bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal properties of tropical wood–polymer composites
Authors: Yap M. G. S. , Que Y. T. , Chia L. H. L. , Chan H. S. O. 
Published: April 2003

AbstractWood–polymer composites (WPC) of Geronggang (GE; Cratoxylon arborescens), a light tropical hardwood, impregnated with methyl methacrylate (MMA), styrene‐co‐acrylonitrile (3: 2; STAN), methyl methacrylate‐co‐bis (2‐chloroethyl) vinyl phosphonate (3 : 1; MVP) and methyl methacrylate‐co‐bis (chloropropyl)‐2‐propene phosphonate (3:1;MPP), were prepared by in situ polymerization using γ‐radiation or catalyst‐heat treatment. Thermal characterization of these WPC by limiting oxygen index measurements (LOI), thermogravimetry (TG), and differential scanning calorimetry (DSC) showed that the impregnants greatly modified the wood properties. The LOI values of the GE–MVP and GE–MPP composites were much higher than that for GE and the other composites, indicating the effectiveness of the phosphonates as flame retardants. Concomitantly, the flaming characteristics also compared favorably against that for GE and the other composites. The decomposition temperature and maximum rate of weight loss determined by TG for GE–MVP and GE–MPP were substantially reduced, whereas the char yields were greatly higher. These observations again indicate that phosphonates imparted flame‐retarding properties to their composites. The thermal properties of GE–MMA and GE–STAN composites were not vastly different from that of untreated GE. Flame retardancy in the phosphonate‐containing composites was effected through both the condensed‐ and gaseous‐phase mechanisms due to the presence of phosphorus and chlorine, respectively. Indication of grafting of polymer to wood was found for GE–STAN, GE–MVP, and GE–MPP composites, but not for GE–MMA. Composites prepared by γ‐radiation or by the catalyst‐heat treatment had similar thermal characteristics.
Polymers derived from 2‐furaldehyde and aromatic diamines. I
Authors: Patel Hasmukh S. , Majmudar Gopal H. 
Published: April 2003

AbstractPoly[imino (cyclopent‐2‐en‐1‐one‐2,4‐diyl) iminoarylenes] were prepared by the condensation of 2‐furaldehyde with various aromatic diamines in solution at room temperature. All polycondensations were carried out in one step and under identical conditions. It was observed that the most likely condensation reaction is through the furan rearrangement that leads to poly[imino (cyclopent‐2‐en‐1‐one‐2,4‐diyl) iminoarylenes]. The structures of all the polymer samples were confirmed by elemental analyses and by comparison of IR spectral characteristics with those of a model compound derived from 2‐furaldehyde and aniline. Number average molecular weights of all polymer samples were estimated from nonaqueous conductometric titration. The viscometric measurements of solutions of polymer samples in a formic acid–acetic acid (85 : 15) (v/v) mixture exhibited polyelectrolyte behavior. The thermal properties of polymer samples were revealed by thermogravimetry. The formation of the polymeric product is also explained. The result of preliminary tests for glass reinforcement of commercial epoxy resin and produced polymer samples suggest that laminate sheets with good mechanical strength can be obtained.
ESR studies of solvent penetration into polymer‐blend‐like material: Particles formed from poly(methyl methacrylate) and polyisobutylene
Authors: Pekcan Önder , Demir Yusuf 
Published: April 2003

AbstractSolvent penetration into nonaqueous dispersions (NAD) of poly(methyl methacrylate) (PMMA) sterically stabilized by PIB were studied by ESR spectroscopy. These colloidal particles were exposed to dilute solution of spin probe 3‐carbomoyl 2,2,5,5‐tetramethyl 3‐pyrolin‐1‐yloxy and the bimodal distribution of ESR spectra of this probe molecules were carefully monitored as a function of time. Fickian type diffusion of spin probes into the particles was observed and a spherical model was employed to obtain the diffusion coefficients (D) in various solvents. D values were found around 10−15 cm2/s, and interpreted as the parameter, inversely proportional to the apparent viscosity of the environment inside the colloid particle. Maximum amount of diffused solvent molecules (M∞) into the PMMA particle was found inversely proportional to polymer‐solvent interaction through the solubility parameters. The interconnected network of PIB was found to be responsible for the penetration of spin‐probe (i.e., solvent) molecules into the glassy PMMA phase and/or PIB‐PMMA interface.
Linear polyesters. Products of interfacial polycondensation of bis(4‐hydroxyphenyl) ether with isomeric phthaloyl chlorides
Authors: Podkoscielny Wawrzyniec , Wdowicka Danuta 
Published: April 2003

