bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation between Molecular Architecture, Morphology, and Deformation Behaviour of Styrene/Butadiene Block Copolymers
Authors: Adhikari Rameshwar , Michler Goerg H. , Huy Trinh An , Ivan'kova Elena , Godehardt Reinhold , Lebek Werner , Knoll Konrad 
Published: June 2004

AbstractThe correlation between the molecular architecture, morphology, and micromechanical deformation behaviour of styrene/butadiene (SB) block copolymers with different architectures (linear and star block copolymers, total styrene content, ΦST = 0.74) was studied using dynamic mechanical analysis (DMA), uniaxial tensile testing, scanning force microscopy (SFM), and high voltage electron microscopy (HVEM). Deformation of the individual phases under uniaxial strain at the molecular level was monitored by Fourier transform infrared (FT‐IR) spectroscopy. It was demonstrated that the morphology and deformation behaviour of these block copolymers are strongly influenced by their molecular topology, block symmetry, and the nature of the interface between the component blocks. While the cylindrical morphology (hexagonal polybutadiene (PB) cylinders in polystyrene (PS) matrix) was observed in a symmetric SBS triblock copolymer with ΦST = 0.74, a “two‐component three‐phase” morphology was found in an asymmetric star block copolymer having an equivalent chemical composition and an SBS arm structure. Likewise, an SBS triblock copolymer with a composition identical to the former ones but with highly asymmetric PS end blocks revealed a lamellar morphology. While no locally confined deformation zones were observed in the lamellar block copolymers, the cylindrical block copolymer was found to deform through the formation of highly localised craze‐like deformation zones.SFM phase images showing lamellae‐like morphology of the star block copolymer ST2, phase difference 25 degrees.imageSFM phase images showing lamellae‐like morphology of the star block copolymer ST2, phase difference 25 degrees.
Kinetic Investigation of the Condensation Reaction of Activated Ester–Amides Containing Oligo(oxyethylene) Segments
Authors: Solaro Roberto , Talamelli Paolo , Carbonaro Laura , Chiellini Emo 
Published: June 2004

AbstractThe kinetics of polycondensation of activated ester–amides, namely pentachlorophenyl α‐amino‐ω‐oligo(ethyleneglycol)succinate hydrochlorides (PSPnNH) having a degree of oligomerization n = 1–3, were investigated in solution in dichloromethane in the presence of excess triethylamine. The large extinction coefficient of the pentachlorophenate formed during the reaction allowed the use of the stopped flow technique. Experimental data resulted in agreement with the existence of concurrent first‐ and second‐order processes, attributable to the intramolecular cyclization and intermolecular polycondensation reactions, respectively. The relative incidence of the cyclization reaction decreased on increasing the monomer concentration and on decreasing the number of oxyethylene units in the monomer. These hypotheses were confirmed by SEC, TLC, FT‐IR, and NMR characterization of the reaction products. The kinetics of PSP3NH are in very good agreement with the predictions of both the collision theory and the condensation theory of linear systems at equilibrium. However, the behavior of shorter chain monomers was opposite to that of the theoretical one, demonstrating that other parameters, such as steric hindrance and solvent interactions, must be taken into proper account. The reported findings clearly evidenced that polymerization of the investigated ester‐amides must be performed in bulk in order to suppress the cyclization reaction and to obtain high‐molecular‐weight polymers.
SEC traces of PSP3NH condensation products obtained at different monomer concentrations (Runs P7–P9).imageSEC traces of PSP3NH condensation products obtained at different monomer concentrations (Runs P7–P9).
Copolymers from tert‐Butyl Methacrylate with Trimethylsilyl Methacrylate or Methacrylic Acid: Models for Resist Polymers
Authors: Ferbitz Jens , Mormann Werner 
Published: June 2004

AbstractFree radical copolymerisation of tert‐butyl methacrylate (1) with trimethylsilyl methacrylate (2) and methacrylic acid (3) has been investigated. Reactivity ratios for methacrylic acid and tert‐butyl methacrylate indicate an azeotropic copolymerisation (r1 = 0.476 ± 0.103; r3 = 0.300 ± 0.032), whereas the two esters show preferential incorporation of 2 (r1 = 0.170 ± 0.050; r2 = 1.170 ± 0.124). Thermal cis‐elimination of isobutylene from the tert‐butyl ester and subsequent formation of six‐membered cyclic anhydride moieties has been studied. For poly(methacrylic acid‐co‐tert‐butyl methacrylate) thermogravimetry could be used to determine copolymer composition. Solvolytic desilylation of the trimethylsilyl ester groups has been investigated as an alternative route to poly(methacrylic acid‐co‐tert‐butyl methacrylate). The tert‐butyl ester is not affected under the conditions of desilylation. Sequence distribution of both copolymers has been calculated using the method introduced by Bruns and Motoc.
Copolymer composition diagram for tert‐butyl methacrylate/methacrylic acid.imageCopolymer composition diagram for tert‐butyl methacrylate/methacrylic acid.
Cloud‐Point Pressure Curves of Ethene/Poly[ethylene‐co‐((meth)acrylic acid)] Mixtures
Authors: Buback Michael , Latz Henning 
Published: June 2004

