bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanistic study of boron trifluoride catalyzed ε‐caprolactone polymerization in the presence of glycerol
Authors: Jiang G. , Walker G. S. , Jones I. A. , Rudd C. D. 
Published: August 2006

AbstractBoron trifluoride catalyzed ε‐caprolactone polymerization in the presence of glycerol can produce poly(ε‐caprolactone) with a high weight‐average molecular weight and a broad molecular weight distribution. This article reports an investigation of the polymerization mechanism to determine the formation of these molecular weight features through a study of the polymerization kinetics and the molecular structure with NMR. The polymerization proceeds via an activated monomer mechanism, resulting in polymer molecules with hydroxyl chain ends. The broad molecular weight distribution can be attributed to the etherification reactions between hydroxyl chain ends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3900–3906, 2006
Surface relief gratings on azo polymer films through reversible photoisomerization by the irradiation of a monochromatic light
Authors: Alam Md. Zahangir , Ohmachi Tomoko , Ogata Tomonari , Nonaka Takamasa , Kurihara Seiji 
Published: August 2006

AbstractSurface relief gratings were induced on azobenzene‐functionalized polymer films by exposure to s‐polarized and circularly polarized Ar+‐laser (488‐nm) irradiation through a photomask. The surface relief structures were investigated with atomic force microscopy. A very regularly spaced surface grating with a modulation depth of about 400 nm was obtained after 30 min of circularly polarized Ar+‐laser irradiation. The diffraction efficiency was measured after irradiation by an Ar+ laser, and an efficiency of about 2% was achieved. The polymer films also showed a very high period of recording. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3123–3126, 2006
Atomic force microscopy analysis of cellulose triacetate surface modified in low temperature argon plasma and its adhesion behavior
Authors: Koo Kang , Mi Park Young , Yeong Yu Jae 
Published: August 2006

AbstractThe surface of cellulose triacetate (CTA) film was modified with gaseous plasma of several discharge power in the presence of Argon (Ar) gas at 0.5 torr pressure. After gas plasma etching, the surface structure of the films is analyzed by atomic force microscopy (AFM) and measured with peel strength. Furthermore, the wetting properties of the CTA film treated with Ar plasma are studied by contact angle measurement. Peel strength after plasma treatment was increased with increasing plasma treatment time. However, treatments of plasma greater than 7 min did not find an additional increase in peel strength, similarly to roughness and morphological changes of AFM. The water contact angle decreased for an initial treatment time due to the improved wettability of the film, but showed an increasing trend for a higher treatment time (7 min). These results show that Ar plasma treatment is a convenient tool for improving the adhesive properties of CTA film. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3963–3971, 2006
Thermal behavior of poly(acrylic acid)–poly(vinyl pyrrolidone) and poly(acrylic acid)–metal–poly(vinyl pyrrolidone) complexes
Authors: Moharram M. A. , Khafagi M. G. 
Published: August 2006

AbstractThermal analysis (TGA and DTA) of samples of PAA, PVP, PAA–PVP complexes, containing different weight fractions of PAA and ternary polymer–metal–polymer complexes, were studied. The activation energy parameters for the thermal degradation were also calculated. The study of the effect of FeCl3, NiCl2, and Ni(NO3)2 on the TGA and DTA curves of the complexes showed that the decompositions are dependent on the concentrations and the nature of the metal ions. The DTA traces of PAA–PVP complex containing FeCl3, NiCl2, and Ni(NO3)2 showed that the treatment of the complex with these metal ions causes considerable changes in the thermal decomposition of PAA–PVP complex. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4049–4057, 2006
Cure kinetics and rheology characterization of soy‐based epoxy resin system
Authors: Liang G. , Chandrashekhara K. 
Published: August 2006

