bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of the orientation and the degree of exfoliation of nanoparticles in poly(ethylene‐vinyl acetate) nanocomposites
Authors: Cser F. , Bhattacharya S. N. 
Published: October 2003

AbstractNanocomposites formed from organically modified montmorillonite and poly(ethylene‐co‐vinyl acetate) were studied by X‐ray diffraction techniques. Wide‐ and small‐angle X‐ray scattering intensities (SAXS and WAXS) were recorded by transmission mode on test bars cut from compression‐molded plaques tilted by different angles with respect to the plane of the plaque. The height of the Bragg peaks characteristic of intercalated particles reduced to the baseline at tilt angles greater than 30°. Guinier analysis of the SAXS characteristic of particle scattering showed a radius of gyration of 0.69 nm and the scattering intensity was slightly dependent on the tilt angle. Recording of WAXS in the usual (i.e., in reflective) mode enhanced the effect of the structural features of the surface area and showed much higher degree of intercalation and particle size of the scattering particles than that in transmission mode. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3026–3031, 2003
Preparation and characterization of thermosensitive poly(N‐isopropylacrylamide)/poly(ethylene oxide) semi‐interpenetrating polymer networks
Authors: Kim Seon Jeong , Lee Chang Kee , Lee Young Moo , Kim Sun I. 
Published: October 2003

AbstractTemperature‐sensitive poly(N‐isopropylacrylamide) hydrogels were successfully synthesized by using poly(ethylene oxide) as the interpenetrating agent. The newly prepared semi‐interpenetrating polymer network (semi‐IPN) hydrogels exhibited much better properties as temperature‐sensitive polymers than they did in the past. Characterizations of the IPN hydrogels were investigated using a swelling experiment, FTIR spectroscopy, and differential scanning calorimetry (DSC). Semi‐IPN hydrogels exhibited a relatively high temperature dependent swelling ratio in the range of 23–28 at room temperature. DSC was used for the determination of the lower critical solution temperature of the semi‐IPN hydrogel. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3032–3036, 2003
Synthesis and property behavior of dioctyl phthalate plasticized styrene–acrylate particles by Shirasu porous glass emulsification and subsequent suspension copolymerization
Authors: Nuisin Roongkan , Omi Shinzo , Kiatkamjornwong Suda 
Published: October 2003

AbstractTwo‐phase model styrene–acrylate copolymers were synthesized with a soft phase consisting of methyl acrylate, butyl acrylate, and butyl methacrylate. Besides the styrenic copolymers, copolymers containing a hard phase of methyl methacylate and methyl acrylate were also synthesized. Comonomer droplets with a narrow size distribution and fair uniformity were prepared using an SPG (Shirasu porous glass) membrane having pore size of 0.90 μm. After the single‐step SPG emulsion, the emulsion droplets were composed mainly of monomers, hydrophobic additives, and an oil‐soluble initiator, suspended in the aqueous phase containing a stabilizer and inhibitor. These were then transferred to a reactor, and subsequent suspension polymerization was carried out. Uniform copolymer particles with a mean diameter ranging from 3 to 7 μm, depending on the recipe, with a narrow particle size distribution and a coefficient of variation of about 10% were achieved. Based on the glass‐transition temperatures, as measured by differential scanning calorimetry, the resulting copolymer particles containing a soft phase of acrylate were better compatibilized with a hard phase of methyl methacrylate than with styrene with dioctyl phthalate (DOP) addition. Glass‐transition temperatures of poly(MMA‐co‐MA) particles were strongly affected by the composition drift in the copolymer caused by their substantial difference in reactivity ratios. Incorporation of DOP in the copolymer particles does not significantly affect the glass‐transition temperature of MMA‐ or MA‐containing copolymer particles, but it does affect the St‐containing copolymer and particle morphology of the copolymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3037–3050, 2003
Effect of interfacial interaction on rheological behavior of blends of a semiflexible liquid‐crystalline polyester and polycarbonate
Authors: Zhao Wei , Chua Yang Choo , Lu Xuehong 
Published: October 2003

