bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐speed living ring‐opening polymerization by a new catalyst based on metalloporphyrin
Authors: Inoue Shohei , Aida Takuzo 
Published: March 2011

AbstractPolymerization of ϵ‐caprolactone and δ‐valerolactone initiated with aluminum porphyrin (1) was much accelerated by the addition of methylaluminum diphenoxide with bulky substituents 2, to give polymers with narrow molecular weight distribution. The polymerization of β‐butyrolactone was also accelerated by 2, to different extents depending on the mode of ring scission. 2 also accelerated the living polymerization of propylene sulfide initiated with zinc porphyrin (3). The effect of 2 is due to the coordinative activation of monomer.
Some linear and branched macromolecules by ring‐opening polymerization
Authors: Schulz Rolf C. 
Published: March 2011

AbstractIn the first part the ring‐opening polymerization of some macrocyclic ether‐acetals is briefly described. Of special interest are acetal polymers with functional groups, for instance C=C‐double bonds. Appropriate unsaturated monomers and their polymerizability are discussed. The second part deals with the polymerization of oxazolines, substituted in 2‐ and/or 4‐position. Branched polymers are obtained by copolymerization of 2‐ethyl‐2‐oxazoline with 2‐hexyl‐2‐oxazoline or 2‐undecyl‐2‐oxazoline. The properties of the random copolymers and corresponding block copolymers are compared. By a “mixed mechanism technique” a block copolymer composed of a poly(tert ‐butyl methacrylate) block and a poly(phenyloxazoline) block was prepared.A new initiator system for the polymerization of oxazolines using alkyl chloroformates is introduced. The chloroformate of a trifunctional alcohol led to a three‐arm star polymer. Telechelics with two chloroformate endgroups form ABA type block copolymers.Finally four chiral oxazolines are described and the influence of substitution in dioxolanes and oxazolines on the polymerizability is discussed.
Synthesis and ionic polymerization of 1,2‐epoxy‐3‐nitropropane
Authors: Lagarde F. , Durand C. , Reibel L. , Franta E. 
Published: March 2011

AbstractThe synthesis of 1,2‐epoxy‐3‐nitropropane (ENP) was improved so that this monomer could be obtained in a pure, stable form with an acceptable yield.Anionic polymerization even using milder conditions causes isomerization of ENP into nitroallylic alcohol.Cationic polymerization using a classical initiator produces a mixture of compounds of low molecular weight.We have studied in detail the cationic polymerization of ENP in the presence of a diol such as ethylene glycol (“Activated Monomer Mechanism”): only the first two steps follow this latter, but a competitive mechanism takes over rapidly which limits severely the molecular weight of the products: this mechanism was analyzed.
Synthesis of degradable copolymers by ring‐opening polymerization
Authors: Albertsson Ann‐Christine , Löfgren Anders , Sjöling Maria 
Published: March 2011

AbstractHydrolysable copolymers made from different cyclic monomers have been studied. The monomers involved are 1,5‐dioxepan‐2‐one (DXO), L‐dilactide, 1,3‐dioxan‐2‐one (TMC), oxepan‐2,7‐dione (AA) and oxepan‐2‐one (ϵ‐CL). The hydrolysis of the DXO/L‐dilactide copolymer showed great differences in degradation rate depending on composition. A statistical copolymer made from TMC and ϵ‐CL was amorphous with a glass transition temperature of −48°C. TMC and AA could form a blockcopolymer with n‐BuLi as initiator in toluene, 0°C.
Ring‐opening polymerization of strained cyclotetrasilanes as a new route towards well defined polysilylenes
Authors: Cypryk M. , Chrusciel J. , Fossum E. , Matyjaszewski K. 
Published: March 2011

AbstractRing‐opening polymerization of cyclic silanes is described as a new synthetic route to well defined high molecular weight polysilylenes (polysilanes). Strained cyclotetrasilanes with phenyl and methyl substituents at each Si atom in the four‐membered ring are prepared by partial dephenylation of octaphenylcyclotetrasilane with triflic acid and the subsequent treatment with methylmagnesium bromide. Chemoselectivity, regioselectivity and stereoselectivity of monomer synthesis is discussed in detail. In addition to classic anionic initiators for the ring‐opening process, new catalysts and initiators based on transition metals (Cu, Pd, Pt) are described. They provide much better control of the microstructure than systems with Li+ counterion.
Molecular conformation of optically active polyesters and their stereocomplexes
Authors: Prud'Homme Robert E. , Ritcey Anna M. 
Published: March 2011

