1、Designation: D789 18Standard Test Method forDetermination of Relative Viscosity of ConcentratedPolyamide (PA) Solutions1This 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 y
2、ear 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 determination of relativeviscosity as it applies to concentrated solutions of poly
3、amide(PA).1.2 This test method does not address measures of viscosityderived from measurements with dilute solutions.1.3 The values stated in SI units are to be regarded asstandard. The values given in brackets are for information only.1.4 This standard does not purport to address all of thesafety c
4、oncerns, 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 1This standard and ISO 307 address the same subject, buy t
5、hetechnical content is different.1.5 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 issued by the World Trade
6、Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D446 Specifications and Operating Instructions for GlassCapillary Kinematic ViscometersD883 Terminology Relating to PlasticsD2162 Practice for Basic Calibration of Master Viscometersand Viscosity Oil S
7、tandardsD6779 Classification System for and Basis of Specificationfor Polyamide Molding and Extrusion Materials (PA)E1953 Practice for Description of Thermal Analysis andRheology ApparatusE2975 Test Method for Calibration or Calibration Verifica-tion of Concentric Cylinder Rotational Viscometers2.2
8、ISO Standards:3ISO 307 Determination of Viscosity Number of Polyamidesin Dilute SolutionsISO 16396-1 PlasticsPolyamide (PA) moulding and extru-sion materialsPart 1: Designation system, marking ofproducts and basis for specificationsISO 17025 General Requirements for the Competence ofTesting and Cali
9、bration 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 for spe
10、cific 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 (which
11、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 Solvents used to prepare concentrated solutions for usein this test method are formic acid (9.2.6.1) and m-cresol(9.2.6.2).4.4 Solvents
12、used to prepare dilute solutions of variouspolyamides are designated in ASTM D6779, ISO 16396, andISO 307. These include: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).C
13、urrent edition approved June 15, 2018. Published July 2018. Originallyapproved in 1944. Last previous edition approved in 2015 as D789 - 15. DOI:10.1520/D0789-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
14、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, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyrig
15、ht ASTM International, 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 Internationa
16、l Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14.4.1 Formic AcidPA 6, PA 46, PA 66, PA 69, PA 610, PAMXD6 and corresponding copolyamides4.4.2 Sulfuric AcidPA6, PA46, PA66, PA69, PA610, PA612, PA MXD6 and corresponding copol
17、yamides4.4.3 m-cresolPA 612, PA1010, PA1012, PA 11, PA 12,PA1212, PA 11/12 copolymers, PA 6T/66, PA 6I/66, PA 6I/6T,PA 6T/6I/66, PA 6T/6I, PA 6I/6T/664.4.4 Phenol/1,1,2,2-tetrachloroethane (where legal)PA6T/66, PA 6I/66, PA 6I/6T, PA 6T/6I/66, PA 6T/6I, PA6I/6T/66, PA 6T/66, PA 6I/66, PA 6I/6T, PA 6
18、T/6I/66, PA6T/6I, PA 10T PA 6I/6T/66, PPA and copolyamides5. Test Specimen5.1 Test specimens for the various tests shall conform 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 give
19、srepeatability and reproducibility statistics for relative viscositytesting.7. Sampling7.1 The material shall be sampled statistically or the sampleshall come from a process that is in statistical control.7.2 Samples in many forms, such as molded powder,molded shapes, or re-grind are permitted. It i
20、s recommendedthat molded specimens be cut into smaller parts prior to testing.8. Conditioning8.1 Test ConditionsDo not remove samples from sealed,airtight containers until ready for testing.TEST METHOD9. Relative Viscosity9.1 GeneralDetermine the relative viscosity of the poly-amide polymer by ASTM
21、Ubbelohde (Suspended-Level)-typeviscometer. The ASTM Ubbelohde-type viscometer is thereference and referee method. Ostwald-type viscometers, pipetviscometer, and rotational viscometer are acceptable as analternative method.9.2 ASTM Ubbelohde (Suspended Level)-typeViscometerTo determine the viscosity
22、 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 thepolyamide 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
23、.1 Constant-Temperature Liquid Bath, set to operate at25 6 0.1C.9.2.1.2 Precision Thermometer, calibrated, for use in theliquid bath (ASTMS45C (non-mercury), and ASTM 45C(mercury-filled). (WarningMercury has been designated bymany regulatory agencies as a hazardous material that cancause serious med
24、ical issues. Mercury, or its vapor, has beendemonstrated to be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product SafetyData Sheet (SDS) for additional information. Users should beaware that selling
25、mercury and/or mercury containing productsinto your state or country may be prohibited by law.)9.2.1.3 Ubbelohde (Suspended Level)-type Viscometer),calibrated, manufactured from low-expansion borosilicateglass.9.2.1.4 Ostwald-type Viscometer, calibrated, manufacturedfrom low-expansion borosilicate g
26、lass.9.2.1.5 Pipet Viscometer,4,5calibrated, manufactured fromlow expansion borosilicate glass.9.2.1.6 Pycnometer, calibrated, 50-mL.9.2.1.7 Automatic Pipet, calibrated, 100-mL.9.2.1.8 Suitable Containers, 250-mLor larger, made of inertmaterial such as heat-resistant glass.9.2.1.9 Shaking Machine.9.
