bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiopaque epoxy resins
Authors: Chatterjee Gautam , Cabasso Israel , Smid Johannes 
Published: April 2003

AbstractTransparent, X‐ray contrast (radiopaque) epoxy resins were obtained by dissolving up to 25 wt % triphenylbismuth in the commercial epoxy resin prepolymers EPON‐815, DER‐330, DER‐383, and DEN‐431 which were then hardened with diethylenetriamine. The radiopacities of the mixtures were found to be proportional to the molar concentration of the radiopaque additive. The systems follow the relationship, R = Ro + (Ra − Ro) Va Ma where R, Ro, and Ra are the radiopacities of the mixture, the pure epoxy resin, and triphenylbismuth, respectively (expressed in mm aluminum/mm resin); Ma and Va denote the molar concentration and molar volume of the bismuth compound. Ra for triphenylbismuth was found to be 7.4 ± 0.2 mm Al/mm resin; the average value of Ro for the four epoxies equals 0.16 ± 0.1 mm Al/mm resin. The amount of amine required to harden the radiopaque resins was far less for the epoxy novolac resin DEN‐431 than for the three bisphenol‐A based epoxies. The concentration of triphenylbismuth required to impart a radiopacity equivalent to that of aluminum measures 14.6 wt % in EPON‐815, 14.8 wt % in DER‐330, 14.9 wt % in DER‐383, and 15.9 wt % in DEN‐431. The radiopaque resins remain transparent indefinitely, even when exposed to water. © 1995 John Wiley & Sons, Inc.
Modification of wettability of a stainless‐steel plate by cathodic plasma polymerization of trimethylsilane–oxygen mixtures
Authors: Wang Tinghao F. , Yasuda Hirotsugu K. 
Published: April 2003

AbstractWettability (by water) of a stainless‐steel plate was modified by depositing an ultrathin layer of a plasma polymer of trimethylsilane (TMS) and an oxygen mixture. Plasma polymerization was carried out by cathodic glow discharge polymerization, in which a substrate stainless‐steel plate was used as the cathode of the de glow discharge. The plasma polymer of TMS (oxygen mol fraction = 0) is very hydrophobic, but the addition of oxygen in the monomer mixture increased the hydrophilicity of the plasma polymer. The value of cos θ (θ: advancing contact angle of water) linearly increased with the mol fraction of oxygen in the monomer mixture. Oxygen in the monomer mixture acts as (1) an ablating agent of a carbon‐based plasma polymer and (2) a comonomer for a silicon‐based plasma polymer. The atomic composition of a plasma polymer, which can be expressed as SiCxOy, changes (x decreases and y increases) as the mol fraction of oxygen increases. © 1995 John Wiley & Sons, Inc.
Synthesis of poly(benzylmethacrylate)‐co‐perfluorooctylethylmethacrylate) and electrooptical properties of the resultant polymer/liquid crystal composite films
Authors: Kawatasuki Nobuhiro , Ono Hiroshi 
Published: April 2003

AbstractMethacrylate copolymers of benzylmethacylate (BMA) and perfluorooctylethylmethacrylate (FMA) were synthesized and applied to the polymer/liquid crystal (LC) composite films. The copolymers were prepared by a radical solution polymerization. The high composition of FMA resulted in a precipitation during the polymerization. The contact angle of the LC on the copolymer films decreased with increasing FMA composition. Due to a small interaction between the LC and the copolymers, the copolymer/LC composite films showed low driving voltage in the range of 18–25 Vrms, corresponding to about 1/3 the value of the poly(methyl methacrylate) (PMMA)/LC composite film. © 1995 John Wiley & Sons, Inc.
Tensile properties of chemically modified ring‐ and rotor‐spun cotton yarns
Authors: Subramaniam V. , Thambidurai S. 
Published: April 2003

AbstractThe effects of chemical treatments and modifications on the tensile properties of ring‐and rotor‐spun cotton yarns is discussed. The rotor‐spun yarns treated with zinc chloride show a higher tenacity at low stretch levels compared to sodium hydroxide, whereas with sodium hydroxide, the rotor‐spun yarns show higher tenacity at higher stretch levels compared with zinc chloride. The aqueous‐treated rotor‐spun yarns show a higher change in tenacity compared to ring‐spun yarns. Sodium hydroxide‐treated yarns before resin treatment show a higher retained tenacity compared to zinc chloride‐treated yarns. The substitution treatment after swelling and stretching to 100% shows a higher tenacity than that of the slack substituted yarns. © 1995 John Wiley & Sons, Inc.
Preparation and characterization of perlite‐filled high‐density polyethylenes. III. Impact properties
Authors: Akin‐Öktem G. , Tinçer T. 
Published: April 2003

