bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of thermal degradation characteristics of poly(arylene sulfone)s using thermogravimetric analysis/mass spectrometry
Authors: Perng Li‐Hsiang 
Published: September 2002

AbstractThermal degradation of poly(arylene sulfone)s had been studied by the combination of thermogravimetric analysis/mass spectrometry (TG/MS) with pyrolysis/gas chromatography/mass spectrometry (Py‐GC/MS) techniques. Through these two methods, the pyrolysates from poly(ether sulfone) (PES) and polysulfone (PSF) were identified in 11 and 21 sets of evolution curves, respectively, from room temperature to 900 °C. Among these pyrolysates, 12 products from PES and 25 products from PSF were obtained. The major mechanism for both PES and PSF was one‐stage pyrolysis involving main chain random scission and carbonization with evolution of SO2 and phenol as major products. Although the initial thermal stability of PES was lower than that of PSF, the formation of sulfide groups in the condensed phase from PES, through reduction of sulfone group by hydrogen radicals, increased the fire retardation behavior of PES. In PES, the ether and sulfone groups showed similar thermal stability. The thermal stability of functional groups in PSF were in the order of sulfone < ether < isopropylidene group. The scission of the ether group in PSF, with evolution of phenol as the major product, reached maximum evolution amount at the temperature of the maximum thermogravimetry loss of TG (Tmax). The scission of isopropylidene groups at high temperature (>580 °C) evolved higher mass derivatives that lower the fire retardancy of PSF. By using a simplified kinetic model, PES showed maximum activation energy with a conversion ratio of 0.2–0.3, which implies a high fire retardant effect of sulfide formation in PES. A comparative study with the proposed model and experimental data showed the theoretical pyrolysis curves to be in agreement with the experimental curves for PES and PSF pyrolysis, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2387–2398, 2001
Corona discharge treatments of plastified PVC samples used in biological environment
Authors: Dumitrascu N. , Borcia G. , Popa G. 
Published: September 2002

AbstractThe effects of the plasticizer content and of the treatments by corona discharge in helium on the morphology and on some physico‐chemical properties of the PVC surface were investigated by scanning electron microscopy (SEM), IR spectroscopy, and contact angle measurements. A biological test of adsorption of some ions (calcium, potassium, and sodium) from human serum sanguine on the surface of PVC was also performed. After corona discharge treatment, the surface morphology presents a cleaning of oligomers and an increase in porosity, depending on the treatment time and on the content of the plasticizer. Surface energy considerably increases and functionalization of the surface is observed after treatment by corona discharge in helium. This functionalization does not change the electrolitical equilibrium of some ions from the serum sanguine, a convenient result that controls the stability of the blood‐PVC sample interface. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2419–2425, 2001
Collagen‐based new biomedicial films: Synthesis, property, and cell adhesion
Authors: Harada Osamu , Kadota Kazushige , Yamamoto Tohei 
Published: September 2002

AbstractGrafted‐collagen films with poly(methyl methacrylate), poly(butyl methacrylate), and poly(styrene) were prepared by photoirradiation of the collagen films in the presence of respective monomers. Cell adhesion onto the films was investigated, and the amount of cells adhered onto every grafted films was almost the same as that onto the collagen film crosslinked with glutaraldehyde. Because the swollen grafted films are stronger than the collagen film, they are expected to be good biomedical materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2433–2438, 2001
Correlation between mechanical damping and interphase content in interpenetrating polymer networks
Authors: Song M. , Hourston D. J. , Schafer F.‐U. 
Published: September 2002

AbstractRecently, some interpenetrating polymer networks with good mechanical damping properties have been synthesized. However, the effect of morphology on this property has not yet been clearly elucidated. Herein, two polystyrene–polyurethane interpenetrating polymer networks, which were grafted using TMI [benzene‐1‐(1‐isocyanato‐1‐methyl ethyl)‐3‐(1‐methylenyl)] and HEMA (2‐hydroxyethyl methacrylate), respectively, have been investigated, as model samples, by modulated‐temperature differential scanning calorimetry and by dynamical mechanical thermal analysis. The results indicate that there is a correlation between mechanical damping and both interphase content and the distribution of composition in the interphase region. The findings should provide valuable information for the design of future damping materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2439–2442, 2001
Foaming of aliphatic polyester using chemical blowing agent
Authors: Kim D. J. , Kim S. W. , Kang H. J. , Seo K. H. 
Published: September 2002