AbstractA novel soy‐based epoxy resin system was synthesized by the process of transesterification and epoxidation of regular soy bean oil, which has the potential to be widely usable in various composite manufacturing processes. Cure kinetics and rheology are two chemical properties commonly required in process modeling. In this work, the cure kinetics and rheology of the soy‐based resin system were measured by means of differential scanning calorimetry (DSC) and viscometer. DSC was used to measure the heat flow of dynamic and isothermal curing processes. The cure kinetics models of the different formulations were thus developed. A Brookfield viscometer was used to measure the change in viscosity under isothermal conditions. A novel neural network‐based model was developed to improve modeling accuracy. The models developed for cure kinetics and rheology for soy‐based epoxy resin system can be readily applied to composite processing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3168–3180, 2006
Crystallization behavior of PVDF in PVDF‐DMP system via thermally induced phase separation
Authors: Gu Minghao , Zhang Jun , Wang Xiaolin , Ma Wenzhong 
Published: August 2006

AbstractThe crystallization behavior of PVDF (poly (vinylidene) fluoride) in PVDF‐dimethylphthalate(DMP) system was investigated in the liquid–liquid (L–L) phase separation region, solid–liquid (S–L) phase separation region and different quenching conditions via thermally induced phase separation (TIPS). Differential scanning calorimetry (DSC) indicated the crystallinity of PVDF in PVDF‐DMP system increased in the early stage of phase separation and polymer‐rich phase crystallized completely in the late stage of phase separation. The scanning electron microscopy (SEM) showed the different quenching temperatures had effects on the spherulite size of polymer rich phase and the ultimate membrane structure in the different phase separation regions. The wide angle X‐ray diffraction (WAXD) was used to quantify the crystal structure of PVDF in PVDF‐DMP system. The α‐phase PVDF was obtained when the system quenched to different temperatures above 40°C, and the area of diffraction peaks changed when quenching temperatures changed. While the β‐phase PVDF was formed when PVDF‐DMP system was quenched form liquid nitrogen and crystallized for 24 h in 25°C water bath. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3714–3719, 2006
Effects of nanoparticle treatment on the crystallization behavior and mechanical properties of polypropylene/calcium carbonate nanocomposites
Authors: Wan Weitao , Yu Demei , Xie Yunchuan , Guo Xiusheng , Zhou Wandi , Cao Jiping 
Published: August 2006

AbstractEffects of nanoparticle surface treatment on the crystallization behavior and mechanical properties of polypropylene (PP)/CaCO3 nanocomposites were investigated by using differential scanning calorimetry (DSC), polarized optical microscope (POM), X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results demonstrated that the interfacial interaction formed between PP and nanoparticles significantly influenced the thermal and mechanical properties of nanocomposites. It was found that CaCO3 nanoparticles modified by a single aluminate coupling agent (CA‐1) could improve the onset crystallization temperature more effectively than that modified by a compound surface‐treating agent (CA‐2) could. However, there is no significant difference in total rate of crystallization for the two PP/CaCO3 nanocomposites (PPC‐1 and PPC‐2), which contained CA‐1 and CA‐2, respectively. In contrast, CA‐2 modified nanoparticles could cause smaller spherulites and induce much more β‐phase crystal in nanocomposites than that of CA‐1 modified nanoparticles. This may be explained by a synergistic effect of aluminate coupling agent and stearic acid in CA‐2, which also resulted in an improved toughness for PPC‐2. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 3480–3488, 2006
Use of radiation grafting of polyethylene‐coated polypropylene nonwoven fabric by acrylamide for the removal of heavy metal ions from wastewaters
Authors: Ibrahim Sayeda M. , El‐Salmawi Kariman M. , El‐Naggar A. A. 
Published: August 2006

AbstractThe graft copolymerization of acrylamide (AAm) monomer onto polyethylene‐coated polypropylene (PE‐co‐PP) nonwoven fabric was carried out by the mutual irradiation method. The general peculiarities of the grafting have been studied by gravimetric, scanning electron microscope (SEM), mechanical properties, and Fourier transform infrared (FTIR) methods. The influence of absorbed dose, dose rate, as well as the monomer concentration on the degree of grafting has been determined. Metal ions uptake of Cu2+, Co2+, Ni2+ by the grafted fabrics was evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3240–3245, 2006
Kinetics of the effect of ageing on tensile properties of a natural rubber compound
Authors: Ngolemasango E. F. , Bennett M. , Clarke Jane 
Published: August 2006

