bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical properties of polymers filled with alkyl dihydrogen phosphate treated calcium carbonate
Authors: Mitsuishi Kazuta , Nishi Katsushi , Kodama Souji , Kawasaki Hitoshi 
Published: April 2003

AbstractPoly(ethylene) (PE) or poly(ethylene‐co‐vinyl acetate) (EVA) and alkyl dihydrogen phosphate ester (APEn, CnH2n+1OPO(OH)2, n = 1, 4, 10, 12, 16) treated calcium carbonate (CaCO3) were mixed on a two roll mill. In order to improve the affinity of polymer‐CaCO3 interface, the CaCO3 surface was treated through chemical reaction with various APEn types. The effect of carbon number of APEn on the tensile elongation and the adhesion properties between CaCO3 particles and polymer matrix was investigated. In the case of PE/CaCO3 series, tensile elongation, modulus of oriented samples and adhesion of polymer‐CaCO3 interface increased with carbon number of APEn (n ≦ 12). In the EVA/CaCO3 series, the dependence of the tensile elongation on the carbon number of APEn was not clearly recognized; the adhesion at the phase interface was improved with the decrease of carbon number of APEn (n ≦ 12).
Synthesis and characterization of a new bismaleimide resin matrix for composites
Authors: Dolui S. K. , Mandal B. K. , Maiti S. 
Published: April 2003

AbstractA bismaleimide monomer containing etherimide linkages was synthesized from 3‐nitrophthalic anhydride, diamino diphenyl ether and bisphenol‐A by the principle of activated nucleophilic displacement reaction and finally reacting the produced diamine with maleic anhydride. The monomer was characterized by elemental analysis, IR and NMR spectroscopy. It is highly soluble in low boiling solvents such as chloroform, tetrahydrofuran, etc. It forms a cross‐linked polymer on heating to 200°C and higher. The cured product is completely insoluble in usual solvents including conc. H2SO4. The thermal behaviour of the bismaleimide was studied by TGA, DTA and isothermal aging. The polymer is stable up to 300°C. Laminates prepared with this resin and carbon fiber are almost void‐free and possess good mechanical and thermal properties. These properties are compared with earlier reported bismaleimide imide prepolymer based composite.
Untersuchungen zum Einfluß von Modifikatoren auf die Thermostabilität von PE‐HD/CaCO3‐Verbunden
Authors: Lühr Jens , Beismann Ruth , Janowski Frank 
Published: April 2003

AbstractDer Einfluß der Füllstoffmodifizierung mit nichtkoppelnden Modifikatoren wie Stearinsäure und Isopropyltriisostearyltitanat (ISTT) auf die thermische Stabilität von PE‐HD/CaCO3‐Verbunden wurde untersucht. Mit Hilfe der thermischen Analyse wurde eine erhöhte Sauerstoffaufnahme für gefülltes PE‐HD nachgewiesen. Eine Zunahme der Modifikatorkonzentration erniedrigt die Temperatur für den Oxidationsbeginn. Dieser Effekt ist für Stearinsäure ausgeprägter im Vergleich zu Titanat.Die zusätzliche thermische Stabilisierung von PE‐HD/CaCO3‐Verbunden ist daher notwendig.
Polycondensation using alkyl chlorosilanes/silicon tetrachloride: Preparation of poly(1,4‐benzamide)
Authors: Galioǧlu Oya , Akar Ahmet 
Published: April 2003

AbstractMixtures of alkyl chlorosilane and silicon tetrachloride were used as condensation agents for the preparation of poly(1,4‐benzamide). Both high yield of polyamide and soluble side products were obtained. This method may be used to regulate the surface structure and the particle size of silicon dioxide side product if a minimum amount of trimethyl chlorosilane was added to silicon tetrachloride catalyst.
Effect of crosslinking on the properties of poly(2‐hydroxyethyl methacrylate) hydrogels
Authors: Davis Thomas P. , Huglin Malcolm B. 
Published: April 2003