AbstractEthene‐methacrylic acid (MAA) and ethene‐acrylic acid (AA) copolymers of narrow polydispersity and high chemical homogeneity have been synthesized at acid unit copolymer contents up to 9 mol‐% within a continuously operated stirred tank reactor at overall monomer conversions of about 2%. Cloud‐point pressures (CPPs) of mixtures of 3 wt.‐% copolymer in ethene (E) have been measured in an optical high‐pressure cell at pressures and temperatures up to 3 000 bar and 260 °C, respectively. The CPP weakly increases with acid copolymer content up to about 3.5 mol‐%. Toward higher acid contents, the CPP is strongly enhanced, in particular at the lower edge of the experimental temperature range at around 200 °C. This increase in CPP is more pronounced for the AA than for the MAA systems. The data suggest that hydrogen‐bonding interactions are operative in the pressurized E/poly(E‐co‐(M)AA) mixtures at temperatures of 260 °C and perhaps even above. E‐AA and E‐MAA copolymers with acid contents of about 5.6 mol‐% have also been completely methyl‐esterified to yield the associated methyl esters. The CPPs of the resulting E‐methyl acrylate and E‐methyl methacrylate copolymers in mixtures with E are significantly below the CPPs of the corresponding E/poly(E‐co‐(M)AA) systems.Cloud‐point pressure vs temperature curves for several E/poly(E‐co‐methacrylic acid) systems. The subscripts denote copolymer content in mol‐%. A cloud‐point pressure curve for E/polyethylene (PE) is included for comparison.imageCloud‐point pressure vs temperature curves for several E/poly(E‐co‐methacrylic acid) systems. The subscripts denote copolymer content in mol‐%. A cloud‐point pressure curve for E/polyethylene (PE) is included for comparison.
New Polymer Syntheses, 112
Authors: Kricheldorf Hans R. , Richter Martin , Steinmann Andreas , Schwarz Gert 
Published: June 2004

AbstractBis(4‐chlorophenyl)sebacate (BCPS) was polycondensed with 1,12‐diamino‐4,9‐dioxadodecane or with its bistrimethylsilyl derivative in three different solvents with variation of time and temperature. The highest molecular weights were obtained in dimethylsulfoxide at 60 °C. The highest fraction of cyclic polyamides was detected by MALDI‐TOF mass spectrometry in the samples with the highest molecular weights. Numerous polycondensations of BCPS and 1,13‐diamino‐4,7,10‐trioxatridecane were performed with variation of solvent, time and temperature. Again the best results were obtained in dimethylsulfoxide at 60 °C. The fraction of cyclic polyamides increased with higher average molecular weights of the samples. The MALDI‐TOF mass spectrum of the sample with the highest molar mass (Mn ca. 30 000 Da) exclusively displayed mass peaks of cycles (detected up to 13 000 Da). No side reactions were observed.
MALDI‐TOF mass spectrum (segment) of polyamide 1 prepared by polycondensation of DDD with BCPS in DMSO at 60 °C/48 h (no. 3, Table 1).imageMALDI‐TOF mass spectrum (segment) of polyamide 1 prepared by polycondensation of DDD with BCPS in DMSO at 60 °C/48 h (no. 3, Table 1).
Synchrotron X‐Ray Study of Liquid Crystalline Polyoxetanes Containing Two Mesogenic Groups Connected by a Flexible Spacer in the Side Chain
Authors: Campo Aránzazu del , Bello Antonio , Pérez Ernesto 
Published: June 2004

