bluuebunny/crossref_metadata_2025_split huggingface dataset:
1H T2‐NMR monitoring of crosslinked polyolefin aging
Authors: Harris Douglas J. , Assink Roger A. , Gillen Kenneth T. 
Published: September 2003

AbstractThis work examines the correlation between the 1H‐NMR T2 relaxation constant and the mechanical properties of aged crosslinked polyolefin cable insulation. T2 experiments on unswollen samples could not differentiate between unaged and highly aged materials; all exhibited 1H T2 constants of approximately 0.5 ms. To accentuate the effects of aging, samples were swollen in various solvents. Unaged samples had T2 values of approximately 15 ms in good solvents. With thermal aging, T2 values decreased as the ultimate tensile elongation decreased. However, the correlation between T2 and elongation differed for samples irradiated with high‐energy radiation and for materials aged above versus below the crystalline melting temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2578–2582, 2003
Compatibilization of PE/PS and PE/PP blends. I. Effect of processing conditions and formulation
Authors: Kallel Tasnim , Massardier‐Nageotte Valérie , Jaziri Mohamed , Gérard Jean‐François , Elleuch Boubaker 
Published: September 2003

AbstractThe objective of this work was to study the effectiveness of low‐cost commercial compatibilizers and several processes (internal mixer, single‐ and twin‐screw extruders) for two types of plastic blends: high‐density polyethylene/polypropylene and high‐density polyethylene/polystyrene blends, to gain insight into the recycling of wastes from those frequently encountered mixed plastics. Blends going from a pure A to a pure B component, with and without a compatibilizer, were prepared using an internal mixer, a corotating twin‐screw extruder, as well as a single‐screw extruder to follow an industrial‐convenient process. In both cases, the analyses of blend morphologies highlighted the poor adherence between the two phases in the uncompatibilized blends. Compatibilized blends display better adherence between phases and the ability to process blends made from both single‐ and twin‐screw extruders. When adding a compatibilizer, the viscosity of each blend (PE/PP or PE/PS) increased due to a better adhesion of the phases. Charpy impact tests showed that the presence of the compatibilizer in PE/PS blends increased their impact properties. Indeed, the improvement of the adhesion between the two phases enabled stress transfer at the interface. A single‐screw extruder seems to be efficient as a processing method on an industrial scale when a compatibilizer is used. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2475–2484, 2003
Influence of the reaction mechanism on the shape accuracy of optical components obtained by photoreplication
Authors: Verstegen E. J. K. , Faasen J. H. P. , Stapert H. R. , Duineveld P. C. , Kloosterboer J. G. 
Published: September 2003

AbstractLight‐induced crosslinking polymerization of both bis‐methacrylates and bis‐epoxides yields highly transparent glassy products, suitable for optical applications. Rheological changes of vitrifying liquids during photopolymerization strongly influence the shape accuracy of the final product. Comparison of a free‐radical‐initiated methacrylate polymerization and a cationically initiated ring‐opening polymerization of an epoxide showed that different reaction mechanisms led to very different chemorheological responses and, hence, to pronounced differences in the shape accuracy of the products obtained with either of these materials. An ethoxylated bisphenol‐A dimethacrylate (HEBDM) gels below 1–2% conversion and vitrifies at 15%. At higher conversion, large stresses develop through polymerization shrinkage. Relaxation occurs upon release of a product from its mold, leading to large shape deviations. Ring‐opening polymerization of the diglycidyl ether of bisphenol‐A (DGEBA) has an intrinsically lower polymerization shrinkage. Moreover, gelation of DGEBA polymer networks occurs at 25–30% conversion, leading to much lower stresses since most of the volume change occurs in the liquid state in which replenishment of a monomer can still occur. Upon release from a mold, there is hardly any driving force for relaxation, so a much better copy of the mold is obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2364–2376, 2003
Computer simulation of the filling process in gas‐assisted injection molding based on gas‐penetration modeling
Authors: Zhou Huamin , Li Dequn 
Published: September 2003

