Download or read book Polymer Oxygen Compatibility Testing written by JM. Waller and published by . This book was released on 2000 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oxygen (O2) compatibility of six polymers used in O2 service was evaluated after 48 h exposures at 121 °C (250 °F) to O2 pressures of 620 and 6200 kPa (90 and 900 psia). Three elastomers were tested: chloroprene rubber (C873-70), fluorocarbon rubber (Viton® A), and silicone rubber (MVQ type); and three thermoplastics were tested: polyhexamethylene adipamide (Zytel® 42), polytetrafluoroethylene (PTFE Teflon® 500A), and polychlorotrifluoroethylene (Neoflon® CTFE M400H). Post-aged changes in mass, dimensions, tensile strength, elongation at break, durometer hardness, and thermomechanical properties were evaluated. For selected materials, gaseous nitrogen- (GN2-) aged controls were used to ascertain the effect of thermal versus oxidative degradation. Finally, the effect of O2 aging on selected ignition (AIT) and combustion (?Hc) properties was determined. As expected, aged polymers were less ignitable and combustible. Special attention was given to Neoflon CTFE; namely, the possible effect of percent crystallinity (quick- versus slow-quenched) on the aging, ignition, and combustion behavior was evaluated.
Download or read book Flammability and Sensitivity of Materials in Oxygen enriched Atmospheres written by B. E. Newton and published by ASTM International. This book was released on 2003 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxygen Compatibility of Polymers Including TFE Teflon Kel F 81 Vespel SP 21 Viton A Viton A 500 Fluorel Neoprene EPDM Buna N and Nylon 6 6 written by TC. Chou and published by . This book was released on 1997 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ten polymeric materials including EPDM, Nylon 6,6, Buna-N and other materials marketed* as TFE-Teflon® (PTFE), Kel-F® 81 (PCTFE), Vespel® SP-21, Viton® A, Viton® A-500, Fluorel®, and Neoprene® were systematically evaluated for their oxygen compatibility property. The specific properties examined included: (1) autoignition temperature (AIT), (2) heat of combustion, and (3) liquid-oxygen (LOX) mechanical impact sensitivity. Test methods and procedures employed for the evaluations were in compliance with those prescribed in the ASTM and BSI standards. Additionally, a BOC in-house high-pressure autoigniticn test rig (HP-AIT) was used for a detailed study on the materials' autoignition behavior. This high-pressure vessel is capable of probing the AIT of a material up to 450°C and at oxygen pressure (prior to a thermal excursion) up to 5000 psig (~34.5 MPa).
Download or read book Flammability and Sensitivity of Materials in Oxygen enriched Atmospheres written by Ting C. Chou and published by ASTM International. This book was released on 1997 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxygen Compatibility of Brass Filled PTFE Compared to Commonly Used Fluorinated Polymers for Oxygen Systems written by Stephen D. Herald and published by . This book was released on 2009 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safe and reliable seal materials for high-pressure oxygen systems sometimes appear to be extinct species when sought out by oxygen systems designers. Materials that seal well are easy to find, but these materials are typically incompatible with oxygen, especially in cryogenic liquid form. This incompatibility can result in seals that leak, or much worse, seals that easily ignite and burn during use. Scientists at the Materials Combustion Research Facility (MCRF), part of NASA/Marshall Space Flight Center, are constantly searching for better materials and processes to improve the safety of oxygen systems. One focus of this effort is improving the characteristics of polymers used in the presence of an oxygen enriched environment. Very few systems can be built which contain no polymeric materials; therefore, materials which have good impact resistance, low heat of combustion, high auto-ignition temperature, and those that maintain good mechanical properties are essential. The scientists and engineers at the MCRF, in cooperation with seal suppliers, are currently testing a new formulation of polytetrafluoroethylene (PTFE) with brass filler. This brass-filled PTFE is showing great promise as a seal and seat material for high-pressure oxygen systems. Early research has demonstrated very encouraging results, which could rank this material as one of the best fluorinated polymers ever tested. This paper will compare the data obtained for brass-filled PTFE with other fluorinated polymers, such as TFE-polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene 81, Viton® A, Viton® A-500, Fluorel®, and Algoflon®. A similar metal-filled fluorinated polymer, Salox-M®, was tested in comparison to brass-filled PTFE to demonstrate the importance of the metal chosen and relative percentage of filler. General conclusions on the oxygen compatibility of this formulation are drawn, with an emphasis on comparing and contrasting the materials performance to the performance of the current state-of-the-art oxygen compatible polymers.
Download or read book Flammability and Sensitivity of Materials in Oxygen enriched Atmospheres written by Joel M. Stoltzfus and published by ASTM International. This book was released on 1991 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Thirty-four papers presented at the symposium of the same name held in Cocoa Beach, Florida, May 1991, begin with a keynote address on combustion fundamentals of low volatility materials in oxygen-enriched atmospheres, and continue in sections on development and evaluation of test methods, ignition and combustion of nonmetals and of metals, analysis of ignition mechanisms, material selection, and miscellaneous topics. Member price, $50.40. Annotation copyrighted by Book News, Inc., Portland, OR.
