1、Designation: D5492 10D5492 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
2、 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 is to be used for determining the 25C xylene-soluble fraction of polypropylene homopolymers andcopolymer
3、s.1.2 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 determine the applicability of regulatorylimitations prior to use.NOTE 1This test
4、 method is technically equivalent to ISO 16152.1.2 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, health and environmental practices and determine the applica
5、bility ofregulatory limitations prior to use.NOTE 1This test method is technically equivalent to ISO 16152.1.3 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of Interna
6、tional Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D883 Terminology Relating to PlasticsD1600 Terminology for Abbreviated Terms Relating to PlasticsE456 Terminology Relating to Qual
7、ity and StatisticsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE2935 Practice for Conducting Equivalence Testing in Laboratory Applications2.2 ISO Standard:ISO 16152 PlasticsDetermination of Xylene Solubles of Polypropylene33. Terminology3.1 Defini
8、tions:3.1.1 For definitions of plastic terms see Terminology D883 and for abbreviations see Terminology D1600.3.2 Definitions of Terms Specific to This Standard:3.2.1 soluble-fraction (SS)the percentage of the polymer mass that does not precipitate out when the polymer solution iscooled from reflux
9、temperature to +25 6 0.5C and held at that temperature for a specified period of time.4. Summary of Test Method4.1 A weighed amount of sample is dissolved in xylene under reflux conditions. The solution is cooled under controlledconditions and maintained at a +25C equilibrium temperature so that the
10、 crystallization of the insoluble fraction takes place.When1 This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials.Current edition approved Aug. 1, 2010Aug. 1, 2017. Published September 2010Augu
11、st 2017. Originally approved in 1994. Last previous edition approved in 20062010as D5492 - 06.D5492 - 10. DOI: 10.1520/D5492-10.10.1520/D5492-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsv
12、olume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indic
13、ation of what changes have been made to 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 co
14、nsidered the official document.*A Summary 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 States1the solution is cooled the insoluble portion precipitates and is isolated by filtration. T
15、he xylene is evaporated from the filtrate,leaving the soluble fraction in the residue. The percentage of this fraction in the plastic is determined gravimetrically.5. Significance and Use5.1 The results of this test provide a relative measure of the total soluble fraction of polypropylene homopolyme
16、rs andcopolymers. The soluble fraction approximately correlates to the amorphous fraction in the polypropylene. Xylene is widely usedfor determining the soluble fraction in polypropylene as it is more specific to the atactic fraction than other solvents. Theconcentration of a soluble fraction obtain
17、ed with a specific solvent has been found to relate closely to the performancecharacteristics of a product in certain applications, for example film and fiber. Data obtained by one solvent and at one precipitationtime cannot be compared with data obtained by another solvent or precipitation time, re
18、spectively.6. Interferences6.1 It is possible that materials with solubilities similar to the soluble fraction, such as additives, can interfere with themeasurement of solubles. When present in concentrations that are judged to impart a significant error to the soluble-fraction data,the level of int
19、erference must be determined and corrections made.6.2 It is possible that small-particle fillers and pigments and insoluble gels present in the polymer can pass through the filterand cause errors in the measurement.6.3 The polymer flakes and spheres must be dried before testing to eliminate moisture
20、 that can influence the initial weight ofsample added to the flask.7. Apparatus7.1 Reflux-Condenser Apparatus, Reflux-Condenser Apparatus,minimum 400 mm,mL, with 24/40 glass joint.7.1.1 The use a teflon seal sleeve around the glass joint is an acceptable option provided it has been determined that c
