1、 FORD LABORATORY TEST METHOD BO 006-03 Date Action Revisions 2000 08 31 Revised Editorial no technical change A. Cockman 1992 07 13 Printed copies are uncontrolled Page 1 of 4 Copyright 2000, Ford Global Technologies, Inc. DETERMINATION OF FILLER CONTENT IN POLYTETRAFLUOROETHYLENE Scope This test me
2、thod outlines the procedure for determining the weight percent of fillers in filled and reinforced polytetrafluoroethylene (PTFE). Application Dry nitrogen or helium gas is used as an inert sweep gas to remove pyrolysis products of the polymer while preventing oxidation of the filler material at hig
3、h temperature. This method is applicable to TFE polymers containing filler materials such as carbon, graphite and glass fiber. Duplicate samples are to be tested and results averaged. When available, a thermogravimetric analyzer (TGA) should be used instead of this test method owing to the improved
4、speed and precision obtainable with a TGA. (Refer to Ford Central Laboratory Serv ices for the recommended TGA procedure.) Note: This test method is not applicable to volatile inorganic fillers (such as CaCO 3 owing to loss of CO 2 during heating) or fillers which contain water of hydration. Apparat
5、us Required Split-Tube Furnace Lind berg Model No. 55035 or equivalent with temperature range to 1100 C. Combustion Boats Platinum. Combustion Tube Vycor glass with spring mounted gas restriction caps. Glass Wool Dry “Zero“ Nitrogen or Helium Gas With regulator and flowmeter (1 ppm max moisture. Dri
6、er required if moisture 1 ppm). FORD LABORATORY TEST METHOD BO 006-03 Page 2 of 4 Copyright 2000, Ford Global Technologies, Inc. Analytical Balance Must have a precision of +/ - 0.05 mg. Drier VWR Catalog 26668 - 007 or equivalent. Required if gas with a moisture content in excess of 1 ppm is used.
7、Conditioning and Test Conditions Al l test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/ - 2 C and 50 +/ - 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Procedure Note: Th
8、is procedure must be carried out with furnace in a fume hood or other facility to assure adequate exhausting of toxic pyrolysis products. The first part of the procedure (heating in a protective atmosphere) determines the total filler con tent. If it is desired to verify the level of fillers which c
9、an be totally oxidized to Co/CO , repeat steps 2 - 8 using oxygen or air in 2 place of the nitrogen or helium. The weight of the resulting residue subtracted from the initial value obtained in step 8 will yield the oxidizable filler. 1. Weigh approximately 2 g of filled PTFE in clean, dry, tared, pl
10、atinum combustion boat. Record weight of sample and boat to an accuracy of 0.1 mg. Weigh duplicate sample in second boat. 2. Carefully place boat s in combustion tube. Insert loose wad of glass wool in inlet end of tube to diffuse incoming gas. Secure caps in place with springs. 3. Adjust nitrogen o
11、r helium gas flow to approximately 0.20 L/minute. Note: The furnace should be completely purged before the furnace is turned on. 4. Set furnace control to approximately 7 1/2. Temperature should stabilize at 760 - 790 C after about 45 minutes. (For faster heat - up, set control at “High“ for approxi
12、mately 10 minutes and then reduce to 7 1/2.) Note : These settings are applicable only to the Lindberg Furnace. Other settings would have to be employed on other furnaces. 5. Maintain temperature at 760 - 790 C with uniform gas flow for 1 - 1 h at heat. FORD LABORATORY TEST METHOD BO 006-03 Page 3 o
13、f 4 Copyright 2000, Ford Global Technologies, Inc. 6. After the allotted time at temperature, t urn off furnace and pull plug. Maintain gas flow until temperature drops to ambient to avoid oxidation of residue and to prevent thermal cracking of glass tube. 7. When temperature has dropped to ambient,
14、 turn off nitrogen (or helium) sweep gas and remov e caps. 8. Reweigh combustion boats containing residue and calculate percentage filler as shown in the following example: Weight (grams) Before Pyrolyzing After Pyrolyzing Sample 1 Gross Wt. 9.1237 7.9123 Tare Wt. 7.0222 7.0 222 Net Wt. 2.1015 .8901
15、 Net Weight After x 100 % = % Residue Net Weight Before .8901 x 100 % = 42.36 % 2.1015 Average results of the duplicate tests and report as required in Engineering Specification. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities. FORD LABORATORY TEST METHOD BO 006-03 Page 4 of 4 Copyright 2000, Ford Global Technologies, Inc. DETERMINATION OF FILLER CONTENT IN POLYTETRAFLUOROETHYLENE Burn - out Set - up Utilizing Spli t Tube Furnace Figure 1
