1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS 8472:2011Methods for the assessmentof the oxo-biodegradationof plastics and of thephyto-toxicity of theresidues in controlledlaboratory conditionsPublishing and copyright info
2、rmationThe BSI copyright notice displayed in this document indicates when the documentwas last issued. BSI 2011ISBN 978 0 580 54339 5ICS 55.100The following BSI references relate to the work on this standard:Committee reference PKW/0Draft for comment 10/30229574 DCPublication historyFirst published
3、June 2011Amendments issued since publicationDate Text affectedBS 8472:2011 BRITISH STANDARDContentsForeword ii0 Introduction 11 Scope 12 Normative references 23 Terms and definitions 24 Principle 35 Materials and apparatus 36 Sample preparation 47 Oxidation tests 48 Biodegradation test 59 Phyto-toxi
4、city test 510 Test report 5Bibliography 8List of figuresFigure 1 Abiotic, biotic and eco-toxicity tests for plastics 3Figure2Testreport template 7Summary of pagesThis document comprises a front cover, an inside front cover, pages i to ii,pages 1 to 8, an inside back cover and a back cover.BRITISH ST
5、ANDARD BS 8472:2011 BSI 2011 iForewordPublishing informationThis British Standard is published by BSI and came into effect on 30 June 2011. Itwas prepared by Technical Committee PKW/0, Packaging. A list of organizationsrepresented on this committee can be obtained on request to its secretary.Relatio
6、nship with other publicationsThe following standard is similar but different in scope to this standard. ASTM D 6954-04, Standard Guide for Exposing and Testing Plastics thatDegrade in the Environment by a Combination of Oxidation andBiodegradation.Presentational conventionsThe provisions of this sta
7、ndard are presented in roman (i.e. upright) type. Itsmethods are expressed as a set of instructions, a description, or in sentences inwhich the principal auxiliary verb is “shall”.Commentary, explanation and general informative material is presented insmaller italic type, and does not constitute a n
8、ormative element.Contractual and legal considerationsThis standard does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.Use of this documentBSI permits the reproduction of BS 8472:2011, Figure 2. This reproduction is onlypermitted w
9、here it is necessary for the user to work/record findings on thefigure/table during each application of the standard.Compliance with a British Standard cannot confer immunity from legalobligations.BRITISH STANDARDBS 8472:2011ii BSI 20110 Introduction0.1 GeneralThe methods described in this British S
10、tandard measure the mineralization ofthe carbon chains of plastic under controlled laboratory conditions, includingthe presence of soil micro-organisms and oxygen. The partially mineralizedproducts of the degradation and oxo-biodegradation tests can then be assessedfor their effect on seed germinati
11、on and plant growth.0.2 Title of the standardThe term “oxo-biodegradation” is defined in 3.8 as it is defined inCEN/TR 15351:2006, 5.2 as “degradation identified as resulting from oxidativeand cell-mediated phenomena, either simultaneously or successively”.Oxo-biodegradation is not restricted to man
12、-made polymers. It was firstrecognized in the biodegradation of natural rubber 1 and it occurs in naturalmaterials such as lignocelluloses, probably mediated by enzymes that producefree radicals 1. This is analogous to the redox reactions of transition metal ions,where oxygen radicals such as .OH an
13、d .OOH are certainly involved in theinitiation step. Propagation of the chain reaction occurs primarily on bothnatural and synthetic products through ROO. This chemistry is readilyunderstood by biochemists since it is widely discussed in both materials andbiological chemistry literature (see 1 to 4
14、and in many text books). Furtherelaboration in this standard does not seem to be appropriate.In the environmental exposure of plastics both mechanisms, abiotic and bioticoperate together and the micro-organisms rapidly remove the biodegradableoxidation products in a synergistic process. It is diffic
15、ult and time consuming toreproduce this in the laboratory and for convenience the two processescorresponding to weathering, which is an abiotic process, and biodegradationhave to be carried out in separate tests.ASTM also recognizes the two operations in ASTM D 6954-04. This isoxo-biodegradation, al
16、though ASTM does not use this term.0.3 Use of this standardThis standard defines a specific template to be used for the reporting of resultsin order to standardize communication and avoid confusion.This standard is not a specification. Testing according to this standard does notprovide any recommend
17、ation about the suitability of the tested products for anyparticular application.1 ScopeThis British Standard describes methods for determining:a) degradation by oxidation (abiotic tests);b) biodegradation (biotic test in soil); andc) phyto-toxicity (plant growth tests);of plastics materials and pro
