ISO 247-1:2018 pdf free download.Rubber-Determination of ash – Part 1 Combustion method.
Rubber — Determination of ash — Part 1:
Combustion method
WARNINI I — Persons using ISO 247-1 should he familiar with normal laboratory practice. ISO 247-1 does not purport to address all of the safety problems, ilany. associated with its use. II is Ike responsibility of the user to establish .appropnate s.iIeIy and health practices and to determine applicability of any national regulatory conditions.
WARNING 2 — Certain procedures specilled In this document might Involve the use or general Ion of substances, or the generation ol waste, that could constitute a local environmental hazard, Reference should be made to appropriate documentation on sale handling and disposal alter use.
1 Scope
ISO 247-1 specifies three methods for 11w determination of ash from raw rubbers, compounded rubbers and vulcanizates. Th methods are applicable to raw, compounded or vulcanized rubbers of the M, N. 0. Rand U fanilhies described in Iso 1629, except that:
— Method A is not used for the deternilnatiun of ash from compounded or vulcanized rubbers containing chlorine, bromine or iodine:
— Method R is used For compounded or vulcaiiized rubbers containing chlorine, bromine or iodine. It shall not be used For uncompounded rubbers;
Method C is intended to be used for the eleterrnlnation of ash from raw, compounded or vulcanized rubber noL containing chlorine. bromine or iodine by wrapping the test portion in ash k’ss filter paper:
— l.ithium and fluorine compounds might react with silica crucihies to Inrni volatile compounds, giving low ash results. Platinum crucibles shall therefore be used For ashing Iluorine-containing and hth iu m-polymerized rubbers.
ISO 247-1 does nut cover the Interpretation of the ash results as to the inorganic chemical cuntetit of a compound or vulcanizate. This is the responsibility of the analyst, who has to be aware of the behaviour of rubber additives at elevated temperatures.
2 Normative references
The following documents are referred to in the text in such a way that some or ,ill of their content constitutes requirements of ISO 247-1. For dated references. only the edition cited applies. For undated references, the latest edit Ion of the relci-enced document (Including any amendments) applies.
ISO 248-1. Rubber, row — DCIL’roWwtloti of vvh,tlk”mottrr content — Port 1: hot-md? method rind oven method
ISO 1795, Rubber, raw natural and raw .cs’nt hetic — .kirnphng and fun her preparative procedures
3 Terms and defiiitions
No terms .imid definitions are listed in ISO 247-1,
4 Principle
4.1 Method A
A weighed test portion is heated in a crucible over a gas burner. After expulsion of 11w volatile decompositlcn products, the crucible is transferred to a multie furnace where It is heated until all the carbonaceous matter has been burnt off and constant mass is attained.
42 Method B
A weighed test portion is heated in a crucible In the presence of sulfuric acid, first by meaiis of a gas burner and then in a muffle furnace until all the carbonaceous matter has been burnt off and constant mass is attained.
4.3 Method C
A weighed test portion Is wrapped in ashless filter paper. pry-ignited at 300 C ± 25 C for I h, followed by incineration in a muffle furnace at about 550 C ± 25 C for 2 h to 4 h until all the carbonaceous matter has been burnt ofl’and constant mass is attaiiwd.
4.4 Test results
The three nwlhods of ashing do not give identical results in all cases, and it is necessary to state in the test report the method crashing employed.
5 Reagent
5.1 Sulfuric acid (For metli.xJ B only), analytical grade,p = 1.114 g/c&.
6 Apparatus
Ordinary laboratory apparatus, f)lLls the following.
6.1 Crucible, of porcelain, silica or platinum, of capacity approximately SO cm-1. For raw synthetic rubbers, It is penmtled to use a crucible of minimum c-apac.Iy 25 cni per gram of test portion
NOTI; Platinum rrucllik’c as used for ushung lluorimw.iuuulaining and lltliiuni-puutymerizt-d u’uhfrs as lithium and fluorine compounds ought rVacl with stlai’j rrum’uI-uIe Iii loran vualitik’ cnmpruuinds. giving luuw sh re-suits
62 Heat-resistant, thermally insulating hoard, 100 mm2 and of thickness approximately 5 mm. with a central hole to .iccimmnmdatc the crucible (6.1). About two-thuds of the crucible shall prolect below the board.
6.3 Bunsen burner, or similar type nl gas burner.
6.4 Muffle furnace, fitted with a flue and with I)rovIsiun for controlling the air flow through the lurnace (Thts may be achieved by adiListing the dour opening.) A temperature-controlling device Is required to maintain a temperature of 300 ‘t ± 2SC or 550 C ± 25t or 950 C ± 25 C.
6.5 Ashless filter paper of 5 cm diameter,
7 PreparaIon of the test portion
7.1 Test portions of raw iutuial rubber shall be cut froni the Iiomogemzed piece prepared in accordance with ISO 1795, Test portions of raw synthetic rubbers shall be cut From the dried rubber obtained alter carrying out the dci i’rmlnatiun ui volatlle’mattcr LuIitCnt In accordance with ISO 248-i.
72 ‘test portions of rubber compounds shall he cominmuted by hand
7.3 Test portions of vulcanizate shall by sheeted or L-rumbesl cm a mill or eumminuted by hand.
7.4 Care shall be taken to •nsurv that Lest portions of rubber compounds and vulcanizates are
representative of the sample.
