‐pyridiylmethyl) octadecylamine, Cu(I)X/N,N,N′,N′,N″‐pentamethyldiethylenetriamine, or Cu(I)X/1,1,4,7,10,10‐hexamethyltriethylenetetramine (X = Br or Cl) catalysts with the initiator‐modified silicate afforded homopolymers with predictable molecular weights and low polydispersities, both characteristics of living radical polymerization. The polystyrene nanocomposites contained both intercalated and exfoliated silicate structures, whereas the poly(methyl methacrylate) nanocomposites were significantly exfoliated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 916–924, 2004
Filler‐polymer interactions of styrene and butadiene units in silica‐filled styrene–butadiene rubber compounds
Authors: Choi Sung‐Seen , Kim Ik‐Sik , Lee Seung Goo , Joo Chang Whan
Published: January 2004

Styrene–butadiene rubber (SBR) is a copolymer of styrene and butadiene, and the butadiene unit is composed of cis‐1,4‐, trans‐1,4‐, and 1,2‐components. Filler‐polymer interactions of each component of SBR in silica‐filled SBR compounds were examined by microstructure analysis of the bound and unbound rubbers. The composition ratio of butadiene and styrene units (butadiene/styrene) of the bound rubber was higher than that of the compounded rubber. Of the butadiene units, the 1,2‐component of the bound rubber was more abundant than the cis‐1,4‐ and trans‐1,4‐components. The filler‐polymer interaction of the butadiene unit with silica was stronger than that of the styrene unit, and the interaction of the 1,2‐component was stronger as compared with the others. The butadiene–styrene ratio of the bound rubber of the compounds containing the silane coupling agent was lower than for the compounds without the silane. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 577–584, 2004
Studies of photooxidative degradation of poly(vinyl chloride)/poly(ethylene oxide) blends
Authors: Kaczmarek H. , Kowalonek J. , Klusek Z. , Pierzgalski S. , Datta S.
Published: January 2004

The photooxidative degradation of blends (in a full range of compositions) of amorphous poly(vinyl chloride) (PVC) with semicrystalline poly(ethylene oxide) (PEO) in the form of thin films is investigated using absorption spectroscopy (UV–visible and Fourier transform infrared) and atomic force microscopy (AFM). The amount of insoluble gel formed as a result of photocrosslinking is estimated gravimetrically. It is found that the PVC/PEO blendsí susceptibility to photooxidative degradation differs from that pure of the components and depends on the blend composition and morphology. Photoreactions such as degradation and oxidation are accelerated whereas dehydrochlorination is retarded in blends. The photocrosslinking efficiency in PVC/PEO blends is higher than in PVC; moreover, PEO is also involved in this process. AFM images showing the lamellar structure of semicrystalline PEO in the blend lead to the conclusion that the presence of PVC does not disturb the crystallization process of PEO. The changes induced by UV irradiation allow the observation of more of the distinct PEO crystallites. This is probably caused by recrystallization of short, more mobile chains in degraded PEO or by partial removal of the less stable amorphous phase from the film surface. These results confirm previous information on the miscibility of PVC with PEO. The mechanism of the interactions between the components and the blend photodegradation are discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 585–602, 2004
Thermophysical properties of polypropylene/aluminum composites
Authors: Boudenne Abderrahim , Ibos Laurent , Fois Magali , Gehin Evelyne , Majeste Jean‐Charles
Published: January 2004

This article is dedicated to the study of the thermal parameters of composite materials. A nonlinear least‐squares criterion is used on experimental transfer functions to identify the thermal conductivity and the diffusivity of aluminum‐polymer composite materials. The density measurements were achieved to deduce the specific heat and thereafter they were compared to values given by differential scanning calorimetry measurement. The thermal parameters of the composite material polypropylene/aluminum were investigated for the two different types of aluminum filler sizes. The experimental data were compared with several theoretical thermal conductivity prediction models. It was found that both the Agari and Bruggeman models provide a good estimation for thermal conductivity. The experimental values of both thermal conductivity and diffusivity have shown a better heat transport for the composite filled with large particles. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 722–732, 2004
Phase ripening in particulate binary polymer blends
Authors: Cheng Mary Hongying , Nauman E. B.
Published: January 2004

