bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical and thermal properties of polyphenylene sulfide/multiwalled carbon nanotube composites
Authors: Jiang Zhenyu , Hornsby Peter , McCool Rauri , Murphy Adrian 
Published: September 2011

AbstractPolyphenylene sulfide (PPS)/multiwalled carbon nanotube (MWCNT) composites were prepared using a melt‐blending procedure combining twin‐screw extrusion with centrifugal premixing. A homogeneous dispersion of MWCNTs throughout the matrix was revealed by scanning electron microscopy for the nanocomposites with MWCNT contents ranging from 0.5 to 8.0 wt %. The mechanical properties of PPS were markedly enhanced by the incorporation of MWCNTs. Halpin‐Tsai equations, modified with an efficiency factor, were used to model the elastic properties of the nanocomposites. The calculated modulus showed good agreement with the experimental data. The presence of the MWCNTs exhibited both promotion and retardation effects on the crystallization of PPS. The competition between these two effects results in an unusual change of the degree of crystallinity with increasing MWCNT content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Miscibility and crystallization behavior of biodegradable poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/phenolic blends
Authors: Yang Fang , Li Zhisheng , Qiu Zhaobin 
Published: September 2011

AbstractPoly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV)/phenolic blends are new miscible crystalline/amorphous polymer blends prepared via solution casting method in this work, as evidenced by the single composition dependent glass transition temperature. The measured Tgs can be well fitted by the Kwei equation with a q value of 13.6 for the PHBV/phenolic blends, indicating that the interaction between the two components is strong. The negative polymer–polymer interaction parameter, obtained from the melting depression of PHBV using the Nishi‐Wang equation, indicating the thermal miscibility of PHBV and phenolic. The spherulitic morphology and crystal structure of PHBV/phenolic blends were studied with polar optical microscopy and wide angle X‐ray diffraction compared with those of neat PHBV. It is found that the growth rates of PHBV in the blends are lower than that in neat PHBV at a given crystallization temperature, and the crystal structure of PHBV is not modified by the presence of phenolic in the PHBV/phenolic blends, but the crystallinity decrease with the increasing of phenolic. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Curing characteristics and mechanical properties of rattan‐powder‐filled natural rubber composites as a function of filler loading and silane coupling agent
Authors: Ismail H. , Othman N. , Komethi M. 
Published: September 2011

AbstractCuring characteristics, tensile properties, morphological studies of tensile fractured surfaces using scanning electron microscopy (SEM), and the extent of rubber filler interactions of rattan‐powder‐filled natural rubber (NR) composites were investigated as a function of filler loading and silane coupling agent (CA). NR composites were prepared by the incorporation of rattan powder at filler loading range of 0–30 phr into a NR matrix with a laboratory size two roll mill. The results indicate that in the presence of silane CA, scorch time (ts2), and cure time (t90) of rattan‐powder‐filled NR composites were shorten, while, maximum torque (MH) increased compared with NR composites without silane CA. Tensile strength and tensile modulus of composites were enhanced whereas elongation at break reduced in the presence of silane CA mainly due to increase in rubber‐filler interaction. It is proven by SEM studies that the bonding between the filler and rubber matrix has improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A combined experimental and theoretical study on vibrational and optical properties of copolymer incorporating thienylene‐dioctyloxyphenyle‐thienylene and bipyridine units
Authors: Ayachi S. , Ghomrasni S. , Alimi K. 
Published: September 2011

AbstractOptical properties of conjugated copolymer incorporating thienylene‐dioctyloxyphenyle‐thienylene and bipyridine units prepared by Stille coupling reactions in the ground and lowest singlet excited states were calculated with Time Dependent Density Functional Theory (TD‐DFT), CIS/3‐21G*, and semiempirical (ZINDO) methods. The complementarities and the good agreement between theoretical and experimental results have permitted us to describe electronic structure and to predict a correlation between structure and properties of this new copolymer. Then, on the basis of these results, we show that this copolymer could be exploited as an active layer in optoelectronic devices. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Characterization of Luffa cylindrica fibers and the effect of water aging on the mechanical properties of its composite with polyester
Authors: Seki Yoldas , Sever Kutlay , Erden Seckin , Sarikanat Mehmet , Neser Gökdeniz , Ozes Cicek 
Published: September 2011

