1、BRITISH STANDARD BS7164-14: 1996 ISO1408: 1995 Chemical tests for raw and vulcanized rubber Part14: Methods for determination of carbon black content ICS 83.060BS7164-14:1996 This British Standard, having been prepared under the directionof the Sector Board forMaterials and Chemicals, waspublished u
2、nder the authorityof the Standards Boardand comes into effect on 15 May 1996 BSI 07-1999 The following BSI references relate to the work on this standard: Committee reference PRI/23 Draft announced in BSI News February 1996 ISBN 0 580 25582 4 Committees responsible for this British Standard The prep
3、aration of this British Standard was entrusted to Technical Committee PRI/23, Chemical testing of rubber, upon which the following bodies were represented: Malaysian Rubber Producers Research Association Ministry of Defence RAPRA Technology Ltd. Royal Society of Chemistry Amendments issued since pub
4、lication Amd. No. Date CommentsBS7164-14:1996 BSI 07-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Method A 2 5 Method B 3 6 Method C 5 7 Test report 6 Figure 1 Typical tube furnace assembly 7 List of references
5、 Inside back coverBS7164-14:1996 ii BSI 07-1999 National foreword This Part of BS7164 has been prepared by Technical Committee PRI/23 and is identical to ISO1408:1995 Rubber Determination of carbon black content Pyrolytic and chemical degradation methods published by the International Organization f
6、or Standardization (ISO). It supersedes BS7164-14:1990 which is withdrawn. The Technical Committee has reviewed the provisions of ISO383:1976 to which normative reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. ISO383:1976is related to
7、 BS572:1991 Specification for interchangeable conical ground glass joints. 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 British Standard does not of itself confer
8、 immunity from legal obligations. Cross-reference Publication referred to Corresponding British Standard ISO1407:1992 BS7164Chemical tests for raw and vulcanized rubber Part3:1992 Methods for determination of solvent extract Summary of pages This document comprises a front cover, an inside front cov
9、er, pages i and ii, pages1 to 8, 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.BS 7164-14:1996 BSI 07-1999 1 WARNING Persons using this Inter
10、national Standard should be familiar with normal laboratory practice. This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any nat
11、ional regulatory conditions. 1 Scope 1.1 This International Standard specifies a pyrolytic method (A) and two chemical degradation methods (B and C) for the determination of the carbon black content of rubber. 1.2 Method A is preferred and should be used for the following polymers, except when certa
12、in compounding materials such as lead and cobalt salts, graphitic carbon blacks, phenolic and other resins, bitumen, or cellulose, etc., which cause the formation of a carbonaceous residue during pyrolysis, are present: polyisoprene, natural or synthetic; polybutadiene; styrene-butadiene copolymers;
13、 butyl rubber; acrylate rubber; ethylene-propylene copolymer; ethylene-propylene terpolymer; polyethers; polyethylene-derived polymers; silicone rubbers; fluorosilicone rubbers; chlorosulfonated polyethylenes containing less than 30% (m/m) of chlorine. The precision of this method may be affected if
14、 mineral fillers, e.g. alumina or calcium carbonate, are present which decompose or dehydrate, or form volatile halides in the case of halogenated polymers, at the pyrolysis temperature. The method cannot be used for either chloroprene rubbers or butadiene-nitrile rubbers having an acrylic acid nitr
15、ile content greater than30%(m/m). 1.3 Method B is chiefly intended to be used with samples not amenable to the pyrolytic method A, although it can be used for all samples based on unsaturated rubbers except for isobutylene-isoprene copolymers. 1.4 Method C is relatively hazardous and should be used
16、only for the analysis of samples based on isobutylene-isoprene copolymers and ethylene-propylene copolymers and related terpolymers when methods A and B fail. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this Intern
17、ational Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
18、Members of IEC and ISO maintain registers of currently valid International Standards. ISO383:1976, Laboratory glassware Interchangeable conical ground joints. ISO1407:1992, Rubber Determination of solvent extract. 3 Principle 3.1 Method A A weighed test piece of the rubber is extracted with acetone
19、and, if bitumen is present, with dichloromethane. The extracted rubber is pyrolized in a combustion boat at850 C in a stream of nitrogen. The boat containing the non-volatile residue is cooled and weighed. The carbon black is then burnt off in air or oxygen in a furnace at the same temperature. The
