1、Designation: D 1879 06Standard Practice forExposure of Adhesive Specimens to Ionizing Radiation1This standard is issued under the fixed designation D 1879; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 The purpose of this practice is to define conditions forthe exposure of polymeric adhesives in bonded specimens toionizing radiation
3、 prior to determination of radiation-inducedchanges in physical or chemical properties. This recommendedpractice specifically covers the following kinds of radiation:gamma or X-ray radiation, electron or beta radiation, neutrons,and mixtures of these such as reactor radiation.1.2 This practice speci
4、fies only the conditions of irradiationbut does not cover the preparation of test specimens, testingconditions, or the evaluation of test. These are covered in thevariousASTM methods or specifications for specific materials.1.3 This practice covers procedures for the following fivetypes of exposure:
5、Procedure AExposure at ambient conditions.Procedure BExposure at controlled temperature.Procedure CExposure in a medium other than air.Procedure DExposure under load.Procedure EExposure combining two or more of thevariables listed in Procedures A to D.NOTE 1The problems of measuring the properties o
6、f materials duringirradiation involve shielding and remote control facilities and are, there-fore, not considered in this practice.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are provided forinformation purposes only.1.5 This standard does not
7、 purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1.5.1 Electrical Hazard: WarningThe users
8、 of this prac-tice must be aware that there are inherent dangers associatedwith the use of electrical instrumentation and that this practicecannot and will not substitute for a practical knowledge of theinstrument used for a particular procedure.1.5.2 Radio Frequency: WarningPersons with pacemak-ers
9、 may be affected by the radio frequency.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 907 Terminology of AdhesivesD 1672 Practice for Exposure of Polymeric Materials toHigh-Energy Radiation3D 2953 Classification System for Polymeric Materials forSer
10、vice in Ionizing Radiation3E 170 Terminology Relating to Radiation Measurementsand DosimetryE 261 Practice for Determining Neutron Fluence, FluenceRate, and Spectra by Radioactivation TechniquesE 666 Practice for Calculating Absorbed Dose FromGamma or X RadiationE 720 Guide for Selection and Use of
11、Neutron Sensors forDetermining Neutron Spectra Employed in Radiation-Hardness Testing of ElectronicsE 2005 Guide for Benchmark Testing of Reactor Dosimetryin Standard and Reference Neutron Fields2.2 ISO/ASTM Standards:2ISO/ASTM 51261 Guide for Selection and Calibration ofDosimetry Systems for Radiat
12、ion ProcessingISO/ASTM 51649 Practice for Dosimetry in an ElectronBeam Facility for Radiation Processing at Energies Be-tween 300 keV and 25 MeVISO/ASTM 51702 Practice for Dosimetry in Gamma Irra-diation Facilities for Radiation ProcessingISO/ASTM 51818 Practice for Dosimetry in an ElectronBeam Faci
13、lity for Radiation Processing at Energies Be-tween 80 and 300 keV2.3 ANSI Document:N1.1 Glossary of Terms in Nuclear Science and Technol-ogy42.3 IEEE Documents:5278 Classifying Electrical Insulating Materials Exposed to1This practice is under the jurisdiction of ASTM Committee D14 on Adhesivesand is
14、 the direct responsibility of Subcommittee D14.80 on Metal BondingAdhesives.Current edition approved March 1, 2006. Published May 2006. Originallyapproved in 1961. Last previous edition approved in 1999 as D 1879 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM
15、 Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.5Available from Institute o
16、f Electrical and Electronics Engineers, Inc. (IEEE),445 Hoes Ln., P.O. Box 1331, Piscataway, NJ 08854-1331.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Neutron and Gamma Radiation323 Qualifying Class 1E Equipment for Nuclear Power
17、Generating Stations3. Terminology3.1 Many terms in this practice are defined in TerminologyD 907 and in Terminology E 170.3.2 gray, nthe unit of absorbed dose when the energy perunit mass imparted to matter by radiation is one joule perkilogram.3.3 rad, nthe unit of absorbed dose when the energy per
18、unit mass imparted to matter by radiation is 100 ergs per gram.NOTE 2To convert from rad to gray (Gy), multiply by 1.00 3 102.1rad = 0.01 gray and 1 megarad (MR) = 10 kilograys (kGy).4. Significance and Use4.1 The procedures outlined in this practice are designed tostandardize the exposure of adhesi
19、ve-bonded specimens for thepurpose of studying the effects of ionizing radiation, but havebeen made flexible enough so that a large variety of conditionsmay be met within the scope of this one irradiation method.Because of this flexibility in the procedures, it is important thatthe experimenter have