AbstractGas‐assisted injection molding can effectively produce parts free of sink marks in thick sections and free of warpage in long plates. This article concerns the numerical simulation of melt flow and gas penetration during the filling stage in gas‐assisted injection molding. By taking the influence of gas penetration on the melt flow as boundary conditions of the melt‐filling region, a hybrid finite‐element/finite‐difference method similar to conventional‐injection molding simulation was used in the gas‐assisted injection molding‐filling simulation. For gas penetration within the gas channel, an analytical formulation of the gas‐penetration thickness ratio was deduced based on the matching asymptotic expansion method. Finally, an experiment was employed to verify this proposed simulation scheme and gas‐penetration model, by comparing the results of the experiment with the simulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2377–2384, 2003
Effect of mercapto‐modified ethylene–vinyl acetate on the curing parameters and mechanical and dynamic mechanical properties of vulcanized nitrile rubber/ethylene–vinyl acetate blends
Authors: Jansen Paulo , Garcia Filiberto G. , Soares Bluma G. 
Published: September 2003

AbstractThe compatibilizing effect of mercapto‐modified ethylene–vinyl acetate (EVALSH) was investigated in vulcanized nitrile rubber (NBR)/ethylene–vinyl acetate (EVA) copolymer blends. EVALSH increased the ultimate tensile strength, mainly in blends containing larger amounts of NBR. In addition, an accelerating effect of this functionalized copolymer was observed in blends vulcanized with the sulfur system. This behavior was confirmed with oscillating disk rheometry and differential scanning calorimetry analyses. The improvement of the mechanical performance was attributed to the interfacial action associated with the increase in the crosslink density of the NBR phase promoted by the mercapto groups in EVALSH. The effects of EVALSH on the morphology and dynamic mechanical properties were also studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2391–2399, 2003
Small‐angle X‐ray scattering from polyethylene: Distorted lamellar structures
Authors: Marega Carla , Marigo Antonio , Causin Valerio 
Published: September 2003

AbstractSome theoretical models, including lamellar distortions of the second kind, are described. To test the influence of lamellar distortions on the small‐angle X‐ray scattering (SAXS) of polymers, some theoretical patterns were calculated with different values of the model parameters. SAXS diffraction profiles were recorded for three commercial copolymer samples of linear low‐density polyethylene containing different comonomers and one commercial homopolymer sample of high‐density polyethylene; these were successively analyzed by a fit to the calculated profiles corresponding to our theoretical models. Transmission electron microscopy images were obtained of the lamellar morphologies of the four samples. From these, we concluded that the homopolymer sample displayed excellent organization on lamellar stacks, whereas the copolymer samples showed more imperfect lamellar morphologies, so it was useful, in the latter case, to introduce a distorted lamellar structure in calculated SAXS diffraction patterns. By use of wide‐angle X‐ray scattering, we also determined the overall crystallinities of the samples. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2400–2407, 2003
Preparation of O‐carboxymethyl chitosans and their effect on color yield of acid dyes on silk
Authors: Wu Yi Guang , Chan Wing Lai , Szeto Yau Shan 
Published: September 2003

AbstractO‐Carboxymethyl chitosans with a low degree of substitution (DS) and a high degree of deacetylation (DD) were prepared directly from chitin and characterized by using 1H‐NMR, 13C‐NMR, and elemental analysis methods. In our study, O‐carboxymethyl chitosans could increase the color yield of Acid Red 44 and Acid Green 25 on silk fabrics without lowering the corresponding washing fastness property. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2500–2502, 2003
Ultraviolet curing kinetics of cycloaliphatic epoxide with real‐time fourier transform infrared spectroscopy
Authors: Chen Jianxia , Soucek Mark D. 
Published: September 2003