AbstractBy means of γ‐irradiation 2‐hydroxyethyl methacrylate has been copolymerized in bulk with two different tetrafunctional monomers, ethylene glycol dimethacrylate and 1,3‐bis(acryloxymethyl) tetramethyl disiloxane and with a hexafunctional monomer, 1,1,1‐trimethylolpropane trimethacrylate. The resultant xerogels were subsequently swollen to equilibrium in water. In order to allow a comparison among the three crosslinkers, their molar masses and funtionalities were taken into account, the theoretical crosslink concentrations being varied from 0.032 to 0.644 mol dm‐3. The relative hydrophobicity of the three crosslinkers was found to have a significant effect on both the equilibrium swelling and elastic modulus of the swollen gels. Non‐freezing water in several gels crosslinked with 1,1,1‐trimethylolpropane trimethacrylate was analysed by differential scanning calorimetry (DSC). The proportion of non‐freezing water in the gel relative to the overall water content was found to increase with increasing crosslink density.
Synthesis and properties of cationic resins derived from aniline/benzylamine‐modified epoxy resins and diethylamines
Authors: Lee Lung‐Ta , Yang Chin‐Ping 
Published: April 2003

AbstractAniline/benzylamine‐modified epoxy resins with different molecular weights, which contain tertiary amines in the middle of the polymer chain, were synthesized by the reaction of aniline/benzylamine with epoxy resin at various molar ratios. The resulting aniline/benzylamine‐modified epoxy resins were reacted with diethylamine and subsequently reacted with 2‐ethylhexanol‐blocked toluene diisocyanate to obtain thermally crosslinkable resins which contain tertiary amines at the end and in the middle of the polymer chain. These resins were partially neutralixed with acetic acid to give thermally crosslinkable cationic resins. The resulting cationic resins were dissolved in suitable solvents and mixed with deionized water to form various emulsions. The emulsion and electrodeposition properties of these resins were studied in some detail to compare the properties of these cationic resins. The results show that the deposition yields and throwing power of the emulsions prepared from benzylaminemodified epoxy resins are higher than those of the emulsions prepared from anilinemodified epoxy resins. The emulsion having proper pH values can give a high throwing power. High throwing power is the characteristic property of these modified cationic resins. Factors determining the throwing power and deposition yield of the emulsions were also investigated.
Thermosensitive microcapsules, II. New azomonomers, homo‐ and cocondensation, microencapsulation, release measurements, size distribution and thermo‐printing
Authors: Nuyken Oskar , Dauth Jochen , Pekruhn Wolfgang 
Published: April 2003

AbstractThermolabile microcapsules are formed by interfacial polycondensation in which one of the wall‐forming reactants contains azo functions. These reactants are compounds of the general structure XRNNRX (X = OH, NH2, NCO, COCl). Their properties are described in detail.Experimental details of the microencapsulation such as particle size, dependence from stirrer speed and stability of the capsules are given. An ink ribbon containing a carrier covered with dye filled microcapsules is applied for thermal‐transfer‐printing.
Mechanisms of photostabilization of polyolefins with N‐alkyl(methyl) HALS. 1. Comparison of the performance of unsubstituted with N‐substituted HALS in polyolefins
Authors: Gugumus F. 
Published: April 2003

AbstractThere is still controversy over the relative efficiency and stabilization mechanisms of secondary and tertiary HALS. In this study the performance of secondary HALS is compared with that of corresponding hindered amines bearing various substitutents at the sterically hindered nitrogen atom. The bulk of the stabilization data concerns unpigmented polypropylene and the comparison of N‐H and N‐methyl derivatives. It is found that in PP films, PP multifilaments, PP tapes and injection molded PP plates the secondary HALS and the corresponding N‐methyl derivatives give the same performance within experimental error. The results available, so far, with PE‐HD films, PE‐HD tapes and PE‐LD films lead to the same conclusion. Saturated alkyl groups other than methyl show also comparable performance. The effect of unsaturated groups such as allyl and benzyl and of oxygen atoms (nitroxyl radicals) varies. Depending on the particular polypropylene batch used, the performance can be comparable, superior or inferior to that of the corresponding NH/N‐methyl compounds.
Study of the acetoxy‐hydroxide transformation in ethylene‐vinyl acetate copolymers
Authors: Fonseca Carmen , Fatou Jose G. , Pereña Jose Manuel 
Published: April 2003