Particulate polymer‐in‐polymer mezodispersions show a pronounced increase in the size of the dispersed particles during melt‐phase annealing. Three ripening mechanisms have been proposed: Brownian coalescence, Ostwald ripening, and hydrodynamic coarsening. The modified Cahn–Hilliard equation predicts growth by Ostwald ripening and diffusion‐induced coalescence. Simulations of this mechanism show a self‐similar particle size distribution, but the distribution broadens with the increasing volume fraction of the minor phase. Hydrodynamic coarsening caused by concentration gradients and random Brownian forces has been simulated according to the hydrodynamic model. The simulations show that concentration‐driven hydrodynamics have little effect on the particle size distribution. Experiments have been performed to investigate the relative importance of these ripening mechanisms for polybutadiene in a polystyrene system. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 603–612, 2004
Shear banding in strained semicrystalline polyamide 6 films as revealed by atomic force microscopy: Role of the amorphous phase
Authors: Ferreiro V. , Coulon G.
Published: January 2004

Atomic force microscopy (AFM) has been used to visualize the plastic deformation mechanisms that are responsible for the yielding of semicrystalline polymers of low degree of crystallinity (<50%). Indeed, AFM, if operated in suitable conditions, is able to image both the amorphous and the crystalline phases. Polyamide 6 films have been drawn at temperatures T < 160 °C. Postmortem AFM observations show that, at yield, shear bands nucleate and propagate in the amorphous phase. They cross the crystalline lamellae and run over the whole surface of the sample. By crossing the lamellae, they form nanoblocks of uniform size. Neither the size of the nanoblocks nor the angle between the tensile axis and the shear bands can be explained in terms of crystal plasticity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 687–701, 2004
Diffraction grating in noncrosslinked polymers
Authors: Kim Eun Hee , Kim Byung Kyu
Published: January 2004

The diffraction efficiency and morphology of the transmission modes of holographic polymer dispersed liquid crystals were studied with respect to the molecular structure of poly(urethane acrylate) (PUA), the film (polymer/liquid crystal) and resin (oligomer/monomer) compositions, and the cell thickness. PUA, based on N‐vinylpyrrolidone and ethyl hexyl acrylate, with low‐molecular‐weight poly(propylene glycol) at a low oligomer content, showed high diffraction efficiency. The results were interpreted in terms of the monomer reactivity and polymer elasticity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 613–620, 2004
Thermally stimulated currents of poly(methyl methacrylate): Comments on the molecular origin of a Debye‐type signal between the α‐ and β‐relaxation modes
Authors: Kalogeras Ioannis M.
Published: January 2004

Several variants of thermally stimulated currents (TSCs) have been used to characterize an unusual room‐temperature (RT) Debye‐type relaxation mode (denoted β′) recorded in the TSC spectra of radically polymerized atactic poly(methyl methacrylate) with a high syndio‐triad content. The β′ signal is sensitive to variations in the adsorbed water content, the time of isothermal aging, and probably the presence of nonpolymerized monomers, unreacted initiator molecules, and radicals. Its molecular origin is extensively discussed under the assumption of the dipole reorientation of carboxymethyl side groups presenting hydrogen‐bond interactions with adsorbed water molecules. An alternative explanation involves the relaxation of polar side groups that experience rotational hindrance through van der Waals and electrostatic interactions by ionic or molecular impurities. A preliminary analysis of the low‐frequency ϵ″(f) spectrum (recorded at RT) suggests that the dielectric relaxation spectroscopy manifestation of the TSC β′ signal, when present, may possibly be confused with structural relaxation losses induced by high‐temperature thermal treatments. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 702–713, 2004
Rheological and thermal study of delayed crystallization in poly(butylene terephthalate)/ethylene‐co‐ethyl acrylate blends
Authors: Huitric J. , Pillin I. , Moan M. , Pimbert S.
Published: January 2004

The effects of the composition and resulting morphology on the crystallization and rheology of blends containing poly(butylene terephthalate) (PBT) and an ethylene‐co‐ethyl acrylate (EEA) copolymer, two immiscible polymers, were studied over the entire range of volume fractions. Differential scanning calorimetry (DSC) thermograms recorded during cooling showed important differences, mainly in terms of the PBT crystallization temperatures, depending on the blend composition. In addition to the classical crystallization peaks of PBT and EEA, a third crystallization peak appeared for blends containing less than 60% PBT. This peak was attributed to a delayed crystallization of PBT. This phenomenon was examined in terms of homogeneous crystallization. Linear viscoelastic measurements allowed the delayed crystallization behavior in these polymer blends to be displayed. Indeed, the variation of the storage modulus with the temperature showed increasing steps during cooling. These sudden increases appeared at temperatures very close to those at which the crystallization peaks were observed in the DSC experiments. This behavior was verified for different blend compositions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 714–721, 2004
Structure and coordination properties of facilitated olefin transport membranes consisting of crosslinked poly(vinyl alcohol) and silver hexafluoroantimonate
Authors: Kim Jong Hak , Min Byoung Ryul , Won Jongok , Kim Chang Kon , Kang Yong Soo
Published: January 2004