AbstractThe photo‐induced curing kinetics of cycloaliphatic epoxide coatings were investigated with real‐time Fourier transform infrared spectroscopy with an optical fiber ultraviolet curing system. The consumption of epoxy group as a function of time was obtained by monitoring of the oxirane absorbance in the 789–746‐cm−1 region. The effect of the type of epoxide, hydroxyl equivalent weight, ratio of oxirane to hydroxyl groups (R), photoinitiator, and exposure time on the curing reaction was investigated. In general, the rate of curing was dependent on the hydroxyl equivalent weight, R, type of epoxide, and photoinitiator. For formulations without polyol, both initiator concentration and exposure time had minimal effects on the curing reaction. However, for formulations with polyol, the curing a reaction was dependent on the initiator concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2485–2499, 2003
Ion‐plasma modification of polyvinylchloride microfiltration membranes
Authors: Vladkova T. G. , Dineff P. , Stojcheva R. , Tomerova B. 
Published: September 2003

AbstractHere we present how the surface and some filtration properties of PVC microfiltration membranes are affected by controlled and well‐defined modification by ion‐plasma treatment in the kinetic region of the high voltage (HVGD) or normal glow discharge (NGD) in air. The surface energy and work of adhesion of the samples were calculated from the contact angle with both polar (H2O) and nonpolar (CH2I2) liquid measurement data. The surface morphology was observed by SEM and the surface chemical composition was analyzed by ESCA. The trans‐membrane water flux, the average pore size, and the pore‐size distribution as well as the “bubble point” were used to control the effect of the ion‐plasma treatment on the filtration properties of the PVC microfiltration membranes. Two characteristic regions of the ion‐plasma treatment in air were found in our experiments where the surface properties and filtration characteristics of the membranes are extremely changed: at a pressure of 10–15 Pa in the region of the HVGD and at a pressure of 100–120 Pa in the region of the NGD. It was shown that the ion‐plasma treatment in air is an effective technological method for regulation of some important surface and filtration properties of PVC microfiltration membranes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2433–2440, 2003
DSC analysis of epoxy molding compound with plasma polymer–coated silica fillers
Authors: Roh J. H. , Lee J. H. , Kim N. I. , Kang H. M. , Yoon T.‐H. , Song K. H. 
Published: September 2003

AbstractSilica fillers were modified by plasma‐polymerization coating of 1,3‐diaminopropane, allylamine, pyrrole, 1,2‐epoxy‐5‐hexene, allylmercaptan, and allylalcohol using RF plasma (13.56 MHz). Modified fillers were then mixed with biphenyl epoxy resin, phenol novolac (curing agent), and optionally triphenylphosphine (catalyst) to prepare samples for DSC analyses. Some samples were also prepared from uncoated silica fillers and monomers used in plasma polymerization coating, instead of plasma polymer–coated silica fillers. Plasma polymer–coated silica fillers were characterized by FTIR, XPS, and water contact angle measurements. In DSC analyses, all samples with plasma polymer–coated silica fillers showed a large peak and an additional one or two small exothermic peaks when catalyst was added, compared to only one large peak with as‐received silica fillers. The large peak could be from epoxy–phenol novolac reaction in the presence of catalyst, whereas small reaction peaks were attributed to the chemical reaction between epoxy resin and functional moieties in the plasma polymer coating, such as amine, OH, and/or SH groups, as evidenced by FTIR and XPS analysis and contact angle measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2508–2516, 2003
Creation of functional materials by use of a slow crystallization process in the nonequilibrium state. I. porous polyamide microparticles
Authors: Asano Yukihiko , Nakayama Kimio , Yao Shigeru 
Published: September 2003

AbstractRecently a number of investigations have focused on the self‐organization process from the nonequilibrium state as a new technique that may be used to develop many functional materials. In many cases, amorphous polymers were used and semicrystalline polymers were seldom used in spite of their importance. In this study, we basically investigated the crystal structure, crystalline process, and inner structures of polyamide by using slow phase separation and crystallization process from the nonequilibrium state of the polymer solution. We were able to observe the crystalline lamella growing twisted from the center of the particle. Between these lamella layers, narrow pores were created. From this investigation, we developed a new method to create functional materials of polyamide, the semicrystalline polymer. Porous spherical particles may be properly applied to functional materials such as adsorption materials, catalyst support materials, and so on. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2428–2432, 2003
Evaluation of isomeric composition of resol‐type phenol formaldehyde matrix resins for silica–phenolic composites and its effect on cure characteristics of the resin
Authors: Scariah K. J. , Usha K. M. , Narayanaswamy K. , Shanmugam K. , Sastri K. S. 
Published: September 2003