AbstractA liquid‐crystalline polyester based on hydroxybenzoic acid, hydroquinone, sebacic acid, and suberic acid (named as BQSESU) was melt blended with polycarbonate (PC) at the BQSESU concentration of 2 wt %. It was found that the extent of viscosity reduction induced by the addition of BQSESU depends on the compounding temperature and the relation between them is not monotonic. The lowest viscosity was achieved by blending at 280°C. GPC measurements indicate that molecular weight reduction induced by the compounding is not a major contributor to the viscosity reduction. SEM study shows that when compounded at 280°C the blend is partially miscible with particle size at the submicron level. At the same time a large Tg depression was observed, which indicates strong interactions between the flexible segments of BQSESU and PC in the interfacial regions. The lowest viscosity achieved by blending at 280°C is thus proposed as an interfacial phenomenon. When compounded at 265°C, BQSESU particle size is larger, which gives a small interfacial area and hence less viscosity reduction. When compounded at 300°C a nearly miscible morphology was achieved, which also leads to less viscosity reduction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3051–3058, 2003
Effect of rubber ratio, carbon black level, and accelerator level on natural rubber/bromobutyl rubber blend properties
Authors: Lewis Chonlada , Buanpa Radtapon , Kiatkamjornwong Suda 
Published: October 2003

AbstractStatistical experimental design, that is, response surface methodology, was used to predict and explain the effects of rubber ratio, carbon black, and accelerator level on the cure characteristics and physical properties of natural rubber/bromobutyl rubber (NR/BIIR) blends. With these three independent variables, 20 designed compounds were mixed by a two‐roll mill and the scorch time, cure time, cure rate index, together with physical properties (hardness, tensile property, and compression set) were all determined by one operator. Multiple linear regression analysis was used to obtain response equations and thus contour plots, which illustrate the effects of the three independent variables on each property, as shown in detail by the diversity of interactions between independent factors and each property. It was found that the carbon black level is the most significant influential factor on scorch time, cure time, tensile properties, hardness, and compression set. The difference in reactivity toward sulfur vulcanization of NR and BIIR resulted in cure behavior and physical properties that are dominated by the NR content in the rubber ratio factor. Finally, the response equations were shown to be useful for making accurate predictions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3059–3068, 2003
Water and water vapor sorption studies in polypropylene–zeolite composites
Authors: Pehlivan H. , Özmıhçı F. , Tıhmınlıoǧlu F. , Balköse D. , Ülkü S. 
Published: October 2003

AbstractWater and water vapor sorption to porous polypropylene–zeolite composites prepared by hot pressing have been studied as a function of zeolite loading. This work presents the first report on the effect of the zeolite as a filler on the water‐sorption properties of PP composites. Water swelling experiments were conducted at 25°C using pure PP and PP–zeolite films samples having different zeolite loadings (6–40 wt %). Because PP is a hydrophobic polymer, it does not sorp any water, but the composites having 10, 20, 30, and 40% zeolites have sorbed 0.63, 1.00, 1.72 and 3.74% water, respectively. The zeolite itself at the same conditions sorbed 24.5% water. As the filler loading in the composites increased, equilibrium uptake values increased also. On the other hand, water vapor sorption and kinetics has been studied using a Cahn 2000 gravimetric sorption system. Within in the range of 0.35–0.95% water vapor was adsorbed by the composites containing 10–40 wt % zeolites. Experimental effective water vapor diffusivities of the composite films was about one order of magnitude higher (10‐fold) than the experimental water diffusion coefficient in composites. The transport of water in composites was slower than that in the liquid water due to the longer diffusion pathway and adsorption on the surface of the composites. Although the liquid water may fill all the voids in the composite, water vapor is adsorbed on the surface of the zeolite only. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3069–3075, 2003
Microstructure and crystallization of melt‐mixed poly(ethylene terephthalate)/poly(ethylene isophthalate) blends
Authors: Kint Darwin P. R. , Martínez de Ilarduya Antxon , Sansalvadó A. , Ferrer Josep , Muñoz‐Guerra Sebastián 
Published: October 2003

