bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photosensitive organosilicon polymers for microlithographic application
Authors: Inoue Takashi , Sugiyama Hisashi , Nate Kazuo , Mizushima Akiko 
Published: March 2011

AbstractTwo new families of photosensitive organo‐silicon polymers are described. One is based on the Si‐Si σ‐bond photochemistry and another is based on the combinations of new alkaline‐soluble organosilicon polymers with diazoquinone photosensitizers. Both of these photoactive materials not only give positive photoresist formulations but can act as oxygen reactive ion etch masks in the double‐layer resist scheme to finally offer steep submicrometer organic patterns with high aspect ratio.
The application of holographic techniques to kinetic studies of photopolymerization reactions
Authors: Lougnot Daniel , Carré Christiane , Fouassier Jean‐Pierre 
Published: March 2011

AbstractThe holographic techniques are applied to the kinetic study of a photopolymerization reaction under steady state illumination. A theoretical approach of this problem is introduced which allows the intrinsic initiating activity of several amine‐derived radicals to be determined.
Network formation by chain crosslinking photopolymerization and some applications in electronics
Authors: Kloosterboer J. G. , Lijten G. F. C. M. , Boots H. M. J. 
Published: March 2011

AbstractTwo applications of photopolymerization are described, viz. the replication of optical discs and the manufacturing of aspherical lenses, used for the read‐out of these discs. The development of these and similar processes has required a thorough understanding of the formation of densely crosslinked networks. Results on the evolution of crosslink density with conversion, the delay of shrinkage with respect to conversion and the occurrence and modelling of inhomogeneous network formation are presented.
Fabrication of microstructures with extreme structural heights by reaction injection molding
Authors: Hagmann P. , Ehrfeld W. , Vollmer H. 
Published: March 2011

AbstractFor fabrication of microstructures with extreme structural heights a reaction injection micromolding process has been developed. It uses mold inserts produced by deep‐etch X‐ray lithography and electroforming which have superior surface quality with a surface roughness Rmax of less than 0.02 μm. For methyl methacrylate base casting resins in combination with an internal mold release agent the molding conditions have been optimized on a laboratory‐scale reaction injection molding machine and correlated with thermomechanical measurements. It has been demonstrated by many experiments that in spite of minimum lateral dimensions of only some micrometers and structural heights of some hundred micrometers a yield of approximately 100 % can be obtained in the micromolding process. This new process may be applied for producing innovative microstructure products, e.g. in the fields of sensors, packaging and interconnection in microelectronics, filtration, microoptics and synthetic fibers.
Functional liquid‐crystalline polyesters based on twin nonamethylene spaced p‐oxybenzoate dyads and dithiols
Authors: Angeloni A. S. , Chiellini E. , Galli G. , Laus M. , Torquati G. 
Published: March 2011

AbstractA new series of thermotropic liquid‐crystalline poly‐(ester‐β‐sulphide)s 9Sn was prepared by reacting the mesogenic nona‐methylene bis[4‐(4‐acryloyloxybenzoyloxy)benzoate] 1 with α,ω‐alka‐nedithiols of varying length. The polymers exhibit nematic and smectic mesophases, which are enantiotropic or monotropic in character, depending on the number n of methylene units in the dithiol precursor (n = 2–10). The phase transition parameters were determined and compared with those of closely related poly(ester‐β‐sulphide)s 6Sn. It is suggested that these systems may be suitable model polymers to test current theory of the existence of highly anisotropic or weakly anisotropic mesophases in polymers.
Electrical studies of heat resistant polymers
Authors: Oraison J. M. , Boiteux G. , Seytre G. , Rabilloud M. , Senneron M. , Sillion B. 
Published: March 2011

AbstractThe present necessity to use heat resistant materials in electronics justify the scientific interest in different heterocyclic polymers. This paper is especially concerned with their applications as dielectric films. The processing to obtain thin films of a polyphenylquinoxaline, a polyhydantoïne and a poly(hydantoïne ‐ imide) was examined and the resulting polymers were characterized thermally and electrically for large ranges of temperature and frequency.
Submillimeter infrared spectroscopy of fluorinated polymers ‐ phase transition study
Authors: Latour M. , Faria R. M. , Moreira R. L. 
Published: March 2011

