1、Designation: D7132 05D7132 13Standard Test Method forDetermination of Retained Blowing Agent in ExtrudedPolystyrene Foam1This standard is issued under the fixed designation D7132; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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 Scope*1.1 This test method covers the determination of retained blowing agent in extruded polystyrene foam.1.2 T
3、his test method applies to organic blowing agents which lend themselves to a convenient analysis by gas chromatography.The method is not applicable to blowing agents such as nitrogen, carbon dioxide, or water.1.3 There is no similar or equivalent ISO standard. The values stated in SI units are to be
4、 regarded as standard. No other unitsof measurement are included in this standard.1.4 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 appropriate safety and health practices and t
5、o determine the applicability of regulatorylimitations prior to use.NOTE 1There is no known ISO equivalent to this standard.2. Summary of Test Method2.1 Polystyrene foams are made with a variety of blowing agents such as hydrocarbons, hydrofluorocarbons, ethers, ketones,and other volatile organic ch
6、emicals. A fraction of the blowing agent used in the manufacture of foam is retained in the product,some residing in the cell walls and some entrapped inside the cells. This test method is based on releasing the retained blowingagent by dissolving the polystyrene foam in a solvent, such as toluene,
7、and then analyzing the solution for its components by gaschromatography. An internal standard is used as a reference analyte and calibration of the gas chromatograph (GC) with standardsolutions allows conversion of the GC response to the amount of blowing agent retained in the foam matrix.3. Interfe
8、rences3.1 The gas chromatogram may has the potential to contain a signal(s) from the polymer matrix that interferes with the signal(s)from the blowing agent components. Test calibration solutions with and without the polymer matrix to rule out any interference.These calibration solutions shall conta
9、in about the same amount of dissolved resin as in the foam sample being analyzed.4. Apparatus4.1 Any GC equipped with a column suitable for resolving blowing agent components can be used. For is suitable for use. Forexample, if separating non-polar blowing agents, a column such as HP-1 100 % dimethy
10、l-polysiloxane with 530-m thick film and30-m length can be used. For is a reasonable selection. If separating polar blowing agents, a column such as HP-17 50 %dipheny/50 % dimethyl polysiloxane column with 530-m thick film and 30-m length can be used. is suitable. Typical operatingparameters for the
11、 GC are:Head pressure (kPa) 50Initial oven temperature (C) 50Initial hold time (min) 3.5Temperature program rate (C/min) 25Final temperature (C) 150Final hold time (min) 3Injector temperature (C) 250Detector temperature (C) 300Carrier gas HeCarrier gas flow rate (cm3/min) 301 This test method is und
12、er the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.Current edition approved July 1, 2005Nov. 1, 2013. Published August 2005November 2013. Originally approved in 2005. Last previous edition approved in 2005 as D7132 05.
13、DOI: 10.1520/D7132-05.10.1520/D7132-13.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 the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM
14、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 Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Bo
15、x C700, West Conshohocken, PA 19428-2959. United States1Injection sample size (L) 0.2NOTE 2An autosampler is not recommended as the transfer of a solution containing volatile components can lead to loss of the volatile analyte.4.2 Analytical balance with at least 150 g full scale and 0.1 mg resoluti
16、on.4.3 Instrument grade air supplied at 515 6 40 kPa, helium at 450 6 40 kPa, and hydrogen at 380 6 40 kPa.4.4 100-cm3 volumetric flasks.4.5 1-cm3 syringe with Chaney Adapter, and 10-cm3 gas tight syringe with Chaney Adapter.4.6 1-L syringe.4.7 I-Chem Tall 200 series Tall, wide mouth 125-cm3 sample
17、bottles with caps and teflon/silicon septa.4.8 30-cm3 serum vials with crimp on teflon/silicon septa.4.9 Rubber sleeve stoppers for volumetric flask.4.10 Septa for GC.4.11 Ice water bath.4.12 Weights to keep sample bottle submerged.4.13 Refrigerator for sample storage.4.14 Insulated mailing containe
