1、Designation: D789 15Standard Test Methods forDetermination of Solution Viscosities of Polyamide (PA)1This standard is issued under the fixed designation D789; 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 These test methods cover the determination of solutionviscosities as they apply to polyamide (PA).1.2 The values stated in SI uni
3、ts are to be regarded asstandard. The values given in brackets are for information only.1.3 This 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 and health practices
4、 and determine the applica-bility of regulatory limitations prior to use.NOTE 1This standard and ISO 307 address the same subject, but thetechnical content is different.2. Referenced Documents2.1 ASTM Standards:2D446 Specifications and Operating Instructions for GlassCapillary Kinematic ViscometersD
5、883 Terminology Relating to PlasticsD6779 Classification System for and Basis of Specificationfor Polyamide Molding and Extrusion Materials (PA)2.2 ISO Standards:3ISO 307 Determination of Viscosity Number of Polyamidesin Dilute SolutionsISO 17025 General Requirements for the Competence ofTesting and
6、 Calibration Laboratories3. Terminology3.1 DefinitionsThe definitions used in these test methodsare in accordance with Terminology D883.4. Significance and Use4.1 These test methods are intended for use as control andacceptance tests. They are also applicable in the partialevaluation of materials fo
7、r specific end uses and as a means fordetecting changes in materials due to specific deterioratingcauses.4.2 The steps involved in running this method are:4.2.1 Calibration of the viscometers,4.2.2 Preparation of solutions,4.2.3 Determination of efflux time,4.2.4 Calculation of relative viscosity (w
8、hich requires thefollowing),4.2.4.1 Determining the density of the polymer/formic acidsolution, and4.2.4.2 Determining the absolute viscosity of the formicacid used.4.3 Viscosity for groups 03, 04, and 05 (PA11, PA12, andPA6,12) in Classification System D6779 shall be measuredusing solvents other th
9、an formic acid. Relative viscosities forGroups 03 and 04 shall be measured using 0.5 g of polymerdissolved in 99.5 g of m-cresol at 25.0 6 0.1C in aCannon-Fenske No. 200 viscometer. Inherent viscosity ofGroup 05 shall be measured using 0.5 g of polymer dissolvedin 100 mLof m-cresol at 25.0 6 0.1C in
10、 a Cannon-Fenske No.200 viscometer. The inherent viscosity is calculated as follows:Inherent viscosity 5lnts/tc!C(1)where:ts= average efflux time for sample solution,tc= average efflux time for solvent, andC = concentration in g/100 mL5. Test Specimen5.1 Test specimens for the various tests shall co
11、nform to therequirements prescribed herein.6. Number of Tests6.1 One determination shall be considered sufficient fortesting each molding powder batch or resin lot. Table 1 givesrepeatability and reproducibility statistics for relative viscositytesting.7. Sampling7.1 The material shall be sampled st
12、atistically or the sampleshall come from a process that is in statistical control.1This test method is under the jurisdiction ofASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials(Section D20.15.09).Current edition approved April 1, 2015.
13、Published May 2015. Originallyapproved in 1944. Last previous edition approved in 2007 as D789 - 071. DOI:10.1520/D0789-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, re
14、fer 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, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor
15、Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.2 Samples in many forms, such as molded powder,molded shapes, or re-grind are permitted. It is recommendedthat molded specimens be cut into smaller parts prior to testing.8. Conditioning8.1 Test ConditionsDo not remove samples fro
16、m sealed,airtight containers until ready for testing.TEST METHOD9. Relative Viscosity9.1 GeneralDetermine the relative viscosity of the poly-amide polymer by ASTM Ubbelohde (Suspended-Level)-typeviscometer. The ASTM Ubbelohde-type viscometer is thereference and referee method. Ostwald-type viscomete
17、rs, pipetviscometer, and rotational viscometer4,5are acceptable as analternative method.9.2 ASTM Ubbelohde (Suspended Level)-typeViscometerTo determine the viscosity of formic acid use anASTM Ubbelohde viscometer Size 1 with an inside diameter of0.58 mm 6 2 %. For use to determine the viscosity of t
18、hepolyamide solutions use the appropriate ASTM Ubbelohdeviscometer as defined in Specification D446, Fig. A2.1 for thepolyamide viscosity range.9.2.1 Apparatus:9.2.1.1 Constant-Temperature Liquid Bath, set to operate at25 6 0.1C.9.2.1.2 Precision Thermometer, calibrated, for use in theliquid bath (A