AbstractImpact properties of perlite‐filled high‐density polyethylene (HDPE) composites were studied with the Charpy method by using both notched and unnotched samples. γ‐Aminopropyltriethoxy silane (γ‐APS, A‐1100) was used as a silane coupling agent to improve the interfacial adhesion. The influences of the molecular parameters of HDPEs, molecular weight, degree of branching, degree of crystallinity, and also the effect of γ‐APS on the impact properties are represented in this work. © 1995 John Wiley & Sons, Inc.
Parameter estimation in emulsion copolymerization using reaction calorimeter data
Authors: Barandiaran María J. , De Arbina Lourdes López , De La Cal José C. , Gugliotta Luis M. , Asua José M. 
Published: April 2003

AbstractThe feasibility of estimating the kinetic parameters of emulsion copolymerization using only calorimetric measurements was investigated by simulation. It was found that for the case in which the average number of radicals per particle exceeds 0.5 only two of the three estimable parameters (kI, ka, and kt) could be estimated together provided that an accurate value for the third parameter is available from independent measurements. For systems with n̄<0.5, the three unknown parameters kI, kd, and ka were accurately estimated. © 1995 John Wiley & Sons, Inc.
Effect of processing conditions on the structure development in the welding region of injection‐molded poly(arylene ether ketone). III
Authors: Ulcer Y. , Cakmak M. , Hsiung C. M. 
Published: April 2003

AbstractEffect of injection‐molding process conditions including mold temperature and injection speed on the structure developed at the weld region of poly(arylene ether ketone) was investigated using MMBX (matrixing micro beam X‐ray diffraction) and image analysis techniques. The polymer exhibited multilayer structural formations at and near the weld region, and these were found to be alternating highly crystalline and low crystalline regions. With the exception of the converging section of the cavity, no significant orientations were observed through the X‐ray diffraction method. However, polarized light microscopy studies revealed that the bands of higher crystallinity possess higher birefringence as compared to the intervening regions. This suggested that these bands are formed under an orientational flow field. The geometrical pattern of these multilayer formations changes depending on the injection‐molding condition particularly with injection speed and mold temperature. Tensile test results indicate that the samples with no weld regions generally possess higher tensile strength. This difference between the tensile properties of the samples possessing weld and no weld decreases at high injection speeds. Izod impact strength exhibited an unusual behavior: The welded parts actually possess higher impact strength. This was attributed to the formation of multilayer structures at the weld zone. © 1995 John Wiley & Sons, Inc.
In‐line dielectric monitoring of monomer conversion in a batch polymerization reactor
Authors: Crowley Timothy J. , Choi Kyu Yong 
Published: April 2003

AbstractIn‐line monitoring of monomer conversion is studied using a low‐frequency dielectric sensor during solution polymerization of methyl methacrylate in a laboratory‐scale batch reactor. It has been found that the induction period due to the presence of an inhibitor can be determined by the dielectric sensor to detect the starting point of polymerization. The dielectric loss factor that changes with the progress of polymerization is empirically correlated with monomer conversion measured by the off‐line gravimetric method at different temperatures and initiator concentrations. It is demonstrated that dielectrometry can be used as an in‐line monitoring method in free‐radical polymerization. © 1995 John Wiley & Sons, Inc.
Thermal aging of bisphenol‐A polycarbonate/acrylonitrile–butadiene–styrene blends
Authors: Guest M. J. , van Daele R. 
Published: April 2003

AbstractThermal aging of immiscible bisphenol‐A polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) blends containing 25, 60, and 75% PC and the PC and ABS blend components have been studied. Changes in Izod impact properties and dynamic mechanical spectra are reported following aging at 90, 110, and 130°C for times up to 1500 h. PC/ABS blends containing 60 and 75% PC were found to retain high impact performance following aging at elevated temperatures, compared to the PC blend component. Dynamic mechanical spectroscopy is an effective probe for investigating the structure–property changes occurring and the mechanisms of aging. For PC and ABS, the changes were mainly due to physical aging of the amorphous polymers when aged below the glass‐transition temperature. For the PC/ABS blends, oxidative degradation additionally contributes to loss of toughness. Although structure–property changes are related to the behavior of the blend components, additional factors of potential importance for multiphase polymer–polymer systems have been identified, including a redistribution of stabilizers during the blend manufacture. © 1995 John Wiley & Sons, Inc.
FT‐IR spectroscopic investigations of photochemical grafting of amphiphiles onto polyacrylonitrile surfaces
Authors: Böhme Peter , Hicke Hans‐Georg , Ulbricht Mathias , Fuhrhop Jürgen‐Hinrich 
Published: April 2003