18、rs with ice packs for shipping samples.5. Reagents and Materials5.1 Certified grade toluene with minimum purity of 99.8 mol%.5.2 Certified grade normal heptane with minimum purity of 99.8 mol%.5.3 Instrument grade standards for blowing agents to be analyzed.6. Hazards6.1 Some blowing agents are comp
19、ressed liquids or gases at room temperature. Appropriate care shall be taken when preparingcalibration solutions from such blowing agents.7. Sampling, Test Specimens, and Test Units7.1 Tare an I-Chem sample bottle with cap and septum. Cut a piece of foam using a sharp knife, transfer it immediately
20、to thesample bottle, and seal with cap and septum. Record the sample weight.NOTE 3The cutting action produces open cells and the blowing agent trapped in these cells is lost immediately. The sample size and shape shall besuch as to minimize the ratio of area of cut surfaces to total surface area. Th
21、e foam sample shall also be of dimensions such that it can easily be placedin the sample bottle without causing any break or tear in the sample. To establish the optimum sample size, make some preliminary measurements asa function of sample size/shape until a constant value of the retained blowing a
22、gent is obtained.7.2 Typically, the sample weight is 1 g.gram.7.3 Store the samples at about 4C, and analyze within a week.NOTE 4When samples need to be shipped, use an insulated container equipped with frozen ice packs. Shipping should be by overnight service.8. Internal Standard Preparation8.1 Aff
23、ix a Chaney adapter to the 10-cm3 syringe and calibrate the syringe in accordance with steps 8.1.1 8.1.3.8.1.1 Measure and record the weight of 100 cm3 of toluene in a 100-cm3 volumetric flask.8.1.2 Fill the 10-cm3 syringe from the flask using the Chaney adapter for volume control.8.1.3 Inject the t
24、oluene into a pre-weighed sample bottle. Weigh the bottle. The weight shall be 110 of the weight obtained instep 8.1.1 within 0.01 g.gram.8.2 Add about 90 cm3 of toluene to another 100-cm3 volumetric flask. Cap the flask with an unused rubber sleeve stopper.Remove any static and dry the outside of f
25、lask with an ionized air blower.8.3 Place the flask on the balance pan, allow it to stabilize, and tare the balance.NOTE 5The flask shall not cause the balance to respond before actually touching the balance pan.8.4 Inject 0.2 to 0.4 cm3 heptane into the flask and weigh to the nearest 0.1 mg (Wistd)
26、.8.5 Dilute to the mark with toluene. It is acceptable to retain this internal standard (ISTD) solution for 24 hours.9. Calibration9.1 Tare an empty 30-cm3 serum vial (with a septa and seal).D7132 1329.2 Fill the serum vial with toluene to about 90 % capacity. Affix the septa and seal. Obtain the we
27、ight of the toluene to 0.1 mg(W1).9.3 Tare the balance with the vial containing the toluene. Inject 1 to 2 g of blowing agent into the vial. Weigh the vial and recordthe weight to the nearest 0.1 mg (W2). This solution may is not to be retained for more than eight hours.NOTE 6See Annex A1 for inject
28、ing volatile or gaseous blowing agents.9.4 Using the calibrated syringe and the technique shown in Fig. 1, withdraw 10.0 cm3 of the ISTD solution and inject into atightly capped empty sample bottle.9.5 Place the sample bottle containing the ISTD on the balance and tare the bottle.9.6 Inject 0.2 to 1
29、.0 cm3 of the solution prepared in step 9.3 into the tared sample bottle and record weight of the solution added(W3).9.7 Place the bottle in the ice bath. Place a weight on the bottle so it will remain upright. Be sure that the water level is evenwith the shoulder of the bottle.9.8 The sample shall
30、remain in the water bath for a minimum of one hour to equilibrate. This calibration solution may is notto be retained for more than eight hours.9.9 The amount of internal standard (Wi) in the calibration solution is Wistd/10 and the amount of blowing agent (Wst) in thecalibration solution is:Wst5W23
31、W3W11W2(1)9.10 Inject 0.2 L of the calibration solution into the GC and calculate the response factor for the blowing agent using thefollowing formula:RF5Wi 3AstWst3Ai(2)where:Ai = peak area of the internal standardFIG. 1 Withdrawing Toluene SolutionD7132 133Ast = peak area of the blowing agent.9.11
32、 Repeat steps 9.4 9.10 with five different injection amounts of the solution from 9.3 (or Step 3 of Annex A1) to generatecalibration solutions bracketing the expected amount of blowing agent in about 1 g of foam sample. Use these solutions to establisha five-point calibration curve.9.12 Repeat steps
