NACE Standard TM0196-96Item No. 21226

StandardTest Method

Chemical Resistance of Polymeric Materialsby Periodic Evaluation

This NACE International standard represents a consensus of those individual members who havereviewed this document, its scope, and provisions. Its acceptance does not in any respectpreclude anyone, whether he has adopted the standard or not, from manufacturing, marketing,purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE International standard is to be construed as granting any right, byimplication or otherwise, to manufacture, sell, or use in connection with any method, apparatus,or product covered by Letters Patent, or as indemnifying or protecting anyone against liability forinfringement of Letters Patent. This standard represents minimum requirements and should in noway be interpreted as a restriction on the use of better procedures or materials. Neither is thisstandard intended to apply in all cases relating to the subject. Unpredictable circumstances maynegate the usefulness of this standard in specific instances. NACE International assumes noresponsibility for the interpretation or use of this standard by other parties and acceptsresponsibility for only those official NACE International interpretations issued by NACEInternational in accordance with its governing procedures and policies which preclude theissuance of interpretations by individual volunteers.

Users of this NACE International standard are responsible for reviewing appropriate health,safety, environmental, and regulatory documents and for determining their applicability in relationto this standard prior to its use. This NACE International standard may not necessarily addressall potential health and safety problems or environmental hazards associated with the use ofmaterials, equipment, and/or operations detailed or referred to within this standard. Users of thisNACE International standard are also responsible for establishing appropriate health, safety, andenvironmental protection practices, in consultation with appropriate regulatory authorities ifnecessary, to achieve compliance with any existing applicable regulatory requirements prior to theuse of this standard.

CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and maybe revised or withdrawn at any time without prior notice. NACE International requires that actionbe taken to reaffirm, revise, or withdraw this standard no later than five years from the date ofinitial publication. The user is cautioned to obtain the latest edition. Purchasers of NACEInternational standards may receive current information on all standards and other NACEInternational publications by contacting the NACE International Membership ServicesDepartment, P.O. Box 218340, Houston, Texas 77218-8340 (telephone +1 281/228-6200).

Approved 1996-03-30NACE InternationalP.O. Box 218340

Houston, TX 77218-8340+1 281/228-6200

ISBN No. 1-57590-009-2© 1996, NACE International

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Foreword

The prediction of performance of polymeric materials, in particular plastics (thermoplasticsand thermosets) and elastomers, is of great importance in selection of materials for serviceinvolving contact with any degrading environment. There is no “corrosion rate” similar to that formetals that allows fairly reliable extrapolation of data to a time when criteria would indicate failure.Therefore, chemical resistance testing of polymeric materials has involved long-term tests (up to12 months) and a great amount of uncertainty in prediction, even after long-term tests.

To date, long-term exposure tests have been recommended. These long-term tests haveproduced valuable and reliable results for common environments and for materials suppliers whohave an interest in providing confident recommendations for the chemical exposures tested. Infact, long-term tests are significantly more desirable for marginal materials, and often a marginalmaterial is an economical or more available selection. However, the materials engineer who mustselect a material for unusual fluids or mixtures of fluids does not often have time for long-termtests. There is a need for a more reliable short-term test.

This NACE standard test method is based on past exposure test methods, especially ASTM(1)

D 471,1 “Standard Test Method for Rubber Property—Effect of Liquids,” but has been modified inorder to increase the confidence of performance predictions and at the same time greatly reducethe test time required. Sequential observations and plotting of data with time allows earlierevaluation than other tests for materials that are patently unsatisfactory or acceptable. This testmethod involves exposure to the test environment followed by a drying (or desorption) period.This procedure allows the determination of final weight change after desorption of absorbedspecies; this may determine whether any leaching of components of the polymer has occurredduring exposure.

Examples of how this test method has been used to advantage were documented by Fisher2

and Niesse.3

This standard was prepared by NACE Task Group T-3L-19, a component of Unit CommitteeT-3L on Technologies for Corrosion Measurement, and is issued under the auspices of GroupCommittee T-3 on Corrosion Science and Technology.

(1) American Society for Testing and Materials (ASTM), 100 Barr Harbor Dr., West Conshohocken, PA 19428-2959.