AbstractCrystal lattices for various polymorphs of poly(α‐methly‐α‐ethyl‐β‐propiolactone) (PMEPL) are proposed on the basis of combined electron and x‐ray diffraction data. Single crystal‐like electron diffraction is observed from melt crystallized thin films of isotactic PMEPL and stereocomplex. Melt‐crystallized isotactic PMEPL exhibits a monoclinic, pseudo orthorhombic lattice with the unit cell parameter c (4.75 Å) equivalent to the periodicity of the planar zigzag conformation typically obtained by sample elongation. The stereocomplex crystallizes in a distinctly different orthorhombic lattice with c = 7.1 Å, implying a 21 helical conformation. In addition, melt‐crystallized mixtures of isotactic PMEPL and isotactic poly(α‐methyl‐α‐n‐propyl‐β‐propiolactone) (PMPPL) are examined by solid state 13C nuclear magnetic resonance spectroscopy and x‐ray diffraction. These techniques reveal that, in such blends, the conformation and crystal structure found for isotactic PMEPL of a given chirality depends on the absolute configuration of the PMPPL present. In samples containing PMEPL and PMPPL of opposite absolute configuration, isotactic PMEPL crystallizes from the melt as a helix, in contrast to its behavior in the pure state, whereas PMPPL adopt the same helical conformation in the blend as when crystallized alone.
Characterisation of fire retardant poly(phenylene ether) high impact polystyrene in the UL‐94 test
Authors: Boscoletto A. B. , Checchin M. , Milan L. , Camino G. , Costa L. , Luda M. P. 
Published: March 2011

AbstractThe distribution of the temperature and the morphology of the charred material formed in the combustion of blends of poly(phenylene ether) (PPE) with high impact polystyrene (HIPS), carried out in the UL94 test, were examined. The effect of the fire retardant triphenyl phosphate is shown to be the decrease of time of burning, of temperature of the specimen and of zone involved in combustion, without apparent modification of the char structure. Hypothesis on gas and condensed phase fire retardant mechanisms are discussed.
Invariant values of kinetic parameters — Evaluation of fire retardancy application to the PP‐APP/PER system
Authors: Édelobel Ren , Bourbigot Serge , Le Bras Michel , Schmidt Yannick , ‐Marie Leroy Jean 
Published: March 2011

AbstractA method allowing the determination of the formulation leading to the best fire retardancy properties is presented in the case of intumescent systems. The method consists in the determination of invariant physicochemical parameters deduced from TG analysis: invariant activation energy and invariant preexponentiel factor. The relation between the values given by an evaluation test (LOI) and the invariant activation energy is then discussed.
The potential applications of x‐ray photoelectron spectroscopy (XPS) to the flame retardance mechanism of polymers
Authors: Wang Jianqi 
Published: March 2011

AbstractIn recent years X‐ray photoelectron spectroscopy (XPS) has rapidly matured and used routinely now in industries / universities providing a wealth of information including elemental composition, chemical bonding and depth profiles of both aspects in the surface of solids. However, few has been reported so far in the flame retardance areas. An attempt has been made in the present paper aiming at introducing and exemplifying examples of XPS applied to the fields relevant to the flame retardance of polymers, such as:degradation of polymers upon heating, synergisms, smoke suppression and structural investigation. All of which were achieved recently in the laboratory.
Flame retardant polymers current status and future trends
Authors: Troitzsch J. 
Published: March 2011

AbstractHigh demands in fire safety have increased the consumption of flame retardant polymers. Environmental issues, raised particularly in Germany, could affect the use of certain halogenated flame retardants in the future. Therefore, equivalent halogenated and non‐halogenated substitutes are currently studied and developed. An overview of the main systems of flame retardants acting in the gas phase and the condensed phase is given. The future belongs to halogenated and non‐halogenated systems with minimal environmental impact and optimal flame retardancy. To this end, enhanced basic research on polymer degradation and on the combustion process is necessary.
Synthesis and fire retardant properties of vinylic polymers bearing phosphonated groups
Authors: Catala J.‐M. , Brossas J. 
Published: March 2011