The high selectivity of solid‐state crosslinked poly(vinyl alcohol) (CPVA) membranes containing silver hexafluoroantimonate (AgSbF6), with respect to olefin/paraffin mixtures, was previously reported. The structure and coordination properties of CPVA/AgSbF6 complexes were investigated in this study with wide‐angle X‐ray scattering (WAXS), differential scanning calorimetry (DSC), X‐ray photoelectron spectroscopy (XPS), and theoretical ab initio calculations, and they were compared with those of poly(vinyl alcohol) (PVA)/AgSbF6 complexes. Contrary to expectations, the measurements of the intersegmental d‐spacings and glass‐transition temperatures indicated that the chain mobility in the PVA/AgSbF6 membranes was lower than that in the CPVA/AgSbF6 membranes. The different extents of transient crosslinking in the two systems were attributed mostly to their different coordination structures; silver ions in PVA/AgSbF6 were coordinated with hydroxyl oxygens located near the polymer main chains, whereas those in CPVA/AgSbF6 were coordinated with aldehyde oxygens located far from the main chains. According to WAXS spectra, AgSbF6 was completely dissolved in both PVA and CPVA, and this disrupted the crystallinity of the polymers. However, our DSC study showed that the silver ions dissolved in both polymer matrices recrystallized into silver oxide at elevated temperatures. The binding energy of Ag3d5/2, as determined from XPS spectra, shifted to lower values with the addition of increasing amounts of the polymer matrix, indicating the increasing coordination of silver ions with polymer chains. The presence of various oxygen species with and without coordination to silver ions was confirmed from O1s XPS spectra of CPVA membranes containing silver ions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 621–628, 2004
Miscibility behavior and hydrogen bonding in blends of poly(vinyl phenyl ketone hydrogenated) and poly(2‐ethyl‐2‐oxazoline)
Authors: Maldonado‐Santoyo M. , Ortíz‐Estrada C. , Luna‐Bárcenas G. , Sanchez I. C. , Cesteros L. C. , Katime I. , Nuño‐Donlucas S. M.
Published: January 2004

The miscibility behavior of poly(2‐ethyl‐2‐oxazoline) (PEOx)/poly(vinyl phenyl ketone hydrogenated) (PVPhKH) blends was studied for the entire range of compositions. Differential scanning calorimetry and thermomechanical analysis measurements showed that all the PEOx/PVPhKH blends studied had a single glass‐transition temperature (Tg). The natural tendency of PVPhKH to self‐associate through hydrogen bonding was modified by the presence of PEOx. Partial IR spectra of these blends suggested that amide groups in PEOx and hydroxyl groups in PVPhKH interacted through hydrogen bonding. This physical interaction had a positive influence on the phase behavior of PEOx/PVPhKH blends. The Kwei equation for Tg as a function of the blend composition was satisfactorily used to describe the experimental data. Pure‐component pressure–volume–temperature data were also reported for both PEOx and PVPhKH. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 636–645, 2004
Completely biodegradable composites of poly(propylene carbonate) and short, lignocellulose fiber Hildegardia populifolia
Authors: Li X. H. , Meng Y. Z. , Wang S. J. , Rajulu A. Varada , Tjong S. C.
Published: January 2004

The composites of biodegradable poly(propylene carbonate) (PPC) reinforced with short Hildegardia populifolia natural fiber were prepared by melt mixing followed by compression molding. The mechanical properties, thermal properties, and morphologies of the composites were studied via static and dynamic mechanical measurements, thermogravimetric analysis, and scanning electron microscopy (SEM) techniques, respectively. Static tensile tests showed that the stiffness and tensile strength of the composites increased with an increasing fiber content. However, the elongation at break and the energy to break decreased dramatically with the addition of short fiber. The relationship between the experimental results and the compatibility or interaction between the PPC matrix and fiber was correlated. SEM observations indicated good interfacial contact between the short fiber and PPC matrix. Thermogravimetric analysis revealed that the introduction of short Hildegardia populifolia fiber led to a slightly improved thermooxidative stability of PPC. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 666–675, 2004
Thermal, crystallization, mechanical, and rheological characteristics of poly(trimethylene terephthalate)/poly(ethylene terephthalate) blends
Authors: Supaphol Pitt , Dangseeyun Nujalee , Thanomkiat Pakin , Nithitanakul Manit
Published: January 2004