20、boat and its contents are cooled and reweighed. The loss in mass represents the carbon black. 3.2 Method B A weighed test piece of the rubber is extracted with acetone. The organic components are destroyed by oxidation with nitric acid, the acid-soluble inorganic components dissolving simultaneously
21、 in the nitric acid. The residue, which consists of carbon black and acid-insoluble mineral fillers is filtered, washed and then dried to constant mass at850 C in a nitrogen atmosphere to avoid oxidation of the carbon black. The weighed residue is reheated at the same temperature (850 C) (to avoid f
22、urther change in mass of the inorganic matter) but this time in air so as to cause oxidation of the carbon black to carbon dioxide. The residue is cooled and reweighed. The loss in mass represents the carbon black.BS7164-14:1996 2 BSI 07-1999 3.3 Method C After swelling of a test piece by hot p-dich
23、lorobenzene, the organic matter is oxidized by tert-butyl hydroperoxide. The undissolved carbon black and mineral fillers are filtered, washed and then dried to constant mass at850 C in a nitrogen atmosphere to avoid oxidation of the carbon black. The weighed residue is reheated at the same temperat
24、ure (850 C) (to avoid further change in mass of the inorganic matter) but this time in air so as to cause oxidation of the carbon black to carbon dioxide. The residue is cooled and reweighed. The loss in mass represents the carbon black. 4 Method A WARNING All recognized health and safety precaution
25、s shall be in effect when carrying out this method. All evaporations shall be carried out in a fume cupboard (hood). 4.1 Reagents During the analysis, unless otherwise stated, use only reagents of analytical reagent grade (or equivalent) and only distilled water or water of equivalent purity. 4.1.1
26、Nitrogen, dry and free from oxygen. NOTE 1Commercial “oxygen-free” nitrogen may require further purification. 4.1.2 Oxygen or air, gaseous, dry. 4.1.3 Xylene, general laboratory grade. 4.1.4 Acetone 4.1.5 Dichloromethane 4.1.6 Ethanol-toluene azeotrope (ETA) Mix7volumes of absolute ethanol with3volu
27、mes of toluene. Alternatively, mix7volumes of commercial-grade ethanol with3volumes of toluene and boil the mixture with anhydrous calcium oxide (quicklime) under reflux for4h. Then distil the azeotrope and collect the fraction with a boiling range not exceeding1 C, for use in the test. 4.2 Apparatu
28、s Ordinary laboratory apparatus, plus the following: 4.2.1 Combustion boat, made of silica, of length50mmto60mm, with handle. 4.2.2 Tube furnace assembly seeFigure 1, comprised of the following component parts: 4.2.2.1 Combustion tube, made of quartz or of impervious aluminous porcelain, and fitted
29、with means for advancing and withdrawing the combustion boat (4.2.1). The inside diameter shall be sufficient to allow the combustion boat to enter the tube and move easily through it. The tube shall be30cm longer than the tube furnace (4.2.2.2). One end of the tube shall be provided with a gas-inle
30、t system for nitrogen, the opposite end with a suitable outlet system for the vapours produced during the pyrolysis. 4.2.2.2 Horizontal-tube furnace, having an inside diameter sufficiently large to allow the combustion tube (4.2.2.1) to enter the heated section of the furnace. The furnace shall be e
31、lectrically heated, thermostatically maintained at850 C 25 C and fitted with a temperature-indicating device. 4.2.2.3 Silica glass rod with hook, of length sufficient to reach through the combustion tube(4.2.2.1) and inlet tube (4.2.2.4), and of diameter sufficient to make tight contact with the rub
32、ber tube in the inlet tube. 4.2.2.4 Inlet tube, with side tube for nitrogen supply and with a short length of rubber tubing in which the silica glass rod (4.2.2.3) is held by an airtight joint but can slide in and out of the combustion tube(4.2.2.1). The tubing used for the gas-inlet system shall be
33、 made of plasticized PVC or other material having a low permeability to oxygen and water vapour. 4.2.2.5 Vapour absorption equipment, consisting of rubber tubing for the connection of the outlet system of the combustion tube (4.2.2.1) with a trap for readily condensable vapours, two gas-washing bott
34、les containing xylene (4.1.3), and flowmeters and flow-controllers for nitrogen or oxygen or air supplies. 4.2.3 Suitable extraction apparatus, as specified in ISO1407. 4.2.4 Desiccator 4.2.5 Muffle furnace, electrically heated, thermostatically controllable at850 C 25 C. 4.3 Sampling Cut a test sam