AbstractPhysical blends of poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate) (PEI), abbreviated PET/PEI (80/20) blends, and of PET and a random poly(ethylene terephthalate‐co‐isophthalate) copolymer containing 40% ethylene isophthalate (PET60I40), abbreviated PET/PET60I40 (50/50) blends, were melt‐mixed at 270°C for different reactive blending times to give a series of copolymers containing 20 mol % of ethylene isophthalic units with different degrees of randomness. 13C‐NMR spectroscopy precisely determined the microstructure of the blends. The thermal and mechanical properties of the blends were evaluated by DSC and tensile assays, and the obtained results were compared with those obtained for PET and a statistically random PETI copolymer with the same composition. The microstructure of the blends gradually changed from a physical blend into a block copolymer, and finally into a random copolymer with the advance of transreaction time. The melting temperature and enthalpy of the blends decreased with the progress of melt‐mixing. Isothermal crystallization studies carried out on molten samples revealed the same trend for the crystallization rate. The effect of reaction time on crystallizability was more pronounced in the case of the PET/PET60I40 (50/50) blends. The Young's modulus of the melt‐mixed blends was comparable to that of PET, whereas the maximum tensile stress decreased with respect to that of PET. All blend samples showed a noticeable brittleness. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3076–3086, 2003
Morphologies of polyethylene–ethylene/propylene/diene monomer particles in polypropylene‐rich polyolefin blends: Flake structure
Authors: Nedkov Todor , Lednický František 
Published: October 2003

AbstractMorphologies of polyethylene–ethylene/propylene/diene monomer (PE/EPDM) particles in 93/7 polypropylene (PP)/PE blends were investigated. SEM micrographs of KMnO4‐etched cut surfaces and fracture surfaces of the blends revealed the existence of the “flake” structure. In the particles, crystalline PE formations with flake shape, which remain after etching, are called flakes. In addition to the PE‐crystalline flakes, amorphous PE, located between PE crystalline lamellae and EPDM rubber, complement the flake structure. The flakes are usually linked with the PP matrix, as seen in the heptane‐treated cut surfaces. These links, although observed with compatibilized samples, originate from the crystalline nature of PE particles, if no compatibilizer is added. Separately, the morphology of Royalene (consisting of high‐density PE and EPDM rubber, used as a PP/PE compatibilizer) was investigated by low‐voltage scanning TEM. The interaction of the components in the PE/EPDM blends can explain the formation of the flakes and toughening of the PP/PE blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3087–3092, 2003
Study on the synthesis of brominated epoxy resins
Authors: Król Piotr , Król Bożena , Dziwiński Euzebiusz 
Published: October 2003

AbstractThe GC/MS/Py method, thermogravimetric analysis (TG), MALDI‐TOF spectrometry, and IR spectra were utilized to investigate structures and thermal stability of brominated epoxy resins synthesized in the reaction of epichlorohydrin (ECH) and tetrabromobisphenol A (TBBA), with varied molar rates of monomers and varied condensation temperatures. A Rheotest viscometer was employed to test rheological properties of the resins, while their mechanical properties were determined after hardening with phthalic anhydride. The research work revealed that the optimum synthesis conditions were ECH : TBBA = 5 : 1, and the condensation temperature reasonably low (e.g., 40°C). The basic properties of the synthesized resins were found to be comparable to those of the commercial product D.E.R. 542 offered by Dow Plastics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3122–3134, 2003
New arylidene–siloxane polyethers: Liquid‐crystalline and photosensitive properties
Authors: Racleş Carmen , Airinei Anton , Cozan Vasile , Cazacu Maria , Sajo Istvan E. 
Published: October 2003

AbstractBy polycondensation reactions, starting from α, ω‐bis(chloromethyl)polydimethylsiloxanes with different molecular weights and 2,6‐bis(4‐hydroxybenzylidene)cyclohexanone, new polyethers were obtained. The structure of resulting polymers was confirmed by IR and 1H‐NMR spectroscopy and their thermal properties and mesophase behavior were studied by TGA, DSC, and polarizing light microscopy. Depending on the length of the siloxane spacer, some of the obtained compounds exhibited thermotropic liquid‐crystalline properties. A possible smectic texture was investigated by X‐ray diffraction measurements at room temperature. A decrease of the transition temperatures values was observed as the spacer length increased. The photochemical behavior of the siloxane polyethers was studied by ultraviolet absorption spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3093–3099, 2003
Modified chitosan. II. H‐chitoPAN, a novel pH‐responsive superabsorbent hydrogel
Authors: Pourjavadi A. , Mahdavinia G. R. , Zohuriaan‐Mehr M. J. 
Published: October 2003