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This standard represents a consensus of those individual members who have reviewed thisdocument, its scope, and provisions. Its acceptance does not in any respect preclude anyone,whether he has adopted the standard or not, from manufacturing, marketing, purchasing, or usingproducts, processes, or procedures not in conformance with this standard. Nothing contained inthis NACE International standard is to be construed as granting any right, by implication orotherwise, to manufacture, sell, or use in connection with any method, apparatus, or productcovered by Letters Patent, or as indemnifying or protecting anyone against liability forinfringement of Letters Patent. This standard represents minimum requirements and should in noway be interpreted as a restriction on the use of better procedures or materials.

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NACE InternationalStandard

Test Method

Chemical Resistance of Polymeric Materialsby Periodic Evaluation

Contents

1. General .................................................................................................................... 12. Test Material and Test Specimens ........................................................................... 13. Test Fluid................................................................................................................. 24. Test Procedure......................................................................................................... 35. Analysis of Data ....................................................................................................... 5References..................................................................................................................... 8

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Section 1: General

1.1 This standard for exposure testing of polymericmaterials gives detailed information on procedures forconducting the “sequential absorption and desorption”test. Limitations and cautions are identified. However,the criteria for prediction of performance are specific toeach application and are not addressed here except invery general terms.

1.2 The test procedures include (1) preparing andmeasuring test specimens; (2) preparing the test fluid asrequired; (3) exposing test specimens to the test fluid; (4)periodically removing the test specimens, measuringselected properties and evaluating the test specimens,and re-exposing the test specimens to the test fluid; (5)removing the test specimens from the test fluid when theimmersion exposure is completed and allowing them toequilibrate in air, preferably at the same temperature asthe exposure temperature; (6) periodically measuringselected properties in air and evaluating the test speci-mens; and (7) plotting the measured properties with time.

1.3 Polymeric materials of construction are generallymore variable and are not as codified or standardized asmetals. Therefore, the identification of the polymericmaterial tested is very important. Trade names andsources, as well as generic names, should be used. Dateof manufacture and the lot number of the polymericmaterial must be used for identification and futurereference. Plastic “blends” and “alloys” are becomingcommon, and specific formulation and trade names areessential.

1.4 This standard addresses absorption or penetration ofspecies into the body of the polymeric material. Adsorp-tion, or surface adherence of species, is not intended tobe part of this standard.

1.5 Although other types of degradation may be oc-curring simultaneously in these tests, this standardfocuses on absorption and desorption effects and maynot detect many other effects. For instance, somechemical attack requires months to become evident.

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Blistering of reinforced thermoset plastics (RTP) fromchemical attack is an example. Also, other propertiessuch as mechanical strength could be affected with littleor no absorption evident.

1.6 Stressed polymeric material may be more affectedby chemical attack than unstressed polymeric material. This standard does not preclude the use of devices tostress test specimens during this test provided the testcan be accomplished with these devices in place. Stresses may also cause environmental stress crackingwith susceptible polymeric materials in an appropriateenvironment. This standard does not directly apply to thedetermination of stress cracking resistance; other testmethods are available for this testing, such as ASTM D16934 or D 2951.5

1.7 Ultraviolet (UV) radiation, commonly from sunlight, isa known cause of degradation of many polymericmaterials. Although some effects of UV exposure aresimilar to those from chemical degradation, this standarddoes not address the degradation of polymeric materialsdue to UV exposure.

1.8 Adhesion of polymeric linings or coatings to sub-strates is a critical factor in evaluation of their perform-ance. This standard does not address the deterioration ofadhesion as a result of chemical exposure.

1.9 For most applications, this NACE periodic evaluationtest method is adequate. Excellent and poor materialscan be quickly identified and marginal materials can beidentified earlier than by other methods. However, forsome applications such as linings or containers (includingpipe) for fluids at elevated temperature, one-side testingshould be considered. There are many test methods forthis approach for pipe. For fiberglass-reinforced plastics(FRP) there is ASTM D 4398.6 A similar test is the “Atlascell” described in ASTM C 868.7 For applications atelevated temperature, the rationale is that permeation isincreased by a temperature gradient in the material.

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Section 2: Test Material and Test Specimens

2.1 The materials tested should be as similar to those tobe used as possible (see Paragraph 1.3). The ideal testmaterial is a sample from the stock to be used; at theleast, the same trade name or proven equivalent is arequirement. Polymeric materials typically have manyadditives that can affect chemical degradation and thatvary with lots even from the same manufacturer. Not

only should the chemical composition and molecularweight distribution of the material be the same, but themanufacturing process should also be the same. Forinstance, for a given polymeric material, an extrudedproduct may not have the same chemical resistance as amolded product. Test specimens should contain welds oradhesive joints if these are to be used in the application.