AbstractThe photoreactive amphiphile p‐(stearyl amido) benzoyl azide (SABAz) was synthesized and grafted onto surface of thin polyacrylonitrile (PAN) films by irradiation with UV light. Two different techniques were applied, namely, Langmuir–Blodgett (LB) deposition and casting from solution. A high degree of order and a hydrophobic surface were established by reflection‐absorption FT‐IR spectroscopy (RA‐IR) and contact angle measurements. The stability against treatment with water, tetrahydrofuran, and chloroform was tested. A considerable amount of amphiphilic molecules remains on the surface also after treatment with chloroform. RA‐IR spectra taken from photomodified PAN films prepared by both techniques are almost identical after chloroform treatment, indicating a similar coupling mechanism. © 1995 John Wiley & Sons, Inc.
Structural changes of PVC plastisols in progress of gelation and fusion as investigated with temperature‐dependent viscoelasticity, morphology, and light scattering
Authors: Kwak Seung‐Yeop 
Published: April 2003

AbstractThe structural changes of poly(vinyl chloride) (PVC) plastisols during mixing of PVC with a plasticizer was investigated; as the temperature was increased, the system was found to transform from a suspension of solid particles in a liquid medium to a swollen gel and ultimately to a fused homogeneous matrix. The dynamic viscoelastic measurements were utilized to continuously monitor the changes of moduli under a controlled heating rate, employing a mechanical spectrometer. Characteristic changes in the viscoelastic behavior were associated with changes in particulate morphology as observed with a scanning electron microscope (SEM). Both viscoelastic and morphological observations were shown to provide details of structural changes in conjunction with the behavior of the PVC–plasticizer interaction, enabling a qualitative discrimination of the gelation and fusion processes. An in situ small‐angle light‐scattering (SALS) method was performed to make a quantitative estimate for the swollen particles of PVC while they were in the progress of gelation and fusion. From the manner of increase in correlation distances, along with the changes in viscoelastic moduli and morphology, the swelling behavior of the particulate structures were examined on the quantitative basis and brief insight into the complex behavior of the PVC–plasticizer interaction began to be unfolded. © 1995 John Wiley & Sons, Inc.
Studies on miscibility of blends of poly(ethylene‐co‐methyl acrylate) and poly(dimethyl siloxane) rubber by melt rheology
Authors: Bhattacharya A. K. , Santra R. N. , Tikku V. K. , Nando G. B. 
Published: April 2003

AbstractRheological studies of the blends of poly(ethylene‐co‐methyl acrylate) (EMA) and poly(dimethyl siloxane) (PDMS) rubber have been carried out at various temperatures and different shear rates by a Monsanto processability tester. The melt viscosities of the blends are found to be higher than that calculated as per the additivity rule, showing a positive deviation, an indication of synergism present in the blends during melt processing. This confirms our earlier finding that the blends are miscible throughout the composition range. The activation energy of flow of the blends are always higher than that calculated as per the additivity rule. The comparatively higher activation energy for the 30 : 70 EMA–PDMS rubber blend among the systems studied confirms our earlier finding that extent of reaction between EMA and PDMS rubber is significantly higher at this proportion of the blends studied. This substantiates the miscibility between blends of EMA and PDMS rubber throughout the composition range. © 1995 John Wiley & Sons, Inc.
Prediction of mechanical properties of weather‐induced degraded plastics in saudi arabia
Authors: Amin M. B. , Hamid S. H. , Rahman F. 
Published: April 2003

AbstractEmpirical equations have been developed to predict the mechanical properties of greenhouse films when exposed to natural weather conditions for long durations. Tensile strength and percent elongation data obtained for the Dhahran site was used to develop empirical equations. Prediction models were developed with exposure time as independent parameter for both tensile strength and percent elongation, which were taken as dependent parameter. The mean deviations for tensile strength and percent elongation were found to be 2.5 and 1.2%, respectively. Weather data of Dhahran for the period of natural exposure is also presented. © 1995 John Wiley & Sons, Inc.
Aspects on interaction between multistage stabilization of polyacrylonitrile precursor and mechanical properties of carbon fibers
Authors: Wang P. H. , Yue Z. R. , Li R. Y. , Liu J. 
Published: April 2003