19、STMS45C (non-mercury), and ASTM 45C(mercury-filled). (WarningMercury has been designated bymany regulatory agencies as a hazardous material that cancause serious medical issues. Mercury, or its vapor, has beendemonstrated to be hazardous to health and corrosive tomaterials. Caution should be taken w
20、hen handling mercury andmercury containing products. See the applicable product SafetyData Sheet (SDS) for additional information. Users should beaware that selling mercury and/or mercury containing productsinto your state or country may be prohibited by law.)9.2.1.3 Ubbelohde (Suspended Level)-type
21、 Viscometer),calibrated by an ISO 17025-accredited laboratory or in accor-dance with the procedure set out in 9.2.3 and manufacturedfrom low-expansion borosilicate glass.9.2.1.4 Ostwald-type Viscometer, calibrated by anISO 17025-accredited laboratory or in accordance with theprocedure set out in 9.2
22、.5 and manufactured from low-expansion borosilicate glass.9.2.1.5 Pipet Viscometer,5,6calibrated by an ISO 17025-accredited laboratory or in accordance with the procedure setout in 9.2.4, 25 mL and manufactured from low expansionborosilicate glass.9.2.1.6 Pycnometer, calibrated, 50-mL.9.2.1.7 Automa
23、tic Pipet, calibrated, 100-mL.9.2.1.8 Erlenmeyer Flasks, 250-mL, heat-resistant glass.9.2.1.9 Shaking Machine.9.2.1.10 Rubber Bulbs.9.2.1.11 Timer, accurate to 0.2 s.9.2.1.12 With the exception of the pipet, Ostwald, andUbbelohde viscometers, apparatus capable of equivalent accu-racy may be substitu
24、ted.9.2.2 Reagents and Materials:9.2.2.1 Acetone, commercial grade.9.2.2.2 Chromic Acid Cleaning SolutionDissolve sodiumdichromate Na2CrO72H2O, technical grade, in concentratedsulfuric acid (H2SO4, sp gr 1.84).9.2.2.3 m-Cresol,5,7having a viscosity of 12.83 cP at 25Cand a density of 1.029 6 0.0011 g
25、/mL at 25C.9.2.2.4 Formic Acid (90 6 0.2 %)Clear, water-white.ACS-grade formic acid with the following additional require-ments: Methyl formate content 0.2 % maximum; density1.1985 6 0.001 gmL at 25C; viscosity 1.56 6 0.02 cP at25C.9.2.2.5 Standard Viscosity Oils8Use certified viscosityoils, which h
26、ave been calibrated by a laboratory-accredited toISO 17025. S-3, S-20, K-50, S-60, and S-200. The approxi-mate kinematic viscosities at 25C are 4.0, 35, 90, 120, and 480cSt, respectively.9.2.2.6 Stopcock Lubricant.5,99.2.2.7 Analytical BalanceCapable of weighing 0.1 mg(four decimal place balance).9.
27、2.3 Calibration of ASTM Ubbelohde (suspended level)-type viscometer (note that a kinetic energy correction factormay be required on all flow times less than 200 seconds, referto 7.2 of Specification D446)Size 1 type used to determineabsolute viscosity of formic acid. Size 3 type used to determinepol
28、yamide polymer-formic acid solutions.9.2.3.1 Add to the viscometer 10-18 mL of viscosity oilstandard from a volumetric pipet. Use S-3 for Size 1 viscom-eter and N-100 for Size 3 viscometers. Immerse the viscometerin the constant temperature bath at 25 6 0.02C and allow it toremain at least 20 minute
29、s. Block off the air arm (not thecapillary) and apply air pressure to the large diameter (filling)tube by means of a rubber bulb so that oil passes into thecapillary until oil is above the upper timing mark. Un-block theair arm and simultaneously allow the oil to flow down. Thisensures that the visc
30、ometer is wet. Again, force oil above theupper timing mark, and observe the time (to 0.2 seconds)required for the liquid to fall from the upper timing mark to thelower timing mark. Repeat until three successive values agreewithin 0.5 %, and record the average for the viscosity oil4The sole source of
31、 supply of the Brookfield viscometer known to the committeeat this time is Brookfield Engineering Laboratories, Inc., 240 Cushing St.,Stoughton, MA 02072.5If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful
32、consider-ation at a meeting of the responsible technical committee,1which you may attend.6The sole source of supply of the Drawing No. 66-1644 known to the committeeat this time is Scientific Glass Apparatus Co., 51 Ackerman St., Bloomfield, NJ07003.7The compound m-cresol is used with n-alkoxyalkyl
33、polyamide 6:6 resinbecause formic acid tends to crosslink this polyamide. It is used with polyamide6:10 resin because of this polyamides insolubility in formic acid. The sole sourceof supply of what is known as No. 5072 is Matheson, Coleman, and Bell Co., EastRutherford, NJ 07073.8Suitable standard
34、viscosity oils are available from a number of companies.9The sole source of supply of “Cello-Grease” known to the committee at thistime is Fisher Scientific Co., 717 Forbes St., Pittsburgh, PA 15219.D789 152standard at 25C as t3(S-3) or t100(N-100). Remove theviscometer from the bath, clean and dry