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2.2 The shape and size of the test specimen can varydepending on many factors. Although shapes may befixed by the application, e.g., o-rings come in one shape,the best data are obtained when sheet stock is used andthe thickness is much less than the width and length. This criterion effectively limits subsequent diffusion to onedirection—normal to the sheet surface. When comparingdifferent polymeric materials, the thicknesses of testspecimens should be similar because comparisons ofweight and the rate of weight change become difficult withvarying thicknesses. These shape recommendations al-low valid comparative data among various polymericmaterials.

2.2.1 Sheet stock may be cut to a convenient shape,even a tensile test shape if desired. The as-producedsurface, which may give different absorption resultsthan a machined surface that exposes the inside ofthe sheet, is a factor that should be considered intest specimen preparation. Absorption may be dif-ferent into edges compared with as-fabricated

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____________________________(2) Occupational Safety and Health Administration (OSHA), 200 Constitutio(3) U.S. Environmental Protection Agency (EPA), 401 M Street SW, Wash

surfaces; thin test specimens as recommendedabove minimize edge effects. Thus, machining athick part to achieve a desired thickness should beavoided.

2.2.2 Parts from equipment such as valve spools,molded parts, or o-rings may be tested directly. Thepart should be of a shape that can be easily dried bywiping, patting, or air blowing so that accuratesequential weight and other observations can bemade; parts with internal recesses or corners may bedifficult to dry adequately.

2.2.3 Fiberglass-reinforced plastic (FRP) test speci-mens should be constructed in accordance withASTM C 581,8 although test specimens smaller (butnot thinner) than specified in this standard are ofteneasier to use. All cut edges must be sealed with thesame resin as the test specimen in accordance withASTM C 581.

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Section 3: Test Fluid

3.1 For existing plant processes, the test specimensshould be exposed to the actual plant process equipmentwhenever feasible so that test conditions are as near toactual conditions as possible. For laboratory exposuretests, samples of the actual operating fluids are preferredfor use as the test fluid. Components of synthetic fluidsused for laboratory exposure tests must be rigorouslyquantified so that differences between the synthetic andactual process fluids are accurately known.

3.2 Noxious or toxic test fluids must be handled usingapproved safety procedures (including appropriate manu-facturers' safety data sheets [MSDS]) and equipment asspecified by the manufacturer, OSHA,(2) EPA,(3) and othergovernment environmental agencies.

3.3 The test fluid may contain low levels of active chem-icals that may be rapidly absorbed or decomposed. Pro-cess fluids transferred to a laboratory test container mayhave unsuspected low levels of these active components.If these situations are expected, then the test fluid mustbe replaced periodically to ensure exposure equivalent toservice conditions. If necessary, the test fluid must bereplaced daily. The interval between test fluid replace-ments depends on the conditions, the level of active com-ponents, and the expected or measured rate of absorption(use) or deterioration. For example, low levels of aroma-tic solvents in an aqueous test fluid may be absorbed

completely in a short time. A hypochlorite solution chem-ically decomposes over a period of time.

3.4 The amount of test fluid used in laboratory exposuretests may affect the time between replacement of the testfluid. If the test fluid is a single chemical such as puretoluene, then test fluid volume must be at least ten timesthe test specimen volume. For mixtures in which theactive component(s) are known to be more than 1% byweight, the volume of the test fluid must be 100 times thetotal test specimen volume. When the active compo-nent(s) are less than 1% by weight, caution is recom-mended. Increased test fluid volume must be consideredand replacement intervals shortened based on test speci-men weight increases. For instance, because test speci-men weight increases indicate absorption of an activecomponent, replacement intervals should be adjusted sothat no more than half the active component is everabsorbed. See Paragraph 4.16 for analysis to determinethe component and quantity absorbed. Note that volatilityof the active component must be considered, becausethis could reduce its concentration and thereby reduceeffects on the test specimen.

3.5 Periodic additions of proper amounts of activecomponents to the test fluid may be used to extendreplacement intervals. Using this approach, the level ofactive component in the test fluid decreases below andthen, upon addition, increases above the nominal level.