AbstractThe progression of polyacrylonitrile (PAN) fibers on multistage stabilization stage has been monitored by following the variations in density, elemental composition, morphological aspect, and mechanical properties. The effects of various processing conditions during the multistage stabilization on the mechanical properties of final carbon fibers were evaluated in detail. To achieve an optimal extent of stabilization of PAN fibers is critical as the final mechanical properties of carbon fibers are concerned. This aim can be realized by adjusting and matching the temperatures in each step and the processing rates during multistage stabilization. Imposing stretching on multistage stabilization is beneficial to mechanical properties of carbon fibers. © 1995 John Wiley & Sons, Inc.
Preparation and characteristics of ultrafine metal particles immobilized on fine polymer particles
Authors: Tamai Hisashi , Sakurai Hiroyuki , Hirota Yoshifumi , Nishiyama Fumitaka , Yasuda Hajime 
Published: April 2003

AbstractUltrafine metal particles immobilized on fine copolymer particles were produced by reduction of copolymer particles–metal ion complexes. Submicrometer‐size copolymer particles containing nitrogen, prepared by emulsifier‐free emulsion polymerization, were applied. Transmission electron microscopy (TEM) observation and X‐ray diffraction analysis indicated that ultrafine noble metal particles with diameter below 10 nm were formed and uniformly immobilized on the surface of copolymer particles. © 1995 John Wiley & Sons, Inc.
Improving adhesion in interleaf composites using plasma processing
Authors: Nay John C. , Pitt William G. , Armstrong‐Carroll Eileen 
Published: April 2003

AbstractA novel radio frequency (RF) plasma processing technique, known as plasma induced polymerization (PIP), was used in a multistep plasma process to deposit a thin, uniform layer of viscoelastic material on Upilex‐S high‐temperature polyimide film in order to enhance adhesion between the film and the resin in carbon fiber interleaf composites using epoxy (Hercules 8551‐7A) resin systems. In a three‐phase study, the processing parameters of residence time, plasma power, plasma pressure, and monomer gas were varied to investigate adhesion improvement. Depositions were characterized using scanning electron microscopy and X‐ray photoelectron spectroscopy (XPS) analysis. Compressive mode II strain energy release rate (GIIc) was characterized by end‐notched flexure testing to rank and predict the best RF process for a thermoplastic film interleaf composite structure using polymide film. Adhesion was improved by as much as 140% over the adhesive performance of untreated Upilex‐S using the epoxy resin system. However, adhesive performance was improved in the relatively low temperatures (177°C) processing system, and this plasma deposition may not be stable at the higher processing temperatures needed for processing polymide matrix systems such as PMR‐15. © 1995 John Wiley & Sons, Inc.
Plasma polymerization of hexafluoropropylene: Film deposition and structure
Authors: Chen R. , Gorelik V. , Silverstein M. S. 
Published: April 2003

AbstractThin, pinhole‐free, highly adhering films for advanced technology applications can be deposited through plasma polymerization, a low temperature, solvent‐free process. This research studies the influence of plasma environment (power, pressure, and monomer mass flow rate (Fm)) on the plasma polymerization of hexafluoropropylene (HFP) using a common industrial parallel‐plate plasma reactor. The deposition and structure of the transparent, yellow, and highly adhering plasma polymerized HFP (PPHFP) film are investigated. The rate of polymerization (Rp) increases with power (W) and reaches a plateau when the plasma changes from energy starved to monomer starved while the rate of etching (Re) continues to increase. The rate of deposition (Rd), the difference between Rp and Re, increases with W, reaches a maximum, and then decreases. In a monomer starved plasma Rd increases with Fm or pressure through a more efficient utilization of the energy supplied at a given W or even at a given W/Fm. The abstraction of F and the preferential scission of the CCF3 bond can explain the F/C ratio of 1.5, the significant amount of double bonds, and the relative lack of CF3 in a PPHFP that consists of CF3, CF2, and CF groups. A gas phase dominated polymerization produces submicrometer particles some of which agglomerate into spheres. Both the particles and the spheres deposit on the surface and are incorporated into the film with further polymerization. © 1995 John Wiley & Sons, Inc.
Surface modification of aromatic polyamide film by aminoethanethiol solution for silicon rubber composites
Authors: Inagaki N. , Tasaka S. , Kawai H. 
Published: April 2003