AbstractThe isomeric composition of several samples of resol‐type phenol formaldehyde resins used for silica–phenolic composites was evaluated by 1H‐ and 13C‐NMR spectroscopy and reverse‐phase HPLC techniques. The variations in the isomeric compositions were attributed to inadvertent variations in the process parameters. A mathematical relation was determined for calculation of free phenol from 1H‐NMR measurements. The samples were cured at 160°C for 8 h in an inert atmosphere of N2. The extent of cure in the hardened samples was measured by FTIR analysis. The effect of isomeric composition on the extent of cure was studied. Free phenol and p‐hydroxymethyl phenol, exhibiting a linear correlation, were found to have a pronounced effect on the extent of cure. The cure kinetics were derived by dynamic DSC measurements. Activation energy (E) for curing exhibited a near linear correlation independently with free phenol content and the extent of cure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2517–2524, 2003
Pervaporation separation of water–isopropanol mixtures using ZSM‐5 zeolite incorporated poly(vinyl alcohol) membranes
Authors: Kittur A. A. , Kariduraganavar M. Y. , Toti U. S. , Ramesh K. , Aminabhavi T. M. 
Published: September 2003

AbstractA solution technique was employed to prepare ZSM‐5 zeolite incorporated poly(vinyl alcohol) (PVA) membranes for the pervaporation separation of water–isopropanol mixtures. The membranes were characterized by Fourier transform infrared spectroscopy and differential scanning calorimeter. Glass transition temperatures of the membranes varied from 102 to 110°C, with increasing zeolite content of the membrane. The effect of zeolite loading and feed composition on pervaporation performance of the membranes was analyzed. The membrane containing 6 mass % of zeolite gave the highest separation selectivity of 216 for 10 mass % of water containing feed mixture at 30°C. Increase in water selectivity of the membrane was explained as due to a reduction in free volume by increasing zeolite content of the membrane. Separation selectivity and permeation flux data are dependent on water composition of the feed mixture, but are comparatively less dependent on temperature. The hindrance of water permeation at higher composition of water in the feed mixture was explained as due to the formation of clusters of water molecules. The overall activation energy and preexponential factors were calculated using Arrhenius equation. Pervaporation data have also been explained on the basis of thermodynamic parameters calculated by using Arrhenius equation as well as relationship proposed by Ping et al. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2441–2448, 2003
Preparation and characterization of a polyaniline/poly(butyl acrylate–vinyl acetate) composite as a novel conducting polymer composite
Authors: Mirmohseni Abdolreza , Valiegbal K. , Wallace G. G. 
Published: September 2003

AbstractThis is the first report on the preparation and characterization of a polyaniline/poly(butyl acrylate–vinyl acetate) composite. The composite was prepared by the emulsion polymerization of aniline in a medium containing poly(butyl acrylate–vinyl acetate). Films prepared from the composite (cast from an aqueous medium) had excellent mechanical properties and could be stretched up to 900%. The resultant composite was soluble in common organic solvents, and a stable water‐based dispersion could also be prepared. An electrical conductivity of 2.2 S cm−1 was obtained. Cyclic voltammograms revealed that the composite was electroactive. It had excellent adhesion to either glass or steel plate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2525–2531, 2003
Processing and characterization of epoxy–anhydride‐based intercalated nanocomposites
Authors: Torre L. , Frulloni E. , Kenny J. M. , Manferti C. , Camino G. 
Published: September 2003