21、omponentsfrom the sleeve or tape are not extracted by the xylene.7.1.2 The use of silicone greases or other greases shall be avoided.7.2 Flat- or Round-Bottom Boiling Flask, Flat-Bottom Boiling Flask,with one or two necks, minimum 400 mLwith 24/40 joint,Erlenmeyer flask, or flat-bottomed cylindrical
22、 bottle.7.3 Insulation Disk, Insulation Disk,made of fiberglass or rock wool.7.4 Electromagnetic Stirrer Unit, Electromagnetic Stirrer Unit,with temperature-controlled heating plate, thermostatted oil bath,or heater blockheater block, or heating mantle capable of maintaining 145 to 150C.7.5 Stirring
23、 Bar.Stirring Bar.7.6 Pipet, Pipet,Class A, 200 mL or equivalent.7.7 Pipet, Pipet,Class A, 100 mL or equivalent.7.8 Glass-Stoppered Volumetric Flask, Glass-Stoppered Volumetric Flask,250 mL.7.9 Thermostatically Controlled Water Bath, Thermostatically Controlled Water Bath,at +25 6 0.5C.7.10 Electrom
24、agnetic Stirrers.Electromagnetic Stirrers.7.11 Filter Paper, Filter Paper,fluted, Whatman No. 4, No. 541,4 or equivalent, at least 125 mm in diameter.7.12 Funnel, Funnel,60, or equivalent, at least 125 mm in diameter.7.13 Heated Vacuum Oven.Heated Vacuum Oven.7.14 Aluminum Aluminum Pans,or stainless
25、 300-mL capacity, steel pans or beaker at a minimum 125 mL capacity, but notlarger than 300 mL, with smooth sides or other suitable container of similar design.7.15 Temperature-Controlled Heating Plate.Temperature-Controlled Heating Plate.7.16 Analytical Balance, Analytical Balance,with minimum weig
26、hing sensitivity to 0.0001 g (a sensitivity of 0.00001 g ispreferred).7.17 Desiccator, Desiccator,containing appropriate desiccant.7.18 Timer, Timer,preferably with an alarm, in minutes.7.19 Oven, Oven,conventional forced air or gravity.4 The sole sources of supply (EU/U.S.) of the apparatus known t
27、o the committee at this time are Whatman Intl. Ltd., Maidstone, England or from Fisher Scientific, 711ForbesAve., Pittsburgh, PA15219. If you are aware of alternative suppliers, please provide this information toASTM International Headquarters.Your comments will receivecareful consideration at a mee
28、ting of the responsible technical committee,1 which you may attend.D5492 1728. Reagents8.1 Reagent-Grade Ortho-Xylene (o-Xylene)Reagent-Grade Ortho-Xylene (o-Xylene)Assay Assay gas chromatography(GC) = 98 % min; less than 2 % ethylbenzene as established by GC; evaporation residue at 140C less than 0
29、.002 g/100 mL;boiling point 144C.8.2 Reagent-Grade Para-Xylene (p-Xylene)Assay gas chromatography (GC) = 98 % min; less than 2 % ethyl-benzene asestablished by GC, evaporation residue at 140C less than 0.002 g/100 mL; boiling point 138C.NOTE 2Mixed xylene may be used within a laboratory if the ratio
30、 of para-xylene to ortho-xylene remains constant and the level of ethyl-benzeneis less than 2 %.8.3 Reagent grade ortho-xylene shall be used as the reference solvent whenever there is a dispute between laboratories on testresults, unless the laboratories agree otherwise.9. Reagent and Specimen Prepa
31、ration9.1 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 be added toprevent degradation. This addition is optional if previous testing ha
32、s 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) methane atan approximate concentration of 0.02 g/L of xylene have been found to be effective stabilizer
33、s. Agitate with a magnetic stirring bar and heat for aminimum of one hour at 80C to 90C to ensure the thorough mixing of the antioxidants and the xylene. This is a suitable heating temperature for BHT,which is highly volatile.9.1.2 Degas the xylene. Using nitrogen gas, purge the xylene for a minimum
34、 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 determine whether the xylene to be used contains significant amounts of evaporationresidue or foreign components. A solvent-blank test for residue shall be run on ev
35、ery new lot of xylene. Test and average thesolvent-blank results, for three aliquots per bottle 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 being opened, the determinationof the blank is not required.