AbstractPoly(butylene adipate‐co‐succinate) (PBAS), a saturated aliphatic polyester cured by dicumyl peroxide (DCP), was prepared and the viscoelastic property was investigated. The viscosity of crosslinked PBAS increased, and it exhibited rubbery behavior as the content of curing agent was increased. The results suggested that the viscosity and elasticity of PBAS could be regulated by adding a small amount of DCP; hence, the processibility could be improved. Prior to foaming, a proper formulation of blowing agent (blowing agent/urea activator = 100:8 phr) was examined to prepare expanded PBAS foam. Low‐density PBAS expanded foams were prepared using a chemical blowing agent and DCP. The effect of the foaming temperature, additive content, and curing agent content on the blowing ratio and morphology of expanded PBAS foams was investigated. A closed‐cell structure PBAS foam of high blowing ratio (density about 0.05 g/cm3) could be obtained by adding 3 phr DCP. To manufacture expanded PBAS foam under 0.1 g/cm3 using a chemical blowing agent, the storage modulus of the matrix polymer should exceed the loss modulus by enough to stabilize growing bubbles. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2443–2454, 2001
IGC study of filler–filler and filler–rubber interactions in silica‐filled compounds
Authors: Zhang Wenjin , Leonov Arkady I. 
Published: September 2002

AbstractA modification of the existing methods for evaluating the dispersive and specific components of surface free energy (γd and γs, respectively) was made to investigate filler–rubber and filler–filler interactions by inverse gas chromatography. Four silicas as fillers and various probes that mimic elastomers were employed in this study. It was shown that the pretreatment of silicas with helium could increase γd and decrease γs. Modification of the silica surface with silane could enhance the dispersive interaction and weaken the specific interaction. The temperature dependence of the interfacial interaction was also investigated, and it was found that lower temperatures favored filler–rubber interactions and mixing efficiency. Tests on different sizes of agglomerates demonstrated the existence of a filler–rubber and filler–filler network. It was also found that γd played a role in agglomeration or filler–filler interaction. Our study showed that the larger the specific surface area was, the stronger the dispersive and specific interactions were. The effectiveness of various fillers and elastomer probes was also compared. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2517–2530, 2001
Mechanism of morphology development in dynamically cured EPDM/PP TPEs. I. Effects of state of cure
Authors: Goharpey F. , Katbab A. A. , Nazockdast H. 
Published: September 2002

AbstractAttempts were made to follow and correlate morphological development with the crosslinking density, or state of cure (SOC), and the surface tension (γ) of the rubber phase in dynamically cured thermoplastic elastomers (TPEs) based on ethylene propylene diene rubber and polypropylene (PP) with 60/40 (w/w) ratios. Samples were taken from a hot running mixer without interruption and quickly quenched in liquid nitrogen both before and after the onset of vulcanization at various SOCs to carry out this process. The quick cooling of the samples prevented the coalescence and agglomeration of the dispersed rubber particles. A two‐phase morphology with the rubber particles dispersed throughout the PP matrix was observed for the uncured but frozen samples, whereas unfrozen blend samples showed a particulate cocontinuous morphology in the uncured state. An increase in the mixing torque with the SOC was observed after the addition of a curing system. This was understood to be caused by the increase in the rubber crosslinking density and also by the enhancement of the interfacial adhesion between the cured rubber phase and the PP matrix, leading to the better wetting of the two phases. Above a certain crosslinking density (SOC), γ of the rubber particles decreased through elastic shrinkage. This phenomenon, together with the breakdown of the agglomerate structure formed by the cured rubber particles, led to a decrease in the mixing torque after a maximum was passed and, finally, to a defined morphology. Based on the obtained results, a four‐stage model is proposed to describe the microstructural development in dynamically vulcanized TPEs. Dynamic mechanical thermal analysis and differential scanning calorimetry results are also used to support the model. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2531–2544, 2001
Reactive processing of polyethylenes on a single screw extruder
Authors: Kumari Isac Sheela , George K. E. 
Published: September 2002

