1、BSI Standards PublicationPlastics Method for artificial accelerated photoageing using medium pressure mercury vapour lampsBS EN 16472:2014National forewordThis British Standard is the UK implementation of EN 16472:2014.The UK committee voted consistently against the enquiry and final draftsof this s
2、tandard since the committee was of the opinion that the title ofthe standard should have been about determining the photo oxidation ofmaterials by FT-IR and carbonyl formation, rather than the procedure ofaccelerated photo aging.The UK participation in its preparation was entrusted to TechnicalCommi
3、ttee PRI/21, Testing of plastics.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions ofa contract. Users are responsible for its correct application. The British Standards Instituti
4、on 2014.Published by BSI Standards Limited 2014ISBN 978 0 580 79506 0ICS 83.080.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 May 2014.Amendments/corrigenda
5、 issued since publicationDate Text affectedBRITISH STANDARDBS EN 16472:2014EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16472 April 2014 ICS 83.080.01 English Version Plastics - Method for artificial accelerated photoageing using medium pressure mercury vapour lamps Plastiques - Mthode de ph
6、otovieillissement artificiel acclr utilisant des lampes vapeur de mercure moyenne pression Kunststoffe - Verfahren zur knstlich beschleunigten Alterung bei Verwendung von Quecksilberdampflampen This European Standard was approved by CEN on 8 February 2014. CEN members are bound to comply with the CE
7、N/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Ce
8、ntre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as t
9、he official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Nethe
10、rlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2014 CEN All rig
11、hts of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16472:2014 EBS EN 16472:2014EN 16472:2014 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 General 5 5 Apparatus .6 5.1 Laboratory l
12、ight source .6 5.2 Test chamber 8 5.3 Specimen holders 9 5.4 Radiometer .9 5.5 Temperature sensor 9 5.6 Temperature controller .9 5.7 Optional facilities 10 6 Test specimens . 10 7 Exposure conditions 10 7.1 Radiation 10 7.2 Temperature 10 7.3 Optional facilities 10 8 Procedure 10 8.1 Verification o
13、f the apparatus . 10 8.2 Mounting the test specimens 11 8.3 Exposure 11 8.4 Measurement of radiant exposure 11 8.5 Determination of changes in properties after exposure . 11 9 Test report . 11 Annex A (informative) Additional filtering of lamp UV radiations . 13 A.1 Additional filtering of UVB radia
14、tions for chromophoric polymers exposed to outdoor conditions 13 A.2 Additional filtering of UV radiations for polymers exposed to indoor conditions . 14 Annex B (informative) Temperature control during photoageing . 15 Bibliography . 16 BS EN 16472:2014EN 16472:2014 (E) 3 Foreword This document (EN
15、 16472:2014) has been prepared by Technical Committee CEN/TC 249 “Plastics”, the secretariat of which is held by NBN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2014 and conflicting n
16、ational standards shall be withdrawn at the latest by October 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the C
17、EN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hung
18、ary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 16472:2014EN 16472:2014 (E) 4 Introduction When a polymeric material is exposed to natural UV radia
19、tion and other moderate environmental stresses, the change in most physical properties is attributable to chemical ageing, and the extent of the chemical changes can be related to the duration of the exposure under natural outdoor weathering conditions. This method attempts to maximize the accelerat
20、ion of photoageing using elevated UV irradiance and temperature that still keep the fundamental photoageing mechanism equivalent to that found in natural ageing. Temperature increase above the natural level should be limited so that the photothermal transformation exceeds any pure thermal conversion
21、. A medium pressure mercury lamp, with radiations of wavelength lower than 290 nm properly filtered out, gives a relevant source with high UV emission intensity and low IR emission. One of the main interests in use of artificial accelerated photoageing tests is to able to provide a relevant lifetime
22、 estimate of polymeric materials exposed in natural outdoor conditions. The relevance of artificial ageing can be determined by comparing the chemical changes that occur in the accelerated test to those that occur in natural weathering (see ISO 10640). Kinetic analysis is recommended to determine th
23、e rate of degradation under different conditions of ageing in order to rank different formulations or to determine the range of acceleration possible for an artificial ageing test compared to a given natural outdoor weathering exposure (without distortion of the photodegradation mechanism of the pol
24、ymer). Chemical changes control the degradation of mechanical properties and contribute to changes in the visual appearance of polymer materials during photoageing. These chemical changes may be analysed primarily by IR spectroscopy, with additional analyses using UV/visible spectroscopy during the
25、photoageing of polymers. BS EN 16472:2014EN 16472:2014 (E) 5 1 Scope This European Standard specifies a method for carrying out artificial accelerated photoageing of test specimens by exposing them to medium pressure filtered mercury vapour lamp as light source, under controlled temperature conditio
26、ns. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any a
27、mendments) applies. EN ISO 4892-1:2000, Plastics Methods of exposure to laboratory light sources Part 1: General guidance (ISO 4892-1:1999) ISO 4582, Plastics Determination of changes in colour and variations in properties after exposure to daylight under glass, natural weathering or laboratory ligh
28、t sources ISO 9370, Plastics Instrumental determination of radiant exposure in weathering tests General guidance and basic test method ISO 10640, Plastics Methodology for assessing polymer photoageing by FTIR and UV/visible spectroscopy 3 Terms and definitions For the purposes of this document, the
29、following terms and definitions apply. 3.1 control material which is of similar composition and construction to the test material and which is exposed at the same time for comparison with the test material Note 1 to entry: An example of the use of a control material would be when a formulation diffe