AbstractEthylene‐vinyl alcohol (EVAL) copolymers and ethylene‐vinyl alcohol‐vinyl acetate (EVALVA) terpolymers with different VA content were achieved by hydrolysis of ethylene‐vinyl acetate (EVA) copolymers of low vinyl acetate content. Several experimental techniques (elemental analysis, thermogravimetry, NMR and IR spectroscopy) were used for the analysis of the composition of copolymers and terpolymers. The results have been critically discussed. Kinetic aspects of the acetoxy‐hydroxide transformation of the EVA copolymers have been analysed, such as the influence of steric and neighbouring group effects on the rate of this transformation. The kinetics can be expressed by a second order kinetic equation and the acetoxy groups joined to hydroxy groups are rapidly transformed. The reaction rate depends on the vinyl acetate content; the higher the vinyl acetate content of the EVA copolymer, the higher is the rate of the transformation process. Another important conclusion is related with the dependence of the rate constant on the concentration of the EVA copolymer in the reaction, on the base of equivalent ester group concentration.
A nonionic hydrogel from the telechelics by utilizing living polymerization of 2‐oxazolines
Authors: Park In‐Hwan , Han In‐Su , Kim Dong‐Kuk , Saegusa Takeo 
Published: April 2003

AbstractN,N′‐dimethyl‐2,2′‐tetramethylene‐bis(2‐oxazolinium) bis(methyl‐p‐toluene sulfonate) (II), a cationic polymerization initiator, was synthesized by the reaction of methyl p‐toluene sulfonate with 2,2′‐tetramethylene‐bis‐2‐oxazoline (I) and a cationic ring‐opening polymerization of 2‐methyl‐2‐oxazoline [MeOZO] in the presence of (II) was carried out to produce poly(MeOZO) telechelics with various molecular weights. These telechelics were hydrolyzed with an aqueous solution of sodium carbonate to obtain hydroxy terminated telechelics of poly(MeOZO). A series of nonionic polyurethane hydrogels was prepared by the crosslinking reactions of the poly(MeOZO) glycol with pluriisocyanates in the presence of ferric acetylacetonate and DMF as the catalyst and reaction medium, respectively. The hydrogels showed good swelling degrees for water and hydrophilic solvents such as DMF, and bad swelling degree for a hydrophobic solvent such as toluene.
Conformation and electrical conductivity of poly(γ‐methyl‐L(LD)‐glutamates) reticulate‐doped with 1,3‐dimethylimidazolium‐7,7,8,8‐tetracyano‐p‐quinodimethane complex salt
Authors: Šorm Miloslav , Dědek Petr , Nešpůrek Stanislav , Kotva Rudolf , Pivcová Hana 
Published: April 2003

AbstractPolymeric composites were prepared by reticulate doping of poly(γ‐methyl‐L‐glutamate) (PMLGA) and poly(γ‐methyl‐LD‐glutamate) (PMLDGA, 1 : 1) having different conformation forms with 1,3‐dimethylimidazolium‐TCNQ complex salt. The heat induced α‐helix to coil transition in PMLGA and α‐helix to β‐form and coil transition in PMLDGA were carried out in chlorobenzene and o‐dichlorobenzene at temperatures between 70 and 150°C. The conductivity of polyglutamate composites thermally treated and prepared at 70°C is higher by approximately two orders of magnitude than that of thermally not treated films cast at ambient temperature. The conductivity of the most conductive reticulate‐doped PMLGA film is higher by more than four orders of magnitude than that of the 1,3‐dimethylimidazolium‐TCNQ complex salt in pressed pellets.
Preparation of block and graft copolymers by peroxycarbamates
Authors: Uyanik Nurseli , Yildirim Hüseyin , Kizilcan Nilgün , Akar Ahmet 
Published: April 2003