AbstractChitosan was modified with polyacrylonitrile (PAN) through ceric‐initiated graft copolymerization. The chitosan‐g‐PAN product was saponified using sodium hydroxide aqueous solution to prepare a novel superabsorbent hydrogel, H‐chitoPAN. Duration of completing the saponification reaction as well as the water absorbency capacity of the hydrogel was decreased with increasing the alkaline concentration. Either chitosan‐g‐PAN or H‐chitoPAN was characterized by FTIR spectroscopy and DSC, TGA, and DTG thermal methods. According to FTIR, all the nitrile groups were converted to carboxylate and carboxamide groups. Both modified chitosans exhibited enhanced thermal stability over chitosan. The H‐chitoPAN superabsorbent hydrogel was recognized to be highly responsive to pH. Study of net effect of H+/OH− concentration (in absent of buffer solution) showed several sharp and large volume changes vs small pH variation in the range of 2–13. This abrupt swelling behavior was explained based on variety of pH‐dependent interactions of functional groups incorporated in the gel network by an external pH modulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3115–3121, 2003
Effect of low molecular weight polybutadiene as processing aid on properties of silica‐filled styrene–butadiene rubber compounds
Authors: Choi Sung‐Seen , Park Byung‐Ho , Nah Changwoon 
Published: October 2003

AbstractBecause silica has strong filler–filler interactions, a silica‐filled rubber compound shows a poor filler dispersion compared to a carbon black‐filled one. Improvement of the filler dispersion in silica‐filled styrene–butadiene rubber (SBR) compounds was studied using low molecular weight polybutadiene (liquid PBD) with the high content of 1,2‐unit. By adding the liquid PBD to the silica‐filled SBR compound, the filler dispersion and flow property are improved. The cure time and cure rate become faster as the 1,2‐unit content of the liquid PBD increases for the compounds containing the liquid PBD. The crosslink density increases linearly with increase in the 1,2‐unit content of the liquid PBD. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3135–3140, 2003
Dynamic mechanical properties of sandwich‐structured epoxy beam composites containing poly(ethyleneterephthalate)/poly(ethyleneglycol) copolymer with shape memory effect
Authors: Chun Byoung Chul , Cha Sang Hyuk , Park Chul , Chung Yong‐Chan , Park Myung Ju , Cho Jae Whan 
Published: October 2003

AbstractTo make smart vibration‐controlling composite laminate, a few poly(ethylene terephthalate) (PET) and poly(ethylene glycol) (PEG) copolymers with shape memory ability were prepared. After selecting the best composition of PET–PEG copolymer in mechanical properties, a crosslinking agent such as glycerine, sorbitol, or maleic anhydride (MA) was included for crosslinked copolymer, followed by analysis of its effect on mechanical, shape memory, and damping properties. The highest shape recovery was observed for copolymer with 2.5 mol % of glycerine, and the best damping effect indicating vibration control ability was from copolymer with 2.5 mol % of sorbitol. With the optimum copolymers in hand, sandwich‐structured epoxy beam composites fabricated from an epoxy beam laminate and crosslinked PET–PEG copolymer showed that impact strength increased from 1.9 to 3.7 times depending on the type of copolymer, and damping effect also increased as much as 23 times for the best case compared to epoxy laminate beam alone. The resultant sandwich‐structured epoxy beam composite can be utilized as structural composite material with vibration control ability, and its glass transition temperature can be controlled by adjustment of PET, PEG, or crosslinking agent composition. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3141–3149, 2003
Preparation and properties of a biodegradable polymer as a novel drug delivery system
Authors: Liu Yu , Guo Li Kun , Huang Long , Deng Xian Mo 
Published: October 2003

AbstractPoly (DL‐lactic acid‐co‐glycolic acid)‐co‐poly(ethylene glycol) was synthesized by bulk ring‐opening polymerization of DL‐lactide/glycolide/poly(ethylene glycol) using stannous chloride as an initiator. The molecular structure of the copolymer was analyzed by IR, 1H NMR, and DSC. The degradation behavior of copolymer was assayed by the reduction of molecular weight, the loss‐in‐mass, and the changes of pH value for degradation medium. The different contents of PGA and PEG in the molecules of the copolymer could control the degradation rate of polymer. Human Serum Albumin (HSA) was chosen as the model hydrophilic drug and encapsulated in the copolymer. The HA‐loaded copolymer microspheres were characterized by the diameter, diameter distribution of the microspheres, and the loading efficiency. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3150–3156, 2003
Molecular migration of aromatic liquids into a commercial fluoroelastomeric membrane at 30, 40, and 50°C
Authors: Kulkarni Sangeeta B. , Kariduraganavar Mahadevappa Y. , Aminabhavi Tejraj M. 
Published: October 2003

