BS 2782-4 Method 451A-1978 Methods of testing plastics - Chemical properties - Determination of acetone-soluble matter in phenolic mouldings《塑料试验方法 第4部分 化学性能 酚醛模制件的丙酮可溶物的测定》.pdf

1、BRITISH STANDARD BS2782-4: Method451A: 1978 ISO59:1977 Methods of testing Plastics Part4: Chemical properties Method451A: Determination of acetone-soluble matter in phenolic mouldings ISO title: Plastics Phenolic mouldings Determination of acetone-soluble matter IMPORTANT NOTE. Before reading this m

2、ethod it is essential to read the foreword, general introduction and instructions to BS2782, issued separately. UDC678.5/.8:678.01:543.832:678.632BS2782-4:Method451A:1978 This British Standard, having been prepared under the directionof the Plastics StandardsCommittee, was published under the author

3、ity ofthe Executive Board on 31 May1978 BSI10-1999 The following BSI references relate to the work on this standard: Committee reference PLC/17 Draft for comment77/50307 DC ISBN 0 580 10217 3 National foreword This method, which has been prepared under the direction of the Plastics Standards Committ

4、ee, is identical with ISO59 “Plastics Phenolic mouldings Determination of acetone-soluble matter”. It replaces method401A of BS2782:1970, which is being withdrawn. WARNING NOTE. This method does not necessarily detail all the precautions necessary to meet the requirements of the Health and Safety at

5、 Work etc. Act1974. Attention should be paid to any appropriate safety precautions, and the method should only be operated by trained personnel. Terminology and conventions. The text of the International Standard has been approved as suitable for publication, without deviation, as a British Standard

6、. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. The comma has been used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal ma

7、rker. Wherever the words “International Standard” appear, referring to this standard, they should be interpreted as “British Standard”. Cross-reference. For the following reference to an International Standard given in the text, there is a corresponding British Standard; this is given below: Additio

8、nal information. The following British Standards are relevant to the reagent specified in clause3 and the apparatus specified in clause4. BS509, Acetone. BS2071, Soxhlet extractors. BS2648, Performance requirements for electrically-heated laboratory drying ovens. A British Standard does not purport

9、to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover

10、, pagesi andii, pages1 and2 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. Reference to InternationalStandard Corresponding British Standard ISO565:1972 BS410:197

11、6 Specification for test sieves Amendments issued since publication Amd. No. Date of issue CommentsBS2782-4:Method451A:1978 BSI 10-1999 i Contents Page National foreword Inside front cover 1 Scope and field of application 1 2 Principle 1 3 Reagent 1 4 Apparatus 1 5 Preparation of sample 1 6 Procedur

12、e 1 7 Expression of results 2 8 Test report 2 Figure Extraction apparatus 1ii blankBS2782-4 Method451A:1978 BSI 10-1999 1 1 Scope and field of application This International Standard specifies a gravimetric method for the determination of the amount of matter that can be extracted by acetone, at a t

13、emperature near its boiling point, from a finely ground sample of a phenolic moulding. The test for acetone-soluble matter is one means for determining the relative degree of cure of phenolic mouldings made from a given material. The process of extraction is carried out under specified conditions fo

14、r a specified time. Although a high proportion of soluble matter is determined, extraction is not necessarily complete. The results are only comparative, because the extracted material normally contains substances other than any undercured resin that may be present, for example lubricants, colouring

15、 matter and plasticizers. 2 Principle Hot extraction of acetone-soluble matter from a test portion which has been reduced to a finely divided state. Evaporation of the acetone, drying of the extract to constant mass and weighing of the dried extract. 3 Reagent Acetone, pure. 4 Apparatus 4.1 Device f

16、or reducing the moulded sample to a finely divided state. 4.2 Sieve with nominal apertures of425m, complying with ISO565 1) . 4.3 Sieve with nominal apertures of250m, complying with ISO565 1) . 4.4 Analytical balance accurate to0,001g. 4.5 Extraction apparatus of the type shown in the Figure. Altern

17、atively, it is permissible to use a Soxhlet-type apparatus, in which the material in the thimble is surrounded by the vapour of the boiling solvent. Any other extraction apparatus may be used, provided that it can be shown to give similar results. 4.6 Oven, circulating air type, capable of being con

18、trolled at50 2 C. 5 Preparation of sample Reduce a fully representative sample of the moulding to powder by filing, milling, grinding, turning or drilling, taking care that no undue heating of the material occurs. Sieve the powder using sieves(4.2) and(4.3), keeping for extraction only that fraction

19、 which passes through sieve(4.2) and is retained by sieve(4.3). Take precautions to avoid absorption of moisture by the powdered sample. 6 Procedure 6.1 Test two portions of the sieved material (clause5). 6.2 Weigh a test portion of approximately3g to the nearest0,001g into a tared open-textured qua

20、ntitative filter paper or a single-thickness extraction thimble(see4.5). 1) ISO565, Test sieves Woven metal wire cloth and perforated plate Nominal sizes of apertures. Figure Extraction apparatusBS2782-4 Method451A:1978 2 BSI 10-1999 6.3 After folding over the thimble or filter paper containing the

21、test portion so that none of the powder can float out, place it in the siphon of the extraction apparatus. Assemble the condenser, siphon tube and flask to which50ml of pure acetone (clause3) has been added. 6.4 Regulate the heating so that siphoning takes place at a rate of20 to30times per hour and

22、 continue the extraction for6h. At the end of this time remove the flask and pour the contents into a smaller flask or a small dish which has been weighed to the nearest0,001g. Wash the empty flask with about20ml of acetone and add the washings to the extract. 6.5 Evaporate the acetone by any conven

23、ient means, taking care that the temperature does not exceed50 C. Place the vessel containing the residue in the oven(4.6) at a temperature of50 2 C for30min. Then withdraw the vessel from the oven, allow to cool in a desiccator to room temperature and weigh. Repeat the operations of heating, coolin

24、g and weighing until constant mass is obtained, i.e.until the difference between two successive weighings does not exceed0,003g. 7 Expression of results The amount of acetone-soluble matter in the sample is given, as a percentage by mass, by the formula Take the arithmetic mean of the values obtaine

25、d from the two test portions as the amount of acetone-soluble matter in the moulding under test. 8 Test report The test report shall include the following particulars: a) reference to this International Standard; b) complete identification of the sample; c) method used to reduce the moulding to a fi

26、ne state of division; d) amount of acetone-soluble matter in each test portion; e) arithmetic mean of the values obtained from the two test portions; f) date of test. where m 0 is the mass, in grams, of the test portion; m 1 is the mass, in grams, of the dry extract. m 1 m 0 -100 blankBS2782-4: Meth

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