ASTM D5492-17 Standard Test Method for Determination of Xylene Solubles in Propylene Plastics.pdf

1、Designation: D5492 17Standard Test Method forDetermination of Xylene Solubles in Propylene Plastics1This standard is issued under the fixed designation D5492; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio

2、n. 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 is to be used for determining the 25Cxylene-soluble fraction of polypropylene homopolymers andcopolymers.1.2 Thi

3、s 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, health and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE 1T

4、his test method is technically equivalent to ISO 16152.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issu

5、ed by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1600 Terminology forAbbreviated Terms Relating to Plas-ticsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an

6、 Interlaboratory Study toDetermine the Precision of a Test MethodE2935 Practice for Conducting Equivalence Testing inLaboratory Applications2.2 ISO Standard:ISO 16152 PlasticsDetermination of Xylene Solubles ofPolypropylene33. Terminology3.1 Definitions:3.1.1 For definitions of plastic terms see Ter

7、minology D883and for abbreviations see Terminology D1600.3.2 Definitions of Terms Specific to This Standard:3.2.1 soluble-fraction (SS)the percentage of the polymermass that does not precipitate out when the polymer solution iscooled from reflux temperature to +25 6 0.5C and held at thattemperature

8、for a specified period of time.4. Summary of Test Method4.1 A weighed amount of sample is dissolved in xyleneunder reflux conditions. The solution is cooled under con-trolled conditions and maintained at a +25C equilibriumtemperature so that the crystallization of the insoluble fractiontakes place.

9、When the solution is cooled the insoluble portionprecipitates and is isolated by filtration. The xylene is evapo-rated from the filtrate, leaving the soluble fraction in theresidue. The percentage of this fraction in the plastic isdetermined gravimetrically.5. Significance and Use5.1 The results of

10、this test provide a relative measure of thetotal soluble fraction of polypropylene homopolymers andcopolymers. The soluble fraction approximately correlates tothe amorphous fraction in the polypropylene. Xylene is widelyused for determining the soluble fraction in polypropylene as itis more specific

11、 to the atactic fraction than other solvents. Theconcentration of a soluble fraction obtained with a specificsolvent has been found to relate closely to the performancecharacteristics of a product in certain applications, for examplefilm and fiber. Data obtained by one solvent and at oneprecipitatio

12、n time cannot be compared with data obtained byanother solvent or precipitation time, respectively.6. Interferences6.1 It is possible that materials with solubilities similar tothe soluble fraction, such as additives, can interfere with themeasurement of solubles. When present in concentrations that

13、are judged to impart a significant error to the soluble-fractiondata, the level of interference must be determined and correc-tions made.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materi-als.Cu

14、rrent edition approved Aug. 1, 2017. Published August 2017. Originallyapproved in 1994. Last previous edition approved in 2010 as D5492 - 10. DOI:10.1520/D5492-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book

15、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.*A Summary of Changes section appears at the end of this standardCopyright ASTM Internation

16、al, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides

17、 and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.16.2 It is possible that small-particle fillers and pigments andinsoluble gels present in the polymer can pass through the filterand cause errors in the measurement.6.3 The polymer flakes and sphe

18、res must be dried beforetesting to eliminate moisture that can influence the initialweight of sample added to the flask.7. Apparatus7.1 Reflux-Condenser Apparatus, minimum 400 mL, with24/40 glass joint.7.1.1 The use a teflon seal sleeve around the glass joint is anacceptable option provided it has b

19、een determined that com-ponents from the sleeve or tape are not extracted by the xylene.7.1.2 The use of silicone greases or other greases shall beavoided.7.2 Flat- or Round-Bottom Boiling Flask, with one or twonecks, minimum 400 mL with 24/40 joint, Erlenmeyer flask, orflat-bottomed cylindrical bot

20、tle.7.3 Insulation Disk, made of fiberglass or rock wool.7.4 Electromagnetic Stirrer Unit, with temperature-controlled heating plate, oil bath, heater block, or heatingmantle capable of maintaining 145 to 150C.7.5 Stirring Bar.7.6 Pipet, Class A, 200 mL or equivalent.7.7 Pipet, Class A, 100 mL or eq

21、uivalent.7.8 Glass-Stoppered Volumetric Flask, 250 mL.7.9 Thermostatically Controlled Water Bath, at +25 60.5C.7.10 Electromagnetic Stirrers.7.11 Filter Paper, fluted, Whatman No. 4, No. 541,4orequivalent, at least 125 mm in diameter.7.12 Funnel, 60, or equivalent, at least 125 mm in diam-eter.7.13