Blends of poly(trimethylene terephthalate) (PTT) and poly(ethylene terephthalate) in the amorphous state were miscible in all of the blend compositions studied, as evidenced by a single, composition‐dependent glass‐transition temperature observed for each blend composition. The variation in the glass‐transition temperature with the blend composition was well predicted by the Gordon–Taylor equation, with the fitting parameter being 0.91. The cold‐crystallization (peak) temperature decreased with an increasing PTT content, whereas the melt‐crystallization (peak) temperature decreased with an increasing amount of the minor component. The subsequent melting behavior after both cold and melt crystallizations exhibited melting point depression behavior in which the observed melting temperatures decreased with an increasing amount of the minor component of the blends. During crystallization, the pure components crystallized simultaneously just to form their own crystals. The blend having 50 wt % of PTT showed the lowest apparent degree of crystallinity and the lowest tensile‐strength values. The steady shear viscosity values for the pure components and the blends decreased slightly with an increasing shear rate (within the shear rate range of 0.25–25 s−1); those of the blends were lower than those of the pure components. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 676–686, 2004
Oniom (MP2:PM3) study of C60–water complex
Authors: Fomina Lioudmila , Reyes Abraham , Guadarrama Patricia , Fomine Serguei
Published: January 2004

The ONIOM (MP2:PM3) model in combination with local implementation of MP2 single‐point energy evaluation was used to model the C60–water complex. In agreement with experimental data, stabilization of the complex can be described in terms of interaction between the lone electron pair of water oxygen and π*‐orbitals of fullerene with electron correlation being the most important contribution to the complex stabilization. It was found that for qualitatively correct description of C60–water complex geometry it is essential to have at least 12 carbon atoms of C60 molecule and water molecule in high MP2 ONIOM layer and use a basis set of at least 6‐31+G(d,p) quality. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Localized molecular orbitals for excited states of polyenals, polyendials, and polyenones
Authors: Pitarch‐Ruiz J. , Evangelisti S. , Maynau D.
Published: January 2004

The work is focused on the generation of localized molecular orbitals for excited states. A recently developed a priori method based in a CAS‐SCF–type algorithm is applied. The method generates directly localized orbitals and can be applied to multireference wavefunctions. A detailed description of the performance of the method as well as the locality of the MOs for the example of the singlet n→π* (CO) excited state is given. It is in general possible to obtain local orbitals for the doubly occupied and virtual valence orbitals. The partial delocalization of the π* (CO) orbital is discussed, as is the effect of the use of different CAS spaces. The systems under study are polyenals, polyendials, and polyenones where the π* (CO) orbital interacts with the rest of the π system. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Isolation of Amylose from Starch Solutions by Phase Separation
Authors: Kim Sanghoon , Willett Julious L.
Published: January 2004

Conventionally, fractionation of the two components of starches, amylopectin and amylose had been achieved by aqueous dispersion or aqueous leaching of granules, and selective retrogradation or alcohol precipitation of amylose. Recently, we found that starch solutions show the same phase behavior as the pseudo‐binary system polystyrene/poly(butadiene) in dioctylphthalate solution. By choosing proper temperature, concentration, and solvent medium, vertical phase separation could be induced in starch solutions. In this article, we show that construction of the phase dia‐gram of the two components of starch solutions provides us with a new simple method for isolating amylose from starch solutions.
Solid State NMR and X‐ray Studies on Amylose Complexes with Small Organic Molecules
Authors: Kawada Jumpei , Marchessault Robert H.
Published: January 2004

Crystalline complexes of amylose with lauric acid, n‐butanol, n‐pentanol, dimethyl sulfoxide and thymol were examined by 13C CP/MAS NMR and X‐ray diffraction methods. The complexes displayed the single helix V‐amylose structure and were heat stable at least up to 90 °C. In addition, the X‐ray diffraction pattern of the amylose‐n‐butanol complex was similar to that of the amylose‐n‐pentanol complex which is interpreted to mean that the guest agents are not present in crystallographic register. It is suggested that the guests are in a matrix, of crystal surfaces, dislocations and chain folds, such that only the amylose chains contribute to the observed crystalline diffraction patterns. After humidification, the NMR spectra showed partial transformation to the double helix B‐polymorph for all complexes except that formed with lauric acid. The transformation is dependent on the alkyl chain length of guest agents. Once the double helix polymorph was formed, it was permanent unless the sample was redissolved.
NC12H8(NH)2[Gd(N3C12H8)4] und [Gd(N3C12H8)3(N3C12H9)]·PhCN: Ein Beitrag zur Reaktivität und Kristallchemie homoleptischer Selten‐Erd‐Pyridylbenzimidazolate
Authors: Müller‐Buschbaum Klaus , Quitmann Catharina C.
Published: January 2004