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This scheme requires analysis of the test fluid todetermine the initial level of the active component andadditional analyses to determine the rate of loss of thecomponent due to test specimen absorption. Theacceptable lower concentration at which additions shouldbe made and the amount to add to maintain the active

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component at an acceptable average level must then bedetermined. The process is difficult to control and mayresult in invalid results because the test fluid no longeracts like the process fluid. Nevertheless, under controlledconditions, periodic additions of the active component toa fluid can be (and have been) used successfully.

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Section 4: Test Procedure

4.1 Test specimens shall be immersed in or suspendedover the test fluid for vapor exposure as appropriate. Vapor exposures are strongly recommended to simulatevessel roofs and other areas above the operating fluid. The test container should be of a material that is inert tothe test fluid; glass, fluorocarbon, and stainless steel arematerials that have been used successfully. Test speci-mens should not touch the container or each other ifmultiple test specimens are exposed in the same con-tainer. Test specimen holder materials must be selectedto provide secure attachment and not affect results byinterference with the test specimen or by reaction with thetest fluid.

4.2 Test specimens of more than one test material maybe exposed in the same container if the test fluid is knownto be chemically benign, that is, if only physical absorp-tion or adsorption is expected. If leaching of a testmaterial component (e.g., a plasticizer) or chemicalattack occurs, the new component in the test fluid couldinfluence the behavior of other test materials. Theseinteractions could have a beneficial or adverse effect onthe performance of other test materials. In these casesindividual exposure in separate containers is recom-mended. If interaction chemistry is not known, the bestapproach is to use one test material in each container.

4.3 Replicate test specimens may be used to increasethe precision of the test results.

4.4 The test may be accelerated by a number of tech-niques. However, the use of these techniques is notrecommended unless the side effects are fully known. Some of these schemes are:

4.4.1 Increase test temperature. This techniquecould allow a new mechanism to become active;therefore, the test would no longer represent theapplication conditions. Also, if the test temperatureincrease passes through the glass transitiontemperature (Tg), the melting point (Tm), or othertransition of the test material, the test material couldact substantially differently.

4.4.2 Apply stress to the test specimen. This tech-nique is known to increase the rate of interactionbetween test fluid and test material and would bedifficult to relate to the application because thestresses in equipment are difficult to quantify.

However, the stress could cause environmentalstress cracking, a result that is very desirable toknow.

4.4.3 Agitate, stir, or use other methods to modifydiffusion rates in the test fluid. Excessive test fluidmotion could cause mechanical effects that wouldinvalidate the test results.

4.4.4 Increase the concentration of the absorbingspecies in the test fluid. This approach may be validif the absorbing species is known beforehand;however, careful monitoring is needed.

4.5 Care must be taken to prevent loss of test fluidduring the test. Test fluids with low volatility may becontained in sealed containers. When volatility is high,test temperature is high, or there are any other potentialcauses of increased pressure, test containers should befitted with an appropriate reflux condenser. If the appli-cation involves pressure, then testing in an autoclavemay be necessary; in this case, the effects of depres-surizing in order to inspect the test specimens should beconsidered.

4.6 For testing above ambient temperature, the testcontainer must be heated to and controlled at the desiredtest temperature by appropriate means. Ovens, heatedbaths, heating tapes, jackets, mantles, etc., can be used.Similarly, cooling techniques can be used for exposuresbelow ambient temperature. A test specimen exposed toair at the same temperature as the test temperature isrecommended to evaluate the effect of temperature aloneon the test specimen. If it is suspected that temperaturemay change the test fluid, a test with no test specimen isrecommended to evaluate the effect of the test temper-ature on the test fluid.

4.7 Before the test and periodically during exposure thetest specimens must be removed, surface dried, exam-ined visually, weighed and/or measured, and usuallyreturned to the test fluid. A geometric inspectionschedule with intervals of 1 day, 2 days, 4 days, 8 days,16 days, etc., is recommended. Time intervals frominitial immersion to the times the test specimen isremoved for inspection should be calculated and recordedto the nearest hour. It is important that the first inspec-tion after immersion be within one day or less becausethe initial rate of absorption may be very high, and the

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measurement made before exposure is sometimes erraticand does not fit with subsequent measurements. Nearthe end of immersion, sufficient observations must bemade so that the rate of change of the observedcharacteristic can be determined.

