bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of surface structure with regard to interfacial delamination in polyester films with incompatible polymers
Authors: Ito Katsuya , Nonomura Chisato , Yamashita Katsuhisa , Suzuki Toshitake , Chinwanitcharoen Charoen , Yamada Toshiro , Ishihara Hideaki 
Published: February 2004

AbstractPoly(ethylene terephthalate) (PET) films containing incompatible polymer particles were analyzed, with particular reference to the relationship between the PET particle interfacial tension and the microvoids, or the protrusion that were formed when the composite material was stretched at 90°C. A model was developed to simulate void formation and surface protrusion due to interfacial delamination between PET and three types of dispersed incompatible polymers, poly(4‐methyl‐1‐pentene), polypropylene, and polystyrene. The numerical results, obtained with the finite element method, were compared with experimental data of the blends for both the internal and subsurface regions. The experimental measurements showed that the increase in the difference in the surface tension between PET and the added incompatible polymer was associated with the formation of larger voids. The protrusions were also generated in the stretching and delamination between PET and the incompatible polymers, but a decrease in the interfacial tension agreed with the formation of a larger protrusion. Modeling studies showed that increasing the interfacial tension between the two components in a blend causes a decrease in the critical stress for delamination. Interfacial tension values related qualitatively to the critical stress for void formation and protrusion calculated with the numerical analysis. A concavity was also necessary for understanding the surface structure of the films, along with protrusion. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1243–1251, 2004
Mechanical and dielectric properties of cured 1,2‐bis(vinylphenyl)ethane resin modified with poly(phenylene oxide)
Authors: Amou Satoru , Yamada Shinji , Takahashi Akio , Nagai Akira , Tomoi Masao 
Published: February 2004

Abstract1,2‐Bis(vinylphenyl)ethane (BVPE) could be cured without curing agents at relatively low temperatures (∼ 180°) in a nitrogen atmosphere. Cured BVPE (CBVPE) resin showed exceptionally low dielectric constant (ϵ = 2.50 at 10 GHz) and low dielectric loss tangent (tan δ = 0.0012 at 10 GHz), and had excellent thermal resistance. Its 5 wt % weight‐loss temperature was 425°C in a nitrogen atmosphere and glass transition temperature was over 400°C. Poly(phenylene oxide) (PPO) was used to improve the toughness of CBVPE resin. PPO was an effective modifier to toughen CBVPE resin: when using 30 wt % of the modifier, the tensile strength and elongation of the modified CBVPE resin were 75 MPa and 26%, respectively. The modified CBVPE resin also showed excellent dielectric properties (ϵ = 2.45 at 10 GHz, tan δ = 0.0015 at 10 GHz). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1252–1258, 2004
Cure kinetics, microheterogeneity, and mechanical properties of the high‐temperature cure of vinyl ester resins
Authors: Li Peng , Yang Xiaoping , Yu Yunhua , Yu Dingsheng 
Published: February 2004

AbstractA kinetic model has been developed that is based on the irreversible thermodynamic fluctuation theory, in which the conversion of comonomers is a function of the curing relaxation time, reaction time, and reaction temperature. This modified model permits a better prediction of the course of the high‐temperature cure reaction of vinyl ester (VE) resins under isothermal conditions. The microheterogeneity in cured resins was investigated through the measurement of the residual heat of isothermally cured samples with differential scanning calorimetry and through the observation of the fracture surfaces of samples under different cure conditions with scanning electron microscopy (SEM). The SEM photographs demonstrated the existence of clusters of microgels of about 20 μm in samples isothermally cured at 80°C for 3 h. The results of the dynamic mechanical thermal analysis of postcured samples verified the microheterogeneity in the cured samples and showed that the glass‐transition temperatures were not affected by the curing conditions. The effect of postcuring on the conversions of VE and styrene varied with the different cure schedules. The postcure for a sample isothermally cured at 80°C increased the tensile strength and flexural strength. On the contrary, the postcure for samples isothermally cured at 120°C reduced the tensile strength and flexural strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1124–1133, 2004
Effects of the blending sequence in polyolefin ternary blends
Authors: Ha M. H. , Kim M. S. , Kim B. K. , Kim W. , Lee M. C. , Kim H. D. 
Published: February 2004