Farblose, transparente Kristalle von NC12H8(NH)2[Gd(N3C12H8)4] konnten in solvensfreier Synthese durch Reaktion von Gd‐Metall mit einer 2‐(2‐Pyridyl)‐Benzimidazol‐Schmelze, sowie transparente, zartgelbe Kristalle der Verbindung [Gd(N3C12H8)3(N3C12H9)]·PhCN aus der thermalen Weiterreaktion von NC12H8(NH)2[Gd(N3C12H8)4] mit Benzonitril erhalten werden. Beide Verbindungen zeigen homoleptische, reine N‐Koordinationen nur der Pyridylbenzimidazolat‐Liganden um Gadolinium; die PhCN Moleküle koordinieren nicht. Während NC12H8(NH)2[Gd(N3C12H8)4] jedoch salzartig und aus (NC12H8(NH)2)+‐ und [Gd(N3C12H8)4]—‐Ionen aufgebaut ist, zeigt [Gd(N3C12H8)3(N3C12H9)]·PhCN einen molekularen Aufbau aus ungeladenen [Gd(N3C12H8)3(N3C12H9)]‐Einheiten.
Zur Kristallchemie der Oxoplatinate
Authors: Müller‐Buschbaum Hanskarl
Published: January 2004

Die Kristallchemie der Oxoplatinate wird mit Blick auf die Koordination von Pt2+ und Pt4+ systematisiert. Allein Pt2+ zeigt im Festkörper eine charakteristische quadratisch planare Koordination, die es mit anderen Elementen, wie Cu2+, Pd2+, Ni2+, teilt. Relativ oft treten gemischte Valenzen (Pt2+/Pt4+) in planarer Sauerstoffkoordination auf. Außerordentlich selten ist dagegen eine hantelförmige O—Pt2+—O‐Koordination. Die Kristallchemie von Pt4+ ähnelt zahllosen oktaedrisch koordinierten Metallionen, und spielt am Aufbau der kristallinen Oxoplatinate nur gelegentlich eine erkennbare Rolle. Es gibt erstaunliche Verwandtschaften der Polyederverknüpfungsmuster bei grundsätzlich verschiedenen Zusammensetzungen, wie an den Beispielen BaLn2PtO5, Ba3Cu2Ln2PtO10, Ba5Ln8Zn4O21, Ba13Ln8Zn4Pt4O37 und Ba17Ln16Zn8Pt4O57 erläutert wird. Ferner wird gezeigt, daß Ba4Sm4Zn3PtO15 mit Ba6Nd2Al4O15 und Ba4NaCu0, 5Pt1, 5O8 mit Ba15Pt6O27 isotyp ist. An Oxoplatinaten mit Elementen, die sterisch wirksame Elektronenpaare enthalten, werden einseitig offene Polyeder beobachtet. Die Positionen der stereochemisch aktiven Elektronenpaare werden mit Berechnungen der Coulomb‐Terme der Gitterenergie ermittelt.
Neue Heteropolyanionen des Wolframs mit Vanadium(IV) als Heteroatom
Authors: Drewes D. , Limanski E. M. , Piepenbrink M. , Krebs B.
Published: January 2004

Die Synthesen zweier neuer Heteropolyanionen mit Vanadium als Heteroatom werden vorgestellt. Sie wurden vollständig durch Röntgenstrukturanalysen sowie IR‐ und Ramanspektroskopie charakterisiert. Die Verbindung ((CH3)4N)6Na4[(VO(H2O)2)2(WO2)2(BiW9O33)2]·18H2O (1) kristallisiert im triklinen Kristallsystem (P1¯) mit a = 13, 299(3)Å, b = 13, 554(3)Å, c = 18, 620(4)Å und α = 90, 22(3)°, β = 91, 99(3)°, γ = 119, 16(3)°. Na5, 4K6, 6[(VO)3(AsW9O33)2]·29H2O (2) kristallisiert in der hexagonalen Raumgruppe P63/mmc mit den Zellkonstanten a = 15, 124(3)Å und c = 24, 209(5)Å.