8 Procedure
8.1 Method
Heat a clean empty crucible (6.1) of appropriate size for about 30 nun in the muffle Furnace [6.4). maintained at 550 C 25 °C allow to cool to ambieiit temperature in a desiccator and weigh to the nearest 0.1 lug. Take a test portion at about S g of raw rubber or I g to S g of compounded rubber or vulcanizate, according to the mass of ash to be expected, and weigh to the nearest 0.1 mg. MacI.’ the weighed Lest portion in the crucible mounted in the hole in the heal-resistant, thermally insulating hoard (62). Heat the crucible gently with the burner 1.6.3) in a hood for proper ventilation, taking care that the rubber does not ignite. if any material is Inst due to spurting or frothing, repeat the above procedure with a new test portion.
When the rubber has decomposed to a charred mass, gradually increase the heat From the’ burner until the volatile decomposition products have been substantially expelled arid a dry carbonaceous residue remains. Transler the crucible and its contents to the mottle furnace, maintained at 550°C f 25°C (for compounds and vulcanlzates, a temperature of 950 °C ± 25 °C may be used), leaving the door a the furnace slightly open for I mm to provide sufficient air to oxidize the carban
Continue heating until the carbon is completely oxidized and a clean ash is obtained. Remove the crucible and its contents from the lurnace. ahlnw to cool to ambient temperature in the desiccator and weigh to the nearest 0,1 fig. Then heat the crucible and its contents again for about 30 mm in the iiiiiff le furnace, maintained at 550°C ± 25°C (Fop compounds and vulcanlzaies, a temperature of 950°C ± 25°C may be used), allow to cool to ,ir,ihlent temperature In the desiccator and re-weigh to the nearest 0,1 mg. l’his mass shall not diflir from the previous niass by inure than 1 mg en the case of raw rubbers or by more than I % relative to the amount of ash for compounds and vulcanizates. If this requirement Is not fulfilled, repeat the heating, cooling and weighing procedure until the difference between two successive weighing meets this requirement.
8.2 Method II
Heat a clean empty crucible (6.1) of appropriate size for about 30 mm in the muffle furnace (6.4). maintained at 950 °C ± 25 C, allow to cool to ambient temperature in a desiccator and weigh to the nearest 0,1 mg. Take a test lrtinn of about I gto S g of the compound or vLilcanizatc and weigh to the nearest 0,1 mg. Place the Lest portion In the crucible and pour about 3,5 cm1 of concentrated sulfuric acid (5.1) over II so that the rubber is completely wetted. Place the crucible and its contents In the hole in the ht’at-reslslant, thermally insulating board (6.2) and heat gently with the burner In a hood for proper ventilatIon. If, during the initial reaction, the mixture swells excessively, withdraw the flame’ to avoid possible loss of material.
ISO 247.1:2018(E)
When the reaction becomes more gentle, Increase the heat front the burner until the excess sulfuric acid is volatilized and a dry. carbonaceous residue remains. Transfer the crucible and Its contents to the muffle furnace, maintained at 950 ‘C ± 25 C. leaving the dour of the furnace slightly open for 1 miii to provide sufficient air to oxidize the carbon and heat for about I h until all the carbon is completely oxidized and a clean ash is obtained. Remcwr the crucible and its contents from the furnace, allow to cixil to ambient temperature in .i desiccator and weigh to the nearest (1,1 p11g. Then heat the crucible and Its contents again for about 30 miii in the muffle turnace. maintained .it 95(1 C t 25 C, allow to cool to ambient temperature in the desiccator and re-weigh o the nearest 0,1 mg.
If this mass dii lers front the previous mass by more thati 1 % relative to the amount of ash, repeat the heating, cooling and weighing procedure until the difference between two successive weighing is less than I % relative to the amount olash.
8.3 Method C
Weigh, to the nearest 0,1 nig, a test portion of S g to 10 got the homogenized rubber. Wrap in ashless filter paper (6.5) and place in a crucible (6.1) which has lweii previously ignited and weighed. Introduce the crucible into a muffle furnace (6.4) a! controlled temperature of 3011 f. ± 25 C for I Ii pre ignition followed by incineration in a muffle lurnace ,1r 550 C t 25 C for 2 h to 4 h until free from carbon. When ashing is completed, allow the crucible to cool in a desiccator and weigh to the nearest 0,1 tug.
This mass shall not differ from the previous mass by inure than I mg, litlils requirement Is not fulfilled. repeat the heating. coiIng and weighing procedure until the difference between two successive weighing meets this requirement.
9 Expression of results
The ash content is given, as a percentage by titass, by FormuL (I)
where
rn(, Is the mass. iii grams. of the test portion; ml is the mass, in grams, of the empty crucible:
m is the mass, in grams. of the crucible intl ash.
10 Precision
Set Anni.x A
11 Test report
The test report shall include the following particulars:
a) all details required For lull IdentiliL’ation of the piece or sample tested;
b) a reIejence to this document. I.e. ISO 247’1:2018;
c) the method employed — method A. method H or met had C;
d) the temperal ore used, and the reason tar its choice it 9S0 C was used lñr method A:
e) the ash determined 11w the product tested, as a percentage by mass.