1、Designation: F 484 02Standard Test Method forStress Crazing of Acrylic Plastics in Contact with Liquid orSemi-Liquid Compounds1This standard is issued under the fixed designation F 484; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method cove
3、rs determination of the crazingeffect that a liquid or semi-liquid test compound will have ontransparent acrylic plastic material that is under bending stress.1.2 Three types of acrylic material are covered. One, two, orall of the materials shall be used in the test, as specified by theprocuring age
4、ncy. When not specified otherwise, all three typesof acrylic shall be used in the test.1.3 This standard does not 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
5、and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water22.2 Military Standards:MIL-PRF-5425 Plastic Sheet, Acrylic, Heat Resistant3MIL-PRF-8184 Plastic Sheet, Acrylic, Modified3MIL-P-25690 Plastic, Sheet
6、s and Formed Parts, ModifiedAcrylic-Basic, Monolithic, Crack Propagation Resistant33. Terminology3.1 Definitions:3.1.1 crazea minute surface crack, sometimes hairline insize.NOTE 1Hairline craze cracks are very difficult to see except withcareful inspection under properly oriented light.3.1.2 cracka
7、 fracture or tear.4. Types4.1 Type A, cast acrylic material shall conform to MIL-PRF-5425, Finish A.4.2 Type B, cast acrylic material shall conform to MIL-PRF-8184, Finish B.4.3 Type C, stretched acrylic material shall conform toMIL-P-25690.5. Apparatus5.1 Stress ApparatusThe means of stressing the
8、acrylicplastic test specimen bars shall be as shown in Fig. 1.6. Test Specimens6.1 The test specimens shall be machined from 0.25 60.025 in. (6.4 6 0.64 mm) thick polished acrylic plastic sheetconforming to the applicable specification.6.2 The test specimens shall be 1 6 0.03 in. (25.4 6 0.8mm) wide
9、 by 7 6 0.05 in. (177.8 6 1.27 mm) long by 0.25 60.025 in. (6.4 6 0.64 mm) thick. Edges shall be a smoothmachined surface without cracks.7. Conditioning7.1 Do not anneal Type C acrylic specimens.7.2 Anneal Type A and Type B acrylic test specimens aftermachining by heating in a circulating air oven a
10、t 195 6 5F (916 3C) for 512 h. Cool the specimens to room temperature inthe oven using a uniform cooling rate of 50F (28C)/h.7.3 Condition all specimens at 75 6 10F and 50 6 5%relative humidity for a minimum of 24 h just before testing.8. Procedure8.1 Test two specimens of each acrylic material spec
11、ified foreach of the test compounds being evaluated.8.2 Conduct the test at a temperature of 75 6 10F (23 65C).8.3 Carefully load the acrylic specimen as a cantilever beamas shown in Fig. 1. Unless otherwise specified, the followingare recommended stress levels:8.3.1 Type A specimens shall be stress
12、ed to an outer fiberstress of 3000 psi (20 685 kPa).8.3.2 Type B specimens shall be stressed to an outer fiberstress of 3500 psi (24 132 kPa).8.3.3 Type C specimens shall be stressed to an outer fiberstress of 4500 psi (31 027 kPa).8.4 Allow the specimen to remain under the designated1This test meth
13、od is under the jurisdiction of ASTM Committee F07 onAerospace and Aircraft and is the direct responsibility of Subcommittee F07.07 onQualification Testing of Aircraft Cleaning Materials.Current edition approved May 10, 2002. Published July 2002. Originallypublished as F 484 77. Last previous editio
14、n F 484 83 (1998)e1.2Annual Book of ASTM Standards, Vol 11.01.3Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave., Philadelphia, PA 19111-5098, Attn: NPODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
15、 States.stress for 10 min; then examine under the lighting and visualinspection conditions shown in Fig. 1 to be sure no crazing hasinitiated. If crazing has occurred, substitute another acrylic testspecimen.8.5 With the test specimen again under the designated load,place an absorbent cotton or flan
16、nel swatch,12 to58 in. (12.7to 15.9 mm) square, on the tension surface (top) of the crazetest specimen directly over the fulcrum. Position the cotton orflannel swatch in the middle of the specimen so there is a clearspace along each edge to avoid initiating crazing at the edge.8.6 Completely soak th
17、e cotton or flannel swatch with thetest fluid or compound to be evaluated. Keep the swatch moistwith the test compound for the duration of the test. Take careto avoid spreading or smearing the test compound to the edgeof the test specimen. No test compound should contact theacrylic specimen within18
18、 in. (3.2 mm) of the edge.8.7 The test duration shall be 8 h. After test compoundexposures of 30 min, 1 h, 2 h, 4 h, and 8 h, inspect thespecimens for crazing or degradation. Do this by sliding themoist swatch approximately 2 in. toward the loaded end.Carefully wipe the test area clean. A clean clot
19、h wet withdistilled or deionized water conforming to SpecificationD 1193, Type IV water may be used to remove dry residue ifnecessary in the cleaning operation.8.8 Carefully examine the top (tension) surface of thespecimen in the manner shown in Fig. 1 for any evidence ofcrazing, cracks, or etching
20、effect on the polished surface of theacrylic test specimen.8.8.1 Use a single point source of concentrated columatedlight, such as a large-size microscopic illuminator, for inspec-tion.8.9 Disregard crazing that initiates at the edge of thespecimen unless it grows and extends across the specimen. In
21、this case, the time of the meeting of the crazing from the edgesshall be taken as the end point of the test. Terminate the test assoon as crazing or degradation is observed, even though thefull 8-h duration has not been reached.8.10 After each examination at the specified intervals duringthe 8-h per
22、iod, move the moist swatch back to its originalposition over the stress area and remoisten it with testcompound as required.9. Report9.1 The report shall include the following:9.1.1 Test compound evaluated,9.1.2 Type of acrylic craze test specimen used,9.1.3 Description of acrylic craze test surface
23、 after test; thatis, not affected, light crazing, cracked, rippled, stained, and9.1.4 Exposure time to craze or degrade surface, whenapplicable.10. Precision and Bias10.1 No statement is made about either precision or bias ofthis test method for measuring the crazing effect of thecandidate test liqu
24、id, on acrylic plastic, since the result merelystates that there is conformance to the criteria for success.Aerospace industry and multilocation laboratory use and ac-ceptance of this test method indicates a high degree ofrepeatability.11. Keywords11.1 acrylic plastics; hairline craze crack; liquid
25、com-pounds; outer fiber bending stress; stress crazingLoad: outer fiber stressouter fiber stressouter fiber stress3000 psi (20 685 kPa) Type A acrylic3500 psi (24 132 kPa) Type B acrylic4500 psi (31 027 kPa) Type C acrylicFormula:load, lb 5 w 3 t23stress in psi24load, g 5 w 3 t23stress in kPa5930whe
26、re:w = width of specimen in inches or millimetres to nearest 0.001 in. or 0.025 mm, respectively, andt = thickness of specimen in inches or millimetres to nearest 0.001 in. or 0.025 mm, respectively. Width and thickness shall be measuredat the stress area.Note: The fulcrum radius shall be14 in. (6.4
27、 mm) where it bears on the acrylic specimen.FIG. 1 Description of Stressing ProcedureF 4842ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination
28、 of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdraw
29、n. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your co
30、mments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).F 4843