18、ducts.BRITISH STANDARD BS 8472:2011 BSI 2011 12 Normative referencesThe following referenced documents are indispensable for the application ofthis document. For dated references, only the edition cited applies. For undatedreferences, the latest edition of the referenced document (including anyamend
19、ments) applies.ASTM D 5510-94(2001), Standard Practice for Heat Aging of OxidativelyDegradable PlasticsBS EN ISO 4892-3, Plastics Methods of exposure to laboratory light sources Fluorescent UV lampsBS EN ISO 17556, Plastics Determination of the ultimate aerobicbiodegradability in soil by measuring t
20、he oxygen demand in a respirometer orthe amount of carbon dioxide evolvedOECD 208, OECD guidelines for the testing of chemicals Terrestrial plant test:seedling emergence and seedling growth test3 Terms and definitionsFor the purposes of this British Standard, the following terms and definitionsapply
21、.3.1 abioticwithout the action of living organisms3.2 biodegradationdegradation of a polymeric item due to cell-mediated phenomenaNOTE Source: PD CEN/TR 15351:2006, 5.2.3.3 bioticthrough the actions of living organisms3.4 carbonyl indexabsorbance of the carbonyl band normalized to an invariant absor
22、bance of thepolymerNOTE See Grassie and Scott 2.3.5 degradationchange in initial properties due to chemical cleavage of the macromoleculesforming a polymeric item, regardless of the mechanism of cleavage3.6 mineralization (aerobic)conversion to carbon dioxide, water and other inorganic chemicals3.7
23、oxo-degradationdegradation resulting from oxidative cleavage of macromoleculesNOTE 1 Similarly, prefixes like thermo (for the action of heat), photo (for the actionof light) are to be used whenever one wants to indicate an identified mechanism ofdegradation.NOTE 2 Source: PD CEN/TR 15351:2006, 5.2.3
24、.8 oxo-biodegradationdegradation resulting from oxidative and cell-mediated phenomena, eithersimultaneously or successivelyBRITISH STANDARDBS 8472:20112 BSI 2011NOTE 1 Similarly, prefix like thermo (for the action of heat), photo (for the actionof light) are to be used separately or in combination w
25、henever one wants toindicate the involvement of various identified mechanisms of degradation.NOTE 2 Source: PD CEN/TR 15351:2006, 5.2.4 PrinciplePlastics specimens are subjected to some or all of the following tests (seeFigure 1).a) An oxidation/abiotic test (see Clause 7) by photo-oxidation and/or
26、bythermal oxidation. Degradation to embrittlement is measured by flex test orby friability test.b) A biodegradation/biotic test (see Clause 8) on residue embrittled byoxidation as per the test in Clause 7. Mineralization is measured as carbondioxide evolved as a percentage of the theoretical yield f
27、or completemineralization of total organic carbon content.c) A phyto-toxicity/plant growth test (see Clause 9) on partially evolved residuefrom the biodegradation test in Clause 8. Phyto-toxicity is measured as seedgermination and crop biomass compared to control soil.5 Materials and apparatusNOTE O
28、ther equipment is required for referenced test methods.5.1 Accelerated weathering device, typically utilizing a UV lamp 400 W emittingbetween 290 nm and 450 nm, capable of alternating exposure to dry, lightconditions and wet, dark conditions at a minimum ratio of 5:1.Figure 1 Abiotic, biotic and eco
29、-toxicity tests for plasticsPlastics samples (Clause 6)10 g advised for all testsPhoto-oxidation/weathering (7.2)Thermal oxidationtest (7.3)Monitored biotic test (8.1)3 samples of 100 mg in100 g of soilBiotic test run to 50%mineralization (8.2)6 g in 3 kg of soilPhyto-toxicity test(Clause 9)BRITISH
30、STANDARD BS 8472:2011 BSI 2011 35.2 Forced-air ventilation oven, capable of maintaining the internal volume at(5070) C 2 C, and not exceeding 80 C in operation, capable of exchangingthe unoccupied volume of the oven once per hour, which conforms toASTM D 5510-94(2001).6 Sample preparation6.1 Select
31、requirements for samples either from the product or based on theanticipated product. In particular, specify samples of a given mass that areeither:a) all or part of the product, including the thickest parts; orb) a sample of the material to be used in a product, at the expected maximumthickness.6.2
32、Measure and/or cut out sufficient samples of sufficient size and mass for theselected tests, from a single batch of material.NOTE It is recommended that 4 g are prepared for the biodegradation test (8.1)and a sample of 6 g is needed for input to the biodegradation process in 8.2 toproduce sufficient
33、 quantities at 50% mineralization for the phyto-toxicity tests(Clause 9). That is, 10 g in total.6.3 Measure and/or cut out test samples on a clean, dry grease-free surface.6.4 Record the dimensions and masses of the prepared samples.7 Oxidation tests7.1 IntroductionOxidation (abiotic) testing shall