AbstractSubmillimeter infrared technique is used to study the phase transitions in poly(vinylidene fluoride) homopolymer and copolymers with trifluorethylene. During the phase transition form II to form I, induced by copolymerization, electrical or mechanical stresses, the spectra show an important increasing of the submillimeter absorption. This behavior is explained by changes of the polarizability at phase transition.
Thermal and chemorheological modelling of the processing of advanced epoxy based composites
Authors: Kenny J. M. , Apicella A. , Nicolals L. 
Published: March 2011

AbstractA general model for the prediction of the rheological behavior of epoxy resins during the processing of epoxy based laminates is presented. The model is able to predict the temperature and the extent of reaction across the laminate thickness during processing. The model leads the computation of the viscosity inside the composite where experimental measurements are not possible. Thermal characterization of the reacting systems gives the input data necessary for the mathematical modelling. The numerical simulation has confirmed the necessity of a controlled temperature ramp in order to obtain a more homogeneous laminated structure. Moreover, the numerical results indicated that the process variables may present anomalous behavior which may affect the physical properties and durability of the final product.
Modeling of interphase in composite materials: Characterization of epoxy resin/aminosilane system
Authors: Sérier A. , Pascault J. P. , My Lam Thanh 
Published: March 2011

AbstractThe system studied here principally is γ‐APS + BADGE (γ‐aminopropyltriethoxysilane + diglycidyl ether of bisphenol A).The reaction takes place even at −20°C. It is first the epoxy‐amine autocatalytic second‐order reaction, but we also have a cross‐linking reaction which needs more time and higher temperature. The behaviour of this system is the same as γ‐APS‐PGE (phenylglycidyl ether) system: we can obtain the complete disappearance of OH groups.The thermomechanical properties of the reaction product considerably change with the temperature, moisture and curing time.
Synthesis and properties of segmented poly(hydroxyether‐siloxane)
Authors: Hedrick J. L. , Haidar B. , Russell T. P. , Hofer D. C. 
Published: March 2011

AbstractSegmented or block poly(hydroxyether‐siloxane) copolymers were synthesized by both a monomer‐oligomer or an oligomer‐oligomer synthetic approach. Perfectly alternating sequence distributions were obtained from the monomer or oligomer(s) bearing mutually reactive end groups, and the hydroxyether linkages are formed simultaneously with the growth of the second block. Differential scanning calorimetry (DSC), Dynamic Mechanical Thermal Analyzer (DMTA), and small angle X‐ray scattering (SAXS) results indicated that microphase separated morphologies were achieved for each of the copolymers, even those structures synthesized by the monomer‐oligomer route. The mechanical properties of the networks ranged from a rubber toughened thermoplastic to a thermoplastic elastomer and depended on which phase was predominantly continuous.
Chemical modification on PVC during the melt: Some fundamental features
Authors: Mijangos C. , Gómez‐Elvira J. M. , Martínez G. , Millán J. 
Published: March 2011

AbstractSubstitution on a commercial sample of PVC with sodium benzenethiolate has been performed in the melt state. The mixing conditions (shear stress, temperature, plasticizer, etc.) have been found to affect both the kinetics and the shape of the rheogram but they scarcely influence the final conversion. The reaction efficiency has been proved to depend linearly on the total amount of nucleophile. The evolution of tactic triads content with degree of substitution has been measured by 13C NMR spectroscopy. To a first approximation, the results agree with those obtained previously in solution which accounts for a mechanism based on the reactivity of some definite conformations.
Fluorination of polyethylene films
Authors: Volkmann Thekla , Widdecke Hartmut 
Published: March 2011

AbstractFluorination of HDPE films (100 and 1800 μm thick) and LDPE films (100 μm thick) with elemental fluorine is described. The films were fluorinated at temperatures between 40°C and 100°C. The degree of fluorination was increased by increasing the concentration of fluorine in the F2/N2 gas mixture. A diffusion‐controlled process was indicated by plotting the measured depth of fluorination against the square root of fluorination time. The chemistry of the process was studied by ESCA measurements or by energy dispersive analyses in the scanning electron microscope.
Photolysis and photo‐oxidation of unsaturated polyesters
Authors: Michaille Sylvie , Khalil Zahi , Lemaire Jacques , Arlaud Patrick 
Published: March 2011

