1、Designation: D6341 14aD6341 16Standard Test Method forDetermination of the Linear Coefficient of ThermalExpansion of Plastic Lumber and Plastic Lumber ShapesBetween 30 and 140F (34.4 and 60C)1This standard is issued under the fixed designation D6341; the number immediately following the designation
2、indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers the determina
3、tion of the coefficient of linear thermal expansion for plastic lumber and plastic lumbershapes to two significant figures. The determination is made by taking measurements with a caliper at three discrete temperatures.At the test temperatures and under the stresses imposed, the plastic lumber shall
4、 have a negligible creep or elastic strain rate, orboth, insofar as these properties would significantly affect the accuracy of the measurements.1.1.1 This test method details the determination of the linear coefficient of thermal expansion of plastic lumber and plasticlumber shapes in their “as man
5、ufactured” form. As such, this is a test method for evaluating the properties of plastic lumber orshapes as a product and not a material property test method.1.2 The thermal expansion of plastic lumber and shapes is composed of a reversible component on which it is possible tosuperimpose changes in
6、length due to changes in moisture content, curing, loss of plasticizer or solvents, release of stresses, phasechanges, voids, inclusions, and other factors. This test method is intended to determine the coefficient of linear thermal expansionunder the exclusion of non-linear factors as far as possib
7、le. In general, it will not be possible to exclude the effect of these factorscompletely. For this reason, the test method can be expected to give a reasonable approximation but not necessarily precisedetermination of the linear coefficient of thermal expansion.1.3 Plastic lumber and plastic lumber
8、shapes are currently made predominately with recycled plastics where the product isnon-homogeneous in the cross-section. However, it is possible that this test method will also be applicable to similar manufacturedplastic products made from virgin resins or other plastic composite materials.1.4 The
9、values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are forinformation only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish
10、 appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE 1There is no known ISO equivalent to this standard.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD4065 Practice for Plastics: Dynamic Mechanical Prope
11、rties: Determination and Report of ProceduresD5033 Guide for Development of ASTM Standards Relating to Recycling and Use of Recycled Plastics (Withdrawn 2007)3D6117 Test Methods for Mechanical Fasteners in Plastic Lumber and ShapesE831 Test Method for Linear Thermal Expansion of Solid Materials by T
12、hermomechanical Analysis3. Terminology3.1 Definitions:1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.20 on Plastic Lumber.Current edition approved Aug. 1, 2014April 1, 2016. Published September 2014April 2016. Origi
13、nally approved in 1998. Last previous edition approved in 2014 asD6341 - 14.D6341 - 14a. DOI: 10.1520/D6341-14A.10.1520/D6341-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume informatio
14、n, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to
15、 the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summa
16、ry of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1 plastic lumber, na manufactured product made primarily from plastic materials (filled or unfilled), typically used as abuil
17、ding material for purposes similar to those of traditional lumber, which is usually rectangular in cross-section. (TerminologyD883)3.1.1.1 DiscussionPlastic lumber is typically supplied in sizes similar to those of traditional lumber board, timber and dimension lumber; howeverthe tolerances for plas
18、tic lumber and for traditional lumber are not necessarily the same. (Terminology D883)3.1.2 plastic lumber shape, na plastic lumber product which is generally not rectangular in cross-section.3.1.3 resin, na solid or pseudosolid organic material often of high molecular weight, which exhibits a tende
19、ncy to flow whensubjected to stress, usually has a softening or melting range, and usually fractures conchoidally. (Terminology D883)3.1.3.1 DiscussionIn a broad sense, the term is used to designate any polymer that is a basic material for plastics. (1982)3.2 Additional definitions of terms applying
