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Polycarbonate

About: Polycarbonate is a research topic. Over the lifetime, 14032 publications have been published within this topic receiving 141740 citations. The topic is also known as: PC & Polycarbonate, PC.


Papers
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Journal ArticleDOI
TL;DR: In this paper, home-made multiwall carbon nanotubes (MWCNTs) were used as a reinforcing conducting filler for a thermoplastic polymer, polycarbonate (PC) and the mechanical and electrical properties of the composites were investigated for electrostatic discharge (ESD) and electromagnetic interference (EMI) shielding applications.
Abstract: Home-made multiwall carbon nanotubes (MWCNTs) were used as a reinforcing conducting filler for a thermoplastic polymer, polycarbonate (PC) and the mechanical and electrical properties of the composites were investigated for electrostatic discharge (ESD) and electromagnetic interference (EMI) shielding applications. A uniformly dispersed MWCNT/PC composite system was fabricated using solvent casting and a combination of solvent casting and compression molding techniques. The effect of MWCNTs on the failure mechanism of the polymer under tensile loading showed a ductile to brittle transition with increasing amount of carbon nanotubes. ESD studies showed that the composite films of 2 and 5 wt% functionalized-MWCNT/PC with respective charge decay times of 1 and 0.6 s show promise as electrostatic dissipative materials. EMI shielding effectiveness of a five-layered system (∼2 mm thickness) of as-synthesized-MWCNT/PC composite films at 20 wt% loading reached 43 dB in the X-band (8.2–12.4 GHz). The primary mechanism of shielding was absorption, suggesting possible use as an EMI absorbing material. By using low pressure (contact pressure) compression molding the EMI shielding properties of bulk composites (∼2 mm thickness) improved by about 14 dB at 10 wt% MWCNT loading.

152 citations

Journal ArticleDOI
TL;DR: A relevant discontinuity of the coefficient of thermal expan­ sion has been observed for PMMAs various tacticities and a so-called α peak was observed at ~60°C and was widely discussed by Neki and Geil.
Abstract: J. M. Cariou, J. Dugas, L. Martin, and P. Michel Laboratoire de Physique des Solides, Associé au CNRS, Université Paul Sabatier, 31062 Toulouse CEDEX, France. Received 30 July 1985. 0003-6935/86/030334-03$02.00/0. © 1986 Optical Society of America. For polymers, the thermal volume expansion coefficient is always much higher than the coefficient for inorganic materials. We have recently shown that the variation of the refractive index of polymers vs temperature is essentially due to the variation of density. From the Lorentz-Lorenz relation, the function (n + 2)/(n 1) appears perfectly linear in the various temperature ranges where no phase transition occurs. The slope of the representative curve exactly follows the thermal expansion coefficient α which keeps a constant value in each temperature range. Thus, α may be easily deduced from the refractive-index measure­ ment at various temperatures. At the same time, the tem­ peratures where discontinuities of (n + 2)/(n 1 ) or its derivative appear conveniently fit with the transition tem­ peratures which may be so determined. A correct observation of such behavior is that the tempera­ ture variations are so slow that the material is continuously kept in thermal equilibrium. Indeed, it is well known that the various molecular processes which induce the transitions are characterized by very large relaxation times. If the material undergoes temperature changes too fast, it remains in a metastable state which is not a true equilibrium state. Waxier et al. have interferometrically measured some optical properties of Plexiglas and Lexan and determined the evolution of dn/dt, with the temperature between -160°C and +60°C. They obtained irregular but continu­ ous curves which do not evidence, even in a crude way, any systematic change in their behavior which may be related to a phase transition. Nevertheless, in the temperature range studied, at about -30°C PMMA (Plexiglas) undergoes the so-called β transition which is attributed to the beginning of the rotation of lateral chains of methacrylate radicals. A relevant discontinuity of the coefficient of thermal expan­ sion has been observed for PMMAs various tacticities. In the same way, for polycarbonate, the glass transition at 125°C is out of the temperature range studied by these authors. However a so-called α peak was observed at ~60°C and was widely discussed by Neki and Geil. No noticeable anomaly appears in the Waxier results. We have measured the refractive index of commercial samples of PMMA (Altuglas) and polycarbonate (Lexan) between about -100°C and +150°C. To avoid any stress which could take place by contact with another material, the measurement method chosen was the minimum deviation of a prism. The PMMA prism was drawn from bulk material

152 citations

Patent
22 Dec 2005
TL;DR: In this paper, the authors proposed a polycarbonate resin composition consisting of a poly-carbonate resin and at least two resins contained as components, wherein the intensity ratio of the absorption peak appearing in a range of 2,933±5 cm -1 to the absorptionpeak appearing in the range of a 2.965−5 cm −1 satisfies the formula.
Abstract: PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition containing a polycarbonate resin and comprising at least two resins contained as components and capable of providing a material having excellent impact resistance. SOLUTION: The polycarbonate resin composition contains a polycarbonate resin and comprises at least two resins contained as components, wherein the intensity ratio of the absorption peak appearing in a range of 2,933±5 cm -1 to the absorption peak appearing in a range of 2,965±5 cm -1 satisfies formula [1]: intensity ratio of infrared absorption peak=I(2,933cm -1 )/I(2,965cm -1 )≥0.43 awherein I(2933cm -1 ): peak intensity of absorption appearing in a range of 2,933±5 cm -1 ; I(2,965cm -1 ): peak intensity of absorption appearing in a range of 2,965±5 cm -1 }. COPYRIGHT: (C)2006,JPO&NCIPI

151 citations

Journal ArticleDOI
22 Jan 1998-Langmuir
TL;DR: In this paper, a photoimmobilization of poly(N-isopropylacrylamide), photoreactive azidophenyl group was connected to the polymer either at a chain terminal or in side chains.
Abstract: Permeation through a porous polycarbonate membrane, on which a thermosensitive polymer, poly(N-isopropylacrylamide), was immobilized, was investigated For photoimmobilization of poly(N-isopropylacrylamide), photoreactive azidophenyl group was connected to the polymer either at a chain terminal or in side chains The two types of derivatized polymers had different lower critical solution temperature (LCST) Prescribed amounts of the derivatized polymer were cast on the polycarbonate membrane and photoirradiated When a small amount of polymer was used, a thin layer of immobilized polymer was not enough to cover pores of the polycarbonate membrane, while a thick gel layer of immobilized polymer was formed on the polycarbonate membrane to cover pores when a large amount of polymer was used The former is represented by “porous membrane”, and the latter by “nonporous membrane” The rate of water permeation through the porous membranes changed at different temperatures, although permeation through nonimmobili

150 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023248
2022471
2021184
2020294
2019390
2018403