33、 9.1 9.11 for each blowing agent.10. Procedure10.1 Using the calibrated syringe and the technique shown in Fig. 1, withdraw 10.0 cm3 of the ISTD solution, and inject intothe bottle containing the foam sample. Shake the bottle to ensure that the entire sample is dissolved.10.2 If the sample weighs mo
34、re than 1.3 g, add toluene (not the ISTD solution) to reduce the concentration to about 10 %polystyrene.10.3 Place the bottle in the ice water bath. Place a weight on the bottle so it will remain upright. Be sure that the water levelis even with the shoulder of the bottle.10.4 Allow the bottle to eq
35、uilibrate in the water bath for a minimum of one hour, but not more than eight hours.10.5 Inject 0.2 L of the solution into the GC. Measure the area of the peak(s) corresponding to each blowing agent and convertthe areas into weight fraction(s) using the response factors determined in 9.10.NOTE 7Dep
36、ending on the sensitivity of the GC detector and the accuracy desired, dissolve the foam sample using 10 to 25 cm3 of the ISTD solutionin 10.1. It is imperative that if an amount of the ISTD solution other than 10 cm3 is used, then the same amount must be used in 9.4 and the calculationof Wi in 9.9
37、adjusted accordingly.11. Daily Quality Assurance11.1 Inject a sample of toluene from the container used to make the internal standard solution. No Normally, no peaks in theISTD or blowing agent peak region shouldshall be detected. If peaks greater than the detection limit are observed then injectano
38、ther aliquot. If contamination peaks are still observed, switch to a fresh bottle of toluene.11.2 Prepare and analyze a calibration solution according to Section 9. The result(s) must agree within 10 % of the expectedvalue or a new five-point calibration curve must be established.12. Precision and B
39、ias12.1 Table 1 summarizes results of ten extruded polystyrene foam samples from the same population tested for their isobutanecontent. Each sample was injected twice. The results reported in Table 1 are typical of the method described here. Multipleinjections of the same sample shall agree to 62.5
40、%. Multiple measurements from the same sample population shall agree to65 %. The practical limit of quantitation of this method is 0.05 wt%.13. Keywords13.1 blowing agent retention; gas chromatography; polystyrene foamANNEX(Mandatory Information)A1. VOLATILE BLOWING AGENT STANDARD PREPARATIONTABLE 1
41、 Test values and Repeatability Standard DeviationSample No. Injection 1 Injection 2 Average (wt %)1 1.703 1.700 1.7022 1.711 1.756 1.7343 1.696 1.704 1.7004 1.686 1.645 1.6665 1.687 1.669 1.6786 1.655 1.686 1.6717 1.673 1.711 1.6928 1.717 1.647 1.6829 1.643 1.663 1.65310 1.664 1.674 1.669average 1.6
42、85standard deviation 0.023D7132 134A1.1 Tare an empty 30-cm3 serum vial (with septa and seal).A1.2 Fill the serum vial with toluene to about 90 % capacity.Affix septa and seal. Record the weight of the toluene to 0.1 mg (W1).Tare the balance with the vial containing the toluene.A1.3 Open the blowing
43、 agent standard cylinder. Set theFIG. A1.1 Volatile Blowing Agent Standard PreparationD7132 135delivery pressure to 70 kPa. To ensure gas purity, purge the line for at least 30 seconds.A1.4 While the gas is flowing, insert the needle into the vial containing the toluene, as shown in Fig. A1.1, and i
44、nject 1 to 2 gof blowing agent. Weigh the vial and record weight to the nearest 0.1 mg (W2).A1.5 Proceed to 9.4.SUMMARY OF CHANGESCommittee D20 has identified the location of selected changes to this standard since the last issue (D7132 05) that may impact the use of this standard. (November 1, 2013
45、)(1) Edited standard for permissive language, removed in mandatory situations and moved non-mandatory options to notes.(2) Removed references to trade names in 4.1, 4.7, and 7.1(3) Updated ISO equivalency statement and moved to Note 1.(4) Revised 11.1 to: “Normally, no peaks in the ISTD or blowing a
46、gent peak region are detected. If peaks are observed”(5) Editorially added units of measurement statement in 1.3.ASTM 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 advi
47、sed that determination 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
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49、you feel that your comments 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). Permission rights to ph