4.8 Removing excess test fluid from the test specimensurface for visual inspection or for weighing is sometimesdifficult, especially for elastomers. If the test specimenrequires rinsing to remove any deposits, the rinseprocedure should be as rapid as practical and should notaffect the test specimen itself. The surface should bewiped or patted as dry as practical with a clean cloth orwiping towel in order to obtain a valid weight. Blowing airgently into crevices can aid in removing test fluid. Allvisible test fluid should be removed. Pressing the testspecimen should be avoided, because this may forceabsorbed test fluid out and result in variable weightsbiased on the low side.

4.9 Procedures for each test specimen observation in atest series should be identical, for example: same timeout of the test fluid, same cleaning procedure, etc. Thetotal time from removal of the test specimen from the testfluid to reimmersion should not exceed 15 minutes,excluding the time the test specimen is sealed in aweighing bottle or some other container to minimizedesorption. If the test fluid is to be changed, the time forthis change should be as short as possible.

4.10 The immersion part of the test shall be consideredcomplete when one of the following conditions is met:

4.10.1 Properties of the test material changebeyond the acceptance criteria; this test materialshall be rejected.

4.10.2 Extrapolated properties are within theacceptance criteria. Acceptance criteria depend onthe application and must be set or approved by theuser. An example of a criterion for a general-purposeapplication is that extrapolated weight gain shall notexceed 10%.

4.11 After the immersion part of the test is complete,desorption must be done in order to evaluate the net lossor gain of weight. Desorption at the same temperature asimmersion is recommended. Desorption at elevatedtemperatures in a forced-air oven or at room temperatureon a bench top is acceptable. An unventilated oven mayprolong desorption time. Evaluations should be madeperiodically, starting one day or less after desorptionstarts. Because desorption usually occurs more rapidlythan absorption (especially when organics are desorbed),desorption is often complete in less than one week. Periodic measurements (every third day is usuallyadequate) should continue until the rate of weight loss islow, indicating that desorption is complete. Somespecies, such as salts, will not desorb and this will result

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in a net weight gain, but the rate of weight change shouldbe very low.

4.11.1 If the final weight (or any weight takenduring immersion) is less than the original weight bymore than one-half percent, the test material hasexperienced leaching, a condition of concern.

4.11.2 Caution should be used during desorptionbecause side effects might occur. Any weightincrease during desorption should be of concern andcause for further investigation. Examples of someside effects are:

4.11.2.1 During immersion, absorption of certainacids or alkalis into the test specimen maycause weight to increase on desorption becauseof reaction with air or absorption of additionalmoisture from the air. For instance, absorptionof strong sulfuric acid could result in furtherabsorption of moisture during the desorptionperiod.

4.11.2.2 Acids or alkalis could concentrate dur-ing desorption and cause physical or chemicaldegradation of the test specimen.

4.11.2.3 Desorption in areas of very high relativehumidity has resulted in additional absorption ofmoisture. In these cases desorption in a des-iccator may be necessary. If this is necessary,the sample should also be desiccated beforeimmersion.

4.12 Sequential inspections of the test specimens shouldinclude, but are not limited to:

4.12.1 Weight,

4.12.2 Dimensions,

4.12.3 Hardness. See ASTM D 22409 or ASTM D141510 for test methods for elastomers and ASTM D258311 or ASTM D 78512 for rigid plastics includingFRP, and

4.12.4 Appearance

4.12.4.1 Cracks, crazing (a pattern of surfacecracks);

4.12.4.2 Change of surface gloss, reflectance;

4.12.4.3 Etching (roughening of the surfacecausing a matte or textured surface finish);

4.12.4.4 Blisters;

4.12.4.5 Pitting;

4.12.4.6 Stickiness or other tactile change;

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4.12.4.7 Color changes;

4.12.4.8 Biodegradation (degradation from theeffect of microbes); and

4.12.4.9 Erosion.

4.13 Mechanical tests should be performed on testspecimens after the completion of the test or on testspecimens during the test. Multiple test specimens arerequired if destructive mechanical tests are performedbefore the end of sequential absorption testing.

4.13.1 Mechanical tests that may be performedare:

4.13.1.1 Tensile strength, modulus, and elong-ation. See ASTM D 63813 for test methods forplastics, ASTM D 41214 for elastomers, andASTM D 508315 for FRP materials.