AbstractTo overcome the use of halogenated compounds, which are usually incorporated in plastics as flame retardant additives, the authors investigated the synthesis possibilities, to introduce with covalent bonds, the flame retarder groups at different positions of the polymer chains. They established correlations between the topology of the phosphonated groups and the flame retardant properties. They attempt to determine the origin of the flame resistance obtained in several cases. Their goal is to extend their interesting results obtained from oligomers, to polymer of high molecular weight.
Flame retarding materials for advanced composites
Authors: Kunz Dieter H.E. 
Published: March 2011

AbstractMechanical properties of advanced composites are often impaired by flame retardants. The least adverse effect is found with synergistic combination of antimony oxides and brominated epoxies. Where low smoke generation is absolutely necessary phenolic resins are used. The new development of combining epoxy and phenolic resin layers in structural applications with high flame retardancy is introduced.
New fire retardant halogenfree polymers
Authors: Schreiber H. , Saur W. 
Published: March 2011

AbstractTodays fire retardant plastics for high strength FRP (fibre‐reinforced polymers) or electronic devices (printed circuit boards, PCB) are based on brominated epoxy resins (EP resins). The smoke gases of this resins are highly toxic and corrosive. A new class of fire retardant duroplastics, based on dihydrobenzoxazines, doesn't contain halogen, sulfur or phosphor. Processibility is equal to that of thermosetting epoxy resins. Mechanical and electrical properties are equal to brominated epoxy resin, heat resistance is considerably enhanced (glass temperature 180 ‐ 280 °C), while density, toxicity and corrosivity of smoke are very low.
A way to halogenfree, flame‐retardant laminates for electronic applications
Authors: Von Gentzkow W. , Huber J. , Rogler W. , Wilhelm D. 
Published: March 2011

AbstractDue to legal specifications and standards flame retardant polymers are used as insulating materials for electrical cable and wire, as casing and constructive materials in electrical engineering, as encapsulation materials for electronic components and in laminates for printed circuit boards. The most effective way to achieve flame retardancy is by using halogenated organic materials. Because of ecological reasons a major trend is the development of halogenfree non‐corrosive flame retardant polymer materials. On the laminate side Siemens R&D developed a way to halogenfree laminates meeting the UL 94V‐O specification.
Hydrolytically stable thermoplastic and thermosetting poly(arylene phosphine oxide) material systems
Authors: D. Smith Carrington , Gungor Atilla , A. Wood Paul , C. Liptak Steven , Grubbs Harvey , Ho Yoon Tae , McGrath James E. 
Published: March 2011

AbstractSeveral thermoplastic and thermosetting polymeric materials containing the phenyl phosphine oxide group were prepared and characterized by physical methods. High molecular weight poly(arylene ether)s and polyimides containing the hydrolytically stable bulky phosphine oxide unit were synthesized and found to be soluble materials with moderately high glass transition temperatures. The phenyl phosphine oxide moiety was further incorporated into epoxy and bismaleimide type crosslinked systems. Phosphorus promoted char formation in air was displayed by both the linear and crosslinked macromolecules, leading to improved self‐extinguishability relative to the non‐phosphorus containing analogous polymeric systems.
Integral fire tests with oil and cable in a nuclear power plant
Authors: Dobbernack R. , Müller K. 
Published: March 2011

AbstractExperiments with oil pool and cable fires were performed in a former Nuclear Power Plant during the last years.The fire room was a closed subcompartment equipped with ventilation ducts, fire dampers, extinguishing lines and connected by a floor to the plant containment to study fires in a real environment under conditions typical for Nuclear Power Plants.Unsolved issues such as behavior of fire damping components and filters; production of soot; fire fighters entrance to a burning room were evaluated as well as ventilation needs of involved rescue areas.The fire behavior was calculated by different types of fire codes.
Pur ‐ sandwich panels in the building industry ‐ development of fire regulations in Europe
Authors: Walter R. , Wittbecker F.‐W. 
Published: March 2011

AbstractThe European Community aims to harmonize standards for fire safety of building products. The report starts with an overview of the existing different testing methods for sandwich panels with PUR‐rigid‐foam core and metal facings. For harmonization of the fire standards experts are looking for a robust longtime solution, which shall have a better relation to the end‐use conditions of the building products. First results of proposed ISO‐Room/Corner‐Tests for PUR‐sandwich panels are discussed.
Laboratory systems to evaluate the toxicity of polymers combustion products and hazard assessment
Authors: Jean‐Michel Jouany , Michel Guerbet , Roland Capron , Eric Dittmar 
Published: March 2011