AbstractBlock copolymers of cyclohexanone‐formaldehyde resin (CF‐resin) and polystyrene and graft copolymers of styrene on ethyl cellulose, respectively, were prepared via peroxycarbamates. NCO/OH ratio was the important parameter during preparation of polymeric peroxycarbamates from prepolymeric isocyanate‐terminated peroxycarbamates and CF‐resin. Cross‐linked copolymers were produced if NCO/OH ratio was above 2:9. Ethyl cellulose with low hydroxy value was used as hydroxy compound for the preparation of peroxycarbamate. About one of every two anhydroglucose units of ethyl cellulose was grafted with polystyrene.
Functionalization of polyethylene and ethylene propylene diene terpolymer in the bulk through dibutyl maleate grafting
Authors: Sen Achintya K. , Mukherjee Bibha , Bhattacharyya A. S. , De P. P. , Bhowmick Anil K. 
Published: April 2003

AbstractFunctionalization of polyethylene (PE) and ethylene propylene diene terpolymer (EPDM) in the bulk through dicumyl peroxide (DCP) initiated grafting of dibutyl maleate (DBM) has been studied in the temperature range from 140 to 200°C. The degree of grafting has been determined by infrared spectrophotometry and DSC. The concentration of DBM and DCP has been optimized. 0.5 wt.‐% and 0.2 wt.‐% DCP for PE and EPDM, respectively, and 10% DBM for both have been found to be the optimum. The kinetics of the grafting reaction is comparable for PE and EPDM. The activation energy of grafting is ca. 145 kJ/mol for PE and ca. 130 kJ/mol for EPDM. The influence of structure of polyolefins on the degree of grafting has also been studied. A higher degree of grafting is obtained for PE than for EPDM. For PE/EPDM blends, the degree of grafting increases with increasing PE content in the blends. A through discussion and proposed mechanism for grafting and other competitive secondary reactions has been provided.
Interfacial adhesion in short‐fibre composites
Authors: Rybnikář František 
Published: April 2003

AbstractFor the evaluation of the interfacial adhesion in short‐fibre composites, a simple method based on fibre pull‐out length distribution was proposed. The experiments with three composites of isotactic polypropylene with 32 wt.‐% of short‐glass fibres confirm the potentials of the method for a sensitive determination of differences in the interfacial adhesion. The effects of temperature, crystallinity and fibre orientation angle on the interfacial adhesion were investigated.
Pervaporation separation of pentane‐alcohol mixtures through ionically crosslinked blended membranes. I. Thermal measurements, electron microscopy and tensile studies
Authors: Balakrishnan Malini , Huang Robert Y. M. 
Published: April 2003

AbstractIonically crosslinked blended membranes were prepared from blends of nylon 6 and poly(acrylic acid) (PAA) with the proportion of PAA ranging from 25 to 45 wt.‐%. The technique consists of casting a film of the blend, followed by drying and immersion in an aluminum salt crosslinking solution for a predetermined time. The glass transition temperature (Tg) of the membranes was determined by differential scanning calorimetry (DSC). All the samples exhibited a single Tg, which is higher than that of either polymer. There is also a shift in the Tg with increasing scanning time. This phenomenon is attributed to the elimination of water molecules and the formation of anhydrides in the non‐crosslinked PAA portion of the membrane. The membrane morphology was studied using scanning electron microscopy (SEM) and shows a dense structure without any pores. No phase separation is observed by scanning cross‐sections of the samples, indicating that nylon 6 and PAA are completely miscible in the ranges studied. The membrane material strength lies in the range of 5 to 26 MPa and varies with the amount of PAA in the membrane. Samples with higher PAA content show lower tensile strength in spite of increased crosslinking density. This is due to the inherent low strength of PAA, coupled with increasing swelling of the membrane with increasing PAA content. The latter is confirmed by the measurement of water uptake into a dry membrane which increases from 23.6% to 76.3% with the membrane PAA content increasing from 25 to 45 wt.%.
Effect of surface structure of porous silica microballoons on dynamic mechanical properties of amine cured epoxy resin composites
Authors: Tanaka Yuko , Nakahara Yoshiko , Takemoto Kiichi 
Published: April 2003