AbstractNew polyesters were obtained by interfacial polycondensation of bis(4‐hydroxyphenyl) ether with phthaloyl, isophthaloyl, and terephthaloyl chlorides. The initial reaction conditions were as follows: the aqueous to organic phase ratio 1 : 1, reaction temperature 25°C, the rate of chloride addition about 10 min, and molar ratio of the reagents diol/acid dichloride 1 : 1.1, benzene‐hexane as an organic phase. To determine the optimal conditions for interfacial polycondensation, the influence of the following factors on yield and value of reduced viscosity were studied: organic phase, excess of sodium hydroxide as an acceptor of HCl, contribution of benzyltriethylammonium chloride as a catalyst, and contribution of an emulsifier, Mersolan. The structure of all polyesters was determined by elemental analysis and infrared spectra. Initial decomposition and initial intensive decomposition temperature were defined by the curves of thermogravimetric analysis. Some mechanical and electrical properties of isophthaloyl polyester, only partly soluble in organic solvents, were determined.
Immobilization of catalase by polyion complex
Authors: Kohjiya Shinzo , Maeda Kazuyuki , Yamashita Shinzo 
Published: April 2003

AbstractCatalase was immobilized in a polyion complex from poly(sodium 2‐acrylamide‐2‐methyl‐1‐propanesulfonate) and poly[2‐(trimethylammonioethyl) methacrylate chloride]. Polyion complex formation between the two polyions was found to proceed stoichiometrically by the turbidimetric titration. Immobilization of catalase was achieved by conducting the complexation in the presence of the enzyme, which was established to be incorporated in the polyion complex networks. The fixed catalase showed higher thermal stability than the original enzyme. Furthermore, the stability and the activity of the fixed catalase were improved by annexing inert components such as albumin, histone, or lecithin at the time of polyion complex formation.
Self‐vulcanizable rubber blend based on neoprene and carboxylated nitrile rubber: Effect of blend ratio on miscibility and physical properties
Authors: Mukhopadhyay Sujata , De S. K. 
Published: April 2003

AbstractMill mixed blend of neoprene and carboxylated nitrile rubber can be vulcanized during molding at high temperatures (180°C) in the absence of any vulcanizing agent, which is supported by FTIR studies. The extent of vulcanization reaction depends not only upon the molding time but also on the blend ratio. Dynamic mechanical analyses and differential scanning calorimeter studies show that neoprene and carboxylated nitrile rubber are not miscible at the segmental level in the self‐vulcanized blend.
SMA polymer thin film electrodeposition on carbon particles
Authors: Desai V. M. , Mahalingam R. , Subramanian R. V. 
Published: April 2003

AbstractElectrodeposition of styrene‐co‐maleic anhydride (SMA) polymer, as thin films on carbon particle substrates, was carried out in a fluidized electrode bed reactor (FEBR). Feeder current, time of deposition, flow rate of anolyte (i.e., bed expansion or bed porosity), concentration of SMA in the anolyte, and pH of the anolyte were the key parameters investigated. The film characteristics were evaluated through SEM and FTIR analyses, the amounts determined by weighing. The effect of these parameters on the electrodeposition process is discussed and optimum conditions for deposition are proposed. Also, a possible mechanism for electrodeposition, particularly for the SMA–carbon system, is discussed. Furthermore, where relevant, the parameters and mechanism are compared with those for our parallel work on the ethylene‐co‐acrylic acid (EAA)–carbon system.
Processing of poly(amide imides) as matrices for high‐performance composites
Authors: Copeland S. Douglas , Seferis James C. , Carrega Marc 
Published: April 2003

AbstractPoly(amide imide) (PAI) has proven to be an excellent engineering thermoplastic. Injection and compression molding processes are currently used to produce poly(amide imide) parts when superior toughness, solvent resistance, and high‐temperature heat performance are required. The objective of this work was to determine the essential features necessary to use these systems as matrices for carbon‐fiber‐reinforced composites. The principal steps utilized were: impregnation of the carbon fibers with a PAI solution, drying the solvent from the individual plies, stacking the plies for final consolidation, and a postcure. A processing cycle was developed applicable to resins with different solvent concentration and molecular weight, giving special attention to the solvent evaporation step. A model capable of predicting the rate of evaporation as a function of temperature was developed using the principle of time–temperature superposition. A viscosity model similar to that for a curing thermoset was developed by combining Arrhenius expressions for the temperature and concentration effects. Collectively, this work then provided insight for matrix requirements in the formulation of PAI composites by solvent impregnation.
Application of computed X‐ray tomography scanning in the study of thermo‐oxidative degradation of thick‐walled filled natural rubber vulcanizates
Authors: Lavebratt H. , Östman E. , Persson S. , Stenberg B. 
Published: April 2003