20、 to this test method appear in Terminology D883 and Practice D5033.4. Summary of Test Method4.1 This test method is intended to provide a means of determining the coefficient of linear thermal expansion of plastic lumberand plastic lumber shapes, which have the potential to contain inclusions and vo
21、ids. This test method is a product test method, andnot a materials test method. Furthermore, this test method is not designed to provide more than two significant figures of accuracyin the result. The test method involves using solid, full cross-sectioned members (see Note 2), as manufactured, of ap
22、proximately12 in. (300 mm) in length. In view of the low thermal conductivity of these materials it is impractical to make dynamic temperaturevariations in a reasonable length of time. Therefore, measurements are taken on each sample after conditioning 48 h or more atthree discrete temperatures, 30,
23、 73.4, and 140F, 6 3.6F (34.4, 23, and 60C, 6 2C), no more than 1 min after removal fromthe temperature chamber. The measuring device used is a caliper capable of measuring to the nearest 0.001 in. (0.025 mm), andis utilized at ambient temperature.NOTE 2It is acceptable to evaluate hollow cross-sect
24、ion products with this test method provided it can be shown that negligible dimensional changesoccur in the prescribed measurement time interval.5. Significance and Use5.1 The coefficient of linear thermal expansion, , between temperatures T1 and T2 for a specimen whose length is L0 at thereference
25、temperature, is given by the following equation:5 1L0L2 2L1T2 2T15 1L0LT (1)Where L1 and L2 are the specimen lengths at temperatures T1 and T2, respectively. is, therefore, obtained by dividing the linearexpansion per unit length by the change in temperature.5.2 The nature of most plastics and the c
26、onstruction applications for which plastic lumber and plastic lumber shapes are used,make 30 to 140F (34.4 to 60C) a practical temperature range for linear thermal expansion measurements. Where testingoutside of this temperature range or when linear thermal expansion characteristics of a particular
27、plastic are not known throughthis temperature range, particular attention shall be paid to the factors mentioned in 1.2 and it is possible that special preliminaryinvestigations by thermo-mechanical analysis, such as what is prescribed in Practice D4065 for the location of transitiontemperatures, wi
28、ll be required, in order to avoid excessive error. If such a transition point is located, a separate coefficient ofexpansion for a temperature range below and above the transition point shall be determined. For specification and comparisonpurposes (provided it is known that no transition exists in t
29、his range), the range from 30 to 140F (34.4 to 60C) shall be used.(For reference, glass transition and melting point temperatures of typical resins used in plastic lumber products are given inAppendix X2 of this test method.)6. Apparatus6.1 Conditioning Chamber, capable of conditioning test specimen
30、s at temperatures in the range of 30 to 140F, 6 1.8F (34.4to 60C, 6 1C).6.2 Caliper, capable of measuring the length of the specimen with an accuracy of 0.001 in. (0.025 mm). For a given test or testseries, the same caliper shall be used for all measurements. The calipers shall be kept and used at r
31、oom temperature (73.4F(23C).D6341 1626.3 Thermometer or Thermocouple, capable of an accuracy of 60.5F (60.3C) when measuring the temperature of theconditioning chamber.7. Test Specimen7.1 Test specimens for determining thermal expansion of plastic lumber and plastic lumber shapes shall be cut from t
32、he “asmanufactured” profile. Great care shall be taken in cutting and machining the ends so that smooth, flat, parallel surfaces and sharp,clean edges result and are parallel to within 1300 of the specimen length perpendicular to the long axis of the specimen. Plasticlumber is generally non-uniform
33、through the cross-section; machining operations other than those required to provide flat, parallelends shall not be carried out. A line parallel to the length shall be marked with an indelible ink marker on an uncut surface alongthe full length of the specimen. Length measurements of the sample are
34、 to be carried out on the surfaces adjacent to the drawnlines (on the cut faces) at each end of the specimen, at a location very near the ends of the line.7.2 The standard test specimen shall be in the form of a right cylinder or prism whose length is a minimum of 12 6 0.25 in.(300 6 6.4 mm) (see No
