Conductive‐plastic enclosures, to compete successfully in the electronics industry, must be easil... more Conductive‐plastic enclosures, to compete successfully in the electronics industry, must be easily and rapidly moldable into a low‐cost, lightweight, structurally sound, flame‐retardant, and electrically‐conductive rigid part. Such a material must combine the design flexibility and moldability of a plastic with the EMI shielding properties approaching those of a metal. PVC filled with aluminum flake makes an excellent conductive composite, provided it is correctly formulated and processed. A critical concentration of metallic filler must be used; it is a function of the plastic formulation; the uniformity of the filler's dispersion; the filler type, size, and morphology; and the method by which it was compounded into the resin.
The glass‐transition temperatures (Tg's) and specific heats (Cp) of poly(vinyl chloride) (PVC... more The glass‐transition temperatures (Tg's) and specific heats (Cp) of poly(vinyl chloride) (PVC) and PVC plasticized with 5–120 phr di(2‐ethylhexyl) adipate (DOA) and tri(2‐ethylhexyl) trimellitate (TOTM) have been determined by differential scanning calorimetry (DSC). Measured Tg's were compared to predictions by the Couchman and Karasz (C–K) thermodynamic theory, three related empirical equations, and a new equation obtained from the C–K relation by assuming the product TgΔCp to be constant. It was found that the Tg's of the PVC/TOTM mixtures are adequately predicted only by the C–K and the derivative relation. The Tg's of the PVC/DOA mixtures follow a sigmoidal or cusp‐like dependence on plasticizer composition as has been observed for some other PVC/plasticizer mixtures. In this case, the approximation afforded by the C–K or derivative equations is still superior to the empirical models over a wide composition range. Dynamic mechanical analysis of the PVC/DOA mixtu...
L'invention concerne un dispositif d'administration iontophoretique (10). Ledit dispositi... more L'invention concerne un dispositif d'administration iontophoretique (10). Ledit dispositif (10) est pourvu d'un circuit electronique (32) comprenant des composants electroniques tels que des piles (30). Le dispositif (10) comprend egalement une paire d'ensembles electrodes (18, 19). Le circuit electronique (32) est relie electriquement aux ensembles electrodes (18, 19) au moyen d'un adhesif electriquement conducteur (34). L'adhesif peut egalement etre utilise pour relier electriquement deux ou plusieurs composants electroniques dans le circuit (32) ou pour relier un composant electronique au circuit electronique (32). Selon un mode de realisation de l'invention, l'adhesif electriquement conducteur (44) fonctionne comme une electrode et relie electriquement le circuit (32) a un reservoir contenant un agent (24, 25). Selon un autre mode de realisation de l'invention, l'adhesif electriquement conducteur (93) fonctionne comme un reservoir d'ag...
Two model drug eluting stents of poly(lactic acid) (PLA)/everolimus and poly(ethylene vinyl alcoh... more Two model drug eluting stents of poly(lactic acid) (PLA)/everolimus and poly(ethylene vinyl alcohol) copolymer (EVAL)/everolimus have been investigated using complementary surface analysis techniques including AFM, XPS, and ATR-IR to assess their structure and its relation to drug release. Different surface morphologies were observed for these stents, with phase separation evident on the PLA coating and a homogeneous system for the EVAL-based coating. This indicates a potentially different drug distribution for the different stents, although both showed a surface enrichment of the drug compared to the bulk. Dissolution studies for PLA/everolimus stents showed an immediate loss of drug from the surface as well as a longer term polymer matrix erosion. The EVAL/everolimus stent also displayed a loss of drug from its surface, but an intact surface after 28 days in dissolution media. These data are discussed in relation to the different release mechanisms occurring in the stents.
Conductive‐plastic enclosures, to compete successfully in the electronics industry, must be easil... more Conductive‐plastic enclosures, to compete successfully in the electronics industry, must be easily and rapidly moldable into a low‐cost, lightweight, structurally sound, flame‐retardant, and electrically‐conductive rigid part. Such a material must combine the design flexibility and moldability of a plastic with the EMI shielding properties approaching those of a metal. PVC filled with aluminum flake makes an excellent conductive composite, provided it is correctly formulated and processed. A critical concentration of metallic filler must be used; it is a function of the plastic formulation; the uniformity of the filler's dispersion; the filler type, size, and morphology; and the method by which it was compounded into the resin.
The glass‐transition temperatures (Tg's) and specific heats (Cp) of poly(vinyl chloride) (PVC... more The glass‐transition temperatures (Tg's) and specific heats (Cp) of poly(vinyl chloride) (PVC) and PVC plasticized with 5–120 phr di(2‐ethylhexyl) adipate (DOA) and tri(2‐ethylhexyl) trimellitate (TOTM) have been determined by differential scanning calorimetry (DSC). Measured Tg's were compared to predictions by the Couchman and Karasz (C–K) thermodynamic theory, three related empirical equations, and a new equation obtained from the C–K relation by assuming the product TgΔCp to be constant. It was found that the Tg's of the PVC/TOTM mixtures are adequately predicted only by the C–K and the derivative relation. The Tg's of the PVC/DOA mixtures follow a sigmoidal or cusp‐like dependence on plasticizer composition as has been observed for some other PVC/plasticizer mixtures. In this case, the approximation afforded by the C–K or derivative equations is still superior to the empirical models over a wide composition range. Dynamic mechanical analysis of the PVC/DOA mixtu...
L'invention concerne un dispositif d'administration iontophoretique (10). Ledit dispositi... more L'invention concerne un dispositif d'administration iontophoretique (10). Ledit dispositif (10) est pourvu d'un circuit electronique (32) comprenant des composants electroniques tels que des piles (30). Le dispositif (10) comprend egalement une paire d'ensembles electrodes (18, 19). Le circuit electronique (32) est relie electriquement aux ensembles electrodes (18, 19) au moyen d'un adhesif electriquement conducteur (34). L'adhesif peut egalement etre utilise pour relier electriquement deux ou plusieurs composants electroniques dans le circuit (32) ou pour relier un composant electronique au circuit electronique (32). Selon un mode de realisation de l'invention, l'adhesif electriquement conducteur (44) fonctionne comme une electrode et relie electriquement le circuit (32) a un reservoir contenant un agent (24, 25). Selon un autre mode de realisation de l'invention, l'adhesif electriquement conducteur (93) fonctionne comme un reservoir d'ag...
Two model drug eluting stents of poly(lactic acid) (PLA)/everolimus and poly(ethylene vinyl alcoh... more Two model drug eluting stents of poly(lactic acid) (PLA)/everolimus and poly(ethylene vinyl alcohol) copolymer (EVAL)/everolimus have been investigated using complementary surface analysis techniques including AFM, XPS, and ATR-IR to assess their structure and its relation to drug release. Different surface morphologies were observed for these stents, with phase separation evident on the PLA coating and a homogeneous system for the EVAL-based coating. This indicates a potentially different drug distribution for the different stents, although both showed a surface enrichment of the drug compared to the bulk. Dissolution studies for PLA/everolimus stents showed an immediate loss of drug from the surface as well as a longer term polymer matrix erosion. The EVAL/everolimus stent also displayed a loss of drug from its surface, but an intact surface after 28 days in dissolution media. These data are discussed in relation to the different release mechanisms occurring in the stents.
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