Das Polyanion in 1 ist isostrukturell zu Anionen des sogenannten M2X2W20‐Typs mit anderen Heteroatomen. Sie sind aus zwei β‐B‐[XW9O33]‐Fragmenten aufgebaut, die sich von Defektstrukturen des Keggin‐Anions ableiten lassen. Diese Untereinheiten sind über zwei WO2‐Gruppen zwei weitere M(H2O)3‐Gruppen (M = Übergangsmetall)verknüpft und bilden so den M2X2W20‐Typ aus. Das Anion in 2 ist ein neuer Vertreter des M3X2W18‐Typs, in dem zwei α‐B‐[XW9O33]‐Einheiten über einen Ring aus drei Übergangsmetallatomen verknüft sind.
The Nature of the Colour Centres in ‘Maya Blue’ — the Incorporation of Organic Pigment Molecules into the Palygorskite Lattice
Authors: Reinen D. , Köhl P. , Müller C.
Published: January 2004

It is shown by optical spectroscopy that indigo molecules, most likely incorporated into the channels of the palygorskite host structure, are the solely colour centres in the ancient Maya Blue pigment — in use during the Maya cultural period in Yucatan and Guatemala. This study also shows that the blue colour of solid indigo shifts toward turquoise and greenish hues when fastened to the host; it is suggested that the corresponding spectral modifications originate from the energy when single indigo molecules undergo hydrogen bonding with the hydroxy‐groups in the channels (or in the open channels on the surface). Indeed artefacts from the Maya culture exhibit rather greenish than pure blue colours.

Similarly a tetrachloro‐derivative of thioindigo forms hydrogen bonds with palygorskite, as evidenced by an again distinct colour change from red‐violet to blueish‐violet. Bulkier pigment molecules bearing hydroxy‐groups, such as anthrachinon derivatives, seem to directly react with the host surface, but without producing very significant colour shifts.
[Mn(H2O)2]4[HNC5H4(COO)]2[C6H2(COO)4]2·4H2O — Ein dreidimensionales Koordinationspolymer mit Gastwassermolekülen in kanalartigen Hohlräumen
Authors: Köferstein Roberto , Robl Christian
Published: January 2004

Einkristalle von [Mn(H2O)2]4[HNC5H4(COO)]2[C6H2(COO)4]2·4H2O wurden in wässeriger Lösung bei 55 °C erhalten. Raumgruppe P1¯ (Nr. 2), a = 999.7(2), b = 1314.4(2), c = 1645.8(2) pm, α = 101.096(8)°, β = 92.796(14)°, γ = 96.03(2)°, V = 2.1053(5) nm3, Z = 2. Die vier kristallographisch unabhängigen Mn2+ sind verzerrt oktaedrisch von zwei Wassermolekülen, drei Sauerstoffatomen der Pyromellitatanionen und einem Sauerstoffatom aus dem Isonicotinsäuremolekül umgeben (Mn—O 208.6(2) — 227.3(3) pm). Aus der Verbindung von Mn2+ mit [C6H2(COO)4]4— resultiert ein dreidimensionales Koordinationspolymer mit zwei unterschiedlichen kanalartigen Hohlräumen, die sich entlang [110] erstrecken und einerseits von Wassermolekülen sowie andererseits durch Isonicotinsäuremoleküle ausgefüllt werden. Bei der thermogravimetrischen Untersuchung an Luft erfolgte die Kristallwasserabgabe in zweiStufen zwischen 97 und 200 °C. Das Anhydrid war zwischen 200 und 340 °C stabil. Die weitere Zersetzung führte zu Mn3O4.
Präparation und Charakterisierung von PbBr2·C4H10O3 (Diethylenglykol)
Authors: Oldag Thorsten , Keller Hans‐Lothar
Published: January 2004

Structural Chemistry of PbBr2·C4H10O3 (Diethyleneglycol)

Crystals of PbBr2·C4H10O3 have been synthesized and structurally characterized by single‐crystal X‐ray diffraction. PbBr2·C4H10O3 crystallizes monoclinic in space group P21/n (No. 14) with a = 9.370(1)Å, b = 10.045(1)Å, c = 21.090(1)Å, β = 98.98(1)° and Z = 8.