4.13.1.2 Flexural strength and modulus. SeeASTM D 79016 for test methods for plastics.

4.13.1.3 Impact tests. See ASTM D 2463,17

ASTM D 302918 for falling dart test, and ASTM D244419 for pipe.

4.13.1.4 Tear resistance. See ASTM D 62420 orASTM D 1938.21

4.13.2 Often measurements of mechanical proper-ties in the exposed condition (“wet properties”) aredesired to evaluate the condition of the polymericmaterial in the process. In this case, propertiesshould be measured shortly after removal from thetest fluid. The time limit between removal and testingdepends on the specific situation. This time may beextended if the test specimen is sealed in a containerafter removal to minimize desorption. A guidelineupper time limit between removal and completion oftesting is 15 minutes.

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4.13.3 Test specimen size must be compatible withmechanical test requirements. Note that shapes forspecific mechanical tests may be generated on testspecimens before immersion, but edge effects areeliminated by generating these shapes from blanksafter the absorption/desorption tests.

4.13.4 Mechanical tests of unexposed test mater-ials should be conducted so that mechanical testresults of the exposed test specimens can becompared with original (unexposed) mechanical testresults.

4.14 The measurements of weight, dimension, or hard-ness changes are most useful, because these providenumerical data. The easiest and most accurate measure-ment is weight. Dimensions can also be measured and,though not usually as precise as weights, they may bevery useful for applications for which dimensional stabilityis a critical variable, such as valve spools. Changes inhardness may be significant for applications such asseals. Hardness changes may signal deterioration of thebasic polymer molecule.

4.15 Observations of the test fluid should also be madeand changes in color, turbidity, etc., should be noted. Samples of the test fluid may be taken initially andperiodically for analysis to determine which component ofthe test fluid is being absorbed, what component of thetest specimen is leaching, or to monitor test fluidcharacteristics such as pH, viscosity, etc.

4.16 The test material may be tested at any time todetermine the extent of change in the polymer moleculeas a result of exposure. Tests that can be performed areFourier transform infrared (FTIR), nuclear magnetic res-onance (NMR), or other appropriate test. Comparisonscan be made with the original, unexposed test material. Normally these tests should be performed on test speci-mens after completion of the immersion and desorptionexposures. If they are done during the absorption test,they interfere with the continuity of the test unless specialtest specimens are included for these tests.

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Section 5: Analysis of Data

5.1 Mathematical analysis and graphical presentation ofthe data are useful. Property data may be plotted versustime. Rates of change must be calculated to determinethe dynamics of the process and facilitate evaluation. Property changes should be normalized to the originalvalue and expressed as a percentage of change (gain orloss). The rate of weight change should be calculated. Samples of plots of property changes with time areshown in Figures 1 and 2. Another advantage of plottingis that scatter of data can be readily evaluated.

5.2 Note that comparisons of percentage weight changeamong different test materials are valid if the testspecimens have similar thicknesses. Low changessometimes indicate minimal effect; conversely, largechanges indicate excessive interaction between testspecimen and test fluid and predict failure. Moderateweight gains may be acceptable for some applications ifthe rate of gain has decreased to very low rates. Similarly, dimensional or growth measurements maypredict acceptable performance if the growth and the rateof growth are low enough to predict good performance tothe limit of desired life. Note, however, that there have

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and evaluation of many polymeric material characteristicsis recommended.

5.3 Because many applications involve structural orload-bearing capability, strength and modulus measure-ments may be desired. These should normally be madeafter completion of the test, but sometimes measure-ments of mechanical properties during or immediatelyafter immersion are desired.

been many cases of deterioration with low weight change,

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5.4 Some test fluids chemically attack polymers or rein-forcement materials. These effects may become evidentonly after some months of exposure. Therefore, detectionof some types of chemical degradation requires longexposure times. Exposure in chemically active fluids,such as acids, should be continued for long exposuretimes, up to one year, to evaluate possible chemicaleffects.

FIGURE 1Figure showing the progress of a sequential absorption test followed by desorption (drying) at the endof the absorption part of the test. Note that desorption which results in a net loss of weight indicates

leaching.

