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Effect of MWCNT on Thermal, Mechanical, and Morphological Properties of Polybutylene Terephthalate/Polycarbonate Blends  [PDF]
C. P. Rejisha,S. Soundararajan,N. Sivapatham,K. Palanivelu
Journal of Polymers , 2014, DOI: 10.1155/2014/157137
Abstract: This paper evaluated the effect of multiwall carbon nanotube (MWCNT) on the properties of PBT/PC blends. The nanocomposites were obtained by melt blending MWCNT in the weight percentages 0.15, 0.3, and 0.45?wt% with PBT/PC blends in a high performance corotating twin screw extruder. Samples were characterized by tensile testing, dynamic mechanical analysis, thermal analysis, scanning electron microscopy, and X-ray diffraction. Concentrations of PBT and PC are optimized as 80?:?20 based on mechanical properties. A small amount of MWCNT shows better increase in the thermal and mechanical properties of the blends of PBT/PC nanocomposite when compared to nanoclays or inorganic fillers. The ultimate tensile strength of the nanocomposites increased from 54?MPa to 85?MPa with addition of MWCNT up to 0.3% and then decreased.The tensile modulus values were increased to about 60% and the flexural modulus was more than about 80%. The impact strength was also improved with 20% PC to about 60% and with 0.15% MWCNT to about 50%. The HDT also improved from 127°C to 205°C. It can be seen from XRD result that the crystallinity of PBT is less affected by incorporating MWCNT. The crystallizing temperature was increased and the MWCNT may act as a strong nucleating agent. 1. Introduction Polyesters like PBT and PET are semicrystalline and possess high stiffness, hardness, dimensional stability, good bearing strength, good electrical properties, excellent flow characteristics, and good resistance to chemicals but have low impact strength. PC has excellent impact strength. Polymer blends are developed in an effort to meet cost/performance required in many engineering applications. In these blends, it is important to establish some level of interfacial adhesion between the components in order to achieve the necessary toughness. The required bonding is achieved in some commercial blends, for example, polybutylene terephthalate/polyethylene terephthalate (PBT/PET), polybutylene terephthalate/polycarbonate (PBT/PC), as a result of the partial miscibility between the blend components [1–5]. PC-PBT is useful for car bumpers, front ends by Bayer (trade name: Macro Blend). DSM also recently announced PC-PET blends. The PBT/PC finds use in many engineering applications like automotive body panels, in outdoor power, or recreational equipment, appliance housings, telecommunication, and so forth. The PC will improve the impact strength and elongation of PBT since PBT like PET has lower impact strength [6–8]. The various blends of PBT and the properties improvement are also given in [8].
Dynamic of taking out molding parts at injection molding  [PDF]
E. Ragan,J. Dobránsky,P. Baron,M. Ko?i?ko
Metalurgija , 2012,
Abstract: Most plastic parts used in automobile production are manufactured by injection molding. Their quality depends also on taking out molding and on the manipulators for it. Task of this contribution is to theoretically describe a transport of molding at taking out after injection molding in relation on its regulation. The following quantities are derived at it: the transition characteristic of the taking out system, the blocking diagram of taking out molding regulation, the amplitude and phase characteristic and the transition characteristic of action quantity at taking out molding regulation.
Barrel Pseudotilings  [PDF]
Undine Leopold
Symmetry , 2012, DOI: 10.3390/sym4030545
Abstract: This paper describes 4-valent tiling-like structures, called pseudotilings, composed of barrel tiles and apeirogonal pseudotiles in Euclidean 3-space. These (frequently face-to-face) pseudotilings naturally rise in columns above 3-valent plane tilings by?convex polygons, such that each column is occupied by stacked congruent barrel tiles or congruent apeirogonal pseudotiles. No physical space is occupied by the apeirogonal pseudotiles. Many interesting pseudotilings arise from plane tilings with high symmetry. As combinatorial structures, these are abstract polytopes of rank 4 with both finite and infinite 2-faces and facets.
Tetramethylammonium hydrogen terephthalate  [cached]
Leila Dolatyari,Samad Shoghpour Bayraq,Sara Sharifi,Ali Ramazani
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812039487
Abstract: The asymmetric unit of the title salt, C4H12N+·C8H5O4 , contains one half of a tetramethylammonium cation and one half of a hydrogen terephthalate monoanion. The N atom of the ammonium cation lies on a twofold rotation axis and the centre of mass of the terephthalate anion is on a centre of inversion. In the crystal, the centrosymmetric terephthalate ions are linked by a very short symmetric O—H...O hydrogen bond [O...O = 2.4610 (19) ] into a one-dimensional polymeric chain along [1-12]. The tetramethylammonium cations and terephthalate anions are then connected through a pair of bifurcated acceptor C—H...O hydrogen bonds, generating a three-dimensional supramolecular network. The carboxylate groups at both ends of the terephthalate anion are charge-shared with an equal probability of 0.5.
Bis(cyclohexylammonium) terephthalate
Meng Ting Han
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812017035
Abstract: In the title molecular salt, 2C6H11NH3+·C8H4O42 , the terephthalate dianion is close to being planar (r.m.s. deviation = 0.049 ). In the crystal, the cations and anions are linked by N—H...O hydrogen bonds into (010) sheets. Of the four terephthalate O atoms, two accept two hydrogen bonds each and two accept one hydrogen bond each.