AbstractA study of sorption profiles and diffusion anomalies of benzene, methyl‐substituted benzenes, and other substituted benzenes (viz., chlorobenzene, nitrobenzene, bromobenzene, and anisole) into commercial fluoroelastomer (FC‐2450) was carried out by gravimetric method. The liquid sorption was studied at 30, 40, and 50°C and the results were analyzed in terms of Fick's diffusion equation. Liquid concentration profiles were also computed by using Fick's equation with the appropriate initial and boundary conditions and these are presented as a function of penetration depth of molecular migration and time of immersion. The temperature dependencies of sorption, diffusion, and permeation were used to compute the Arrhenius activation parameters and the results were discussed in terms of molecular size of liquids and interactions. Similarly, the diffusion coefficients and activation energies for diffusion exhibit systematic dependence on the size of the penetrant molecules and in some cases these are influenced by the interactions between the membrane and liquid molecules. The results reported here are useful in the applications of fluoroelastomer in hazardous waste chemical ponds and other similar situations. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3100–3106, 2003
Kinetic analysis of thermal degradation in poly(ethylene–vinyl alcohol) copolymers
Authors: Alvarez V. A. , Ruseckaite R. A. , Vázquez A. 
Published: October 2003

AbstractThermal analysis of EVOH copolymers with different ethylene content, were performed by TGA/DTGA under dynamic conditions. Apparent kinetic parameters were determined using different classical kinetic approaches. The apparent activation energy values obtained confirm that thermal stability of EVOH increases with ethylene content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3157–3163, 2003
Electrical polarization effects on LDPE morphology
Authors: Robert R. , de Souza G. P. , Juraitis K. R. , Akcelrud L. 
Published: October 2003

AbstractThe thermal and dynamic mechanical behavior of polarized low‐density polyethylene (LDPE) was investigated, by applying electric fields in the range of 5.37 to 31.7 MV/m, for 2.75 to 43.5 h. The polarization strongly affected DSC and DMA spectra, indicating that a new and more ordered phase is formed, which disappears gradually after the removal of the electrical field. A shift of −21.3°C was found in the DMTA spectra for the Tg of the polarized material, and no changes could be found in comparing the results of WAXS analyses of the original and treated materials. Very similar effects were observed with mechanical loading of the materials, leading to the conclusion that the amorphous phase of LDPE might be orienting under high electric fields in a similar manner. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3107–3114, 2003
A scheduling scheme for variable‐length packets in an input‐buffered ATM switch with priority of active buffer
Authors: Nakaki Yousuke , Okazaki Kohei , Sakamoto Kenji , Nishino Yoshiyuki , Sasase Iwao 
Published: October 2003

AbstractIn ATM (asynchronous transfer mode) we propose a VOQ (virtual output queuing) switch in which the same number of buffers as the number of output ports are provided in each input port, serving as an input‐buffered switch to avoid HoL (head of line) blocking. In addition, in order to handle the recent increase of IP traffic, the IP‐PIM (IP‐parallel iterative matching) scheme is proposed as the scheduling scheme for the VOQ switch using variable‐length packets. However, the IP‐PIM scheme has the problem that the queue lengths in other buffers are increased, since cells belonging to the same packet are always handled continuously, which degrades the packet loss probability. Consequently, this paper proposes a scheduling scheme with active buffer priority in which the buffer receiving the cells belonging to the packet under consideration is defined as the active buffer and is given priority. In the proposed scheme, the queue length is reduced by giving the priority to the active buffer, and efficient switching is realized. The packet loss probability and the average packet delay are evaluated by computer simulation. It is found that the proposed scheme can greatly improve the packet loss probability compared to the conventional scheme, with degradation of the average packet delay by approximately 20 slots. It is also shown that a satisfactory loss probability is realized even if the buffer size is small, and that good expandability with regard to the switch size is achieved. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 87(2): 79–90, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10120