20、 some idea of the kind of changes thatwill occur, and of the conditions that will affect these changes.5. Effects of Irradiation5.1 Exposure to radiation can result in changes in mono-mers, oligomers and high polymers, which owe some of theirproperties to chemical links formed within molecular struc
21、-tures. These structures may be cross-linked by radiation intoinsoluble, three-dimensional networks, may be cleaved intosmaller molecules, or unaffected by radiation exposure.Crosslinking and cleavage or scission may occur at the sametime.5.2 One effect of the reaction of ionizing radiation withpoly
22、mers is the formation of free radicals, atoms containingunpaired electrons. In some instances, the rate at which freeradicals are formed may be much greater than their rate ofextinction. In a few instances, this can lead to trapped reactivespecies within the irradiated material and to the possibilit
23、y ofcontinuing reactions for days or weeks after the specimen hasbeen removed from the radiation field. Because of these limitedpost-irradiation reactions it has been found necessary tostandardize the times and conditions of storage betweenirradiation and testing of specimens.5.3 The resultant chang
24、es in the morphology of polymericmaterials caused by exposure to radiation can be dependent onthe respective rates of recombination, crosslinking, or cleavageof the material segments. These rates are affected by themobility of the excited atoms (free radicals or ionized) whichin turn is influenced b
25、y temperature and by the concentration ofthe excited or ionized atoms.5.4 The concentration of reactive species will vary with therate of absorption of radiation. Both radiation exposure or doseand dose-rate should be specified in reporting the results oftests. The effect of dose, dose-rate and spec
26、imen thickness cansometimes be observed when irradiations are carried out in air,that is in the presence of oxygen, wherein oxygen reacts withradicals produced in the irradiated material. This oxygenreaction is diffusion controlled. The reactivity of some irradi-ated specimens toward oxygen makes it
27、 necessary to specifywhether irradiations are carried out in air or in an inertatmosphere. The accessibility to an air supply undepleted inoxygen should be assured if possible.5.5 The localized concentration of reactive species duringirradiation will vary, depending on the type of radiationemployed.
28、 The proton and carbon recoils from neutron bom-bardment produce densely ionized tracks in the specimencompared to the diffuse ionization in the wake of protons orelectrons. The effect of different types of radiation maytherefore be different. It is required that the type of radiation towhich the sp
29、ecimen has been exposed be reported as well asthe irradiation dose in terms of energy absorbed units, that is,grays or kiloGrays (kGy).5.6 Various chemical structures respond differently on ex-posure to radiation. The exposure levels for testing should bebased upon the end-use of the bonded assembly
30、 and uponconsideration of the chemical structure of the adhesive mate-rial.Aromatic materials, such as polystyrene (PS), polycarbon-ates (PC) and polyethylene terephthalate (PET), tend to beunaffected, in terms of physical properties, by modest radiationexposure. Materials with an abstractable hydro
31、gen, such aspolyethylene (PE), will crosslink, with the radiation responsebeing very dependent on the specific morphology of a givengrade and its additives. Materials with tetra-substituted carbonatoms, such as polymethylmethacrylate (PMMA), polytet-rafluorothylene (PTFE) and polyvinylidene chloride
32、 (PVdC),will exhibit scissioning and generally a weakening of physicalproperties. The exposure levels or cumulative dose should bethose which will produce measurable changes in a stipulatedproperty rather than a specified fixed irradiation dose. Suchchanges in property may progress at different rate
33、s, with somematerials changing rapidly once a change has been initiated,while others may change quite slowly. It is necessary thereforeto irradiate to several fixed levels of property change in orderto establish the rate of change (see 13.2).5.7 Some materials that have been exposed to reactorradiat
34、ion in terms of neutron flux may become radioactive.These can be metallic and other inorganic adherends and fillers.For exact work, where the reactor spectrum is being studied,exposure in a reactor would give the only accurate results.6. Test Specimens6.1 Wherever possible, use the type of specimens