AbstractA study of the kinetic and thermal characterization of an epoxy resin (DGEBA) polymerized with a methyl tetrahydrophthalic anhydride reinforced with montmorillonite‐layered silicates is presented. The nanoreinforcement used was compatibilized by exchanging the cations between the silicate layers with alkylammonium salts, containing long hydrocarbon chains. The aim of this study was to develop new nanocomposites based on thermoset resins with improved thermal stability, suitable for electronic applications. Differential scanning calorimetry was used here to produce the polymerization kinetics data, while thermogravimetric analysis was used to evaluate the effects of the nanoreinforcements on the thermal stability and to analyze the degradation kinetics. Unexpected strong effects of the nanocomposite on the polymerization kinetics of the epoxy–anhydride system were detected and evaluated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2532–2539, 2003
Matrix‐assisted laser desorption/ionization mass spectrometry of synthetic polymers. VI. Analysis of phenol–urea–formaldehyde cocondensates
Authors: Schrod M. , Rode K. , Braun D. , Pasch H. 
Published: September 2003

AbstractPhenolic resoles can be regarded as copolymers of phenol and formaldehyde that are distributed in the chain length and the number of methylol groups per molecule. While other spectroscopic methods like FTIR and NMR only give average structures, MALDI–TOF mass spectrometry is able to resolve the oligomer distribution of phenolic resoles. Using 2,5‐dihydroxybenzoic acid or 2,4,6‐trihydroxyacetophenone as matrices, MALDI–TOF spectra are obtained where each oligomer peak can be assigned to a particular chemical structure. Thus, the degree of polymerization and the number of reactive methylol groups can be determined. For urea‐modified resoles, in addition to phenol–formaldehyde and urea–formaldehyde structures, for the first time, phenol–urea–formaldehyde cocondensate structures can be identified directly. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2540–2548, 2003
Investigation of ethylene and styrene copolymerization initiated with dinuclear constrained geometry catalysts holding polymethylene as a bridging ligand and indenyl as a cyclopentadienyl derivative
Authors: Noh Seok Kyun , Yang Youngdo , Won Seok Lyoo  
Published: September 2003

AbstractA series of polymethylene‐bridged dinuclear constrained geometry catalysts (CGC) [Me2Si(Ind)(NtBu) TiCl2]2[(CH2)n] (1, n = 6; 2, n = 9; 3, n = 12) were synthesized to study the copolymerization of ethylene and styrene. The experiments display that the polymerization activity of the dinuclear catalysts increased in the order of 1 < 2 < 3, which indicated that the dinuclear CGC with the longest methylene units as a bridge showed the greatest activity. According to the activity correlation with the monomer ratio, all the catalysts exhibited maximum polymerization activity at the monomer ratio of ([styrene]/[ethylene]) of 2. The dinuclear CGC 2 and 3 represented excellent characteristics of styrene reactivity while catalyst 1 represented considerably low styrene reactivity. The relation between the molecular weights of the polymers and the catalysts used in the polymerization is not straightforward. The steric interference in catalyst 1, containing just six methylene bridges, can be applied to explain not only the strikingly decreased activity but also the very low styrene content in the copolymer. In contrast, the electronic effect seems to be more pronounced in manipulating the polymerization properties of catalysts 2 and 3 having nine and 12 methylene bridges, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2469–2474, 2003
Electrochemical preparation of poly(2‐bromoaniline) and poly(aniline‐co‐2‐bromoaniline) in acetonitrile
Authors: Şahin Yücel , Peŗin Sabriye , Şahin Mutlu , Özkan Güleren 
Published: September 2003

AbstractElectrochemical preparation of poly(2‐bromoaniline) (PBrANI) and poly(aniline‐co‐2‐bromoaniline) [P(An‐co‐2‐BrAn)] was carried out in an acetonitrile solution containing tetrabutylammonium perchlorate (TBAP) and perchloric acid (HClO4). The cyclic voltammograms during the copolymerization had many features similar to those for the usual polymerization of aniline. The copolymer exhibits a higher dry electrical conductivity value than that of PBrANI and a lower one than that of PANI. The observed decrease in the conductivity of the copolymer relative to PANI is attributed to the incorporation of bromine moieties into the polyaniline chain. The structure and properties of the polymer and copolymer were elucidated using cyclic voltammetry (CV), FTIR, and UV‐vis spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2460–2468, 2003