AbstractThe study of the mesophase behaviour of a family of new side chain liquid crystalline polymers by means of synchrotron X‐ray diffraction is reported. These systems contain two bibenzoate rigid units in the side chain that are interconnected through a flexible spacer. A polymerisable oxetane unit is linked to one end of the dimer structure, and a flexible terminal chain is linked to the other end. All the polymers form phases with variable degree of order (from low ordered smectic to crystalline) depending on the chemical constitution of the different segments. The influence of the length, parity, and lateral substitution of the spacers on the transitional parameters and the symmetry of the mesophases that are formed is analysed. Close similarities were found between the phase behaviour of the monomer precursors and the derived polyoxetanes. The arrangement of the mesogens, the flexible groups and the polymeric backbone in the layered structure is discussed with respect to the L/d ratio. Different values were obtained depending on the parity of the central spacer and on the degree of order of the mesophase. Interpenetrated structures, where the flexible groups of different lengths are mixed, seem to be compatible with low ordered smectic phases, but sterically disfavoured when building up highly ordered mesophases.
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Pressure Effects on the Thermodynamics of trans‐Decahydronaphthalene/Polystyrene Polymer Solutions: Application of the Sanchez‐Lacombe Lattice Fluid Theory
Authors: Jiang Shichun , An Lijia , Jiang Bingzheng , Wolf Bernhard A. 
Published: June 2004

AbstractThe cloud‐point temperatures (Tcl's) of trans‐decahydronaphthalene(TD)/polystyrene (PS, Mw = 270 000) solutions were determined by light scattering measurements over a range of temperatures (1–16 °C), pressures (100–900 bar), and compositions (4.2–21.6 vol.‐% polymer). The system phase separates upon cooling and Tcl was found to increase with rising pressure for constant composition. In the absence of special effects, this finding indicates positive excess volume for the mixing. Special attention was paid to the demixing temperatures as a function of pressure for different polymer solutions and the plots in the T‐ϕ plane (where ϕ signifies volume fractions). The cloud‐point curves of polymer solutions under different pressures were observed for different compositions, which demonstrated that pressure has a greater effect on the TD/PS solutions when far from the critical point as opposed to near the critical point. The Sanchez‐Lacombe lattice fluid theory (SLLFT) was used to calculate the spinodals, the binodals, the Flory‐Huggins (FH) interaction parameter, the enthalpy of mixing, and the volume changes of mixing. The calculated results show that modified PS scaling parameters can describe the thermodynamics of the TD/PS system well. Moreover the SLLFT describes the experimental results well.Pressure dependence of the phase transition temperature for the TD/PS polymer solutions at the indicated compositions (In SI units: 1 bar = 105 N · m−2).imagePressure dependence of the phase transition temperature for the TD/PS polymer solutions at the indicated compositions (In SI units: 1 bar = 105 N · m−2).
Polyacetylenes Bearing Mesogenic Side Groups: Synthesis and Properties, 2
Authors: Stagnaro Paola , Conzatti Lucia , Costa Giovanna , Gallot Bernard , Tavani Cinzia , Valenti Barbara 
Published: June 2004

AbstractWe report on the synthesis of novel liquid crystalline polyacetylenes derived from monosubstituted acetylene monomers. In the monomers A1OBP‐Acn obtained from 3‐bromo‐1‐propyne, the acetylenic moiety is linked through a very short spacer to a biphenyl mesogenic core. Several linear acyl groups of different length are introduced as tail groups. Most of the monomers show liquid crystalline behavior. Polymerizations are carried out in solution with typical metathesis catalysts based on Mo and W and yield polyacetylenes with fairly high molecular weight (MW), soluble in common organic solvents. Polymers PA1OBP‐Acn are fully characterized in terms of molecular structure, by GPC, FT‐IR, NMR and UV/VIS techniques, and of thermal and morphological behavior, by TGA, DSC, POM and X‐ray diffraction experiments. THF solutions of the polymers show a quite relevant photoluminescence with a broadened maximum located around 450 nm.POM analysis on monomer A1OBP‐Ac6: crystal transformation on heating at 76 °C.imagePOM analysis on monomer A1OBP‐Ac6: crystal transformation on heating at 76 °C.
The Effect of Phase Structure on the Tribological Properties of PA66/HDPE Blends
Authors: Chen Zhao‐Bin , Li Tong‐Sheng , Yang Yu‐Liang , Zhang Yu , Lai Shi‐Quan 
Published: June 2004