AbstractNatural rubber (NR) undergoes chemical changes on heat and air ageing. These changes affect its physical properties and as such, affect the service life of the rubber compound. In this study, a vulcanized NR compound of a typical engine mount composition was subjected to thermo‐oxidative ageing at temperatures from 70 to 110°C, to assess the effect on the tensile properties. The kinetics of degradation of the rubber compound, in terms of changes in these properties, was investigated. A fractional rate law was used to describe the kinetics of ageing in terms of its effect on modulus. Rates of ageing, in terms of effect on modulus, passed through a minimum at about 80°C, indicating the danger of trying to extrapolate in‐service ageing behavior from high temperature ageing data. The activation energy of ageing in terms of its effect on modulus, determined for temperatures of 90–110°C, was 151 kJ mol−1. A second order rate law was used to describe the kinetics of ageing in terms of its effect on tensile strength and elongation at break, with activation energies of 88.32 and 74.3 kJ mol−1, respectively. According to Ahagon's (Ahagon et al., Rubber Chem Technol, 1990, 63, 683) classification of ageing mechanisms, Type I and Type III ageing mechanisms were predominant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3732–3740, 2006
Structure and mechanical properties of poly(trimethylene terephthalate)/poly(hydroxy ether of bisphenol A) blends
Authors: González I. , Eguiazábal J. I. , Nazábal J. 
Published: August 2006

AbstractCompatible poly(trimethylene terephthalate) (PTT)/poly(hydroxy ether of bisphenol A) (Phenoxy) blends were obtained by direct injection molding throughout the composition range. Two amorphous phases with minor amounts of the other component were found in the blends. Reactions occurred in PTT‐rich blends. By comparing the miscibility level of these blends with that of other blends based on polyalkylene terephthalates, it is proposed that a miscibility limit delimited by a 3/1 methylene–carbonyl ratio in the polyalkylene terephthalate exits in these blends. The synergism in the Young's modulus of the blends is discussed as a consequence of the changes in the crystallinity of PTT, the specific volume and the orientation produced by blending. Ductility is approximately proportional to blend composition, indicating compatibility, and is attributed to the combined effects of a small particle size and a good adhesion level, the latter being a consequence of the partially miscible nature of the blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3246–3254, 2006
Synthesis and characterization of water soluble poly(N‐acetyl)iminoethylene and poly(ethyleneimine) by ion‐exchanged clay montmorillonite
Authors: Hachemaoui Aïcha , Yahiaoui Ahmed , Belbachir Mohammed 
Published: August 2006

AbstractThe cationic polymerization of 2‐méthyl‐2‐oxazoline was carried out at 0°C in acetonitrile using an acid‐exchanged montmorillonite as acid solid ecocatalyst (Maghnite‐H+). The effect of the amount of catalyst, solvent, and times of polymerization on yield and viscosity of polymer was studied. A typical reaction product (PMOX) was analyzed by infrared and nuclear magnetic resonance spectroscopy as well as by gel‐permeation chromatography and MALDI‐TOF MS. The polymers presented similar spectrometric results and narrow molecular weight distribution. The poly(N‐acetyl)iminoethylene was hydrolyzed in acid medium obtaining a linear poly(ethyleneimine). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3741–3750, 2006
Effect of compatibilizer and silane coupling agent on physical properties of ethylene vinyl acetate copolymer/ethylene‐1‐butene copolymer/clay nanocomposite foams
Authors: Kim Dong‐Woo , Park Keun‐Wan , Chowdhury Subhendu Ray , Kim Gue‐Hyun 
Published: August 2006

AbstractIn this study an attempt was made to obtain lower density of ethylene‐vinyl acetate copolymer (EVA)/ethylene‐1‐butene copolymer (EtBC) foams without sacrificing mechanical properties. For this purpose EVA/EtBC/clay nanocomposite foams were prepared. To investigate the effect of compatibilizer and silane coupling agent on the physical properties of the EVA/EtBC/clay foams, maleic anhydride‐grafted EtBC (EtBC‐g‐MAH) and the most commonly used silane coupling agent in rubbers, bis(3‐triethoxysilylpropyl) tetrasulfide (Si‐69) were used in the preparation of EVA/EtBC/clay nanocomposite foams. The formation of EVA/EtBC/clay nanocomposite foams was supported by X‐ray diffraction results. And, using a compatibilzer and silane coupling agent, lower density of EVA/EtBC/clay nanocomposite foams were obtained without sacrificing mechanical properties except compression set. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3259–3265, 2006
Intercalation of epoxy resin in organically modified montmorillonite
Authors: Hutchinson John M. , Montserrat Salvador , Román Frida , Cortés Pilar , Campos Lourdes 
Published: August 2006