22、Heated Vacuum Oven.7.14 Aluminum or stainless steel pans or beaker at aminimum 125 mL capacity, but not larger than 300 mL, withsmooth sides or other suitable container of similar design.7.15 Temperature-Controlled Heating Plate.7.16 Analytical Balance, with minimum weighing sensitiv-ity to 0.0001 g

23、 (a sensitivity of 0.00001 g is preferred).7.17 Desiccator, containing appropriate desiccant.7.18 Timer, preferably with an alarm, in minutes.7.19 Oven, conventional forced air or gravity.8. Reagents8.1 Reagent-Grade Ortho-Xylene (o-Xylene)Assay gaschromatography (GC) = 98 % min; less than 2 % ethyl

24、benzeneas established by GC; evaporation residue at 140C less than0.002 g/100 mL; boiling point 144C.8.2 Reagent-Grade Para-Xylene (p-Xylene)Assay gaschromatography (GC) = 98 % min; less than 2 % ethyl-benzene as established by GC, evaporation residue at 140Cless than 0.002 g/100 mL; boiling point 1

25、38C.NOTE 2Mixed xylene may be used within a laboratory if the ratio ofpara-xylene to ortho-xylene remains constant and the level of ethyl-benzene is less than 2 %.8.3 Reagent grade ortho-xylene shall be used as the refer-ence solvent whenever there is a dispute between laboratorieson test results, u

26、nless the laboratories agree otherwise.9. Reagent and Specimen Preparation9.1 Preparation of the Xylene:9.1.1 Stabilization of the xylene is not required.NOTE 3When testing non-stabilized polypropylene powders, (that is,unstabilized reactor products) it is recommended that antioxidants beadded to pr

27、event degradation. This addition is optional if previous testinghas shown there is no significant change in xylene soluble level.NOTE 4Butylated hydroxyl toluene (BHT), 4,4 thiobis (6-tert-butyl-m-cresol), or tetrakis (3,5-di-tert-butyl-4-hydroxy-hydrocinnamate) meth-ane at an approximate concentrat

28、ion of 0.02 g/L of xylene have beenfound to be effective stabilizers. Agitate with a magnetic stirring bar andheat for a minimum of one hour at 80C to 90C to ensure the thoroughmixing of the antioxidants and the xylene. This is a suitable heatingtemperature for BHT, which is highly volatile.9.1.2 De

29、gas the xylene. Using nitrogen gas, purge thexylene for a minimum of 1 h every 24 h.9.2 Determine the Level of Contamination in the Xylene(Solvent Blank):9.2.1 The purpose of the solvent blank is to determinewhether the xylene to be used contains significant amounts ofevaporation residue or foreign

30、components. A solvent-blanktest for residue shall be run on every new lot of xylene. Testand average the solvent-blank results, for three aliquots perbottle or lot of xylene. Each aliquot shall be 200 mL.9.2.2 If the xylene is an extra pure grade (minimum 99.5 %)and is used within three days after b

31、eing opened, the determi-nation of the blank is not required. If used more than three daysafter being opened, a solvent blank must be run.NOTE 5It is recommended that xylene be purchased in glass orglass-lined containers and of a size such that the xylene is used withinthree days, once opened. Conta

32、iners of larger size may be used if thexylene is used up within a short period of time. The purpose of the shorttime period is to ensure purity and minimize moisture pickup and othercontaminants.9.2.3 Pipet 200 mL of unstabilized or stabilized xylene intoa clean empty flask.9.2.4 Place a 125-mm diam

33、eter or larger No. 4 filter paperor equivalent in a 125-mm diameter of larger funnel in a funnelrack over a 250-mL glass-stoppered flask.9.2.5 For each sample blank, pour the contents from theflask into a funnel and allow the filtrate to drip into a secondflask. Continue the filtration until all the

34、 filtrate has beencollected.4The sole sources of supply (EU/U.S.) of the apparatus known to the committeeat this time are Whatman Intl. Ltd., Maidstone, England or from Fisher Scientific,711 Forbes Ave., Pittsburgh, PA 15219. If you are aware of alternative suppliers,please provide this information

35、to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.D5492 1729.2.6 Dry the aluminum or stainless steel vessel (or othersuitable container) for 30 min in an oven at 200C. Cool thepans in a desic