AbstractThe aging of five thick‐walled natural rubber compounds has been studied by computed X‐ray tomography scanning and crosslink density measurements. The compounds were compouded as ordinary carbon‐black‐filled rubbers with sulfur and peroxide as curing agents. The rubber samples were aged in air at 70, 100, and 150°C for 1000h. The relatively new technique of computed X‐ray tomography scanning proved to be a good method for studying the aging procedure, and especially for following the crack propagation in the surface. Antioxidants (TMQ and 6PPD) had a low effect on the resistance toward oxidative degradation and crosslinking under these conditions. Surprisingly, the efficient sulfur‐vul‐canized material had a poor resistance toward thermal degradation. When the crosslink density and the computed X‐ray tomography scanning results were compared, it was assumed that the computed X‐ray tomograph detected oxygen in the surface, both as elementary oxygen and as oxygen in degradation products, i.e., in carbonyls. The results agree well with the theory that oxidative aging is limited by the ability of the oxygen to diffuse into the material.
Photocrosslinking reactions of polyfunctional monomers with vinyl ether or propargyl ether groups
Authors: Nishikubo Tadatomi , Hayashi Yasuyuki , Iizawa Takashi , Sasaki Takashi , Matsumoto Tsuyoshi , Fukudome Toshiyuki 
Published: April 2003

AbstractPhotocrosslinking reactions of di(2‐vinyloxy)ethyl ether of bisphenol‐A (BPAEVE), dipropargyl ether of bisphenol‐A (BPAPE), and diglycidy ether of bisphenol‐A (BPAGE) were carried out using various cationic photoinitiators in 1,2‐dichloroethane. The reaction of BPAEVE occurred with high conversion to give the gel products, and the reaction rate of BPAEVE was higher than that of BPAGE. While, the photocrosslinking reaction of BPAPE did not take place under the same conditions.Photoinitiated Michael addition reactions of BPAEVE, BPAPE, and other dipropargyl ethers or ester with pentaerythritol (2‐tetramercapto)propionate (PETMP) also proceeded very smoothly to give the gel products by using benzophenone as a photosensitizer in THF. Although the rate of addition reaction of BPAEVE was strongly influenced by the photosensitizer concentration, the addition reaction of BPAEVE with PETMP propagated effectively to give the gel products even without the presence of photosensitizer when irradiated with UV light in THF or toluene solution.
Plasma polymerization of organosiloxanes
Authors: Cai Shide , Fang Jianglin , Yu Xuehai 
Published: April 2003

AbstractPlasma polymerization of disiloxanes containing various functional groups—hexamethyldisiloxane (HMDSO), tetramethyl‐1,3‐bis(chloromethyl)‐disiloxane (CMDSO), tetramethyl‐1,3‐bis(hydroxylbutyl)‐disiloxane (HBDSO), and tetramethyl‐1,3‐bis(amino propyl)‐disiloxane (APDSO)— was carried out using an inductively coupled electrodeless glow discharge. The monomer polymerization kinetics and the distribution of chemical species deposited showed that monomer reactivity varied among the different siloxanes. Monomers of APDSO and CMDSO possessed higher rates of polymerization. Polymer IR spectra and ESCA analyses indicated that the chemical structures of plasma‐polymerized products of HMDSO, HBDSO, and CMDSO resembled that of crosslinked polydimethylsiloxane. The polar hydroxyl and chlorine functionality in the HBDSO and CMDSO monomers was not present in the deposited films. In contrast, the polymerized product of APDSO retained amino functionality and also formed new Si–H bonds.
Interpenetrating polymer networks: High molecular weight natural rubber and poly(2,6‐dimethyl‐1,4 phenylene oxide)
Authors: De Barros G. G. , Huang M. W. , Frisch H. L. 
Published: April 2003

AbstractSimultaneous interpenetrating polymer networks (IPNs) of high molecular weight natural rubber (NR) from Manihot glaziovii and poly(2,6‐dimethyl‐1,4 phenylene oxide) were prepared and characterized. A number of pseudo IPNs and blends of these materials were also studied. A single phase morphology is found in full IPNs with either high or low weight percent of NR. The intermediate composition full IPNs, pseudo IPNs, and blends all exhibited microphase separation, as seen by both DSC and SEM studies with domains sizes in the range of 1000–4000 nm. In the discussion we briefly compare these IPNs with the other previously prepared IPNs of poly(2,6‐dimethyl‐1,4‐phenylene oxide).
Surface modification of UHSPE fibers through allylamine plasma deposition. I. Infrared and ESCA study of allylamine plasma formed polymers
Authors: Li Z.‐F. , Netravali A. N. 
Published: April 2003