AbstractLuffa cylindrica of Turkey's Aegean Region was evaluated in terms of fiber characterization and the mechanical properties of its composite with polyester. Characterization of Luffa cylindrica was carried out by Fourier transform infrared spectrophotometer, X‐ray photoelectron spectroscopy (XPS), scanning electron microscopy, and thermogravimetric analysis. Cellulose, hemicellulose, and lignin contents of Luffa cylindirica were also determined. Deconvolutions of XPS data enable determining the distributions of functional groups on the surface of Luffa cylindrica. Luffa cylindrica‐reinforced polyester composite was subjected to water aging under a steam of seawater containing 5% sodium chloride for 170 h at 50°C. After water aging, tensile strength, flexural strength, interlaminar shear strength, and tensile elongation at break values of the composite decreased ∼ 28%, 24%, 45%, and 31%, respectively. However, tensile modulus and flexural modulus did not change significantly. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Positive temperature coefficient effect and interaction based on low‐density polyethylene/graphite powder composites
Authors: Zhang P. , Xue W.T. , Zhao Y. , Liu P. 
Published: September 2011

AbstractIn this article, the positive temperature coefficient (PTC) and interaction based on low‐density polyethylene (LDPE) filled with the loading of graphite (G) powder have been investigated. The dependence of the room temperature resistivity on filler content showed the significant decrease. The PTC behavior enhanced with increasing graphite content but this was not always the case. The maximum PTC effect was observed in LDPE/G composites (G, 45 wt %) with the relatively low room temperature resistivity. The thermal behavior was measured by differential scanning calorimetry (DSC). The structure characteristic for LDPE/G composites was examined by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (SEM), and stress–strain test. The fact was revealed that the slight interaction between LDPE matrix and graphite may lead to change the thermal‐electric properties of the PTC materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rheological investigation of cure kinetics and adhesive strength of polyurethane acrylate adhesive
Authors: Jaruchattada J. , Fuongfuchat A. , Pattamaprom C. 
Published: September 2011

AbstractIn this work, we used rheological techniques to study both the cure characteristics and the degree of cure of polyurethane acrylate adhesive, a type of reactive adhesive used in hard disk component assembly. These results were then correlated with the tensile shear strengths of adhesives. Here, the cure characteristics of polyurethane adhesive were investigated at isothermal conditions ranging from 25 to 120°C. From the rheological results, the gelation time, the vitrification time, as well as the time required to reach the maximum degree of cure, decreased when increasing the curing temperature. The cure rates of adhesive increased with temperature in three temperature ranges, which were retardation zone, vitrification zone, and reaction‐controlled zone. The cure rates in these zones were controlled by slow diffusion, fast diffusion, and the rate of reaction, respectively. From the temperature sweep of fully‐cured adhesives, we found that the crosslinking level of adhesives increased with curing temperatures at different rates depending on the temperature zones as well. Moreover, the adhesive strength measured by tensile shear test was found to also increase correspondingly with the adhesives' Tg, indicating that the crosslinking level directly affected the adhesive strength. The strong dependence of adhesive strength with crosslinking level indicates that the crosslinking level was essential for high adhesive strength. The correlation of cure characteristics and adhesive strengths at various curing temperatures performed in this study can further provide useful information for planning appropriate curing schemes of polyurethane acrylate adhesives used in electronic and other industries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Characterization of polymeric LB thin films for sensor applications
Authors: Erdogan Matem , Özbek Zikriye , Çapan Rifat , Yagci Yusuf 
Published: September 2011