Download or read book Some Issues Related to the Selection of Polymers for Aerospace Oxygen Systems written by D. Hirsch and published by . This book was released on 2006 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Materials intended for use in aerospace oxygen systems are commonly screened for oxygen compatibility following NASA STD 6001. This standard allows qualification of materials based on results provided by only one test method. Potential issues related to this practice are reviewed and recommendations are proposed that would lead to improved aerospace oxygen systems safety.
Download or read book Test Developments for Polymers in Oxygen Enriched Environments written by F. Benz and published by . This book was released on 1991 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two newly developed methods are discussed that examine ignition and flammability characteristics of polymers in oxygen-enriched environments. These methods were tested with three types of polymers (acrylonitrile butadiene, high-density polyethylene, and polytetrafluoroethylene). The first method comprises a tube furnace assembly and a quartz tube through which a test gas is flowed over a polymer sample located in a combustion boat. The combustion gas flowing through the infrared test cell is analyzed for pyrolysis products using a Fourier transform infrared (FTIR) spectrometer. By measuring the spectral characteristics of the reactant products (spectral absorption bands) as a function of the sample temperature, it is possible to determine some of the pyrolysis properties of the materials. Inspection of the sample while the temperature increases is made possible by viewing the sample through an oblique field-of-view angle to the quartz sampling tube. The sample is monitored visually or recorded with a video camera. Visual monitoring for flame emissions allows for positive identification of the auto-ignition temperature (AIT). With the exception of the high-density polyethylene, the AIT results were in good agreement with previously published values. The FTIR spectrometer was demonstrated to be extremely sensitive for characterizing the compatibility of polymer materials with oxygen. The second method discussed is a modification to a Differential Scanning Calorimeter (DSC). This device, which utilizes a silicon photodiode coupled to the DSC chamber via a light pipe assembly, is used to detect radiative flame emissions from a polymer test sample, The modification provides a method of identifying the AIT threshold, while simultaneously measuring endothermic and exothermic responses. The photodiode detector assembly has been adapted for use with the high-pressure DSC cell configuration. The visible wavelength bandpass of the silicon photodiode has a weak response to the radiation heat of the sample or DSC chamber for temperatures under 500 K. Thus, flames with temperatures in excess of 500 K are easily distinguished from the radiative response of the chamber or slow reaction rates (no visible flame emissions). The testing of the DSC demonstrated the merit of using the radiative flame emissions as the primary signature for the identification of the auto-ignition condition. The method reduces or eliminates ambiguity associated with interpretation of exothermic reactions. Thus, the new instrumentation provides viable methods of determining the AIT for polymers in oxygen-enriched environments.
Download or read book A Perspective on Gaseous Impact Tests written by BL. Werley and published by . This book was released on 1993 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gaseous impact testing has been accomplished in assorted ways dating back to at least the 1950s. ASTM Committee G-4 grappled with disparate views and melded them into ASTM G 74 in 1982. Criticized for being both too sensitive and too insensitive, recent data has unfortunately also led to calls for the test's abandonment. A historical review of the test is presented, speculation on desirable elements in an improved G 74 test are presented, and several arguments for preserving the test are presented. An attempt to analyze the test dynamic is offered. The principal virtue of the test is argued to be its potential simplicity and low cost implementation which may enable compatibility testing by smaller laboratories previously forced to rely on the data of others. A possibly unique ability to study aging effects in polymers is also cited. The greatest need in restructuring the test is argued to be the optimization of geometry to allow data to not only rank materials but to reflect worst-case real-world exposures and perhaps allow inference about materials autoignition temperatures.
Download or read book Compatibility of Polymeric Materials with Fluorine and Fluorine oxygen Mixtures written by Louis M. Russell and published by . This book was released on 1966 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flammability and Sensitivity of Materials in Oxygen enriched Atmospheres written by Joel M. Stoltzfus and published by ASTM International. This book was released on 1993 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flammability and Sensitivity of Materials in Oxygen enriched Atmospheres written by David B. Hirsch and published by ASTM International. This book was released on 2006 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flammability and Sensitivity of Materials in Oxygen enriched Atmospheres written by Dwight D. Janoff and published by ASTM International. This book was released on 1995 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aircraft Oxygen Systems and Equipment Tests for the Compatibility of Materials in the Presence of Oxygen written by British Standards Institute Staff and published by . This book was released on 1999-10-15 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft components, Breathing apparatus, Oxygen, Oxygen masks, Air transport engineering, Non-metals, Plastics, Polymers, Compatibility, Chemical-resistance tests, Fire tests, Ignition, Temperature, High-pressure tests, Pressure testing, Service pressure, Liquefied gases, Impact testing, Bomb methods, Test equipment, Design, Testing conditions, Test specimens, Specimen preparation, Filling
Download or read book Safe Use of Oxygen and Oxygen Systems written by and published by ASTM International. This book was released on with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Tech Briefs written by and published by . This book was released on 1987 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Note written by and published by . This book was released on 1966 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