AbstractThe modification of low density polyethylene, linear low density polyethylene, and their blend by dicumyl peroxide at the time of the extrusion on a single screw extruder is reported. The study shows that the optimum conditions of modification can be determined on a torque rheometer and these can then be applied for actual extrusion. A low level of crosslinking can be introduced by reactive extrusion for improving the heat stability without adversely affecting the processing behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2545–2549, 2001
Influence of pendent groups on the tensile properties of polyisoprene vulcanizates
Authors: Van Der Merwe M. J. , Gradwell M. H. S. , McGill W. J. 
Published: September 2002

AbstractGum compounds of polyisoprene were vulcanized with a number of different curing systems to give networks with crosslink densities in two different ranges. Stress–strain curves were obtained upon rapid (500 mm/min) and slow (0.5 mm/min) extension. In tetramethylthiuram disulfide (TMTD)/sulfur and zinc dimethyldithiocarbamate/sulfur vulcanizates, which crystallize readily, failure occurred at higher tensile values upon rapid than upon slow extension and this is attributed to a greater contribution to tensile strength by a larger amount of stress‐induced crystallites. X‐ray diffraction showed that 2‐benzothiazole‐2,2′‐disulfide (MBTS)/sulfur vulcanizates did not stress‐crystallize and failure occurred at lower tensile values. Furthermore, samples extended rapidly failed at lower tensile values than did slowly extended samples. These differences, compared to TMTD vulcanizates, are attributed to extensive main‐chain modifications (pendent groups), causing delays in the movement of sections of the chain, leading to the load being unequally distributed between chains. The fewer load‐bearing chains ensure earlier failure. The addition of zinc stearate to TMTD/sulfur and MBTS/sulfur formulations increases the ability of vulcanizates of similar crosslink density to crystallize and enhances tensile properties of vulcanizates with similar crosslink densities, outcomes that are attributed to zinc stearate's promoting crosslinking of pendent groups and reducing impediments to crystallization and chain movement. Dicumyl peroxide–cured networks crystallize readily and exhibit a very rapid upturn in the stress–strain curve. However, failure occurs at lower stress values than apply to accelerated sulfur networks and it is suggested that the distribution of subchain lengths between crosslinks may contribute to their inferior properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2587–2596, 2001
Reactive bonding of natural rubber to metal by a nitrile–phenolic adhesive
Authors: Sasidharan Achary P. , Gouri C. , Ramaswamy R. 
Published: September 2002

AbstractThe mechanism of adhesive bonding of rubber to metal using an interlayer of bonding agent (adhesive) is discussed with respect to various physical and chemical events such as adsorption at the metal surface, chemical crosslinking within the adhesive, interdiffusion, and formation of interpenetrating networks at the rubber–adhesive interface. An investigation on the peel strength of a natural rubber (NR)–adhesive–metal joint, made by vulcanization bonding using nitrile–phenolic adhesive containing various concentrations of toluene diisocyanate–nitrosophenol (TDI–NOP) adduct, is presented. A single‐coat adhesive, consisting of a p‐cresol phenol formaldehyde resin, nitrile rubber (NBR), and vulcanizing agents in methyl ethyl ketone solvent, was selected for the study. Considerable improvement in the peel strength was obtained by the incorporation of TDI–NOP adduct into the nitrile–phenolic adhesive. The peel strength increases as the concentration of TDI–NOP adduct in the adhesive composition increases, then levels off with a transition from interfacial failure to cohesive tearing of rubber. The peel strength improvement is believed to be attributed to the interfacial reactions between the bonding agent and natural rubber, when TDI–NOP adduct is incorporated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2597–2608, 2001
Morphology of the transparent IPN‐like system PE: (BMA‐co‐S)
Authors: Borsig Eberhard , Thomann Ralf , Fiedlerová Agnesa , Mülhaupt Rolf 
Published: September 2002