AbstractThe Quartz Crystal Microbalance (QCM) system is utilized to investigate the relationship between mass uptake and associated swelling for Langmuir‐Blodgett (LB) organic thin films obtained from pyrene end‐capped polystyrene (PS). The study was carried out using three different molecular weights of polymeric chains. The changes in resonance frequency associated with mass changes can be attributed to the swelling behavior of polymeric thin films during vapor absorption. This swelling is due to the capturing of organic vapor molecules in the sensor environment. To quantify real‐time QCM data for swelling, early‐time Fick's law of diffusion was adopted to fit the results, and a good linear relationship was observed between the mass uptake and square root of the swelling time. The diffusion coefficients for swelling were thus obtained from the slopes of the fitting curves and was found to be correlation with the amount of organic vapor content in the cell. It was also observed that diffusion of the organic vapor into higher molecular weight polystyrene thin films are much faster than low molecular weight ones in sensor applications. Diffusion coefficients were found to be 0.2–3.0 × 10−16, 5.0–13 × 10−16, and 1.0–1.6 × 10−15 cm2/s for PS1, PS2, and PS3 LB thin films, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis mechanisms of poly[styrene‐co‐(acrylic acid)]‐supported TiCl4 catalysts modified by magnesium compounds
Authors: Lijun Du , Jian Ye , Jingdai Wang , Binbo Jiang , Yongrong Yang 
Published: September 2011

AbstractSoluble poly[styrene‐co‐(acrylic acid)] (PSA) modified by magnesium compounds was used to support TiCl4. For ethylene polymerization, four catalysts were synthesized, namely PSA/TiCl4, PSA/MgCl2/TiCl4, PSA/(n‐Bu)MgCl/TiCl4, and PSA/(n‐Bu)2Mg/TiCl4. The catalysts were characterized by a set of complementary techniques including X‐ray photoelectron spectroscopy, Fourier‐transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, and element analysis. Synthesis mechanisms of polymer‐supported TiCl4 catalysts were proposed according to their chemical environments and physical structures. The binding energy of Ti 2p in PSA/TiCl4 was extremely low as TiCl4 attracted excessive electrons from COOH groups. Furthermore, the chain structure of PSA was destroyed because of intensive reactions taking place in PSA/TiCl4. With addition of (n‐Bu)MgCl or (n‐Bu)2Mg, COOH became COOMg‐ which then reacted with TiCl4 in synthesis of PSA/(n‐Bu)MgCl/TiCl4 and PSA/(n‐Bu)2Mg/TiCl4. Although MgCl2 coordinated with COOH first, TiCl4 would substitute MgCl2 to coordinate with COOH in PSA/MgCl2/TiCl4. Due to the different synthesis mechanisms, the four polymer‐supported catalysts correspondingly showed various particle morphologies. Furthermore, the polymer‐supported catalyst activity was enhanced by magnesium compounds in the following order: MgCl2 > (n‐Bu)MgCl > (n‐Bu)2Mg > no modifier. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
PLA/chain‐extended PEG blends with improved ductility
Authors: Park Byung‐Sik , Song Jun Cheol , Park Duk Hoon , Yoon Keun‐Byoung 
Published: September 2011

AbstractMelt blending of polylactic acid (PLA) and a chain‐extended polyethylene glycol (CE‐PEG) have been performed in an effort to toughen the PLA without significant loss of modulus and ultimate tensile strength. The chain‐extended PEG was prepared with melt condensation of a low molecular weight PEG and 4,4′‐methylenebis(phenylisocyanate) (MDI) for enhancement of the molecular weight of PEG. The thermal and mechanical properties, miscibility and phase morphologies of blends were investigated. By using thermal and fracture surface analysis, the blends were found to be a partially miscible system with shifted glass transition temperatures. The addition of CE‐PEG leads to slight decrease in tensile strength and modulus, while the elongation at break is characterized by an important increase (540%), compared with neat PLA and PLA/PEG (low molecular weight PEG, Mn = 35,000). The relative ductility of PLA/CE‐PEG is 40 times higher than that of neat PLA. The brittle fracture of neat PLA was transformed into a ductile fracture by the addition of CE‐PEG. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Optimal geometry design of the coat‐hanger die with uniform outlet velocity and minimal residence time
Authors: Han Wanli , Wang Xinhou 
Published: September 2011