30、rent from one currently being used is being evaluated. In that case, the control would be the plastic made with the original formulation. SOURCE: EN ISO 4892-1:2000 3.2 reference material material of known performance 4 General When correctly powered and maintained, the plasma of a medium pressure m
31、ercury arc discharge emits mainly UV and the visible radiation. This lamp allows the acceleration of the photochemical process by high UV irradiance without high infrared emission. Specimens of the samples to be tested are exposed to the laboratory light source under controlled temperature condition
32、. The temperature activates the photochemical process. BS EN 16472:2014EN 16472:2014 (E) 6 Optionally, the samples can be exposed to immersion and/or dark periods. The design of the equipment shall achieve the appropriate specifications as well as the UV irradiance (radiant exposure) and temperature
33、 set points. For comparing the performance of the test material to that of the control, it is recommended that at least one control be exposed during each test. 5 Apparatus 5.1 Laboratory light source 5.1.1 General Medium pressure mercury vapour lamps consist of a quartz burner filled with a mixture
34、 of gas and mercury where the discharge takes place, the burner being located in a borosilicate bulb. These lamps are available in different power categories. The radiation they emit consists of lines of variable intensity within the range from 250 nm to 800 nm. Irradiance at wavelengths shorter tha
35、n 290 nm is filtered out by the bulb. Therefore only lines at wavelength 297 nm, 302 nm, 313 nm, 334 nm, 365 nm, 391 nm, 405 nm, 436 nm, 492 nm, 547 nm and 579 nm remain. BS EN 16472:2014EN 16472:2014 (E) 7 A typical filtered spectrum of a medium pressure mercury vapour lamp is shown in Figure 1. Ke
36、y X wavelength, nm Y spectral irradiance, mWm-2nm-1Figure 1 Typical spectrum of a filtered medium pressure mercury vapour lamp The filtered light emitted by a medium pressure mercury-arc does not simulate full spectrum sunlight but can be used to investigate photochemical phenomena. The relevancy to
37、 outdoor data shall be carefully considered. The only requirement is a relevant control of the chemical change in the solid state under polychromatic light. Additional optical filters may be used for specific applications. Annex A provides information on additional filtering of lamp UV radiations. E
38、nsure the lamp has been pre-aged for 100 h prior to use, since the transmittance spectrum of borosilicate bulb may change significantly during this initial period. NOTE Commonly, the light output (intensity and wavelength) does not vary more than 20 % during the lifetime of the lamps (see 5.4 or 8.1
39、). 5.1.2 Spectral irradiance of medium pressure mercury vapour lamps The minimum and maximum levels of the relative spectral irradiance in the UV region are given in Table 1. BS EN 16472:2014EN 16472:2014 (E) 8 Table 1 Relative spectral irradiance of medium pressure mercury vapour lamps Spectral pas
40、sband ( = wavelength in nm) Relative spectral irradiance a b cMinimum % Maximum % 290 300 0,0 2,0 300 320 5,0 20,0 320 360 8,0 14,0 360 380 46,0 61,0 380 400 1,0 5,0 400 420 14,0 25,0 aThis table gives the irradiance in the given passband, expressed as a percentage of the total irradiance between 29
41、0 nm and 420 nm. To determine whether a mercury vapour lamp meets the requirements of this table, the spectral irradiance shall be measured from 250 nm to 420 nm. The total irradiance in each wavelength passband is then summed and divided by the total irradiance from 290 nm to 420 nm. bThe minimum a
42、nd maximum limits in this table are based on a round robin test performed by five laboratories on several lamps from three suppliers, by using different spectroradiometers. The spectroradiometers shall be calibrated and shall have a FWHM (full width at half maximum) resolution 2,5 nm. cThe minimum a
43、nd maximum columns will not necessarily sum to 100 % because they represent the minima and maxima for the measurement data used. For any individual spectral irradiance, the percentages calculated for the passbands in this table will sum to 100 %. For any individual mercury vapour lamp, the calculate
44、d percentage in each passband shall fall within the minimum and maximum limits given. Exposure results can be expected to differ if obtained using mercury-arc apparatus in which the spectral irradiances differ by as much as that allowed by the tolerances. Contact the manufacturer of the mercury vapo
45、ur apparatus for specific spectral irradiance data for the mercury vapour lamp and filters used. 5.1.3 Irradiance uniformity The irradiance at any position in the area used for specimen exposure shall be at least 80 % of the maximum irradiance. Requirements for periodic repositioning of specimens wh
46、en this requirement is not met are described in EN ISO 4892-1. NOTE For some materials of high reflectivity, high sensitivity to irradiance and temperature, periodic repositioning of specimens is recommended to ensure uniformity of exposures, even when the irradiance uniformity in the exposure area
47、is within the limits. 5.2 Test chamber The test chamber comprises a box the walls of which are made of a chemically inert material that will not affect test results and in which the following facilities may be located: a) light source(s), consisting of one or more medium pressure mercury vapour lamp
48、s; b) temperature measuring system that allows to control the temperature of a chosen test specimen; c) inlets and outlets to renew air in the test chamber; d) frame supporting the specimen holders (see 5.3). It is recommended to use a rotating frame carrying the specimen holders to improve the unif
49、ormity of the exposure. BS EN 16472:2014EN 16472:2014 (E) 9 5.3 Specimen holders Specimen holders and their supporting frames shall be made of a chemically inert material that will not affect test conditions and test specimens (for example non-oxidizing alloys of aluminium or stainless steel). The specimen holders shall have minimal influence on the temperature of the test specimens. If a backing is used, it may affect the results, as may any space between the backing and the test specimen, particularly with
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