34、 be by photo-oxidation/weathering (7.2) and/orby thermal oxidation (7.3), using separate samples if both tests are performed.7.2 Photo-oxidation testExpose the samples (6.1) to artificial weathering in the accelerated weatheringdevice (5.1) in general accordance with an exposure cycle in BS EN ISO 4
35、892-3.7.3 Thermal oxidation testExpose the samples (6.1) in the forced-air ventilation oven (5.2) either: at arange of temperatures or at a single temperature between ambient and thetemperature at which chemical decomposition becomes significant.7.4 Measurement of oxidationAt intervals appropriate t
36、o the material tested (chosen by trial and error)measure the degree of oxidation by one of the following embrittlement tests ofthe samples.a) By bending the sample so that its opposite edges touch and assess whetherthe sample fractures in a brittle manner.NOTE 1 A more precise assessment of the degr
37、ee of oxidation may be obtainedby measuring the flexural properties in accordance with BS EN ISO 178.b) By rubbing the sample between thumb and first finger (friability) and assesswhether the sample fragments.NOTE 2 A more precise assessment of the degree of oxidation may be obtainedby measuring the
38、 impact-failure energy using a falling dart test in accordancewith BS 2782-3.BRITISH STANDARDBS 8472:20114 BSI 2011NOTE 3 Care should be taken to collect sufficient clean material, whether intact orfragmented, for subsequent tests.NOTE 4 IR spectroscopy of the test residue to find the carbonyl index
39、 is a usefulmethod for confirming oxidation.NOTE 5 Samples that are not embrittled under 7.4a) or 7.4b) may be returned tothe test chamber for further exposure.7.5 Test terminationTerminate the test and record the time to embrittlement when:a) samples break under the embrittlement test in 7.4a); orb
40、) samples fragment under the embrittlement test in 7.4b).8 Biodegradation test8.1 Test three samples recovered from the oxidation test (Clause 7) that havereached condition 7.5a) or 7.5b) according to the biodegradation (biotic) test inBS EN ISO 17556, with the possibility of terminating the test be
41、yond six monthsand recording the test duration.8.2 Obtain samples for the plant growth test by: running the biodegradationprocess in bulk using at least6gofoxidized material in 3 kg of soil (a startingconcentration double that recommended in BS EN ISO 17556) and taking thesample as soon as practicab
42、le after the point where the monitored test hasreached 50% of theoretical mass of carbon dioxide evolved.NOTE It may be necessary to use a higher concentration of sample to soil thanrecommended in BS EN ISO 17556. Care has to be taken to maintain otherexperimental conditions.9 Phyto-toxicity testMea
43、sure the effect of the partly evolved plastics samples on plant germinationnumber and biomass, in accordance with OECD 208, using 0.5 kg per pot. Usethe test substance from 8.2 and use the negative control samples from thebiodegradation test. Use at least two plant species from two of the threementi
44、oned categories of OECD 208. Record the germination number andbiomass crop yield of plants, compared to the control soil.10 Test reportA test report containing the following information as a minimum shall beprepared following the template shown in Figure 2.a) For all tests:1) a reference to this sta
45、ndard, i.e. BS 8472:2011;2) the material, its constituents and/or its unique manufacturersidentification code; and3) initial sample size(s), thickness(es) and mass(es).b) For photo-oxidation tests:1) the type of UV lamp used as categorized in BS EN ISO 4892-3;2) the total exposure time and the expos
46、ure cycle to which the sampleshave been subjected; and3) the relevant test criteria and results as required in 7.4 and 7.5.BRITISH STANDARD BS 8472:2011 BSI 2011 5c) For thermal oxidation tests:1) the rate of airflow through the sample/total flow, the temperature dueto the forced-air ventilation ove
47、n, and the total time of exposure; and2) the relevant test criteria and results as required in 7.4 and 7.5.d) For biotic tests: the information required for a test report toBS EN ISO 17556.e) For phyto-toxicity tests: the results required by OECD 208.BRITISH STANDARDBS 8472:20116 BSI 2011Figure 2 Te
48、st report templateReport on materials test to BS 8472:2011Test laboratory: Date of report:Material tested Known constituents Manufacturers ID codeNumber ofsamplesSample thicknesses(mm)Sample sizes (largestdimension, mm)Sample masses (mg)Photo-oxidation Tested: Yes/NoLamp usedA)Exposure cycleA)and to
49、talexposure timeTest used and resultsA)Type of lamp and exposure cycle selected from BS EN ISO 4892-3.Thermal oxidation Tested: Yes/NoRate of airflow Temperature and total exposuretimeTest used and resultsBiotic test, report attached as per BS EN ISO17556 reportingrequirementsYes/NoDuration of testPhyto-toxicity test, report attached as per OECD 208 reportingrequirementsYes/NoBRITISH STANDARD BS 8472:2011 BSI 2011 7BibliographyStandards publicationsFor dated references, only the edition cited applies. For undated references, thelatest