AbstractIn this article a method combining the orthogonal array design and the numerical simulation is used to optimize the geometry parameters of the coat‐hanger die with uniform outlet velocity and minimal residence time. The outlet velocity and the residence time are obtained by simulating the three‐dimensional nonisothermal polymer flow in the coat‐hanger die, while the optimal geometry design is accomplished via the orthogonal array method. The effects of the manifold angle, the land height and the slot gap on the outlet velocity and the residence time are investigated. The results show that the effects of all the three parameters are significant for the outlet velocity. For the residence time, the manifold angle and the slot gap are the significant factors, while the effect of the land height is insignificant. The optimal geometry parameters of the coat‐hanger die achieved in this study are that the manifold angle is 5°, the height land is 70 mm, and the slot gap is 3 mm. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of nucleation mechanism on complex poly(L‐lactide) nonisothermal crystallization process, part 2: Crystallization kinetics analysis
Authors: Martinelli Andrea , Calì Massimo , D'Ilario Lucio , Francolini Iolanda , Piozzi Antonella 
Published: September 2011

AbstractIn the first part of this article, we reported the crystalline memory effect on the nonisothermal crystallization of poly(L‐lactide). The experiments were carried out by using polymer single crystals growth from dilute solution as standard starting material. In this article (Part II), we have analyzed in detail the effect of the melting condition on the overall crystallization kinetics by applying the Nakamura‐Avrami model to DSC results. The absence or the low concentration of foreign infusible heterogeneous nuclei in our system allowed us to exalt the self‐nuclei role in polymer crystallization, to follow their concentration decrease during the melting process and to find the limiting melting temperature for their disappearance. Below such a temperature, a stable equilibrium number of self‐nuclei was observed, probably deriving from ordered structures, persisting in the melt, and originated from the single crystals thickening process during the polymer dynamic melting in the DSC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Application of nickel (II) complex of dithiocarbamate‐modified starch for anionic dyes removal from aqueous solutions
Authors: Cheng Rumei , Xiang Bo , Li Yijiu 
Published: September 2011

AbstractThe work presents the synthesis of nickel (II) complex of dithiocarbamate‐modified starch (DTCSNi). It is characterized by elemental analysis, infrared spectrum, and thermogravimetry methods. A batch system was applied to study the adsorption of DTCSNi for four anionic dyes removals. The adsorption with respect to the pH was investigated. It is found that the capacity of DTCSNi for each dye is pH dependent, and the adsorption is governed by coordination. At the suitable pH 4, two kinetic models, that is, pseudo‐first‐ and pseudo‐second‐order, were tested to investigate the adsorption process. The kinetic parameters of the models were calculated and discussed. The results suggest that the best fit model is the pseudo‐second‐order equation. The Langmuir–Freundlich model agrees very well with experimental data and the maximum adsorption capacity sequence is AO7 > AG25 > AR18 > AO10. The Fourier transform infrared spectra and thermogravimetric analysis verified the chelating molecular mechanism. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Plasticized and unplasticized PLA/organoclay nanocomposites: Short‐ and long‐term thermal properties, morphology, and nonisothermal crystallization behavior
Authors: Gumus Serap , Ozkoc Guralp , Aytac Ayse 
Published: September 2011

AbstractThe short‐ and long‐term thermal properties, organoclay dispersion state, and the nonisothermal crystallization kinetics of organoclay based nanocomposites of poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) plasticized PLA were investigated. Differential scanning calorimetry analyses showed that plasticization of PLA/PEG blend was diminished due to physical aging by the time. The change in thermal properties such as glass transition temperature, cold crystallization temperature, and melting temperature was monitored. It was revealed from X‐ray diffraction analyses that in long term, the exfoliated and/or intercalated organoclay structure of nanocomposites observed in short term (just after processing) was differentiated to a tactoidal form (i.e., nonseparated clays). The nonisothermal crystallization behavior and kinetics were examined by using Avrami, Ozawa, and combined Avrami–Ozawa models. Moreover, the nucleating effect of clays was investigated in terms of Gutzow and Dobrewa approaches. It was found out that clays did not act as nucleating agents in plasticized PLA nanocomposites, which was also in good agreement with activation energy values obtained from Kissinger and Takhor models. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation of polydimethylsiloxane‐coated α‐alumina fillers with cold plasma for elastomer thermal interface materials
Authors: Liu Yu , Zhang Li‐Qun , Wang Wen‐Cai , Yu Hai‐Tao , Lu Yong‐Lai 
Published: September 2011