36、If used more than three days after being opened, a solvent blank must be run.NOTE 5It is recommended that xylene be purchased in glass or glass-lined containers and of a size such that the xylene is used within three days,once opened. Containers of larger size may be used if the xylene is used up wi
37、thin a short period of time. The purpose of the short time period is to ensurepurity and minimize moisture pickup and other contaminants.9.2.3 Pipet 200 mL of unstabilized or stabilized xylene into a clean empty flask.9.2.4 Place a 125-mm diameter or larger No. 4 filter paper or equivalent in a 125-
38、mm diameter of larger funnel in a funnel rackover a 250-mL glass-stoppered flask.9.2.5 For each sample blank, pour the contents from the flask into a funnel and allow the filtrate to drip into a second flask.Continue the filtration until all the filtrate has been collected.9.2.6 Dry the aluminum or
39、stainless steel vessel (or other suitable container) for 30 min in an oven at 200C. Cool the pans ina desiccator until ready to use. For each sample weigh a clean, dry vessel on the analytical balance to the nearest 0.0001 g.9.2.7 With a Class A pipet, pipet a 100-mL aliquot of the filtered xylene i
40、nto the weighed vessel.9.2.8 Place the vessel on a temperature-controlled heating plate maintained at 145 to 150C.Allow the aliquot to obtain a rollingboil to prevent splashing. Blanket the pan with a slow stream of nitrogen. Continue heating the vessel until the residue in the dishis almost dry.9.2
41、.9 Place the vessel into a vacuum oven at 100 6 10C at a pressure less than 13-13.5 kPa for a known suitable time whereconstant weight is observed.9.2.10 Cool the vessel to room temperature in a desiccator for a minimum of 15 minutes and weigh the pan to the nearest 0.0001g. Calculate the average bl
42、ank-residual mass of the three determinations.9.3 Determine the Percent Soluble Fraction in the Polymer:9.3.1 Dry polypropylene reactor powder before analysis. If pellets or other large particles are used, drying is not necessaryunless it is known that they contain high levels of moisture. If necess
43、ary, 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. Cool the sample in a desiccator to prevent moisture pickup.NOTE 6For large pellets or other large particles where there is concern that the polymer sample will not dissolve in a reasonable ti
44、me frame, grindthe pellets or particles to an appropriate size to afford a faster dissolution. Avoid subjecting the sample to excessive mechanical shear, which can leadto an increase in residual solubles level. Ground material shall be dried as specified in 9.3.1.10. Procedure10.1 Preparation Weigh
45、out a sample in accordance with Table 1of the Xylene:. When the expected solubles level is unknownor referee testing between laboratories is being conducted, a 2.0 6 0.1 g sample shall be used, unless there is agreement betweenD5492 173the laboratories to use a different sample size. Determine the m
46、ass of the sample to the nearest 0.0001 g. Pour the sample into aflat-bottom boiling flask. Place a magnetic stirring bar in the flask.9.1.1 Stabilization of the xylene is not required.NOTE 3When testing non-stabilized polypropylene powders or spheres, antioxidants may be added to prevent degradatio
47、n. This addition is optionalif previous testing has 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) methane atan approximate concentration of 0.02 g/L of
48、 xylene have been found to be effective stabilizers. Agitate with a magnetic stirring bar and heat for aminimum of one hour at 80C to 90C to ensure the thorough mixing of the antioxidants and the xylene. This is a suitable heating temperature for BHT,which is highly volatile.9.1.2 Degas the xylene.
49、Using nitrogen gas, purge the xylene for a minimum of 1 h every 24 h.10.2 Table 1Determine the Level of Contamination in the Xylene (Solvent Blank): provides a choice of sample mass. Use thelargest sample mass possible to minimize variability of the test data, unless from prior experience it is known that thepolymer/xylene solution does not filter readily as in 10.15.9.2.1 The purpose of the solvent blank is to determine whether the xylene to be used contains significant amounts of evaporationresidue or foreign components. A solvent-blank test for