AbstractSummary: In this paper, immiscible, partially miscible and miscible blends of polyamide 66 (PA66) and high density polyethylene (HDPE) were obtained by changing compatibilizer concentrations. Mechanical and tribological properties of materials were tested. It was found that the addition of compatibilizer greatly improved the mechanical properties of PA66/HDPE blends. The wear of PA66/HDPE blends was strongly affected by the phase structure. The best blend for lower friction coefficient and higher wear resistance was the blend with a miscible structure, which significantly improved the tribological properties of PA66 and HDPE. SEM investigations on the worn surface and the steel counterface indicated that, for the immiscible and partially miscible blend systems, the dispersed HDPE particles were pulled out from the worn surfaces during sliding because of the poor adhesion between HDPE and PA66, while this was not observed in the miscible blend system.SEM micrograph of the worn surface formed by PA66/HDPE blend without HDPE‐g‐MAH.magnified imageSEM micrograph of the worn surface formed by PA66/HDPE blend without HDPE‐g‐MAH.
Kinetic Study of Hindered Amine Light Stabilizer Photografting in Poly(propylene) Films under Natural Weathering and Accelerated UV Conditions: Effect of Additive Concentration
Authors: Kaci Mustapha , Hebal Ghania , Touati Naima , Rabouhi Aida , Zaidi Lynda , Djidjelli Hocine 
Published: June 2004

AbstractFull Paper: The objective of this work is aimed at determining the kinetics of HALS photografting in PP films as a function of the additive concentration under both natural weathering and accelerated UV conditions. The stabilizer studied had a single structure that combined HALS and a UV absorbing unit detectable at 308 nm in the UV spectrum of PP, capable of inducing a photoreaction with the polymer matrix. The kinetics of HALS photografting on PP films at various additive concentrations was determined by direct spectroscopic measurements on film samples through the absorption band of the stabilizer positioned at 308 nm in the UV spectra, which was attributed to the highly conjugated methylenic double bond. The content of free HALS was determined as a function of exposure time by UV spectroscopy for all the additive concentration ratios used. It is shown that the kinetics of HALS photografting increase with a decrease in the additive concentration ratio. The whole grafting process under conditions of natural weathering occurred in the PP film after almost 350 h of exposure, while approximately 20 h were necessary under accelerated UV conditions. Moreover, these kinetics are well described by a third order polynomial model, validated by a maximum value of the coefficient of correlation close to unity. This was also confirmed by a comparison of the time values measured at 50% of the total grafting calculated from the model with those observed experimentally. This finding was consistent with the data obtained on the free HALS content determined by UV spectroscopy.The percentage of HALS photografting in PP films as a function of time under natural weathering, determined by UV spectroscopy.magnified imageThe percentage of HALS photografting in PP films as a function of time under natural weathering, determined by UV spectroscopy.
The Reinforcement of Elastomeric Networks by Fillers
Authors: Bokobza Liliane 
Published: June 2004

AbstractSummary: The mechanisms involved in rubber reinforcement are discussed. A better molecular understanding of these mechanisms can be obtained by combining characterization of the mechanical behavior with an analysis of the chain segmental orientation accompanying deformation. While the strain dependence of the stress is the most common quantity used to assess the effect of filler addition, experimental determination of segmental orientation can be used to quantify the interfacial interactions between the elastomeric matrix and the mineral inclusions.SEM micrograph of natural rubber containing 10 wt.‐% of organomodified clay.magnified imageSEM micrograph of natural rubber containing 10 wt.‐% of organomodified clay.
Some properties of monotone rearrangement with applications to elliptic equations in cylinders
Authors: Berestycki H. , Lachand‐Robert T. 
Published: June 2004

AbstractThis paper is concerned with properties and applications of monotone rearrangement as defined in [18]. Unlike the Schwarz and Steiner symmetrization, in the monotone rearrangement framework, the inequality for the Dirichlet integral holds for all functions in H1 (not only H10). Further, we state and prove a necessary and sufficient condition for equality to hold in this inequality.These properties allow us to give several applications of monotone rearrangement to semilinear elliptic equations. We study such problems in cylinders with general boundary conditions (Neumann, mixed and Robin type). For these problems, we establish the existence of solutions which are monotone in one direction. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enveloppes polynômiales d'ensembles compacts invariants
Authors: Bou Attour Latifa , Faraut Jacques 
Published: June 2004

AbstractWe consider the following problem: letVℂbe a finite dimensional vector space, andUbe a compact group of ℂ‐linear automorphisms ofVℂ. The polynomial envelope$ \hat Q $of a compact setQ⊂Vℂis defined aswhere 𝒫(Vℂ) denotes the space of holomorphic polynomial functions onVℂ. The problem is to determine the polynomial envelope of a compact set which isU‐invariant. We solve the problem whenUis the isotropy subgroup at the origin of the automorphism group of a bounded symmetric domain of tube type. The case of a domain of type II has been solved by C. Sacré [1992], and, for a domain of type IV, it has been solved by L. Bou Attour [1993]. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Locally boundedly A‐p‐convex algebras
Authors: El Kinani A. , Oudadess M. 
Published: June 2004