AbstractAllylamine (CH2CHCH2NH2) was polymerized through rf generated plasma at varying powers and times. Chemical groups and elemental compositions in the polymers were studied using ESCA and infrared spectroscopy. It was observed that plasma derived polymers contained a significant number of primary amines, along with some secondary and tertiary amines, imines, and nitrile groups. Plasma derived polymers had a complex structure and contained unsaturated groups. A considerable amount of oxygen, primarily from residual air in the plasma reaction chamber, and possibly from atmosphere when plasma polymers were exposed to air, was responsible for carbonyl, amide, ether, and hydroxyl groups found in the polymer structure. Some silicon was also detected in the plasma deposited films.
Effects of poly(vinyl alcohol) suspension medium on critical current density of Ba2Y1Cu3 oxide superconducting filaments produced by suspension spinning method
Authors: Goto Tomoko , Yamada Keisaku 
Published: April 2003

AbstractSuperconducting Ba2Y1Cu3 oxide filament was produced by means of the suspension spinning method. The effects of poly(vinyl alcohol) (PVA) suspension medium on structure and critical current density (Jc) of the filament sintered were explored with PVA of various degrees of polymerization (DP) in dimethyl sufoxide (DMSO), hexamethylphosphoric triamide (HMTA) and the mixed solution of DMSO and HMTA (1 : 1). Although the PVA was removed as a volatile component by heating treatment of the filament, the dispersion behavior of the oxide powder in the filament was dependent on the suspension medium, hence the microstructure and superconducting properties of the filament obtained was affected by the suspension medium. The filament spun through the mixed solution of DMSO and HMTA had a high Jc of 77 K more than 100 A/cm2 at the wide range of DP and powder content. The crystal grains of the oxide in the sintered filament grew finer with increasing the DP of PVA. On the other hand, the Jc of the filament produced by pure solution of DMSO and HMTA was not detected at DP of 3000 and 2450, respectively, due to the influence of entanglement of the molecular chains of PVA.
The effect of chloro‐functional molecules on the ammonia plasma treatment of silicone elastomers
Authors: Gaboury Scott R. , Urban Marek W. 
Published: April 2003

AbstractAttenuated total reflectance (ATR) FTIR spectroscopy was utilized for surface studies of ammonia/plasma‐modified poly(dimethylsiloxane) (PDMS) elastomer networks containing residual chloro‐functional molecules. Ammonia/plasma modification of PDMS containing chloro‐functional molecules causes the formation of surface amide groups, but due to the parallel formation of surface ammonium chloride, amide groups are not chemically bonded to the PDMS surface. The two primary sources of chlorine‐containing species are residual traces of freon and cross‐linking initiators present in the network. In the absence of chloro‐functional molecules, ammonia/plasma surface modifications of PDMS leads to the formation of stable surface amide groups.
Mechanical and thermal behavior of cotton cellulose grafted with hydroxyethyl methacrylate using photoinitiation
Authors: Shukla S. R. , Rao G. V. Gopala , Athalye A. R. 
Published: April 2003

AbstractThe textile properties of tensile strength and thermal decomposition of cotton cellulose grafted by photoinitiation technique using 2‐hydroxyethyl methacrylate monomer were studied. The photoinitiators, namely, uranyl nitrate (UN) and ceric ammonium nitrate (CAN), were used during grafting of unswollen and swollen cotton samples. The tensile strength decreased with increase in graft add‐on, whereas, the thermal stability was imparted to the grafted cotton according to the level of graft add‐on.
Study of curative interactions in cis‐1,4‐polyisoprene (IR). V. General experimental procedure
Authors: Kruger F. W. H. , McGill W. J. 
Published: April 2003

AbstractThe tetramethylthiuram disulfide (TMTD) and zinc dimethyldithiocarbamate (ZDMC) related vulcanization of cis‐1,4‐polyisoprene (IR) were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and electron spin resonance (ESR). The progress of the reactions in a given compound was monitored by analyzing the vulcanizate at selected points along the DSC curing curve. Full details of the analysis procedures are given. Analysis were mainly concerned with measurement of the crosslink densities, percentage of polysulfidic crosslinks, and the types and quantities of extractable compounds by thin layer chromatography (TLC) and high‐performance liquid chromatography (HPLC).
Study of curative interactions in cis‐1,4‐polyisoprene. VI. Interaction of some combinations of sulfur, tetramethylthiuram disulfide, and ZnO
Authors: Kruger F. W. H. , McGill W. J. 
Published: April 2003