AbstractTernary blends of isotactic polypropylene (PP), ethylene–octene copolymer (mPE), and high‐density polyethylene (HDPE) were prepared by melt mixing in a twin‐screw extruder with two different sequences of mixing: the simultaneous mixing of the three components (method I) and the premixing of mPE and HDPE followed by mixing with PP (method II). Regardless of the mixing sequence, mPE encapsulated HDPE in the PP matrix, although better mechanical properties were generally obtained with method II. The domain size was mainly determined by the viscosity ratio of mPE to PP in method I and by the viscosity ratio of the binary blend (mPE/HDPE) to PP in method II. Specimens prepared by injection molding gave much finer dispersions than compression‐molded specimens. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 804–811, 2004
Sorption studies of volatile organic compounds in a divinyl‐terminated poly(dimethylsiloxane)–oligo polymer
Authors: Zhen Hanfei , Jang Steven , Teo W. K. 
Published: February 2004

AbstractThe sorption equilibria and kinetics of three volatile organic compounds (VOCs)—benzene, chloroform, and acetone—in a newly developed divinyl‐terminated poly(dimethylsiloxane) (PDMSvi)–oligo polymer were studied. The PDMSvi–oligo polymer was prepared from a hexane solution consisting of PDMSvi as the polymer, oligosilylstyrene as the crosslinker, and a platinum–divinyltetramethyldisiloxane complex as the Karstedt catalyst. The sorption uptake of each VOC by the polymer was measured gravimetrically at different VOC partial pressures at a constant temperature and at different temperatures between 24 and 50°C. The rate of VOC sorption was monitored until equilibrium was established. The solubility coefficient increased when the VOC activity increased, and the results revealed that the PDMSvi–oligo polymer was a good sorbent for the three VOCs examined. Relatively high solubilities of these VOCs were obtained in this polymer in comparison with those reported for conventional silicone rubbers. The Flory–Huggins model fit the observed equilibrium sorption isotherms of the benzene and chloroform systems very well, whereas the Koningsveld–Kleinjtens variation law had to be combined with the Flory–Huggins model to describe the sorption isotherm of acetone in the polymer film. The rates of sorption of the three VOCs in the polymer samples were generally rapid and controlled by Fickian diffusion. The diffusivities of benzene, chloroform, and acetone at 24°C, determined with the diffusion equation, were approximately 10−6 cm/s. The sorption and diffusion data revealed that the newly developed PDMSvi–oligo polymer was an excellent sorbent for the three VOCs examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 920–927, 2004
Thermoplastic olefin/clay nanocomposites: Morphology and mechanical properties
Authors: Mehta Sameer , Mirabella Francis M. , Rufener Karl , Bafna Ayush 
Published: February 2004

AbstractThermoplastic olefin (TPO)/clay nanocomposites were made with clay loadings of 0.6–6.7 wt %. The morphology of these TPO/clay nanocomposites was investigated with atomic force microscopy, transmission electron microscopy (TEM), and X‐ray diffraction. The ethylene–propylene rubber (EPR) particle morphology in the TPO underwent progressive particle breakup and decreased in particle size as the clay loading increased from 0.6 to 5.6 wt %. TEM micrographs showed that the clay platelets preferentially segregated to the rubber–particle interface. The breakup of the EPR particles was suspected to be due to the increasing melt viscosity observed as the clay loading increased or to the accompanying chemical modifiers of the clay, acting as interfacial agents and reducing the interfacial tension with a concomitant reduction in the particle size. The flexural modulus of the injection moldings increased monotonically as the clay loading increased. The unnotched (Izod) impact strength was substantially increased or maintained, whereas the notched (Izod) impact strength decreased modestly as the clay loading increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 928–936, 2004
Preparation and characterization of hybrid organic–inorganic epoxide‐based films and coatings prepared by the sol–gel process
Authors: špírková Milena , Brus Jiří , Hlavatá Drahomíra , Kamišová Helena , Matějka Libor , Strachota Adam 
Published: February 2004