35、 in accor-dance with the ASTM test methods for the specific propertiesto be measured.6.2 Where it is not possible to utilize standard test speci-mens, make irradiated and non-irradiated specimens of thesame size and shape.6.3 Since organic adherends may be sensitive to radiation,they should be teste
36、d independently of the adhesive assemblyunder the same conditions, using irradiated and non-irradiatedadherend specimens.7. Conditioning7.1 Condition specimens to be exposed in air in accordancewith Procedure A of Practice D 618.D 1879 0627.2 Condition specimens to be exposed in a gas other thanair
37、at the temperature of exposure in an appropriate containerat a pressure of 10 Pa (103mm Hg) or less for at least 8 hfollowed by three flushes with the gas to be present duringexposure. After flushing, fill the container with the exposuregas and seal it.7.3 Condition specimens to be exposed in a vacu
38、um at thetemperature of exposure in an appropriate container at apressure of 10 Pa (103mm Hg) or less for at least 48 h. Thenseal the container from the vacuum system. Where increase inpressure due to outgassing may be undesirable or where theoutgassing products themselves may be undesirable, thevac
39、uum in the container may be maintained by pumpingcontinuously during the irradiation.7.4 Condition specimens to be exposed in a liquid mediumin accordance with 7.1 before placing in the liquid medium.Immerse the specimens completely in the liquid during theentire period of irradiation.7.5 Depending
40、upon the type and energy of radiation,inorganic adherends may have a shielding effect on theadhesive bond. Because of this position the specimens so thatthe shielding effect is uniform over all the adhesive layer.8. Procedure AExposure at Ambient Conditions8.1 After conditioning in accordance with 7
41、.1, expose thespecimens on suitable racks or in containers such that freeaccess to air is assured on all sides.8.2 When the radiation source requires that the specimensbe enclosed in a container, package the specimens in theStandard Laboratory Atmosphere (7.1).NOTE 3It is likely that the composition
42、 of the atmosphere in thecontainer will be changed by radiation-induced reactions. Therefore, itshould be clearly stated in the report that the irradiation was made in aclosed container.8.3 If irradiation is performed using a beam-emitting accel-erator, convey the specimens in some manner such that
43、theytraverse the radiation beam; hold the ratio of exposure time tonon-exposure time constant throughout this procedure. In theabsence of a conveyor type system, place the specimens in afixed position in the beam where it is known that thisirradiation dose will be uniform throughout the area andthic
44、kness of the specimen. Expose the specimens to only onetotal dose. For each new total dose, expose additional properlyconditioned specimens. Exposure in nuclear reactors or othersources having uniform radiation fields will not require tra-versing the radiation field.8.4 After the required period of
45、time, remove the specimensfrom the field and condition prior to test in the StandardLaboratory Atmosphere (7.1), for no less than 16 and no morethan 32 h, unless it is necessary to store the specimens forlonger periods of time because of radioactivity or otherreasons. Report the time and condition o
46、f such storage.8.5 Condition non-irradiated control specimens in accor-dance with 7.1 prior to test in the Standard LaboratoryAtmosphere.9. Procedure BExposure at Controlled Temperatures9.1 Follow the procedure outlined in 8.1 and 8.2.9.2 Irradiate the specimens as described in 8.3 at the desiredtem
47、perature. Place a dummy specimen containing a groundedthermocouple in the radiation field at the same conditions asthe test specimens to determine the temperature. If the tem-perature varies by more than 65C, it should be reported.9.3 Condition the specimens as outlined in 8.4.9.4 After conditioning
48、 in accordance with 7.1, expose non-irradiated control specimens to the same temperature employedin 9.2 for the same period of time as the irradiated specimens.9.5 After treatment, condition the control specimens alongwith the irradiated specimens in accordance with 7.1 prior totest.10. Procedure CE
49、xposure in Medium Other than Air10.1 After conditioning in accordance with 7.2, 7.3,or7.4,irradiate the specimens as described in 8.3.10.2 After removal from the medium, condition the speci-mens according to the procedure outlined in 8.4.10.3 The non-irradiated control specimens that have beenconditioned in accordance with 7.2, 7.3,or7.4 shall remain inthe selected medium for the same period of time as theirradiated specimens.10.4 After treatment, condition the control specimens alongwith the irradiated specimens in accordance with 8.4 prior totest.11. Procedure D