36、cator until ready to use. For each sample weigha clean, dry vessel on the analytical balance to the nearest0.0001 g.9.2.7 With a Class A pipet, pipet a 100-mL aliquot of thefiltered xylene into the weighed vessel.9.2.8 Place the vessel on a temperature-controlled heatingplate maintained at 145 to 15

37、0C. Allow the aliquot to obtaina rolling boil to prevent splashing. Blanket the pan with a slowstream of nitrogen. Continue heating the vessel until theresidue in the dish is almost dry.9.2.9 Place the vessel into a vacuum oven at 100 6 10C ata pressure less than 13-13.5 kPa for a known suitable tim

38、ewhere constant weight is observed.9.2.10 Cool the vessel to room temperature in a desiccatorfor a minimum of 15 minutes and weigh the pan to the nearest0.0001 g. Calculate the average blank-residual mass of thethree determinations.9.3 Determine the Percent Soluble Fraction in the Polymer:9.3.1 Dry

39、polypropylene reactor powder before analysis. Ifpellets or other large particles are used, drying is not necessaryunless it is known that they contain high levels of moisture. Ifnecessary, dry the samples in a vacuum oven at 70 6 5C, at apressure range of 13-13.5 kPa for a minimum of 20 min. Coolthe

40、 sample in a desiccator to prevent moisture pickup.NOTE 6For large pellets or other large particles where there is concernthat the polymer sample will not dissolve in a reasonable time frame, grindthe pellets or particles to an appropriate size to afford a faster dissolution.Avoid subjecting the sam

41、ple to excessive mechanical shear, which canlead to an increase in residual solubles level. Ground material shall bedried as specified in 9.3.1.10. Procedure10.1 Weigh out a sample in accordance with Table 1. Whenthe expected solubles level is unknown or referee testingbetween laboratories is being

42、conducted, a 2.0 6 0.1 g sampleshall be used, unless there is agreement between the laborato-ries to use a different sample size. Determine the mass of thesample to the nearest 0.0001 g. Pour the sample into aflat-bottom boiling flask. Place a magnetic stirring bar in theflask.10.2 Table 1 provides

43、a choice of sample mass. Use thelargest sample mass possible to minimize variability of the testdata, unless from prior experience it is known that thepolymer/xylene solution does not filter readily as in 10.15.10.3 Pipet 200 mL of unstabilized or stabilized xylene intothe flask.10.4 Attach the flas

44、k to the condenser.10.5 Place an insulation disk on top of the electromagneticstirrer plate to prevent localized heating of the flask. Positionthe flask and condenser system on top of the insulation disk(see Fig. 1, which shows a flat-bottom boiling and Erlenmeyerflask). Position the nitrogen inlet

45、tube in the top of thecondenser. Turn on the cooling water to the condenser.10.6 Blanket the contents of the boiling flask with a slowflow of nitrogen directed across the top of the condenser, notdirectly into the condenser, to minimize possible xylene loss.Nitrogen flow rate shall be approximately

46、2 L/h. Ensure thatnitrogen and water is flowing in the condenser with the aid ofbubblers or indicator devices to ensure flow.10.7 Heat the polymer/xylene mixture to reflux temperaturewhile vigorously stirring. The stirring shall be vigorous enoughto obtain a deep vortex, which keeps the boiling unde

47、r controland prevents boiling up into the condenser. Ensure that thereflux is gentle so that localized burning, splashing, andsticking of the polymer to the flask walls does not occur.10.8 Once the reflux temperature is reached, stir the solutionfor an additional 30 min. The liquid will appear water

48、-clear.NOTE 7For some polymers the total dissolution time can be longerthan 30 min for the liquid to appear water-clear.10.9 Remove the heating plate from beneath the flask.Detach the flask from the condenser and lightly stopper theflask. Cool the solution temperature from reflux temperature tobelow

49、 100C by cooling the flask in air for 12 to 14 min. ATABLE 1 Sample SizeExpected Solubles Initial Sample Mass, gA30.0 % by mass 2.0000 0.1000 or 1.0000 0.1000ASee 10.2.FIG. 1 Equipment SetupD5492 173timer, preferably with an alarm, must be used to ensure that thesolution is cooled to within a narrow range of temperature fromrun to run.10.10 Transfer the flask to a thermostatically controlledwater bath at 25 6 0.5C. Do not shake the flask to break upany precipitate before immersing the flask in the bath.10.11 The water bath shall have