AbstractThe photolytic and photo‐oxidative evolution of unsaturated polyesters, crosslinked or not, exposed to polychromatic light is studied using IR, FTIR, UV spectrometries. The influence of each elaboration parameter (nature and concentration of diacids like maleic anhydride, fumaric acid or phthalic acids, nature of glycols, nature and concentrations of crosslinking agents, mode of crosslinking) is determined. The mechanism involving primary excitation of the maleate‐fumarate or of phthalate units and radical reactions accounts for the appearance of hydroxylated and carbonylated groups. Photoyellowing of unsaturated polyesters is related either to the styrene oligomers or to the phthalate units. Through parallel studies of photochemistries in polystyrene (PS) and poly(butylene terephthalate) (PBT) at long wavelengths, the different sources of photo‐yellowing are precised.
Investigations of the phase behavior of rod‐like polyesters and polyamides substituted by flexible side chains
Authors: Ballauff M. 
Published: March 2011

AbstractThe phase behavior of a number of rigid‐chain polyesters and polyamides is reviewed and compared to the result obtained from low‐molecular‐weight model systems. The dilution of the steric forces by flexible side chains appended to the rigid main chains is discussed. It is shown that even stiff‐chain polyamides may be transformed to a thermotropic mesophase and an isotropic melt if the number and length of side chains per repeating unit is high enough.
Polycondensation of low‐active monomers in mesomorphic‐like reaction mixtures and in presence of polymeric matrix
Authors: Zhubanov Bulat A. , Solomin Victor A. , Lyakh Elena N. , Lyapunov Vladimir V. , Dubitsky Yuri A. 
Published: March 2011

AbstractThe study results of the synthesis of polyheterocycles based on dianhydrides, obtained by photochemical reaction of aromatic compounds with maleic anhydride, have been presented. In comparison with aromatic analogues the low reactivity of anhydride cycles is characteristic for tricyclodecenetetracarboxylic dianhydrides. This fact made unsuitable the traditional two‐stage method to synthesize high‐molecular polyheterocycles on the basis of these monomers. There has been estimated a possibility of chain growth of oligomeric polyamic acids (PAMA) in mesomorphic‐like state of its solutions in mixed solvents. In this conditions the PAMA polymerization degree changed from 7 up to 60. These peculiarities have given the opportunity to synthesize polyheterocycles in mild conditions. The features of polycondensation of tricyclodecenetetracarboxylic dianhydrides with bis(4‐aminophenyl) ether in the presence of poly‐4‐vinylpyridine, polyacrylic and polymethacrylic acids have been studied. There have been synthesized high‐molecular‐weight polyimides and polyamidoimides, possessing good physicomechanical and thermal properties.
Laser‐induced polymerization of functional derivatives of acetylene
Authors: Karpacheva Galina , Khoroshilova Valentina , Davydov Boris 
Published: March 2011

AbstractPhotochemical and photophysical processes leading to the formation of polymers with a conjugated double bond system under He‐Cd laser irradiation have been considered. Phenyl‐ and diphenylpropargylamines are utilized as monomers. The polymerization of these monomers is carried out only in the presence of an electron acceptor such as tetrabromomethane. The polymer formation process is directed to obtaining an intermediate compound followed by its polymerization. The polymerization of intermediate compound is carried out by cationic reaction of triple bond in the presence of electron acceptor. The polymer structure and properties have been investigated. The parameters of lightsensitive layers based on diphenylpropargylamine have been determined.
Two‐dimensional NMR methods for studying solid polymers
Authors: Spiess H. W. 
Published: March 2011

AbstractA survey is given about two‐dimensional (2D) NMR experiments on solid polymers involving 2H‐ and 13C‐NMR. 2D exchange NMR spectra of static samples directly reflect the distribution of rotational angles resulting from ultraslow molecular motions. Typical examples are the chain motion above the glass transition or rotations around a helix axis in semi‐crystalline polymers. 2D‐Magic angle spinning not only allows the detection of molecular order and motion. By combining rotor synchronized MAS with rotations in spin space the correlation of order and mobility can be studied.
The interaction between artificial antigenes based on synthetic polyelectrolytes with immune system cell: Physico‐chemical aspects
Authors: Yaroslavov A. A. , Polinsky A. S. , Sukhishvili S. A. , Kabanov V. A. 
Published: March 2011

AbstractThe model study on physico‐chemical basis of the tentative mechanism of artificial immunogene action was undertaken. Monodisperse carboxylated polystyrene latex was used as model to investigate the following problems: reversibility of polycation adsorption on the negatively charged surface, migration of macromolecules between particles, adsorption of polycation in the presence of abundant proteins. Polycation was proven to adsorb reversibly and, despite its high affinity to the negatively charged surface, to pass from one disperse phase particle to another. Neither positively nor negatively charged proteins prove to hinder polycation adsorption on the surface.
Physico‐chemical properties of polyampholytes in solutions
Authors: Bekturov Esen A. , Kudaibergenov Sarkyt E. 
Published: March 2011

