Polyester porous

Externally cast membranes are first formed on the iaside of paper, polyester, or polyolefin tubes. These ate then iaserted iato reusable porous stainless-steel support tubes inside diameters ate ca 12 mm. The tubes ate generally shrouded in bundles to aid in permeate collection. 

The membrane is usually made from one of several materials. Woven polyester or cotton, the most commonly used and least expensive material, is adequate for temperatures up to 150°C. Siatered plastic is used where a low cost, washable surface is desired. This material is temperature limited by the polymer material to about 60°C and the flow of some powders may cause a static charge build-up on the membrane that could be hazardous ia some operatioas. Wovea fiberglass fabric or porous ceramic block is used for temperatures up to about 425°C. Siatered stainless steel powder or bonded stainless mesh is used for corrosion resistance, and for temperatures up to 530 to 650°C. Additional information can be found ia the Hterature (38,39). 

De Groot JH, de Vrijer R, Pennings AJ, Klompmaker J, Veth RPH, and Jansen HWB. Use of porous polyurethanes for meniscal reconstruchon and meniscal prosthesis. Biomaterials, 1996, 17, 163-174. Borkerhagen M, Stoh RC, Neuenschwander P, Suter UW, and Aebischer P. In vivo performance of a new biodegradable polyester urethane system used as a nerve guidance channel. Biomaterials, 1998, 19, 2155-2165. 

Schindler, A., Research Triangle Institute, Porous bioabsorb-able polyesters as controlled-release reservoirs for high molecular weight drugs, Eur. Patent Appl. EP 223708 A2, May 27, 1987. 

Alcaligenes eutrophus produces a massive amount of intracellular polyester (poly-3-hydroxybutyrate [PHB]), specifically as high as 70% of the cell weight. This bacterium was selected for porous-media plugging studies [1316]. 

This publication established that crosslinking of the polystyrene was not necessary to support the pore structure in monolith nanoporous samples, that mild chemical degradation of an aliphatic polyester is a practical methodology for the generation of bulk porous samples, and that the hydroxyl group derived from the juncture of the PS-PLA material decorated the pore walls of the material. 

It is known that increased char yield is usually associated with improved flammability behavior ( 1). This can be understood if one considers that the volatile flammable products can only diffuse with difficulty through the char, and that the thermal conductivity of a porous char layer is relatively poor (2). The structure of the polymer can contribute to the amount of char formed based on the character of the functional groups present and the nature of the backbone (2,3). Ritchie ( ) found that for a series of unsaturated polyesters and their copolymers, the temperatures at which carbon dioxide is eliminated was in the range of 280 to 345°C depending on the structure of the polyester. Aliphatic polyesters and their copolymers have less thermal... 

Aneurysms can be repaired through reinforcement of the artery wall with a tube of woven PTFE or polyester. Replacement of sections of the artery can be done using a tube of porous PTFE. One remaining problem is the difference in elasticity between the woven and porous materials and the arteries themselves. 

A cumulative success of artificial ion-channel functions by simple molecules may disclose a wide gate for the design of ion channels and possible applications to ionics devices. Incorporation of these channels into bilayer lipid membrane systems may trigger the developments towards ionics devices. The conventional BLM system, however, is not very stable, one major drawback for the practical applications, and some stabilization methods, such as impregnating the material in micro-porous polycarbonate or polyester filters, are required. On the other hand,... 

An optically transparent, porous platinum film has been produced by photoelectrodeposition on an InP semiconductor substrate [15], Polyester sheet covered with a thin film of sputtered gold has also proved suitable as an OTE [71]. When overcoated with a layer of Ti02, these electrodes exhibited electrochemical behavior consistent with a microelectrode array, including cyclic voltammetric current plateaus instead of clearly defined peaks, although this feature was not recognized at the time [71]. 

Collection on porous filter media is perhaps the most efficient means of particle removal. Aerosol filtration is an effective means of air purification, while at the same time it has been widely used for sampling airborne material for mass and chemical composition determination. A wide variety of filter media is available, ranging from fibrous mats of relatively inert material to porous membranes. Fibrous mats and model filter arrays appear microscopically as stacks of overlaid cylinders, where the cylinders may be smooth or rough. In contrast, the membrane media are plastic films with microscopic holes of nearly uniform size nuclepore filters, for example, are produced of sheets of polyester, and the holes are introduced by neutron bombardment. 

A carrier or reinforcement is usually a thin fabric, cloth, or paper used to support the semicured adhesive composition to provide a tape or film. In tapes, the carrier is the backing on which the adhesive is applied. The backing may be used for functional or decorative purposes. In epoxy films or structural tape, the carrier is usually porous and the adhesive saturates the carrier. Glass, polyester, and nylon fabric are common carriers for supported B-staged epoxy adhesive films. In these cases, the carrier provides for a method of applying the adhesive and also may act as reinforcement and a internal shim to control the thickness of the adhesive. 

Ruorocarbon treatment generally improves the penetration resistance of porous fabrics, both woven and nonwoven, to liquids and particles. The fluorocarbon reduces die differences between the resistances of 100% cotton and various cotton/polyester blends. Durable press finishes reduce penetration resistance to liquids. Studies of soil releasing treatments are inconclusive. Laundering reduces the effectiveness of finishes diey must be renewed periodically. 

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