35、te 3).NOTE 3It is acceptable to utilize this test method to determine the linear coefficient of thermal expansion for other sample directions (that is, widthor thickness) if desired. However, the accuracy of the measurements will be significantly reduced due to the generally smaller linear dimension
36、8. Conditioning8.1 ConditioningCondition the test specimens at 30, 73.4, and 140F 6 3.6F (34.4, 23, and 60C 6 2C) for not less than48 h at each temperature prior to testing, unless otherwise specified by the customer or product specification. In cases ofdisagreement, the tolerance shall be 61.8F (6
37、1C).8.2 Test ConditionsConduct measurements in a laboratory atmosphere of 73.4 6 3.6F (23 6 2C), within 1 min or less afterremoval from the conditioning environment unless otherwise specified by the customer or product specification. In cases ofdisagreement, the tolerance shall be 61.8F (61C).NOTE 4
38、Experience indicates that the linear coefficient of thermal expansion of plastic lumber products is not affected by humidity.8.3 If products are tested for which the linear coefficient of thermal expansion is known or believed to be potentially affectedby humidity then humidity control settings shal
39、l be as agreed upon by the contractual parties.9. Number of Test Specimens9.1 A sample size of five shall be used. Each specimen shall be tested at each of the three measurement temperatures.10. Procedure10.1 Prepare and mark each specimen to be tested in accordance with 7.1 and 7.2. Condition the s
40、pecimens at 30 6 3.6F(34.4 6 2C) in accordance with 8.1.10.2 Measure the length of each of the conditioned specimens within 1 min of removal from the conditioning chamber at roomtemperature to the nearest 0.001 in. (0.025 mm) with the caliper (see 6.2 and Note 5). Record the actual conditioning temp
41、eratureto the nearest 0.2F (0.1C) to obtain T1, and the caliper reading. Average the caliper readings and report this value as L1.NOTE 5To minimize errors due to the formation of ice or condensation on the surface of specimens whose temperature is below the dew point, wipeoff the surfaces to be meas
42、ured with an absorbent cotton rag just prior to making the measurements.10.3 Repeat the steps described in 10.1 and 10.2 at a conditioning temperature of 73.4 6 3.6F (23 6 2C) to obtain T2 andL2.10.4 Repeat the steps described in 10.1 and 10.2 at a conditioning temperature of 140 6 3.6F (60 6 2C) to
43、 obtain T3 and L3.11. Calculation11.1 Calculate the coefficient of linear thermal expansion over the temperature range used as follows:5 1L2m (2)where: = coefficient of linear thermal expansion,L2 = length of test specimen at room temperature, 73.4 6 3.6F, andm = slope of the best fit line to the da
44、ta points (L1, T1), (L2, T2), (L3, T3), (representing L/T) determined by the least squarescriterion, and is given by:m 53(LiTi!2(Li!(Ti!3(Ti2!2(Ti!2 for I 51to 3 (3)D6341 163where:Li = the sample length at temperature, Ti.NOTE 6The following relationship will prove most useful to those designing wit
45、h these materials (an example calculation is provided in AppendixX3:L 5L0 T! (4)where: = Coefficient of linear thermal expansion in (in./in.)/F (cm/cm)/C),L = change in length of test specimen, in in. (cm) due to heating or to cooling,L0 = length of test specimen in in. (cm) at a reference temperatu
46、re, T0 (usually ambient temperature), andT = temperature difference, in F (C), over which the change in the length, L, of the specimen is measured.12. Report12.1 Report the following information:12.1.1 Complete identification of the material tested, including type, source, manufacturers code number,
47、 form, principaldimensions, and previous history,12.1.2 Laboratory name,12.1.3 Date of test,12.1.4 Method of preparing test specimens,12.1.5 Type of test specimen and dimensions,12.1.6 Conditioning procedure used, if non-standard conditioning has been employed,12.1.7 Atmospheric conditions in test r
48、oom, if non-standard conditioning has been employed,12.1.8 Measurement temperatures if other than or in addition to the temperatures specified in this test method,12.1.9 Number of specimens tested, and12.1.10 Average coefficient of linear thermal expansion for the specimens tested.13. Precision and
49、Bias13.1 RepeatabilityA 2014 study was undertaken by the Plastic Lumber Trade Association at PFS Laboratory (in CottageGrove, WI) to assess the repeatability of the determination of thermal expansion (in units of inches per inch per F), in accordancewith this test method.13.1.1 The study utilized five different commercial plastic lumber deck board materials, which will be identified as materialsA through E below.NOTE 7The materials used in this repeatability study were also used in