AbstractThe interaction of curatives in the systems cis‐1,4‐polyisoprene (IR)–sulfur, IR–sulfur–ZnO, IR–tetramethylthiuram disulphide (TMTD), and IR–sulfur–TMTD were studied. Thermal events observed in the differential scanning calorimetry curing curves characteristic of these systems were explained in terms of the melting/liquefaction of compounds, the evaporation of gases, and the vulcanization process itself. The similarity of the IR–sulfur and IR–sulfur–ZnO curing curves suggested that sulfur and ZnO were unreactive during vulcanization. On heating the IR–TMTD and IR–sulfur–TMTD systems, gases such as Me2NH and CS2 formed easily. Although the maximum crosslink densities in the latter systems were low, the crosslink formation was found to be strongly exothermic. The sulfur efficiency parameter E was estimated for the IR–sulfur–TMTD system and decreased steeply from 37.5 (at 143.2°C) to 16.6 (at 151.0°C). This was taken as evidence that much of the bound sulfur was initially combined in pendent groups. Then E increased dramatically toward the advanced stages of cure, emphasizing the extraordinary inefficient manner in which sulfur was utilized to form crosslinks.
Structure–property relationships for styrene crosslinked polyesters. I. Network structure and rubbery elastic modulus
Authors: Bellenger V. , Mortaigne B. , Grenier‐Loustalot M. F. , Verdu J. 
Published: April 2003

AbstractTen unsaturated polyester prepolymers differing by the nature of the diol, by the maleate/phthalate molar ratio, or by the chain length, were crosslinked by about 40% by weight of styrene and then analyzed by IR spectrophotometry, solid state NMR, and rubbery elasticity measurements.The spectrometric measurements revealed a practically complete conversion of the styrene/fumarate copolymerization. The rubbery elastic modulus varies in a complex way with the presumed network structure.A non‐ideality factor f was defined from the current theories; f is a decreasing function of the average number of flexible bonds between crosslinks.The networks based on dimeric diols display a practically ideal behavior.The influence of dangling chains, corresponding essentially to polyester chain ends, is taken into account by the Graessley's formula in which trifunctional and tetrafunctional crosslinks are distinguished. A method for the estimation of the nature and weight fraction of dangling chains was proposed.
Physical properties and dyeability of silk fibers modified with ethoxyethylmethacrylate polymer
Authors: Tsukada Masuhiro , Freddi Giuliano , Matsumura Masaaki , Shiozaki Hideki , Kasai Nobutami 
Published: April 2003

AbstractThe structural characteristics, physical properties, and dyeing behavior of Bombyx mori silk fibers containing ethoxyethylmethacrylate (ETMA) polymer are reported in relation to the add‐on. The add‐on value increased with the reaction time and attained a maximum after 60 min at 80°C. The surface of silk fibers with an add‐on value of 40% showed the presence of several irregular granules, consisting of ETMA oligomers. The infrared spectrum of the silk fibers containing the ETMA polymer showed overlapped absorption bands due to the molecular conformation of untreated silk and ETMA polymer, giving evidence that the ETMA polymerization occurred inside the fiber matrix. The DSC results suggested that the thermal decomposition behavior of the silk fiber remained almost unchanged, except that the decomposition temperature shifted slightly to higher temperature. The tensile properties of the silk fiber remained unchanged regardless of the ETMA polymerization. The rate and extent of acid dye uptake was greatly increased by the polymerization of ETMA into the silk fibers as well as the transfer printing properties.
Dynamic light scattering and ultrasonic investigations during the cure reaction of an epoxy resin
Authors: Alig Ingo , Lellinger Dirk , Nancke Katja , Rizos Apostolos , Fytas George 
Published: April 2003

AbstractBrillouin scattering (BS), photon correlation spectroscopy (PCS), and ultrasonic (US) measurements were conducted to study the curing process of diglycidyl ether of bisphenol A with butane‐1,4‐diol at a curing temperature of 100°C. The experimental techniques probe the primary glass‐rubber transition during the curing reaction. The primary relaxation time τ obtained from the BS and US velocity and absorption increases with curing time and hence the BS experiment measures τ at earlier stages of cure than the US experiment. The relaxation times at a different extent of reaction and for different measuring temperatures are consistent with BS, US, PCS, and DSC measurements and conform to a single reduced Vogel–Fulcher–Hesse–Tamann equation. Furthermore, the US experiments show evidence of secondary relaxations in the epoxy system.