AbstractSeveral laboratory systems have been proposed to evaluate the toxicity of combustion products of materials. Generally, the “fire models” were poorly instrumented, excepted the analysis of the major toxicants. Better informations being needed in this respect, a furnace has been made, based on the 2 zones NBS model, and allowing the evaluation of flammability, heat release and weight loss. Moreover, opacity and toxic gases are monitored. The time to incapacitation is probably the more realistic toxicological evaluation. It is worth while to rank materials by an hazard assessment, separating the variables involved in the fire hazard and the variables corresponding to the toxicological hazards and to plot them in a two‐dimensional graphic which looses less information than an index.
The thermal susceptibility of poly(chloroethyl methacrylates)
Authors: G. popović Ivanka , Katsikas Lynne , žana Sne , Rangelov M. , Veličkovič Jovan S. , Schnabel Wolfram 
Published: March 2011

AbstractThe non‐oxidative thermal degradation kinetics and mechanism of poly(2‐monochloro, 2, 2‐dichloro and 2, 2, 2, ‐trichloroethyl methacrylates) were studied. The influence of the antioxidant IRGA‐NOX 1010 on the thermal degradation of the monochloroethyl derivative was also investigated. Initial hydrolysis data on the major degradation products, the corresponding monomers, were obtained.
Flame‐resistance of polyetherimides
Authors: Rusanov A. L. , Serkov B. B. , Kazakova G. V. , Bulycheva E. G. , Kolosova T. N. , Dzhashiashvili T. K. , Matvelashvili G. S. 
Published: March 2011

AbstractPolyetherimides containing isopropylidene and hexafluoroisopropylidene groupings were obtained by the interaction of m‐phenylenediamine with the dianhydrides of 2, 2‐bis[4‐(3, 4‐dicarboxyphenoxy) phenyl]‐propane and 2, 2‐bis[4‐(3, 4‐dicarboxyphenoxy) phenyl] hexafluoropropane using high‐temperature solution polycyclocondensation in phenolic solvents. The same procedure was used for the preparation of the isopropylidene‐ and hexafluoroisopropylidene‐containing polyetherimides on the basis of 3, 3′ 4, 4′‐tetracarboxy(diphenyl ether) dianhydride and 2, 2‐bis[4‐(3‐aminopheno‐xy)phenyl] hexafluoropropane. Investigation of the polymers obtained has demonstrated that the replacement of isopropylidene groupings for hexafluoroisopropylidene fragments in polyetherimides leads to the increasing of the polymers flame‐resistance.
Mechanism of fire retardance in poly(2,6‐dimethyl‐1,4‐phenylene ether)‐high impact polystyrene
Authors: Checchin M. , Boscoletto A. B. , Camino G. , Luda M. P. , Costa L. 
Published: March 2011

AbstractPreliminary results are presented of a study concerning the mechanism of action of triphenyl phosphate (TPP) added to blends of poly(phenylene ether) (PPE) and high impact polystyrene (HIPS), 65/35 w/w. Comparison of effectiveness of TPP in increasing either the oxygen index or the nitrous oxide index of the polymeric blend, indicates that the fire retardant may act by a mixed gas‐condensed phase mechanism. The thermogravimetric behaviour of the fire retarded blend is compatible with this suggestion.
Factors affecting the burning behaviour of combustion modified high resilience polyurethane foams
Authors: Horrocks A. R. , Price D. , C. Edwards N. L. 
Published: March 2011

AbstractNine different flexible polyurethane foams of varying density and containing melamine and a phosphorus‐based flame retardant at different concentrations have been assessed for burning behaviours using oxygen index techniques at ambient and elevated temperatures. Major foam variables influencing flammability are density and melamine flame retardant content.
Investigation of the mechanisms underlying the influence of flame retardant on cotton (cellulose) pyrolysis in air
Authors: Price D. , Colemann G. V. , Faroq A. A. , Horrocks A. R. 
Published: March 2011

AbstractAn investigation is being undertaken into the influence of flame retardant type on the pyrolytic degradation of cotton (cellulose) fabrics in air over the temperature range 300–100°C. Thermal analysis techniques (TGA and DSC), detailed evolved gas analysis and extent of char formation measurements have all been utilised. The information obtained is used to develop a detailed model for the pyrolytic degradation of cellulose in air and the influence of flame retardants thereon. This paper reports the use of differential scanning calorimetry to further investigate the proposed CELLULOSE → CELLULOSE* transition.
Flammability of macrocyclic polymers and their complexes with metals
Authors: Aseeva R. M. , Zaikov G. E. 
Published: March 2011