Radiation effects in polycarbonate capacitors  [PDF]
Vujisi? Milo?,Stankovi? Koviljka,Doli?anin Edin,Jovanovi? Bojan
Nuclear Technology and Radiation Protection , 2009, DOI: 10.2298/ntrp0903209v
Abstract: The aim of this paper is to examine the influence of neutron and gamma irradiation on the dissipation factor and capacitance of capacitors with polycarbonate dielectrics. The operation of capacitors subject to extreme conditions, such as the presence of ionizing radiation fields, is of special concern in military industry and space technology. Results obtained show that the exposure to a mixed neutron and gamma radiation field causes a decrease of capacitance, while the loss tangent remains unchanged.
Slow crack growth in polycarbonate films  [PDF]
Pierre-Philippe Cortet,Stéphane Santucci,Loic Vanel,Sergio Ciliberto
Physics , 2007, DOI: 10.1209/epl/i2005-10077-3
Abstract: We study experimentally the slow growth of a single crack in polycarbonate films submitted to uniaxial and constant imposed stress. The specificity of fracture in polycarbonate films is the appearance of flame shaped macroscopic process zones at the tips of the crack. Supported by an experimental study of the mechanical properties of polycarbonate films, an analysis of the stress dependence of the mean ratio between the process zone and crack lengths, during the crack growth, show a quantitative agreement with the Dugdale-Barenblatt model of the plastic process zone. We find that the fracture growth curves obey strong scaling properties that lead to a well defined growth master curve.
Morphological, Mechanical, Thermal, Electrical and Rheological Properties of Polycarbonate Composites Reinforced with Surfaces Modified Mica  [PDF]
M. Rahail Parvaiz, P. A. Mahanwar, Smita Mohanty, Sanjay K. Nayak
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.911071
Abstract: The mica fillers reinforced Polycarbonate (PC) composites were fabricated using compression molding technique. The mica surface was chemically modified using vinyltrimethoxy silane and 3–Aminopropyltriethoxy silane. The properties of treated mica PC composites were examined in terms of scanning electron microscopy, thermo gravimetric analysis, differential scanning calorimetry and rheological behavior. The modified mica was observed to disperse more uniformly than the unmodified counterpart. The tensile strength and modulus also improved with treated mica filled PC composites. Polycarbonate (PC) / mica composites were prepared by twin screw extruder at 250 °C. Rheological behavior of PC/mica composites was investigated. The PC / mica composites were characterized by parallel plate rheometer system. As increasing the mica particle size and the content, storage and loss modulus of the PC / mica composites were increased.
Experimental and theoretical studies of agglomeration effects in multi-walled carbon nanotube-polycarbonate melts
eXPRESS Polymer Letters , 2009, DOI: 10.3144/expresspolymlett.2009.94
Abstract: In this study we report on morphological and rheological characterization of multi-walled carbon nanotube (MWNT)-polycarbonate composites produced by injection molding. The main focus is to carry out nonlinear viscoelastic experiments that allow following the structural rearrangements of carbon nanotubes in the polycarbonate melt. Small angle X-ray scattering reveals only a slight orientation of MWNTs in the as-received samples, i.e. after application of extremely high shear rates. Thus, the main structural effect observed during the stress growth experiment is the breakage of MWNT agglomerates. To study this effect in detail a flocculation experiment, in which the sample undergoes oscillatory deformation first at a small strain amplitude in the linear regime succeeded by higher amplitudes in the nonlinear regime, has been carried out. The agglomeration process manifests itself in an increase of the storage and loss moduli in the linear regime, whereas the deagglomeration process does vice versa. The corresponding effects can be described in the frame of a superposition approach that takes into account the stress contribution of the polycarbonate matrix, the hydrodynamic reinforcement due to embedded nanotubes and the viscoelastic stress due to the presence of a MWNT-network.
Electrochemical impedimetric biosensor based on a nanostructured polycarbonate substrate
Chen YS, Wu CC, Tsai JJ, Wang GJ
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S27225
Abstract: trochemical impedimetric biosensor based on a nanostructured polycarbonate substrate Original Research (3134) Total Article Views Authors: Chen YS, Wu CC, Tsai JJ, Wang GJ Published Date January 2012 Volume 2012:7 Pages 133 - 140 DOI: http://dx.doi.org/10.2147/IJN.S27225 Received: 10 October 2011 Accepted: 30 November 2011 Published: 06 January 2012 Yu-Shan Chen1, Chia-Che Wu1, Jaw-Ji Tsai2, Gou-Jen Wang1,3 1Department of Mechanical Engineering, National Chung-Hsing University, 2Department of Medical Education and Research, Taichung Veterans General Hospital, 3Graduate Institute of Biomedical Engineering, National Chung-Hsing University, Taichung, Taiwan Abstract: This study integrates the techniques of nanoelectroforming, hot-embossing, and electrochemical deposition to develop a disposable, low-cost, and high sensitivity nanostructure biosensor. A modified anodic aluminum oxide barrier-layer surface was used as the template for thin nickel film deposition. After etching the anodic aluminum oxide template off, a three-dimensional mold of the concave nanostructure array was created. The fabricated three-dimensional nickel mold was further used for replica molding of a nanostructure polycarbonate substrate by hot-embossing. A thin gold film was then sputtered onto the polycarbonate substrate to form the electrode, followed by deposition of an orderly and uniform gold nanoparticle layer on the three-dimensional gold electrode using electrochemical deposition. Finally, silver nanoparticles were deposited on the uniformly deposited gold nanoparticles to enhance the conductivity of the sensor. Electrochemical impedance spectroscopy analysis was then used to detect the concentration of the target element. The sensitivity of the proposed scheme on the detection of the dust mite antigen, Der p2, reached 0.1 pg/mL.
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