35、ple of at least1,5g from the laboratory sample, preferably from more than one place, so that proper representation of the whole sample is achieved.BS 7164-14:1996 BSI 07-1999 3 4.4 Procedure 4.4.1 Prepare the test sample by passing the rubber six times between the rolls of a laboratory mill set to a
36、 nip not exceeding0,5mm. Cut from the sheet a test piece having a mass of approximately0,1g to0,5g. If it is not possible to pass the sample through the mill, the sample may be cut into pieces less than1mm per side. 4.4.2 Weigh the test piece to the nearest0,1mg (mass m 0 ). Record this mass. Wrap t
37、he test piece in filter paper and extract with acetone (4.1.4) for4h or until the solvent in contact with the test piece is colourless. If bitumen is present in the compound, extract with dichloromethane (4.1.5) for4h or until the solvent in contact with the test piece appears colourless. Uncured co
38、umpounds cannot be extracted with dichloromethane. ETA (4.1.6) may be used instead of acetone or dichloromethane. NOTE 2Extraction with dichloromethane is only necessary if materials not completely soluble in acetone, such as bitumen, are present. Extraction can be facilitated by comminuting the tes
39、t piece before weighing. To do this, pass it through a mill with minimum clearance between the rolls. 4.4.3 Remove the extracted test piece from the filter paper and dry in an oven maintained at100 C 3 C until the solvent is completely removed. 4.4.4 Quantitatively transfer the dried test piece to t
40、he combustion boat (4.2.1) and place the boat in the combustion tube (4.2.2.1) near the nitrogen inlet system. 4.4.5 Close the tube with the entry fitting and connect to the nitrogen supply (4.1.1). Introduce the combustion tube into the furnace (4.2.2.2) heated to850 C 25 C but keep the boat in the
41、 cool part of the combustion tube. Connect the opposite end of the tube to the vapour absorption equipment(4.2.2.5). 4.4.6 Pass nitrogen through the tube at about200cm 3 /min for5min or more to eliminate the air contained in the combustion tube. 4.4.7 Reduce the rate of nitrogen flow to about100cm 3
42、 /min and move the boat slowly into the heated zone of the combustion tube over a period of about5min. 4.4.8 Leave the boat in the hot zone for a further5min in order to complete the pyrolysis. 4.4.9 Withdraw the boat to the cold part of the tube and allow to cool for10min, while still maintaining t
43、he flow of nitrogen. 4.4.10 Transfer the boat to the desiccator (4.2.4), complete the cooling and weigh to the nearest0,1mg (mass m 1 ). Record this mass. 4.4.11 Place the boat in the combustion tube again and close the tube; connect the inlet system of the tube to the oxygen or air supply (4.1.2) a
44、nd pass the gas through the tube at about100cm 3 /min. Move the boat to the heated zone and keep it there until all traces of carbon black have been removed. 4.4.12 As an alternative to 4.4.11, heat the boat in the muffle furnace (4.2.5) at850 C 25 C until all traces of carbon black have been remove
45、d. 4.4.13 Transfer the boat to the desiccator and allow to cool to room temperature. 4.4.14 Weigh the boat to the nearest0,1mg (massm 2 ). Record this mass. 4.4.15 Carry out the determination in duplicate. 4.5 Expression of results Calculate the carbon black content, as a percentage by mass, from th
46、e formula where NOTE 3The test piece may be taken from previously extracted material. In this case, a correction for solvent extract level would normally be made to obtain m 0 . NOTE 4Any matter volatile at850 C in the carbon black (as purchased) will be lost during the pyrolysis in nitrogen. The fi
47、nal result for the mass percentage of carbon black will therefore be low by this amount. In cases where the carbon black type and origin are known, a suitable correction can be made. 5 Method B WARNING Because of possible health and safety hazards inherent in this method, recognized health and safet
48、y precautions shall be observed with the use of acids and solvents. All operations shall be carried out in a properly ventilated fume hood, and safety glasses shall be worn during digestions, extractions and washings. m 0 is the mass, in grams, of the test piece (see4.4.2); m 1 is the mass, in grams
49、, of the combustion boat and its contents after heating in nitrogen (see4.4.10); m 2 is the mass, in grams, of the combustion boat and its contents after combustion of the carbon black in oxygen or air (see4.4.14).BS7164-14:1996 4 BSI 07-1999 5.1 Reagents Reagents specified in 4.1, plus the following: 5.1.1 Nitric acid ( = 1,42Mg/m 3 ). 5.1.2 Hydrochloric acid solution Add2parts by volume of concentrated hydrochloric acid ( = 1,18Mg/m 3 ) to98parts by volume of water. 5.1.3 Chloroform 5.1.4 Acetone-chlorofo