27、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 substituted.9.2.2 Reagents and Materials:9.2.2.1 Acetone, commercial grade.9.2.2.2 Chromic Acid Cleaning SolutionDissolv
28、e sodiumdichromate Na2CrO72H2O, technical grade, in concentratedsulfuric acid (H2SO4, sp gr 1.84).9.2.2.3 m-Cresol,5,6having a viscosity of 12.83 cP at 25Cand a density of 1.029 6 0.0011 g/mL at 25C.9.2.2.4 Formic Acid (90 6 0.2 %)Clear, water-white.ACS-grade formic acid with the following additiona
29、l require-ments: Methyl formate content 0.2 % maximum; density1.1985 6 0.001 g/mL at 25C; viscosity 1.56 6 0.02 cP at25C.9.2.2.5 Standard Viscosity Oils7Use viscosity oils, S-3,S-20, K-50, S-60, and S-200, which have been certified by alaboratory that has been shown to meet the requirements ofISO 17
30、025 by independent assessment. The approximate kine-matic viscosities at 25C are 4.0, 35, 90, 120, and 480 cSt,respectively, and the certified viscosity reference standardsshall be traceable to master viscometer procedures described inPractice D2162.9.2.2.6 Stopcock Lubricant.5,89.2.2.7 Analytical B
31、alanceCapable of weighing 0.1 mg(four decimal place balance).4The 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, NJ07003.5If you are aware of alternative suppliers, please provide this information to
32、ASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.6The compound m-cresol is used with n-alkoxyalkyl polyamide 6:6 resinbecause formic acid tends to crosslink this polyamide. It is used with pol
33、yamide6:10 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 07073.7Suitable standard viscosity oils are available from a number of companies.8The sole source of supply of “Cello-
34、Grease” known to the committee at thistime is Fisher Scientific Co., 717 Forbes St., Pittsburgh, PA 15219.D789 1829.2.3 Calibration of ASTM Ubbelohde (suspended level)-type viscometer (note that a kinetic energy correction factor isrequired on all flow times less than 200 seconds, refer to 7.2 ofSpe
35、cification D446)Size 1 type used to determine absoluteviscosity of formic acid. To determine the viscosity of thepolyamide solutions use the appropriate ASTM Ubbelohdeviscometer as defined in Specification D446, Fig. A2.1 for thepolyamide viscosity range.9.2.3.1 Add to the viscometer 10-18 mL of vis
36、cosity 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 minutes. Block off the air arm (not thecapillary) and apply air pressure to the large di
37、ameter (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 viscometer is wet. Again, force oil above theupper timing mark, and observe the time (
38、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 oilstandard at 25C as t3(S-3) or t100(N-100). Remove theviscometer from the bath, clean and dry the insi
39、de 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 ft3df3tf(1)where:f= absolute viscosity of formic acid, kPa s(106cP)ft= Size 1 visco
40、meter tube factor, mm2/s(cSt)/s = 3/t3df= density of formic acid at 25C, g/mL = 1.1985tf= 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= average efflux
41、 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 aligns with th
42、e 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 mark. Place
43、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 lower.Determ
44、ine 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 (2)where:f20= kinematic viscosity of S-20 oil, mm2/s (cST)/t20,f60= ki
45、nematic 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)Viscometer(Not
46、e 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 allow it t
47、o 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 thetime (to 0
48、.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 theabove proc
49、edure, using 10 mLof 90 % formic acid. Record theaverage efflux time as tf. Calculate the absolute viscosity of the90 % formic acid as follows:f5 ftdftf(3)where:f= absolute viscosity of formic acid, kPa s (106cP),ft= viscometer tube factor, mm2/s (cSt)/s = 3/t3,3= kinematic viscosity of Oil 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