AbstractIn the study of interpenetrating polymer networks (IPN)‐like systems consisting of polyethylene (PE) and butyl methacrylate (BMA)–styrene (S) copolymer PE/(BMA‐co‐S), the effect of the crosslinker on the morphology of IPN by using electron microscopy and atomic force microscopy (AFM) was investigated. The IPN‐like system PE/(BMA‐co‐S) represents a two‐phase system with finely dispersed domains of crosslinked PE matrix. The interphase between dispersed domains and PE matrix is inhomogeneous and is considered the most interpenetrated part of this IPN‐like system. The size of the domains decreases with the content of crosslinker used. The AFM micrographs allowed the observation of PE lamellae with lengths of about 25 nm. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2615–2620, 2001
Grafting of methyl methacrylate (MMA) onto Antheraea assama silk fiber
Authors: Das A. , Saikia C. N. , Hussain S. 
Published: September 2002

AbstractGraft copolymerization of methyl methacrylate (MMA) onto nonmulberry silk fiber Antheraea assama was investigated in aqueous medium using the KMnO4–oxalic acid redox system. Grafting (%) was determined as a function of the reaction time, temperature, and monomer and initiator concentrations. The rate of grafting increased progressively with increase of the reaction time up to 4 h and then decreased. The extent of grafting was maximum at 55°C. The extent was also dependent upon monomer and initiator concentrations up to 75.5 × 10−2 and 6 × 10−3 M, respectively. The grafted products were evaluated by infrared spectroscopy and their thermal decompositions were studied by TG and DTG techniques in static air at 20°C min−1 and 30°C min−1 in the range 30–800°C. The kinetic parameters for ungrafted and grafted fibers were evaluated using the Coats and Redfern method. The grafted products were found to be thermally more stable than were those of the ungrafted fibers. The surface characteristics of the ungrafted and grafted fibers were evaluated by scanning electron microscopy. The water‐retention values (WRVs) of the grafted fibers were in decreasing order with increase in the grafting (%). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2633–2641, 2001
Phase behavior of semicrystalline polyester resin in supercritical fluid solvents and solvent mixtures: Implications for supercritical fluid processing
Authors: Conway S. E. , Lim J. S. , McHugh M. A. , Wang J. D. , Mandel F. S. 
Published: September 2002

AbstractCloud‐point data between 40 and 240°C and pressures to 2750 bar are presented for a low molecular weight, semicrystalline polyester resin of 53.4 mol % adipic acid and 46.6 mol % 1,4‐cyclohexanedimethanol in supercritical CO2, dimethyl ether (DME), and chlorodifluoromethane (CDFM), and in mixtures of CO2 with DME, CDFM, methanol, ethanol, butanol, octanol, hexafluoroisopropanol, acetone, and cyclohexane. Carbon dioxide, by itself, is an extremely weak supercritical fluid (SCF) solvent because this polyester only dissolves at pressures in excess of 2000 bar and at temperatures over 180°C. However, DME and CDFM are excellent solvents for this polyester, which dissolves at 16 bar and 40°C in CDFM and at 167 bar and 55°C in DME. The melting point of this polyester is reduced from 105 to 40°C in CDFM and to 55°C in DME, which makes the polyester amenable to high intensity mixing for the efficient dispersion of inorganics or crosslinking agents and other hard to deposit materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2642–2648, 2001
Cure kinetics of biphenyl epoxy resin system using latent catalysts
Authors: Kim Whan Gun , Yoon Ho Gyu , Lee Jun Young 
Published: September 2002

AbstractThe investigation of the cure kinetics of a biphenyl epoxy–phenol resin system with different kinds of latent catalysts was performed by differential scanning calorimetry using an isothermal approach. All kinetic parameters of the curing reaction including the reaction order, activation energy, and rate constant were calculated and reported. The results indicated that the curing reaction of the biphenyl epoxy resin system in this experiment proceeded through an autocatalytic kinetic mechanism, irrespective of the kind of catalyst. The epoxy resin system with acid/diazabicycloundecene (DBU) salt as the latent catalyst showed a second overall reaction order; however, a third reaction order was represented for microencapsulated triphenylphosphine (TPP). The storage stability tests for these systems were performed, and a good shelf life was observed in the epoxy resin system with pyromellitic acid/DBU salt, trimellitic acid/DBU salt, and microencapsulated TPP as the latent catalyst. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2711–2720, 2001
Syntheses and thermal properties of poly(hydroxy)urethanes by polyaddition reaction of bis(cyclic carbonate) and diamines
Authors: Kim Mi‐Ra , Kim Hooi‐Sung , Ha Chang‐Sik , Park Dae‐Won , Lee Jin‐Kook 
Published: September 2002