AbstractWe consider locally p‐convex algebras the bornologies of which coincide with the ones of p‐normed or multiplicatively p‐convex topologies. Two new classes of these algebras are introduced here. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The finite Hilbert transform and weighted Sobolev spaces
Authors: Elliott David , Okada Susumu 
Published: June 2004

AbstractThe boundedness of the finite Hilbert transform operator on certain weighted Lp spaces is well known. We extend this result to give the boundedness of that operator on certain weighted Sobolev spaces. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Slow and fast convergence to local dimensions of self‐similar measures
Authors: Olsen L. 
Published: June 2004

AbstractLetKandμbe the self‐similar set and the self‐similar measure associated with an iterated function system with probabilities (Si, pi)i=1,…,Nsatisfying the Open Set Condition. Let Σ = {1, …,N}ℕdenote the full shift space and letπ: Σ →Kdenote the natural projection. The (symbolic) local dimension ofμatω∈ Σ is defined by$ \lim _{n} { {\log \mu K _{\omega \vert n}} \over {\log {\rm diam} \, K_{\omega \vert n} } } $whereKω|n=S○ … ○S(K) forω=ω1ω2… ∈ Σ, and the (symbolic) multifractal spectrum ofμis defined bywhere dim denotes the Hausdorff dimension. In this paper we study the speed with which the ratio$ { {\log \mu K _{\omega \vert n}} \over {\log {\rm diam} \, K_{\omega \vert n} } } $converges. In particular, we prove that for all (sufficiently large) speedsγ, the set of pointsfor which the ratio log$ { {\log \mu K _{\omega \vert n}} \over {\log {\rm diam} \, K_{\omega \vert n} } } $converges to its limit with speed equal toγ, has full dimension. i.e.(© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On many‐sorted algebraic closure operators
Authors: Climent Vidal Juan , Soliveres Tur Juan 
Published: June 2004

AbstractA theorem of Birkhoff‐Frink asserts that every algebraic closure operator on an ordinary set arises, from some algebraic structure on the set, as the corresponding generated subalgebra operator. However, for many‐sorted sets, i.e., indexed families of sets, such a theorem is not longer true without qualification. We characterize the corresponding many‐sorted closure operators as precisely the uniform algebraic operators. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A remark on the Riemann‐Hilbert problem with a vanishing coefficient
Authors: Virtanen J. A. 
Published: June 2004

AbstractThis paper concerns the existence of nontrivial solutions of the Riemann‐Hilbert problem with a continuous coefficient whose values belong to two rays in the complex plane. Our results extend those recently obtained by E. Shargorodsky and J. F. Toland [6]. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of the Atmosphere on the Reactivity of Peroxidic Species upon Photooxidation of Polymers
Authors: Fraïsse Frédéric , Kumar Ashutosh , Commereuc Sophie , Verney Vincent 
Published: June 2004

AbstractSummary: This paper gives an account of preliminary results about the impact of an oxidative atmosphere on peroxidation. Attention is focused on the level, nature, and reactivity of (hydro)peroxides with respect to the oxidative component concentration. Our main result is surprising: a lower peroxidation rate occurs, but a higher content of hydroperoxides are formed in air than in pure oxygen atmospheres. The results may lead to an approach to understand the influence of atmospheric factors on the outdoor weathering of polymers.The device used to measure the oxygen uptake of the systems studied here.imageThe device used to measure the oxygen uptake of the systems studied here.
Novel Biodegradable Copolymers with a Periodic Sequence Structure Derived from Succinate Butan‐1,4‐diol, and Butan‐1,4‐diamine
Authors: Abe Hideki , Doi Yoshiharu 
Published: June 2004

AbstractSummary: Novel biodegradable copolymers derived from succinate, butan‐1,4‐diol, and butan‐1,4‐diamine were synthesized by two‐step polycondensation reactions. The obtained copolymers had a periodical‐sequence structure consisting of ester and amide units, and the melting temperatures of the periodic copolymers increased with an increase in amide content. The crystalline structure of the periodic copolymers differs from that of butylene succinate homopolymer (PBS), and these results suggest that the periodically introduced amide units are included in the crystalline phase forming a novel crystalline structure.Periodic copolyester‐amides derived from succinate, butane‐1,4‐diol, and butan‐1,4‐diaminemagnified imagePeriodic copolyester‐amides derived from succinate, butane‐1,4‐diol, and butan‐1,4‐diamine