AbstractThe surface modification of poly(p‐phenylene terephthalamide) (PPTA) film with 2‐aminoethanethiol (AET) to adhere to silicon rubber was investigated. The combination of the AET treatment and the silane coupling treatment is an effective surface modification of the PPTA film for this adhesion. The x‐ray photoelectron spectroscopy (XPS) analyses show that the AET treatment does not generate sulfur functionalities at the surface of the PPTA film but does generate oxygen functionalities. In the AET treatment process, a part of the amide groups near the surface of the PPTA film is hydrolyzed to form carboxylic acid groups and amino groups. The oxygen functionalities are condensed at the film surface, and nitrogen functionality is diluted at the film surface. The C(O)O moiety at the PPTA film surface may be a key factor for the adhesion with silicon rubber. The C(O)O moiety is mobile from the bulk of the PPTA film to the film surface. Hot water treatment of the original PPTA film makes the impossible adhesion with the silicon rubber possible. The hot water treatment, however, is not as powerful a surface modification as the AET treatment. © 1995 John Wiley & Sons, Inc.
Rheological characteristics of proanthocyanidin polymers from Pinus radiata. I. Rheological behavior of water‐soluble extract fractions and phlobaphenes
Authors: Kim Seungrok , Mainwaring David E. 
Published: April 2003

AbstractThe rheological characteristics of the solutions of the whole extracts and their fractions from the Pinus radiata bark were investigated. The viscosity changes upon addition of aqueous NaOH solution into the solutions of the hot water extracts are due mainly to the dissolution of the phlobaphene fraction. The polyelectrolyte character was established from the solutions of the hot‐water extracts. The kinetics of the size growth of naturally forming phlobaphenes could be observed by photon correlation spectroscopy (PCS) from the solutions of hot‐water extracts. Mild sonication could degrade phlobaphenes partly and this indicates that the formation of phlobaphenes is partly associated with colloidal interaction. © 1995 John Wiley & Sons, Inc.
Isothermal cure kinetics of a diglycidyl ether of bisphenol A/1,3‐bisaminomethylcyclohexane (DGEBA/1,3‐BAC) epoxy resin system
Authors: Barral L. , Cano J. , López A. J. , López J. , Nogueira P. , Ramírez C. 
Published: April 2003

AbstractBy employing differential scaning calorimetry, DSC, we have studied, under isothermal conditions, the kinetics of the cure reaction for a system containing a diglycidyl ether of bisphenol A (DGEBA) and 1,3‐bisaminomethylcyclohexane (1,3‐BAC) as a curing agent, over the temperature range of 60–110°C. We have determined the conversions reached at several cure temperatures and the reaction rates. The experimental data, showing an autocatalytic behavior, were compared with the model proposed by Kamal, which includes two rate constants, k1 and k2, and two reaction orders, m and n. This model gives a good description of cure kinetics up to the onset of vitrification. The activation energies for these rate constants were 44–57 kJ/mol. The reaction orders present a moderate change but their sum is in the range 2.5–3. Diffusion control is incorporated to describe the cure in the latter stages (postivitrification region). By combining the autocatalytic model and a diffusion factor, it was possible to predict the cure kinetics over the whole range of conversion. © 1995 John Wiley & Sons, Inc.
Creep, stress rupture, and isothermal aging of reinforced polyphthalamide
Authors: Lyons Jed S. , Tinio Edgardo G. , Berry Scott F. 
Published: April 2003

AbstractThe effects of time, temperature, and particulate filler on the tensile behavior of short fiber‐reinforced polyphthalamide (PPA) were investigated experimentally. Creep and stress‐rupture characteristics and tensile properties before and after isothermal aging were determined. Temperatures ranged from 23 to 150°C and tests lasted up to about 4000 h. Stress‐rupture master curves were created, using a WLF‐type analysis, which can be used for interpolation with reasonable accuracy. Creep rates were low but were affected by increased moisture absorption in the lowest temperature environment. All properties were affected by chemical degradation of the PPA matrix at the highest temperature. Under most conditions investigated, the mineral filler improved the creep resistance and stiffness of the PPA resin at the expense of strength and ductility. Scanning electron microscopy examinations of fractured specimens indicated that the mineral filler embrittled the matrix and may have damaged the fibers during processing. © 1995 John Wiley & Sons, Inc.