35、the inside surfacesthoroughly.9.2.3.2 Repeat the above procedure, using 10-18 mL of90 % formic acid in a Size 1 tube. Record the average effluxtime as tf. Calculate the absolute viscosity of the 90 % formicacid as follows:f5 ft3 df3 tf(2)where:f= absolute viscosity of formic acid, kPa s(E+6cP)ft= Si
36、ze 1 viscometer tube factor, mm2/s(cSt)/s = 3/t3df= density of formic acid at 25C, g/mL = 1.1975tf= average efflux time for 90 % formic acid at 25C, s3= kinematic viscosity of Oil S-3 mm2/s (cSt)100= kinematic viscosity of Oil N-100, mm2/s (cSt)t3= average efflux time for oil S-3 at 25C, st100= aver
37、age efflux time for oil N-100 at 25C, s9.2.4 Calibration of Pipet Viscometer(Note that a kineticenergy correction factor may be required on all flow times ofless than 200 seconds, refer to 7.2 of Specification D446.) UseOil S-20. Assemble the pipet viscometer so that the lowestmark on the pipet alig
38、ns with the 50-mL mark on the reservoirto the pipet. Place the assembly in the water bath adjusted to atemperature of 25 6 0.1C. After at least 20 min, apply airpressure to the reservoir or vacuum to the capillary, by meansof a rubber bulb, to drive the oil up into the pipet above theupper timing ma
39、rk. Place a finger over the top of the pipet, andrelease the pressure by opening the system to air. Remove thefinger and allow pipet to drain. Repeat at least three times towet the pipet thoroughly, and then record the time (to 0.2 s) forthe liquid level to fall from the upper timing level to the lo
40、wer.Determine the efflux time, t20, repeating until three successivevalues agree within 0.5 %, and record the average. Repeat theprocedure with Oil S-60 to obtain t60. Calculate the viscometertube factor as follows:tube factor 5 f201f60!/2 (3)where:f20= kinematic viscosity of S-20 oil, mm2/s (cST)/t
41、20,f60= kinematic viscosity of S-60 oil, mm2/s (cST)/t60,t20= average efflux time of S-20 oil, s, andt60= average efflux time of S-60 oil, s.This value shall be used in calculating the relative viscosityof a polymer solution, as shown in 9.2.8.9.2.5 Calibration of Ostwald (Cannon-Fenske Routine)Visc
42、ometer(Note that a kinetic energy correction factor maybe required on all flow times of less than 200 seconds, refer to7.2 of Specification D446.)Add to the viscometer 10 mLof OilS-3 at approximately 25C from a volumetric pipet. Immersethe viscometer in the constant-temperature bath at 25 6 0.1Cand
43、allow it to remain at least 20 min.Apply air pressure to thelarge diameter leg by means of a rubber bulb until oil is abovethe upper timing mark. Allow the oil to flow down. Repeatseveral times to ensure thorough wetting of the viscometer.Again, force oil above the upper timing mark, and observe the
44、time (to 0.2 s) required for the liquid to fall from the uppertiming mark to the lower timing mark. Repeat until threesuccessive values agree within 0.5 %, and record the averagefor Oil S-3 at 25C as t3. Remove the viscometer from the bath,clean and dry the inside surfaces thoroughly, and repeat the
45、above procedure, using 10 mLof 90 % formic acid. Record theaverage efflux time as tf. Calculate the absolute viscosity of the90 % formic acid as follows:f5 ftdftf(4)where:f= absolute viscosity of formic acid, kPa s (E+6cP),ft= viscometer tube factor, mm2/s (cSt)/s = 3/t3,3= kinematic viscosity of Oi
46、l S-3, mm2/s (cSt),t3= average efflux time for Oil S-3 at 25C, s,df= density of 90 % formic acid at 25C, g/mL, = 1.1975,andtf= average efflux time for 90 % formic acid at 25C, s.9.2.6 Preparation of Solutions:9.2.6.1 Preparation of Polyamide Polymer-Formic AcidSolutionsWeigh 11.00 g of polyamide pol
47、ymer into a clean,dry, 250-mL, ground-glass stoppered Erlenmeyer flask (seeNote 2). Add, by means of the calibrated 100-mL automaticpipet, 100 mL of 90 % formic acid at 25 6 1C. Slowly shakethe flask while adding the acid to prevent the polymer fromforming a gelatinous mass. Set the flask in an oven
48、 at 50C for15 min, if needed, to obtain complete solutions. Then putstopcock lubricant on the glass stopper, insert it tightly into theflask, and place the flask and contents on a shaking machine.Agitate until the solution is complete (see Note 3).NOTE 2It is best if the polymer contains less than 0
49、.28 % moisture. Ifit contains more than 0.28 %, the polymer can be dried. Normally, dryingat 70C in a vacuum for 4 to6hor90C for 20 min is adequate.NOTE 3Heating can be continued for a maximum of 2 h while shakingat a temperature not exceeding 50C.9.2.6.2 The procedure for the preparation of n-alkoxy-alkylpolyamide 6:6 and polyamide 6:12 polymers in m-cresol is thesame as for the preparation of formic acid solutions, except thatthe quantity of polyamide polymer shall be 9.44 g instead of11.00 g, and the m-cresol shall b