AbstractIn this study, we synthesized poly(hydroxy)urethanes by the polyaddition reaction of bis(cyclic carbonate) and diamine. Bis(cyclic carbonate) was prepared from diglycidyl ether based on bisphenol S and carbon dioxide. Thermal properties and solubilities of the poly(hydroxy)urethanes of five different diamines were compared. The thermal properties of the poly(hydroxy)urethanes depended on the structure of the diamine as well as the structure of the monomer. These poly(hydroxy)urethanes were soluble only in aprotic solvents because of the hydrophilic character of the hydroxy group. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2735–2743, 2001
Ultrasonic modification of aramid fiber–epoxy interface
Authors: Liu L. , Huang Y. D. , Zhang Z. Q. , Jiang B. , Nie J. 
Published: September 2002

AbstractAn ultrasonic irradiation technique is used during the process of fabricating aramid fiber–epoxy resin reinforced composites to improve the interfacial adhesion performance. Under the ultrasonic treatment, the change of the resin viscosity is studied. The results of a microbond test show obvious improvement in the interfacial shear strength after ultrasonic treatment. The mechanical properties of the composites, such as the interlaminar shear strength and tensile strength, are measured. Combined with the SEM results, these show it is the mechanical properties that are improved and the fracture modes are varied from the interface between the fibers and resin to the fibrillation of fibers and resin. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2764–2768, 2001
Surface characterization and antibacterial activity of chitosan‐grafted poly(ethylene terephthalate) prepared by plasma glow discharge
Authors: Huh Man Woo , Kang Inn‐Kyu , Lee Du Hyun , Kim Woo Sik , Lee Dong Ho , Park Lee Soon , Min Kyung Eun , Seo Kwan Ho 
Published: September 2002

AbstractPoly(ethylene terephthalate) (PET) texture was exposed to oxygen plasma glow discharge to produce peroxides on its surfaces. These peroxides were then used as catalysts for the polymerization of acrylic acid (AA) in order to prepare a PET introduced by a carboxylic acid group (PET‐A). Chitosan and quaternized chitosan (QC) were then coupled with the carboxyl groups on the PET‐A to obtain chitosan‐grafted PET (PET‐A‐C) and QC‐grafted PET (PET‐A‐QC), respectively. These surface‐modified PETs were characterized by attenuated total reflection Fourier transform IR spectroscopy, electron spectroscopy for chemical analysis, and a contact angle goniometer. The amounts of AA, chitosan, and QC grafted on the PET surfaces as determined by the gravimetric method were about 6, 8, and 9 μg/cm2, respectively. The antibacterial activity of the surface‐modified PET textures was investigated using a shake flask method. After 6 h of shaking, the growth of bacteria was markedly inhibited by PET with ionically (86% in PET‐A−‐C+) and covalently (75% in PET‐A‐C) grafted chitosan and with covalently grafted QC (83% in PET‐A‐QC). After the laundering the inhibition of the growth of the bacteria was maintained in the range of 48–58%, showing the fastness of the chitosan‐grafted PET textures against laundering. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2769–2778, 2001
Photopolymerizable acrylic resin: Effect of curing time and temperature
Authors: Dolez Patricia , Marek Monica , Love Brian J. 
Published: September 2002

AbstractA photopolymerizable resin was closely examined for its capacity as an adhesive via cure advancement in submerged water at cold temperatures. The effects of curing time and temperature were studied by bond strength measurements and extracted monomer quantification with high pressure liquid chromatography. In both cases the cure was performed under water, and there was one wet interface. Both methods showed the progression of the photopolymerization with time and had similar characteristic times. The adhesion strength was measured by lap shear and remained nearly constant over the entire temperature range studied (around 2 MPa for a 2‐min cure), while a slight increase in the extracted uncured monomer quantity of one of the resin components was obtained for increasing temperatures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 546–554, 2001