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FIGURE 2Absorption behaviors in a sequential absorption test

A. Absorption with decreasing rate. Acceptable depending on the criteria for the application intended.B. and C. Unacceptable—curves show both absorption and leaching.D. Unacceptable—excessive absorption and not sufficient decrease in rate of absorption.E. Excessive leaching—unacceptable.F. Excessive leaching—determined to be unacceptable early in the test.

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References

1. ASTM D 471 (latest revision), “Standard Test Methodfor Rubber Property—Effect of Liquids” (West Con-shohocken, PA: ASTM).

2. A.O. Fisher, “Sequential Test Method for ChemicalEvaluation of Nonmetallic Materials,” paper no. 29 inManaging Corrosion with Plastics, vol. VII (Houston, TX: NACE International, 1985).

3. J.E. Niesse, “Experience in Using a New ChemicalTest Method for Plastics and Elastomers,” COR-ROSION/94, paper no. 96 (Houston, TX: NACE, 1994).

4. ASTM D 1693 (latest revision), “Standard TestMethod for Environmental Stress-Cracking of EthylenePlastics” (West Conshohocken, PA: ASTM).

5. ASTM D 2951 (latest revision), “Standard TestMethod for Resistance of Types III and IV PolyethylenePlastics to Thermal Stress-Cracking” (West Consho-hocken, PA: ASTM).

6. ASTM D 4398 (latest revision), “Standard TestMethod for Determining the Chemical Resistance ofFiberglass-Reinforced Thermosetting Resins by One-SidePanel Exposure” (West Conshohocken, PA: ASTM).

7. ASTM C 868 (latest revision), “Standard Test Methodfor Chemical Resistance of Protective Linings” (WestConshohocken, PA: ASTM).

8. ASTM C 581 (latest revision), “Standard Practice forDetermining Chemical Resistance of ThermosettingResins Used in Glass-Fiber-Reinforced StructuresIntended for Liquid Service” (West Conshohocken, PA: ASTM).

9. ASTM D 2240 (latest revision), “Standard TestMethod for Rubber Property—Durometer Hardness”(West Conshohocken, PA: ASTM).

10. ASTM D 1415 (latest revision), “Standard TestMethod for Rubber Property—International Hardness”(West Conshohocken, PA: ASTM).

11. ASTM 2583 (latest revision), “Standard Test Methodfor Indentation Hardness of Rigid Plastics by Means of aBarcol Impressor” (West Conshohocken, PA: ASTM).

12. ASTM D 785 (latest revision), “Standard Test Methodfor Rockwell Hardness of Plastics and ElectricalInsulating Materials” (West Conshohocken, PA: ASTM).

13. ASTM D 638 (latest revision), “Standard Test Methodfor Tensile Properties of Plastics” (West Conshohocken,PA: ASTM).

14. ASTM D 412 (latest revision), “Standard TestMethods for Vulcanized Rubber and ThermoplasticRubbers and Thermoplastic Elastomers—Tension” (WestConshohocken, PA: ASTM).

15. ASTM D 5083 (latest revision), “Standard TestMethod for Tensile Properties of Reinforced Thermo-setting Plastics Using Straight-Sided Specimens” (WestConshohocken, PA: ASTM).

16. ASTM D 790 (latest revision), “Standard TestMethods for Flexural Properties of Unreinforced andReinforced Plastics and Electrical Insulating Materials”(West Conshohocken, PA: ASTM).

17. ASTM D 2463 (latest revision), “Standard TestMethod for Drop Impact Resistance of Blow-MoldedThermoplastic Containers” (West Conshohocken, PA: ASTM).

18. ASTM D 3029 (latest revision), “Standard TestMethods for Impact Resistance of Flat, Rigid PlasticSpecimens by Means of a Tup (Falling Weight)” (WestConshohocken, PA: ASTM).

19. ASTM D 2444 (latest revision), “Standard TestMethod for Impact Resistance of Thermoplastic Pipe andFittings by Means of a Tup (Falling Weight)” (WestConshohocken, PA: ASTM).

20. ASTM D 624 (latest revision), “Standard Test Methodfor Tear Strength of Conventional Vulcanized Rubber andThermoplastic Elastomers” (West Conshohocken, PA:ASTM).

21. ASTM D 1938 (latest revision), “Standard TestMethod for Tear-Propagation Resistance of Plastic Filmand Thin Sheeting by a Single-Tear Method” (WestConshohocken, PA: ASTM).

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