AbstractThe results of studying the hydrodynamic properties, complexation ability and catalytic activity of some synthetic polyampholytes are presented. Much attention has been paid to studying the hydrodynamic and conformational characteristics of amphoteric polyelectrolytes at their isoelectric point (i.e.p.). Specific binding of low molecular weight ions by polyampholytes and complexation of polyampholytes with protein, anionic and cationic polyelectrolytes, surfactants, dyes and metal ions are discussed.
Soluble polyelectrolytes based on some heterocyclic compounds
Authors: Shaikhutdinov Erengaip M. , Kurmanaliev Oraz S.H. , Ermaganbetov Mubarak E. 
Published: March 2011

AbstractWith the purpose of synthesizing the new types of soluble polyelectrolytes for special purposes radical polymerization and copolymerization of a number of heterocyclic compounds in solvents of different types with wide interval of pH medium was investigated. Interrelationships between reaction ability of the studied monomers and dielectric polarization of the media was established. An essential influence of water and pH medium on the polymerization rate and molecular weight of the synthesized polymers is found. The obtained effects are described on the basis of ionized monomers. The possibility to synthesize stereoisomeric polymers based on individual 3‐buten‐1‐ynylpiperidinol isomers was shown. Some perspective ways of their practical application are given.
The influence of the molecular structure of polymers on their reactivity in polycondensation
Authors: Ignatov Vladimir N. , Vasnev Valeri A. 
Published: March 2011

AbstractThe influence of the conditions of synthesis, the chain length and the chemical structure of macromolecules on their reactivity is examined. The main emphasis is placed on the connection between polymer molecular structure and macromolecular effects in polycondensation. The far order effect is presented as the principal chemical factor determining the reactivity of macromolecules in solution polycondensation reactions.
Chemical and spectroscopic methods for investigating polymer degradation and stabilization: Oxidative degradation of a hydrogenated nitrile rubber
Authors: Carlsson D. J. , Chmela S. , Wiles D. M. 
Published: March 2011

AbstractThe oxidation of a hydrogenated butadiene‐acrylonitrile (2:1 mole ratio) rubber has been examined by infrared (IR) spectroscopy and the use of γ‐initiation to give a controlled initiation step. The resolution and sensitivity of the IR technique was enhanced by the use of chemical derivatization in which carboxylic acids were measured as acid fluorides, hydroperoxides as nitrates and alcohols as nitrites. In all of these compounds, their spectra are sensitive to the precise substituents (primary, secondary or tertiary). Oxidation produced hydroperoxides from both tert. H‐C‐C=N and sec. H‐C‐H groups (≈︁1:1.1 mole ratio) as well as chain‐end carboxylic acids [‐CH2‐C(=O)OH]. From a comparison with measurements of peroxyl radicals produced at low temperature, average kinetic chain lengths for the various oxidation products were estimated and compared with these from other ethylene copolymers.
Organoboron antioxidants, 2 boric acid derivatives as secondary antioxidants
Authors: König T. , Männel D. , Schwetlick K. 
Published: March 2011

AbstractBoric acid esters and arylboronic esters and amides are known to be good primary antioxidants, but they are also capable of destroying hydroperoxides effectively. We have found three principal ways of hydroperoxide decomposition. At first, simple alkyl, but also other esters catalytically destroy hydroperoxides, e. g. cumyl and tert‐butyl hydroperoxide, after an induction period. In a second route, reduction of the hydroperoxides takes place under transformation of oxidizable parts of the organoboron compound. Boric acid catechol esters, for example, reduce tert‐butyl hydroperoxide giving a black precipitate, a reaction product of the instable o‐benzoquinone. Catechol and hydroperoxide in the absence of boron compound do not react. Finally, p‐phenylboronic acid esters reduce hydroperoxides to give alcohol and the corresponding boric acid ester. Many boron derivatives can react in two or all three ways, e. g. 2‐phenyl‐1, 3, 2‐benzodioxaborole. 1 mol of this compound destroys 2 mol of cumyl hydroperoxide giving cumyl alcohol, and more than 10 mol to give acetone and phenol. In side reactions, cumyl hydroperoxide is converted into dicumyl peroxide and acetophenone. The last compound indicates a reaction passing via radicals; but in all cases, this reaction is not important.
Effect of radiolysis on the glass transition temperature of poly (methyl methacrylate)
Authors: Thominette F. , Pabiot J. , Verdu J. 
Published: March 2011

