1、 FORD LABORATORY TEST METHOD EU-AP 050-03 Date Action Revisions 2001 01 31 Revised Editorial no technical change A. Cockman 2000 04 19 Editorial no technical change A. Cockman 1993 01 04 Printed copies are uncontrolled Page 1 of 5 Copyright 2001, Ford Global Technologies, Inc. DETERMINATION OF ANTI-
2、DEGRADANTS IN RUBBER BY THIN LAYER CHROMATOGRAPHY Application This procedure describes a method for “fingerprinting“ the anti-degradants (e.g. anti-ozonants, anti-ozidants, anti-fatigue agents) in rubber compounds, and as such is used to check consistency of formulation for specific applications whe
3、re close control is required. The method may also be used in certain cases for comparison work (e.g. to measure loss of anti-degradant from rubber due to environmental factors). The method is not intended to be used, either for identification of anti-degradants or to predict the performance of a rub
4、ber compound, unless a degree of caution in interpretation is applied. Equipment Required Thin Layer Plates Silica gel 60 F 254 precoated size 20 x 20 cm; layer thickness 0.25 mm. Sources: Merck, Andermann, BDH Developing Tank with Lid 22 x 6 x 21 mm or close approximation. Syringe 5.0 l capacity Sp
5、otting Guide (optional) Aerosol Spray Unit A fine spray type as supplied for use in chromatography. Spray Reagent A freshly prepared 1 % solution of 2:6 dibromo-p-benzoquinone-4-chlorimine in industrial methylated spirit, unless otherwise stated on appropriate specification. *Developing Solvent A mi
6、xture of the following: Benzene 100 parts Ethyl acetate 5 parts Acetone 2 parts FORD LABORATORY TEST METHOD EU-AP 050-03 Page 2 of 5 Copyright 2001, Ford Global Technologies, Inc. Reference solutions Solutions of anti-degradant are used for reference purposes in order to ensure consistency of the te
7、chnique and for comparisons of spot intensity. An 0.1 % solution in acetone of one or more of the following may be used unless otherwise required: Suppliers N, NdiphenylpPhenyleneDiamine ICI, Monsanto N-Phenyl-B-Naphthylamine Bayer, ICI, Monsanto Acetone/Diphenylamine Reaction Product ICI, Monsanto
8、6-Ethoxy-2,2,4-Trimethyl-1,2-Dihydroquinoline Monsanto Standard Laboratory Equipment Such as filter paper, flasks, soxhlet, etc. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 C and 50 +/- 5 % relative humidi
9、ty for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Procedure 1. Extract the rubber compound (1.0 g) for 24 h in acetone. See ASTM D 297 for details. Concentrate the extract to 3 mL. 2. Prepare the developing tank by lining with filter paper sa
10、turated with the developer solution, and maintain a depth of approx 10 mm at the bottom of the tank. (Tank must be cleaned and solution changed once per 2 days minimum). Tank should be covered and allowed to stand overnight for the atmosphere to equilibrate. 3. Mark out TLC plate with pencil as show
11、n on the accompanying sketch. 4. Preheat plate for 1 h at 75 C then cool. 5. Using syringe, spot 5 l of extract solution onto plate as shown on line B. Do likewise with the reference solution(s) ensuring that there is adequate spacing (12 mm min) between spots. To keep spot size to a minimum it is h
12、elpful to dry during spotting with clean pressurized air. FORD LABORATORY TEST METHOD EU-AP 050-03 Page 3 of 5 Copyright 2001, Ford Global Technologies, Inc. 6. Immerse the plate in the tank and allow to stand until the developer solution has eluted as far as line A, ensuring that the tank is sealed
13、 by means of the lid. 7. Remove the plate from the tank, allow 5 minutes to dry, then place in oven for 2 minutes at 100 C. Allow to cool. 8. Place the plate under a fume hood and spray evenly with reagent, noting the formation of coloured spots, and withdraw the spray when no further intensificatio
14、n of the spot occurs. Do not overspray as the background will darken, and lack of contrast will result. 9. Allow the plate to stand for 16 h minimum, then assess results. Evaluation An assessment of each spot on the plate is made according to: (a) Colour (b) Intensity (or Area) (c) R Value = a (see
15、sketch) b Assessments are normally made on a qualitative basis, by making comparisons on the same plate. Plates may be retained as standards, however, but due allowance must be made for any change in storage. (Dulling and darkening of the plate can be almost eliminated if contact with air and light
16、is avoided). A more permanent record such as coating with clear lacquer, or same size colour photographs, is essential where a more quantitative comparison is required. *Alternative Method can be used if stated on appropriate specification or other document, if there is unsatisfactory separation of
17、the desired spots. The procedure is identical except for: Spray Reagents (1) A freshly prepared 1 % solution of 2.6 dichloro-p-benzoquinone-4-chlorimine in industrial methylated spirit. (2) A freshly prepared 2 % solution of sodium tetraborate in 40 % ethanol (in water). FORD LABORATORY TEST METHOD
18、EU-AP 050-03 Page 4 of 5 Copyright 2001, Ford Global Technologies, Inc. Developing Solvent A mixture of: Benzene 48 % n-Hexane 48 % Acetone 4 % Procedure Detail Allow 5 minutes between application of the two spray reagents, then heat for 10 minutes at 100 C and cool. Chemicals, materials, parts, and
19、 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 EU-AP 050-03 Page 5 of 5 Copyright 2001, Ford Global Technologies, Inc. DETERMINATION OF ANTI-DEGRADANTS IN RUBBER BY THIN LAYER CHROMATOGRAPHY Caution: The rubber additives/chemicals should be handled with care, and contact with the skin avoided.