The compound contains compact Pb—Br groups, which build colums parallel to [0 1 0] direction by Hydrogen Bonding.
Raman Investigation of the Low Temperature Phase Transitions in Monoclinic TlReO4
Authors: de Waal Danita , Kiefer Wolfgang
Published: January 2004

The Raman spectrum of monoclinic TlReO4 is presented together with a factor group analysis and assignment of the bands. The phase transitions of monoclinic TlReO4 is investigated below room temperature, and two phase transitions were identified between room temperature and 90 K. The room temperature monoclinic phase was converted to the orthorhombic phase at 170 K upon cooling, and to the tetragonal phase at 150 K. Upon heating back to room temperature the tetragonal phase persisted until the orthorhombic phase could be identified at 210 K and 220 K. From 230 K to room temperature the monoclinic phase could again be observed.
Structure and Bonding of the Mixed‐Valent Platinum Trihalides, PtCl3 and PtBr3
Authors: von Schnering Hans Georg , Chang Jen‐Hui , Freiberg Maria , Peters Karl , Peters Eva‐Maria , Ormeci Alim , Schröder Liane , Thiele Gerhard , Röhr Caroline
Published: January 2004

The isotypical crystal structures of the mixed valent trihalides PtCl3 and PtBr3 were redetermined by single crystal methods (space group R3¯; trigonal setting; PtCl3: a = 21.213Å, c = 8.600Å, c/a = 0.4054; Z = 36; 1719 hkl; R = 0.035; PtBr3: a = 22.318Å, c = 9.034Å; c/a = 0.4048; Z = 36; 1606 hkl; R = 0.027). A cubic closest packing of X— anions forms the basis of an optimized arrangement of cuboctahedrally [Pt6X12] cluster molecules with PtII and enantiomers of helical chains of edge‐condensed [PtX2X4/2] octahedra with PtIV in cis‐Δ‐ and cis‐Λ‐configuration, respectively. The bond lengths vary with the function of the X— ligands (d¯(PtII—X) = 2.315 and 2.445Å; d¯(PtII—PtII) = 3.336 and 3.492Å; d(PtIV—X) = 2.286 — 2.417Å and 2.437 — 2.563Å). The PtII atoms are shifted outwards the X12 cuboctahedra by 0.045Å and 0.024Å, respectively. The symmetry governed Periodic Nodal Surface, PNS, perfectly separates the regions of different valencies. Quantum chemical calculations exclude the possible additional interactions between PtII and one of the exo‐ligands of PtIV.
Synthese und Kristallstruktur der Monoammoniakate von Lithiumhalogeniden: LiBr·NH3 und LiI·NH3
Authors: Jacobs Herbert , Friedriszik Martin
Published: January 2004

Für röntgenographische Strukturbestimmungen geeignete Kristalle von LiBr·NH3 und von LiI·NH3 wurden durch Umsetzung von Li mit NH4Br bzw. LiH mit NH4I bei 523 K bzw. 423 K in Autoklaven erhalten. An Kristallen ermittelte Zellparameter sind:

LiBr·NH3: P21/n, a = 7, 077(2)Å, b = 7, 026(2)Å, c = 7, 490(2)Å β = 114, 84(3)°, Z = 4

LiI·NH3: P21, a = 4, 493(1)Å, b = 6, 077(1)Å, c = 7, 512(2)Å β = 107, 15(3)°, Z = 2

Die Ammoniakate sind unterschiedlich aufgebaut. Beide enthalten Schichten verknüpfter Tetraeder Li(NH3)X3/3 mit X = Br, I. Beim Bromid treten Tetraederdoppeleinheiten mit einer Br‐Br Kantenverknüpfung auf, während beim Iodid alle Tetraeder ausschließlich über Iodatome zu gewellten Schichten eckenverknüpft sind. IR‐ und Raman‐spektroskopische Messungen zeigen, dass schwache H‐Brücken N‐H···X vorliegen und dass die NH3‐Liganden bei Raumtemperatur lagefixiert sind.
Alkalimetallbismutide ABi und ABi2 (A = K, Rb, Cs) — Synthesen, Kristallstrukturen, Eigenschaften
Authors: Emmerling Franziska , Längin Nina , Petri Denis , Kroeker Martin , Röhr Caroline
Published: January 2004

Die Zintlphasen ABi (A = K/Rb/Cs; monoklin, Raumgruppe P21/c, a = 1422.3(2)/1474.2(2)/1523.7(3), b = 724.8(1)/750.2(1)/773.7(1), c = 1342.0(2)/1392.1(2)/1439.9(2) pm und β = 113.030(3)/113.033(2)/112.722(3)°, Z = 16) kristallisieren im β‐CsSb Strukturtyp und enthalten Ketten zweibindiger Bi—‐Atome. Es handelt sich damit und nach den berechneten elektronischen Strukturen um Halbleiter mit kleinen Bandlücken von ca. 0.5 eV. Dagegen sind die Phasen ABi2 (A = K/Rb/Cs; kubisch, Raumgruppe Fd3¯m, a = 952.1(2)/962.4(8)/972.0(3) pm, Z = 8) Laves‐Phasen und zeigen entsprechend typische metallische elektronische Leitfähigkeiten und keine Bandlücken.
Synthese von dreidimensional geordneten Einlagerungsverbindungen des Hectorits
Authors: Breu Josef , Seidl Wolfgang , Senker Jürgen
Published: January 2004