AbstractDynamic mechanical properties were studied for epoxy resin filled with porous silica microballoons with varying surface area, pore radius, pore volume and adsorbed water. The glass transition temperature (Tg) of the composites is 12–14°C lower than the Tg of the unfilled epoxy resin. This Tg depression is attributed to the preferential adsorption of curing agents on the porous silica microballoons. Tg of the composite increases with increase in the adsorbed water on fillers. The storage modulus has a distinct correlation with the Hg‐surface area of silica microballoons, which corresponds to the sum of the surface area of pores with radii larger than about 4 nm.Tan δc tan δm decreases with increasing Hg‐surface area.
Zur reaktionstechnischen und fluiddynamischen stabilität von multirohrreaktoren für die massepolymerisation
Authors: Weickert G. 
Published: April 2003

AbstractInfolge der sich mit steigendem Monomerumsatz stark verändernden Viskosität der Reaktionsmasse existieren im Multirohrreaktor mit Kühlung mindestens drei stationaäre Punkte bezüglich des Einzelrohrmassenstromes gleichzeitig. Als Konsequenz ergibt sich eine Ungleichverteilung der Rohrbelastung, die sowohl die Reaktorstabilität als auch die Polymerqualität negativ beeinflußt. Das Betreiben einer Rückführung kann das Reaktorverhalten stabilisieren. In der vorgelegten Arbeit werden einige fundamentale Aspekte der Anwendung von Multirohrreaktoren für die Massepolymerisation von Styrol untersucht.
Oberflächenstrukturierung polymerer fasern durch UV‐laserbestrahlung. 11. Oberflächenstrukturierung von polypropylen‐folien und ‐geweben
Authors: Kesting Wolfgang , Knittel Dierk , Schollmeyer Eckhard 
Published: April 2003

AbstractEs wird aufgezeigt, daß Materialien, die UV‐Licht nur schwach absorbieren, wie z. B. Polypropylen (PP), durch eine Imprägnierung mit starken Absorbern wie Benzophenon einer Bearbeitung mit UV‐Lasern zugänglich gemacht werden können. Durch die dann erzielbaren hohen Absorptionskoeffizienten der so dotierten Polyolefine lassen sich hohe Ätzraten durch die Laserbestrahlung erzielen. Darüber hinaus können rollenähnliche Oberflächenstrukturen erzeugt werden, so wie diese von z. B. Polyester‐ und Polyamidfasern bekannt sind. Die Dimensionen dieser Strukturen liegen im Bereich von 10 bis 25 μm bei einer Tiefe von etwa 3 μm. Dagegen werden an biaxial verstreckten PP‐Folien tropfenförmige Strukturen erzeugt, die auf eine Dominanz thermischer Effekte schließen lassen. An schwach absorbierenden Systemen wie etwa an gefärbten PP‐Fasern lassen sich nur Verschmelzungen von Einzelfilamenten erreichen. Durch einen mechanischen Kontakt einer undotierten PP‐Probe mit einer Poly(ethylenterephthalat) (PETP)‐Folie lassen sich durch die Laserbestrahlung ebenso rollenähnliche Strukturen an der PP‐Oberfläche gewinnen.
Synthesis, dielectric and X‐ray powder diffraction studies of Fe(III), Co(II) and Ni(II) chelate polymers with 5,8‐dihydroxy‐1,4‐naphthoquinone
Authors: Rao T. Ramkrishan , Rao P. Raghunath , Lingaiah P. , Deshmukh Lalitha Sir 
Published: April 2003

AbstractCoordination polymers of Fe(III), Co(II) and Ni(II) with 5,8‐dihydroxy‐1,4‐naphthoquinone have been synthesized and characterized by elemental analysis, IR and magnetic moment studies. From DSC data, the order of the decomposition reaction and the activation energy for the decomposition of the different polymers have been evaluated. Electrical properties like the dielectric constant and the dc conductivity of the polymers have been measured. From x‐ray powder diffractograms cell parameters were calculated, the pattern indexed, and the symmetry determined.
Porous copolymers of N‐vinylcarbazole and divinylbenzene
Authors: Kolarz Bożena N. , Wojaczyńska Maria , Pielichowski Jan 
Published: April 2003