AbstractHybrid organic–inorganic coatings and free‐standing films were prepared and characterized. The hybrids were prepared from [3‐(glycidyloxy)propyl]trimethoxysilane, diethoxy[3‐(glycidyloxy)propyl]methylsilane, poly(oxypropylene)s of different molecular weights end‐capped with primary amino groups (Jeffamines D230, D400, and T403), and colloidal silica particles with hydrochloric acid as a catalyst for the sol–gel process and water/propan‐2‐ol mixtures as solvents. The structure evolution during the network formation was followed by NMR spectroscopy and small‐angle X‐ray scattering; the surface morphology was tested by atomic force microscopy. The influence of the reaction conditions (the organosilicon precursor, oligomeric amine, ratio of functional groups, and method of preparation) on the network buildup and product properties was studied and examined. The mechanical testing, based on stress–strain experiments, in combination with dynamic mechanical thermal analysis served as an effective instrument for the optimization of the reaction conditions for the preparation of products with desired properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 937–950, 2004
New postfunctional method to synthesize C60‐containing poly(ethylene oxide)
Authors: Li Zhen , Shao Pin , Qin Jingui 
Published: February 2004

AbstractThis article reports the detailed synthesis and structural characterization of two new C60‐containing poly(ethylene oxide)s by a new postfunctional method. A predesigned amino end‐functionalized poly(ethylene oxide) was prepared, and this reactive macromolecular intermediate was reacted with C60 molecules in chlorobenzene to yield the C60‐containing poly(ethylene oxide)s. The molecular structures of the polymers were characterized with 1H‐NMR, IR, and ultraviolet–visible spectra. The polymers exhibited good solubility in common organic solvents and water and were stable in air. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 867–870, 2004
On the use of extruders as chemical reactors
Authors: Natov Milcho , Mitova Violeta , Vassileva Stefanka 
Published: February 2004

AbstractComposites of polyamide‐6 (PA‐6) and poly(butadiene acrylonitrile) (PBAN), varying in the quantity of the elastomer and the content of its nitrile groups, were examined during extrusion in a 45‐mm extruder at 225 ± 2°C and with a shear rate over 450 s−1. It was established that these two incompatible polymers can be mixed and the blends display solubility in formic acid. This fact is explained by chemical transformation of the nitrile groups followed by chemical interaction between the polyamide and elastomer components. As a result, graft copolymers were most probably formed. The reaction proceeds easily if the PA‐6 contains water. The extrusion leads to improved compatibility of the polymers and enhanced impact strength of the extrudates. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 871–877, 2004
Preparation of hyperbranched polyester photoresists for miniaturized optics
Authors: Feng Zongcai , Liu Minghua , Wang Yuechuan , Zhao Lin 
Published: February 2004

AbstractHyperbranched polymers containing carboxyl and acryloxyl groups were prepared through a one‐step synthesis with metatrimellitic anhydride, epichlorohydrin, and methylacrylic acid glycidic ester. The photo‐sensitivity coefficients of the polymer resists varied with the resin acid values and formulas. The linear depth was the reverse of the contrast. When the contrast was less than 0.49, the linear depth could reach 43 μm. The hyperbranched polyester resists were used to prepare microlens arrays. Moreover, there was a slight discrepancy between the element profile and simulated profile of the formed resists. The etching depth could reach 50 μm. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1259–1263, 2004
Preparation and release behavior of carboxymethylated chitosan/alginate microspheres encapsulating bovine serum albumin
Authors: Zhang Lina , Guo Ji , Peng Xianghong , Jin Yong 
Published: February 2004

AbstractMicrospheres were prepared from carboxymethylated chitosan (CM‐chitosan) and alginate by emulsion phase separation. Their structure and morphology were characterized with IR spectroscopy and scanning electron microscopy. Bovine serum albumin (BSA) was encapsulated in the microspheres to test the release behavior. The swelling behavior, encapsulation efficiency, and release behavior of BSA from the microspheres at different pHs and with a pH‐gradient condition were investigated. The BSA encapsulation efficiency was calculated to be 80%. The degree of swelling of the microspheres without BSA loaded at pH 7.2 was much higher than that at pH 1.0. The encapsulated BSA was quickly released in a Tris–HCl buffer (pH 7.2), whereas a small amount of BSA was released under acid conditions (pH 1.0) because of the strong electrostatic interaction between NH2 groups of CM‐chitosan and COOH groups of alginic acid and a dense structure caused by a Ca2+ crosslinked bridge. For the simulation of the processing of the drug under the conditions of the intestine, the microspheres were tested in a pH‐gradient medium, in which an acceleration of the release occurred at pH 7.4 after a lag time at a low pH (5.8–6.8). At pH 7.4, a large amount of BSA was released from the microspheres in a short time because of the rapid swelling of the microspheres. However, the release only depended on the diffusion of BSA at relatively low pHs, this resulted in a relatively low release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 878–882, 2004
Solid polymer electrolytes. VII. Preparation and ionic conductivity of gelled polymer electrolytes based on poly(ethylene glycol) diglycidyl ether cured with α,ω‐diamino poly(propylene oxide)
Authors: Liang Wuu‐Jyh , Chen Ting‐Yen , Kuo Ping‐Lin 
Published: February 2004

