1、BRITISH STANDARD BS 2782-4: Method 470C:1991 ISO 3451-3: 1984 Methods of testing Plastics Part 4: Chemical properties Method 470C: Determination of ash of unplasticized cellulose acetate IMPORTANT NOTE. Before reading this method it is essential to read BS2782-0, Introduction, issued separately.BS27
2、82-4:Method 470C:1991 This British Standard, having been prepared under the directionof the Plastics and Rubber Standards Policy Committee, was published underthe authority of the Standards Board and comesintoeffect on 30April1991 BSI 12-1999 The following BSI references relate to the work on this s
3、tandard: Committee reference PRM/21 Draft for comment 80/52357 DC ISBN 0 580 19567 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Plastics and Rubber Standards Policy Committee (PRM/-) to Technical Committee PRM/21, upon which the fol
4、lowing bodies were represented: British Plastics Federation British Steel Industry British Telecommunications plc Department of Trade and Industry (National Physical Laboratory) EEA (the Association of Electronics, Telecommunications and Business Equipment Industries) Electrical and Electronic Insul
5、ation Association (BEAMA Ltd.) Electrical Installation Equipment Manufacturers Association (BEAMA Ltd.) GAMBICA (BEAMA Ltd.) Man-made Fibres Producers Committee Ministry of Defence Packaging and Industrial Films Association PIRA Plastic Industrial Containers Association Plastics and Rubber Institute
6、 RAPRA Technology Ltd. Standards Association of Australia Yarsley Technical Centre Ltd. Amendments issued since publication Amd. No. Date CommentsBS2782-4:Method470C:1991 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 R
7、eferences 1 3 Principle 1 4 Apparatus 1 5 Procedure 1 6 Number of determinations 1 7 Expression of results 1 8 Test report 2 Publication(s) referred to Inside back coverBS2782-4:Method 470C:1991 ii BSI 12-1999 National foreword This method has been prepared under the direction of the Plastics and Ru
8、bber Standards Policy Committee and is identical with ISO3451-3:1984 “Plastics Determination of ash Part 3: Unplasticized cellulose acetate”, published by the International Organization for Standardization (ISO). The Technical Committee has reviewed the provisions of ISO585:1982, to which reference
9、is made in the text, and has decided that they are acceptable for use in conjunction with this British Standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a Brit
10、ish Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard ISO 3451-1:1981 BS 2782 Methods of testing plastics Method 470A:1991 Determination of ash (general methods) (Identical) Summary of pages This document compri
11、ses a front cover, an inside front cover, pages i and ii, pages1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS2782-4:Method 470C:19
12、91 BSI 12-1999 1 1 Scope and field of application 1.1 This part of ISO3451 specifies a method for determining the ash, consisting of inorganic residue, yielded by unplasticized cellulose acetate. 1.2 This method applies to unplasticized cellulose acetate free of additives, fillers, dyes or other mat
13、erials which may affect the result. 1.3 When plasticizers, additives, fillers or dyes which may affect the result are present, they shall be separated by a method agreed between the interested parties. 1.4 The ash content at575 25 C is a reasonable measure of the mineral salts and inorganic foreign
14、matter in the cellulose acetate. The weight of ash obtained varies with the temperature of ignition. Higher temperatures such as850 C will convert calcium carbonate and other carbonates to the oxides and thus give lower values for the ash. The composition of ash may vary with the pulping process use
15、d in manufacture, which limits the significance of the ash determination in absolute terms. 2 References ISO 585, Plastics Non-plasticized cellulose acetate Determination of moisture content. ISO 3451-1, Plastics Determination of ash Part1: General methods. 3 Principle Ignition of a test portion and
16、 calcination in a muffle furnace maintained at575 25 C or850 50 C (as agreed between the interested parties), in accordance with ISO3451-1, method A (direct calcination). 4 Apparatus 4.1 Crucible, of capacity50 to200ml, made of silica, platinum or porcelain. 4.2 Bunsen burner, with silica triangle a
17、nd tripod, or other suitable heating device. 4.3 Muffle furnace, thermostatically controlled at575 25 C or850 50 C. 4.4 Analytical balance, accurate to0,1mg. 4.5 Desiccator, containing a drying agent, for example anhydrous chloride. 4.6 Weighing bottle 5 Procedure 5.1 Prepare the crucible (4.1) by h
18、eating in the muffle furnace (4.3) at575 25 C or850 50 C until constant mass is reached. Allow to cool in the desiccator (4.5) to room temperature for at least1h and weigh to the nearest0,1mg. 5.2 Introduce into the tared weighing bottle (4.6) a quantity of test sample, predried as prescribed in ISO
19、585 or with a known moisture content, corresponding to5 to50mg of ash (usually10 to25g) and weigh it to the nearest0,1mg. NOTEIf the crucible will accommodate the quantity of test portion corresponding to the5 to50mg of ash, this quantity may be weighed directly into the crucible. High bulk material
20、s may be compressed into tablets which may be broken up into fragments of appropriate size. 5.3 Half fill the crucible with the test portion from the weighing bottle. Heat the crucible directly on the heating device (4.2) so that the sample burns slowly and loss of ash is avoided. Allow to cool and
21、add another part of the test portion. Repeat this operation until the total quantity of the test portion is consumed. 5.4 Place the crucible in the muffle furnace, preheated to575 25 C or850 50 C, and calcine for30min. 5.5 Remove the crucible from the muffle furnace, place in the desiccator, allow t
22、o cool to room temperature for1h and weigh to the nearest0,1mg. 5.6 Calcine again under the same conditions until constant mass is reached, i.e. until the results of two consecutive weighings do not differ by more than0,5mg. 6 Number of determinations Carry out two determinations. Calculate the arit
23、hmetic mean of the results. If the single test results differ by more than10% of their mean, repeat the procedure until two successive results do not differ from each other by more than10% of their mean. 7 Expression of results The ash expressed in grams per100g of dry cellulose acetate, is given by
24、 the formula where m is the mass of ash, in grams; m 0 is the mass of dry acetate, in grams, calculated from the actual mass of the test portion and its moisture content determined in accordance with ISO585. m m 0 -100 BS2782-4:Method 470C:1991 2 BSI 12-1999 8 Test report The test report shall inclu
25、de the following particulars: a) reference to this International Standard; b) complete identification of the sample; including type manufacturers code number, source, trade name, etc.; c) temperature used for calcination; d) treatment of the sample before the test, if any; e) single results of the t
26、wo determinations and the average for the ash.BS2782-4:Method 470C:1991 BSI 12-1999 Publication(s) referred to See national foreword.BS 2782-4: Method 470C:1991 ISO 3451-3: 1984 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible f
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