Durch die Einlagerung großer kationischer Abstandshalter wie 1, 4‐Dimethyl‐1, 4‐diazabicyclo[2.2.2]oktan (DDABCO2+) in synthetischen Cs‐Fluorohectorit wurde ein mikroporöses Material („pillared clay”︁) hergestellt. Dieser Kationenaustausch verläuft unter geeigneten Bedingungen vollständig und unter Phasenerhalt. Ausgehend von einem dreidimensional (3D) geordneten [1], ladungshomogenen [2] Cs‐Hectorit ist es so zum ersten Mal gelungen, eine einkristalline und 3D geordnete Einlagerungsverbindung eines Smectits zu synthetisieren und über Einkristallstrukturverfeinerung strukturell zu charakterisieren ([DDABCO0.25]zwi[Mg2.5Li0.5]okt[Si4]tetO10F2 , monoklin, C2/m, a = 5.2635(9) Å, b = 9.1278(14) Å, c = 13.984(3) Å, β = 96.89 (2)°, V = 667.0(2) Å3, Z = 2). Die organischen Zwischenschichtkationen überbrücken, ähnlich wie Cs+ in der Ausgangsverbindung, den Zwischenschichtraum in definierter Weise, indem sie auf beiden Seiten in die Vertiefungen der Silicatoberfläche greifen und die hexagonalen Kavitäten genau gegenüber anordnen. Die Zwischenschichtkationen sind dabei mit ihrer C3‐Achse in der Ebene der Zwischenschicht orientiert.
Synthesis and Crystal Structure of the Hydrogen Polyphosphide Bis(Tetraphenylphosphonium) hydrogenheptaphosphide‐ammonia(1/3) (PPh4)2HP7 · 3NH3
Authors: Aschenbrenner Jürgen C. , Korber Nikolaus
Published: January 2004

(PPh4)2HP7 · 3NH3 was prepared by the reaction of K3P7 with a proton‐charged ion exchange resin in the presence of (PPh4)Br in liquid ammonia, and characterized by low temperature X‐ray structure analysis. The thermally very unstable compound contains the hydrogenheptaphosphide anion HP, the nortricyclane‐like cage of which is slightly distorted by the attachment of the hydrogen atom.
A disordered microstructure material model based on fractal geometry and fractional calculus
Authors: Carpinteri A. , Chiaia B. , Cornetti P.
Published: January 2004

Fractal patterns often arise in the failure process of materials with a disordered microstructure. It is shown that they are responsible of the size effects on the parameters characterizing the material behaviour in tensile tests (i.e. the strength, the fracture energy, and the critical displacement). Based on fractal geometry, a simple model of a generic disordered material is set. The physical quantities describing the stress‐strain state of such fractal medium are pointed out. They show anomalous (non integer) physical dimensions. In terms of these fractal quantities, it is possible to define a fractal cohesive law, i.e. a constitutive law describing the tensile failure of an heterogeneous material, which is scale invariant. Then we propose new mathematical operators from fractional calculus to handle the fractal quantities previously introduced. In this way, the static and kinematic (fractional) differential equations of the model are pointed out. These equations form the basis of the mechanics of fractal media. In this framework, the principle of virtual work is also obtained.
Micropolar fluid flow due to rotating and oscillating circular cylinder: 6th order numerical study
Authors: Kamal M.A. , Siddiqui A.Z.A.
Published: January 2004

The ‘time‐marching study’ of non‐steady flow around a rotating and oscillating circular cylinder of a viscous incompressible micropolar fluid, for low values of Keulegan‐Carpenter number Kc and different values of Stokes parameter β is being undertaken. In the present studies we have investigated the Magnus effects on stirring or orbital flow for different values of rotation parameter α in the range 0 to 4.5 at various time levels. In this numerical attempt we have adopted the scheme, which consists of two steps. In the first step a 4th order special finite‐difference method is used to approximate the constitutive equations. This method transforms the governing partial differential equations to a system of finite‐difference equations, which are solved numerically by S.O.R. iterative method. In the second step, the results obtained are further refined and upgraded by Richardson's extrapolation method. That is why this scheme yields the sixth order accurate solution. To check the accuracy of the results these results are compared on five different grid sizes. The results compare very well.