AbstractVarious methods of preparation of epoxy resin/clay mixtures, before the addition of the crosslinking agent and curing to form epoxy‐based polymer layered silicate (PLS) nanocomposites, have been investigated to determine their effect on the nanostructure. Organically modified montmorillonite clay was used, and the mixtures were prepared by both simple mixing and solvent‐based methods. X‐ray diffraction shows that intercalation of the resin into the clay galleries occurs for all clay loadings up to 25 wt % and for both preparation methods, but the dispersion of the clay in the resin, observed by optical microscopy, is significantly better for the solvent preparation method. Differential scanning calorimetry (DSC) shows that the intercalated resin has the same molecular mobility as the extra‐gallery resin, but suggests that the intercalated resin does not penetrate completely into the galleries. Prolonged storage of the resin/clay mixtures at room temperature leads to changes in the DSC response, as well as in the response to thermogravimetry, which are interpreted as resulting from homopolymerization of the epoxy resin, catalyzed by the onium ion in the modified clay. This confirms and explains the earlier observation of Benson Tolle and Anderson (J Appl Polym Sci 2004, 91, 89) that “conditioning” of the resin/clay mixtures at ambient temperature has a significant effect when the crosslinking agent is subsequently added, and indicates that the preparation method has important consequences for the nanostructure development in the PLS nanocomposites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3751–3763, 2006
Structural modification and characterization of lignosulfonate by a reaction in an alkaline medium for its incorporation into phenolic resins
Authors: El Mansouri Nour‐Eddine , Farriol Xavier , Salvadó Joan 
Published: August 2006

AbstractWe studied the enhancement of lignin reactivity in an alkaline medium, using sodium hydroxide in a microreactor set. The chemical composition and structural characterization of the reacted lignosulfonate in terms of the phenolic hydroxyl groups, aromatic protons, weight‐average molecular weight, number‐average molecular weight, and lignosulfonate content of all reacted lignins were determined. The techniques that we used were ultraviolet spectroscopy, proton nuclear magnetic resonance spectroscopy, and aqueous gel permeation chromatography. Using response surface methodology, we studied how the temperature and reaction time affected the lignin properties. The reaction conditions were temperatures between 116 and 180°C and reaction times between 18 and 103 min. Modeled response surfaces showed that the two factors affected the lignin properties within the studied ranges. The phenolic hydroxyl groups, aro matic protons, and lignosulfonate content increased when the severity of the treatment increased. The weight‐average molecular weight, number‐average molecular weight, and solid yield (%) decreased when the severity of the treatment increased. The reactivity of the modified lignins was studied with a formaldehyde reactivity test: more severe conditions produced greater improvements in the formaldehyde reactivity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3286–3292, 2006
Electrical conductivity modeling of carbon‐filled liquid‐crystalline polymer composites
Authors: Keith Jason M. , King Julia A. , Barton Rodwick L. 
Published: August 2006

AbstractElectrically conductive resins are needed for bipolar plates used in fuel cells. Currently, the materials for these bipolar plates often contain a single type of graphite powder in a thermosetting resin. In this study, various amounts of two different types of carbon, carbon black and synthetic graphite, were added to a thermoplastic matrix. The resulting single‐filler composites were tested for electrical conductivity, and electrical conductivity models were developed. Two different models, the Mamunya and additive electrical conductivity models, were used for both material systems. It was determined how to modify these models to reduce the number of adjustable parameters. The models agreed very well with experimental data covering a large range of filler volume fractions (from 0 to 12 vol % for the carbon black filled composites and from 0 to 65 vol % for the synthetic graphite filled composites) and electrical conductivities (from 4.6 × 10−17 S/cm for the pure polymer to 0.5 S/cm for the carbon black filled composites and to 12 S/cm for the synthetic graphite filled composites). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3293–3300, 2006
Environmental effects on poly‐p‐phenylenebenzobisoxazole fibers. I. Mechanisms of degradation
Authors: Walsh Peter J. , Hu Xianbo , Cunniff Philip , Lesser Alan J. 
Published: August 2006