AbstractCrosslinked polymer electrolyte networks were prepared from poly(ethylene glycol) diglycidyl ether blended with an epoxy resin (diglycidyl ether of bisphenol A) in different ratios and then cured with α,ω‐diamino poly(propylene oxide) in the presence of lithium perchlorate (LiClO4) as a lithium salt. The ionic conductivities of these polymer electrolytes were determined by alternating current (AC) impedance spectroscopy. Propylene carbonate (PC) was used as a plasticizer to form gelled polymer electrolyte networks. The conductivities of the polymer electrolytes containing 46 wt % PC plasticizer were approximately 5 × 10−4 S cm−1 at 25°C and approximately 10−3 S cm−1 at 85°C. These polymer electrolytes were homogeneous and exhibited good mechanical properties. The effects of the polymer composition, plasticizer content, salt concentration, and temperature on the ionic conductivities of the polymer electrolytes were examined. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1264–1270, 2004
Microwave‐promoted rapid synthesis of new optically active poly(amide imide)s derived from N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine diacid chloride and aromatic diamines
Authors: Mallakpour Shadpour , Shahmohammadi Mohammad Hassan 
Published: February 2004

AbstractA pyromellitic dianhydride (benzene‐1,2,4,5‐tetracarboxylic dianhydride) was reacted with L‐isoleucine in acetic acid, and the resulting imide acid [N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine] (4) was obtained in a high yield. 4 was converted into N,N′‐(pyromellitoyl)‐bis‐L‐isoleucine diacid chloride by a reaction with thionyl chloride. The polycondensation reaction of this diacid chloride with several aromatic diamines, including 1,4‐phenylenediamine, 4,4′‐diaminodiphenyl methane, 4,4′‐diaminodiphenylsulfone (4,4′‐sulfonyldianiline), 4,4′‐diaminodiphenylether, 2,4‐diaminotoluene, and 1,3‐phenylenediamine, was developed with two methods. The first method was polymerization under microwave irradiation, and the second method was low‐temperature solution polymerization, with trimethylsilyl chloride used as an activating agent for the diamines. The polymerization reactions proceeded quickly and produced a series of optically active poly(amide imide)s with good yields and moderate inherent viscosities of 0.17–0.25 dL/g. All of the aforementioned polymers were fully characterized by IR, elemental analyses, and specific rotation. Some structural characterization and physical properties of these optically active poly(amide imide)s are reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 951–959, 2004
Viscosity‐reducing effects of two semiflexible liquid‐crystalline polyesters with different chain rigidities in a matrix of polycarbonate
Authors: Zhao Wei , Zhao Jianhong , Chen Yu , Wei Xu Jian , Lu Xuehong 
Published: February 2004

AbstractTwo liquid‐crystalline polyesters (LCPs) with different chain rigidities were synthesized and melt‐blended with polycarbonate (PC) at an LCP concentration of 2 wt %. The first LCP (LCP1) was based on hydroxybenzoic acid (HBA), hydroquinone (HQ), sebacic acid (SEA), and suberic acid (SUA) and contained a relatively high concentration of flexible units (SEA and SUA). The other one (LCP2) was based on HBA, hydroxynaphthoic acid, HQ, and SEA and contained a lower concentration of flexible units. LCP2 had a much lower melting point, a higher clearing temperature, and a lower shear viscosity than LCP1. The blending was carried out at 265, 280, and 300°C for both systems. The extent of the viscosity reduction induced by the addition of LCP1 depended on the compounding temperature, and the lowest viscosity was achieved with blending at 280°C. This was attributed to the large interfacial area and interactions between the flexible segments of LCP1 and PC chains at the interface. For PC/LCP2, the viscosity reduction was not significantly dependent on the compounding temperature, and when it was compounded at 280°C, its viscosity was significantly higher than that of PC/LCP1 at high shear rates, even though LCP2 had lower viscosity. A scanning electron microscopy study revealed that, with compounding at 265 and 280°C, LCP2 was poorly dispersed in the PC matrix in comparison with LCP1, and the glass‐transition‐temperature depression caused by the addition of LCP2 was relatively small. This indicated that interfacial interactions in PC/LCP2 were weaker, thereby explaining their different rheological behavior in comparison with PC/LCP1. With compounding at 300°C, the compatibility of both systems improved because of transesterification reactions, but this did not lead to a lower viscosity because of the lack of physical interfacial interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 960–969, 2004
Preparation and characterization of highly oriented poly(γ‐benzylL‐glutamate) networks and gels with long channels with micrometer‐scale diameters
Authors: Yamane Yuji , Kanekiyo Masahito , Koizumi Satoshi , Zhao Chenhua , Kuroki Shigeki , Ando Isao 
Published: February 2004