AbstractThe peculiarities of thermal degradation and the flammability of nitrogen‐containing macrocyclic polymers have been investigated. It has been shown that the thermal and thermo‐oxidative stability of these polymers depend on the structure of the macrocycle, the type of organic radicals of the main unit and the metal nature. The effect of the type of n‐conjugated macromolecules, as well as of the planarity and symmetry of macrocycle, on thermal stability as well as flammability of macrocyclic polymers has been studied. Metals (Cu, Co, Ni) in the coordination sphere increase the thermal stability and decrease the thermo‐oxidative degradation of macrocyclic polymers.
Flame retardant polymeric additives for polyolefines. Different role of phosphoric and boric acids as FR agents in their reaction products with triglycidyl isocyanurate
Authors: De Chirico A. , Audisio G. , Provasoli F. , Armanini M. , Franzese R. 
Published: March 2011

AbstractTwo adducts based on triglycidyl isocyanurate and phosphoric or boric acid have been compared by means of thermogravimetric analysis to investigate their activity as flame retardants and thermostabilizing agents respect to polypropylene. Better behaviour of phosphoric acid adducts have been observed.
Vertical burning tests UL 94‐V and IEC 249–1 (4.3.4) theoretical considerations and experimental results
Authors: Schreiber H. 
Published: March 2011

AbstractExperimental results show, that the UL 94 classifications V0 or V1 are not in accordance with the real inflammability properties. For ignition times up to 20 s the classification is very erratic and accidental. More flammable materials may yield a better classification and vice versa. These results are explainable and confirmed by theoretical considerations.
The application of composites in aerospace
Authors: Bolding G. 
Published: March 2011

AbstractAfter the introduction of the advanced composite materials, i.e. carbon‐ and aramidfibre reinforced thermosets, in the late 60's, for a long time the application of these materials used to be considered a panacea for many problems in civil aircraft structures. After many years of trial and error, it is becoming clear that these materials most certainly contribute to better aircraft, but are not a miracle cure. And if there is a key role for composite materials, there is still a long way to go to the all composite (commercial) aircraft.The applications in the aerospace market started with components that used to be designed in glassfibre reinforced thermosets. Although the manufacturing technology was well known, the approach to designing in advanced composites changed in the sense, that the designs had to be optimized for minimum weight (to obtain lower DOC). Also the materials had to be recognized by the designer as being anisotropic (high allowable stresses in the fibre direction). Soon it became evident that also the material‐ and process technology had to be optimized for the advanced composites.Due to the cost involved in the manufacturing of highly loaded composite components, the design philosophy changed from design for minimum weight to (more or less) design for minimum cost. Also the service experience and resulting remarks from the operators, changed the design approach. The maturity of automated manufacturing will enable further cost reduction and after sufficient service experience with the components that are flying at this moment, the aircraft industry will be ready for the next step: the application of the advanced composite materials in primary, flight‐critical aircraft components. The close cooperation between the aerospace industry and the material suppliers will be an essential condition for success in the quest for a “better” aircraft.
Stimulating innovative research (on special polymers) in The Netherlands
Authors: van Der Torren Hendrik‐Jan , van Mechelen Tony 
Published: March 2011

AbstractInnovation is considered one of the keys to a successful and competitive industry. The Dutch Ministry of Economic Affairs therefore stimulates research and development in strategic subject areas of potentially significant importance for the industry. It has created several national stimulating instruments, such as IOP (Innovation Oriented Research Programme), PBTS (Programmatic Business Oriented Technology Stimulation) and TOK (Technical Development Loan). At an European level it stimulates participation in the Eureka programme.The precompetitive IOP is meant to generate new technology, to add value to promising research activities, to establish new and strenghten existing skill pools and to cluster existing and newly established research groups. It enhances the orientation of university groups towards the needs of industry.The IOP “Polymer Composites and Special Polymers” is a.o. concerned with topics on special (functional) polymers like non‐linear optically active polymers, electrically active polymers and liquid crystalline polymers. In this presentation the current status is reviewed of research on special (functional) polymers in the Netherlands. Insight is given in policies and rational of selecting specific IOP‐programmes in this area. In addition attention is paid to a post‐IOP perspective and a possible participation of dutch companies in Eureka projects.