AbstractPorous copolymers of N‐vinylcarbazole (NVC) and divinylbenzene (DVB) of different composition (crosslinking degree) have been studied. The copolymers were obtained by suspension polymerization carried out in the presence of diluents, mixtures of ‘good’ (isopentanol and toluene) and ‘bad’ solvents (dodecane and toluene).The supermolecular structure of the copolymers was found to depend not only on the crosslinking degree, but on the thermodynamic quality of diluents. In the presence of good solvents, copolymers of the porous‐gel type were formed at relatively small crosslinking degree (<20% DVB).Sorption properties of porous NVC‐DVB copolymers with respect to p‐nitrophenol were found to be similar to those of acrylonitrile‐DVB copolymers.
Copolymerization reactivity ratios of N,N‐dimethyl acrylamide and isopropyl methacrylate determined by 1H‐NMR spectroscopy
Authors: Srinivasulu B. , Rao P. R. , Sundaram E. V. 
Published: April 2003

AbstractCopolymers of N,N‐dimethyl acrylamide (DMA) and isopropylmethacrylate (IPM) were prepared in dimethyl formamide using azoisobutyronitrile as initiator. The composition of copolymers was determined by 1H‐NMR analysis. Reactivity ratios (rDMA = 0.58, rIPM = 2.76) were calculated from these values by using the Kelen‐Tüdős differential linear equation.
Polymer molecular properties and hydrodynamic lubrication
Authors: Figini Ruben Victor , Tinta Clotilde Goday 
Published: April 2003

AbstractA general numerical procedure is presented to calculate the modification of the basic equation for hydrodynamic lubrication brought about by the use of polymeric fluids with shear depending viscosity. The procedure is based on the generalized Newtonian fluid model and allows to treat continuously all the flow regions between the pure Newtonian and the power law behavior. The results show that the influence of the viscosity depending on shear stress is completely characterized by one dimensionless number, namely U.·τ*/h*, where U is the relative sliding velocity, h* is the characteristic film thickness, and τ* is a characteristic time of the lubricant. The procedure is exemplified by applying it for the determination of the influence of the molecular weight and concentration of the polymeric component of the lubricant on the hydrodynamic lubrication. This influence is brought about by the strong relation between the polymer properties and τ*.
Oxygen permeability in polymers, III. Dependence of the oxygen permeability on the chemical structure of styrene‐maleic acid‐copolymers
Authors: Kraus N. , Israel G. , Müller F. W. , Schiller K. , Rätzsch M. 
Published: April 2003

AbstractThe paper gives a report on the oxygen permeability in films of poly(styrene‐comaleic acid) halfesters and halfamides as well as other polymers containing carboxylic groups in comparison with commercially available glass forming polymers at room temperature. The presence of oxygen in the polymer layers was proved by the quenching of the delayed fluorescence of pyronin B. The permeability of the halfesters/halfamides (Pox = 2…7.10‐14 cm2/Pa .s) corresponds to that of common polymers like poly(methyl methacrylate) (PMMA) or poly(vinyl acetate) (PVAc), and is nearly one order of magnitude higher than that of poly(acrylic acid) (PAAc), poly(styrene‐comaleic acid) (SMAc) and carboxymethylcellulose (CMC). Presumably, intramolecular hydrogen bonds in the halfester/halfamides compete successfully with the intermolecular interactions and hence cause an increase in permeability as also do bulky substituents. Addition of bases like dimethyl aminopropanol (DMAP) and dimethyl aminopropyl acrylamide (DMAPAA) decreases the permeability to about 1/40 of the initial value. The permeability is then similar to the low permeability of polymers with predominant ionic interaction sodium polyacrylate (NaPAAC), sodium carboxymethylcellulose (NaCMC)).