AbstractPoly(γ‐benzylL‐glutamate) (PBLG) gels with highly oriented α‐helix chains were prepared by the crosslinking of PBLG chains through changes in the concentration of ethylenediamine, used as a crosslinker, in 1,4‐dioxane in the presence of the strong magnetic field of an NMR magnet with a strength of 10.5 T. The experimental results showed that in one of these gels, long channels with an average diameter of about 100 μm were formed by phase separation between crosslinked PBLG and the solvent. Furthermore, three‐dimensional1H‐NMR imaging patterns showed that the long channels were aligned in the direction parallel to the α‐helix axis. The PBLG gel was swollen in the direction perpendicular to the α‐helix axis, but it was not swollen in the direction parallel to the α‐helix axis. The X‐ray diffraction patterns of the gel showed that the interchain distance between the two nearest neighboring PBLG chains changed from 13.4 to 18.1 Å with a change in the swelling degree. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1053–1060, 2004
Film‐forming process from globular polytetrafluoroethylene latex particles
Authors: Dürrschmidt Th. , Hoffmann H. 
Published: February 2004

AbstractFilm formation from an aqueous polytetrafluoroethylene (p‐TFE) latex dispersion on glass tissues was studied. The p‐TFE particles were of globular shape, had a diameter of 220 ± 20 nm, and were of high crystallinity (∼ 100%). The melting point of the material was 332°C. For the study of the film formation, stripes of glass tissues were dipped in a concentrated p‐TFE latex dispersion and then removed. The samples were then dried in an oven at well‐defined temperatures below and above the melting temperature Tm of the p‐TFE latex. The film formation from the particles was then studied by taking SEM micrographs of the surface of the samples at various times and conditions. It was observed that the globular particles kept their globular shape and did not coalesce to a film as long as the temperature of the sample was kept below Tm. When the samples were tempered with T > Tm the film formation started. The neighboring globular particles coalesced into wormlike particles that grew in length with time. During the growth of the particles the thickness of the particles remained constant. In the first stages the film can be imagined as a porous network from short wormlike objects. It is concluded that the coalescence begins above Tm when the polymer chains become mobile along their axis. The chains of neighboring particles can therefore interdigitate into each other along their main axis and crosslink the particles. The proposed mechanism of film formation is confirmed by AFM micrographs on which the individual particles from the dispersion are still visible in the wormlike objects. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 733–742, 2004
Polymers with palladium nanoparticles as active membrane materials
Authors: Yu J. , Liu R. Y. F. , Poon B. , Nazarenko S. , Koloski T. , Vargo T. , Hiltner A. , Baer E. 
Published: February 2004

AbstractA new in situ infusion method was used to incorporate small amounts (∼1 wt %) of metal and metal oxide particles into a polymer matrix. Nanosized particles were observed by both transmission electron microscopy and atomic force microscopy. Oxygen (O2) and carbon dioxide (CO2) transport properties of the infused materials were investigated using a dynamic diffusion approach in which both testing and purge gases can be controlled. It was discovered that trace amounts (∼2%) of hydrogen (H2) in the purge gas were sufficient to considerably reduce the O2 flux of FEP films infused with palladium (Pd) nanoparticles, up to a 200‐fold decrease. In contrast, H2 essentially had no effect on the transport of CO2. The generality of the remarkable reduction in oxygen flux was also demonstrated with films of PP, LLDPE, PET, and nylon 6,6 infused with Pd nanoparticles. This oxygen‐scavenging effect became more pronounced at lower oxygen concentrations. The catalytic role of Pd in the reaction of O2 and H2 and the enormous surface area provided by the dispersed nanoparticles were responsible for this highly efficient oxygen‐scavenging effect. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 749–756, 2004