AbstractA novel method for the organic modification of a ceramic thermal conductive filler (α‐alumina) with cold plasma was developed for the preparation of elastomer thermal interface materials with high thermal conductivities and low moduli. The α‐alumina fillers were first coated with low‐molecular‐weight polydimethylsiloxane (PDMS) by solution dispersion and then treated in argon plasma for different time. The modified α‐alumina fillers were characterized with high‐resolution transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. The results revealed that a thin PDMS film with several nanometers thick was tightly coated on the surface of the alumina filler after plasma treatment, and this thin film could not be removed by 48 h of Soxhlet extraction with n‐hexane at 120°C. Plasma modification of the alumina could dramatically weaken the strength of the filler–filler networks and, thus, remarkably reduce the modulus of the alumina‐filled silicone rubber composites but did not affect the thermal conductivity of the composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of the compatibility of a polyacrylic block copolymer/tackifier blend on the phase structure and tack of a pressure‐sensitive adhesive
Authors: Nakamura Yoshinobu , Sakai Yu , Imamura Keigo , Ito Keiko , Fujii Syuji , Urahama Yoshiaki 
Published: September 2011

AbstractAdhesion and viscoelastic properties and morphology of a polyacrylic block copolymer/tackifier blend were investigated. Special rosin ester resins with different weight average molecular weights of 650, 710, 890, and 2160 were used as the tackifier and blended with a polyacrylic block copolymer consisting of poly(methyl methacrylate) and poly(n‐butyl acrylate) blocks at tackifier content levels of 10, 30, and 50 wt %. The compatibility decreased with an increase in molecular weight. From TEM observation, the number of formed agglomerates of the tackifier with sizes on the order of several tens of nanometers increased with increasing tackifier content and molecular weight of the tackifier in the range from 650 to 890. For the tackifier with a molecular weight of 2160, micrometer‐sized agglomerates were observed. The storage modulus at low temperature and the glass transition temperature of adhesive measured by a dynamic mechanical analysis increased dependent on the number of formed nanometer sized agglomerates. Tack was measured using a rolling cylinder tack tester over wide temperature and rolling rate ranges, and master curves were prepared in accordance with the time‐temperature superposition law. Tack and peel strength were optimum at a blend combination of intermediate compatibility, i.e., the molecular weight of 890. These optimum properties were correlated to maximal values of the storage modulus at room temperature and the glass transition temperature. Therefore, it was found that these features of blend properties are strongly affected by the nanometer sized agglomerates of tackifier. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Stab resisting behavior of polymeric resin reinforced p‐aramid fabrics
Authors: Kim Hodong , Nam Inwoo 
Published: September 2011

AbstractThe stab resistant performance of p‐aramid fabrics reinforced with thermoplastic LDPE resin and thermoset epoxy resin was investigated by quasi‐static or drop tower stab resistance testing, and the stab resistance behavior against different shapes of impactors was also evaluated. The destruction behavior of LDPE reinforced p‐aramid fabrics against a knife impactor shows three distinctive steps; the initial penetration step with maximum strength, the cutting step by knife edge, and the destruction step of accumulated fiber bundles. On the other hand, epoxy resin reinforced p‐aramid fabrics against a knife impactor exhibit just two steps without the accumulation of fiber bundles. In the case of a spike impactor, the maximum stab resistant strength is observed from the initial penetration step; however, the stab resistant strength after initial penetration drastically decreased regardless of the reinforcing resins. It is also found that, even if the LDPE reinforced fabrics are multilayered, the performance improvement by resin reinforcement is observed only from the initial penetration step and the stab resistant strengths of the cutting step and the fiber accumulation step are not improved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012