AbstractA bulk PMMA sample was irradiated by gamma rays (0.69 Gy. s−1), and its structural changes were monitored by steric exclusion chromatography, differential scanning calorimetry, dynamic mechanical spectroscopy and dilatometry. The glass transition temperature Tg decreases more than predicted from the molecular weight data, but the corresponding excess of change is not thermoreversible and can be suppressed by annealing. Strong not thermoreversible changes are also observed around the first secondary transition temperature (≈︁ 60°C) as well as in mechanical spectra and in dilatometric curves. Various hypothetical explanations are examined.
Effect of previous thermal history on physical aging of amorphous poly (ethylene terephthalate)
Authors: Cortés P. , Montserrat S. 
Published: March 2011

AbstractPhysical aging of amorphous PET, at aging temperatures (Ta) of 40 and 60°C and different aging times (ta), has been studied by DSC using two kinds of samples with different thermal history: Liquid‐Nitrogen‐Quenched samples (LNQ) and DSC cooled samples at a controlled cooling rate of 60 K/min (CC). At Ta = 40°C, a sub‐Tg peak appears in LNQ samples but is not clearly observed in the CC samples. At Tg = 60°C, a superposed peak to Tg is observed in both kinds of samples. This different behaviour can be explained considering the distribution of relaxation times in the polymer.
Synthesis and applications of olefin‐contaning polymers
Authors: Amerik Yuri B. 
Published: March 2011

AbstractThe problems of ionic coordination polymerization of higher α‐olefins are summarized briefly. During the polymerization such monomers as 3‐methyl‐butene‐1, vinylcyclohexane and others isomerize into unreactive isomers, and the rate of polymerization and final yield of polymer are sharply decreased as compared with the polymerization of lower olefins. The modification of polypropylene by ionic coordination copolymerization of propylene with higher α‐olefins and polar monomers is considered. Significant modification of carbochain polymers may be obtained by the insertion of heteroatoms in the backbone. New possibilities for chemical “modification” of olefins by direct interaction with sulphur and the unusual aspects of the polymerization of olefin sulfides are also considered. The subsequent transformation of polyolefin sulfide gives polymers which have properties drastically differing from those of polyolefins. In conclusion, some new application areas are described.
Stabilization mechanisms of hindered amines
Authors: Klemchuk Peter P. , Gande Matthew E. 
Published: March 2011

AbstractAs a result of studying the interaction of hindered amine stabilizers (2, 2, 6, 6‐tetramethylpiperidines) with simple hydroperoxides, peroxy radicals, and acylperoxy radicals, the last two in AIBN‐initiated oxidation experiments in chlorobenzene, the following conclusions have been reached:Hindered amines have multiple mechanisms of functioning as photostabilizers of polymers.Reactions between tetramethylpiperidines and simple hydroperoxides are too slow at moderate temperatures to make a significant contribution to polymer stabilization.Reactions between tetramethylpiperidines and alkylperoxy radicals at moderate temperatures occur at varying rates with varying effectiveness for stabilization. With favorable alignment among reaction rates for oxidation propagation and termination, reactions between tetramethylpiperidines and alkylperoxy radicals can play a significant role in oxidation inhibition.Hydrocarbon polymer photooxidation proceeds by two major paths ‐ the usually accepted alkyl radical/alkylperoxy radical/hydroperoxide route and the usually neglected aldehyde/acyl radical/acylperoxy radical/peracid route.Hindered amine stabilizers are able to participate in inhibiting both photooxidation reactions ‐ they trap acylperoxy radicals, converting them to carboxylic acids and are converted to nitroxyl radicals in the process; the nitroxyl radicals trap alkyl radicals and the hindered amines trap alkylperoxy radicals to inhibit the other oxidation pathway.Nitroxyls are regenerated from N‐alkyloxy hindered amines in a fast, efficient reactions with acylperoxy radicals and in slow reactions with alkylperoxy radicals. We postulate neither reaction yields peroxides: carboxylic acids and oxidized alkyloxy substituents are obtained from the first reaction; alcohols and oxidized alkyloxy substituents are obtained from the second reaction.