AbstractThis is the first of a two‐part series investigating the degradation mechanisms of PBO fiber and approaches to alleviating degradation and improving fiber properties. Poly‐p‐phenylenebenzobisoxazole (PBO) fiber is a high strength and modulus fiber with remarkable thermal stability. Recent in‐service failures of this fiber have revealed that the fiber degrades rapidly in relatively mild environmental conditions of moisture and heat. In this work the mechanisms of degradation due to moisture, the presence of acid, and the effect of radiation from the UV–vis spectrum are investigated. It is found that exposure to moisture results in the loosening of the fiber morphology leading to an increase in the number and size of defects. The presence of aqueous acid causes both loosening of the fiber structure and hydrolysis of the oxazole ring structure. The effect of UV–vis radiation is primarily hydrolysis of the material near the fiber surface with attendant formation of amide linkages. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3517–3525, 2006
Synthesis, characterization, and antimicrobial properties of oligo‐4‐[(pyridine‐3‐yl‐methylene) amino] phenol
Authors: Kaya İsmet , Bilici Ali , Saçak Mehmet 
Published: August 2006

AbstractThe oxidative polycondensation reaction conditions of 4‐[(pyridine‐3‐yl‐methylene) amino]phenol (4‐PMAP) were studied using H2O2, atmospheric O2, and NaOCl oxidants in an aqueous alkaline medium between 30°C and 90°C. Synthesized oligo‐4‐[(pyridine‐3‐yl‐methylene) amino] phenol (O‐4‐PMAP) was characterized by 1H‐, 13C NMR, FTIR, UV–vis, size exclusion chromatography (SEC), and elemental analysis techniques. The yield of O‐4‐PMAP was found to be 32% (for H2O2 oxidant), 68% (for atmospheric O2 oxidant), and 82% (for NaOCl oxidant). According to the SEC analysis, the number–average molecular weight, weight–average molecular weight, and polydispersity index values of O‐4‐PMAP was found to be 5767, 6646 g mol−1, and 1.152, respectively, using H2O2, and 4540, 5139 g mol−1, and 1.132, respectively, using atmospheric O2, and 9037, 9235 g mol−1, and 1.022, using NaOCl, respectively. According to TG and DSC analyses, O‐4‐PMAP was more stable than 4‐PMAP against thermal decomposition. The weight loss of O‐4‐PMAP was found to be 94.80% at 1000°C. Also, antimicrobial activities of the oligomer were tested against B. cereus, L. monocytogenes, B. megaterium, B. subtilis, E. coli, Str. thermophilus, M. smegmatis, B. brevis, E. aeroginesa, P. vulgaris, M. luteus, S. aureus, and B. jeoreseens. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3327–3333, 2006
Corn oil‐based composites reinforced with continuous glass fibers: Fabrication and properties
Authors: Lu Yongshang , Larock Richard C. 
Published: August 2006

AbstractNovel thermosetting composites have been successfully developed using glass fibers to reinforce regular corn oil (COR) and conjugated corn oil (CCOR) resins prepared by cationic copolymerization with styrene (ST) and divinylbenzene (DVB). The dependence of morphology and physical properties of the composites on the contents of glass fibers and DVB was determined by scanning electron microscopy, dynamic mechanical analysis, thermogravimetric analysis and tensile testing. The glass fiber loading and polymer matrix composition play an important role in improving the mechanical properties and thermal stability of the resulting composites. As the glass fiber content increases from 0 to 45 wt %, the COR‐based composites show an increase in Young's modulus from 4.1 to 874 MPa and tensile strength from 1.7 to 8.4 MPa. Furthermore, the composites exhibit good damping properties and are suitable for applications where reduction of both unwanted noise and vibration is important. Compared with the composites from COR, the CCOR‐based composites exhibit slightly higher thermal stabilities and mechanical properties, due to higher reactivity of CCOR with comonomers. Increasing the DVB content improves the crosslink density of the polymer matrix, leading to a significant improvement in the thermal stabilities and mechanical properties of the resulting composites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3345–3353, 2006