1、Designation: D789 071Standard Test Methods forDetermination of Solution Viscosities of Polyamide (PA)1, 2This 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 rev
2、ision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEAdded research report information to Section 10 editorially in September 2010.1. Scope*1.1 These test methods cover the determination
3、 of solutionviscosities as they apply to polyamide (PA).1.2 The values stated in SI units 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 theresponsibi
4、lity of the user of this standard to establish appro-priate safety and health practices 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:3D
5、446 Specifications and Operating Instructions for GlassCapillary Kinematic ViscometersD883 Terminology Relating to PlasticsD4000 Classification System for Specifying Plastic Materi-alsD6779 Classification System for Polyamide Molding andExtrusion Materials (PA)2.2 ISO Standards:4ISO 307 Determinatio
6、n of Viscosity Number of Polyamidesin Dilute SolutionsISO 17025 General Requirements for the Competence ofTesting and Calibration Laboratories3. Terminology3.1 DefinitionsThe definitions used in these test methodsare in accordance with Terminology D883.4. Significance and Use4.1 These test methods a
7、re intended for use as control andacceptance tests. They are also applicable in the partialevaluation of materials for specific end uses and as a means fordetecting changes in materials due to specific deterioratingcauses.4.2 Since some materials require special treatment, refer tothe ASTM test meth
8、ods applicable to the material being tested.Classification System D4000 lists materials that would beapplicable to the tests contained in these test methods.4.3 The steps involved in running this method are:4.3.1 Calibration of the viscometers,4.3.2 Preparation of solutions,4.3.3 Determination of ef
9、flux time,4.3.4 Calculation of relative viscosity (which requires thefollowing),4.3.4.1 Determining the density of the polymer/formic acidsolution, and4.3.4.2 Determining the absolute viscosity of the formicacid used.4.4 Viscosity for groups 03, 04, and 05 (PA11, PA12, andPA6,12) in Classification S
10、ystem D6779 shall be measuredusing solvents other than 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 pol
11、ymer dissolvedin 100 mLof m-cresol at 25.0 6 0.1C in 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 mL1This test me
12、thod is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.15 on Thermoplastic Materials(Section D20.15.09).Current edition approved Sept. 1, 2007. Published September 2007. Originallyapproved in 1944. Last previous edition approved in 2006 a
13、s D789 - 06a. DOI:10.1520/D0789-07E01.2There is no similar or equivalent ISO standard.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary
14、 page onthe ASTM website.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, U
15、nited States.5. 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 givesrepeatability and reproducibility statistics
16、 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 is recommendedthat molded specimens be cut int
17、o 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 nylonpolymer by ASTM Ubbelohde (Suspended-Level)-type vis-cometer. The A
18、STM Ubbelohde-type viscometer is the refer-ence and referee method. Ostwald-type viscometers, pipetviscometer, and rotational viscometer5, 6are acceptable as analternative method.9.2 ASTM Ubbelohde (Suspended Level)-typeViscometerTo determine the viscosity of formic acid use anASTM Ubbelohde viscome
19、ter 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:9.2.1.1 Constant-Temperature Liquid Bath, set to
20、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 byEPA and many state agencies as a hazardous material that cancause central nervous system, kidney and liver damage. Mer
21、-cury, or its vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional informati
22、on. Users should be aware that selling mercuryand/or mercury containing products into your state may beprohibited by state law.)9.2.1.3 Ubbelohde (Suspended Level)-type Viscometer),calibrated by an ISO 17025-accredited laboratory or in accor-dance with the procedure set out in 9.2.3 and manufactured
23、from 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 9.2.5 and manufactured from low-expansion borosilicate glass.9.2.1.5 Pipet Viscometer, calibrated by an ISO 17025-accredited laboratory
24、 or in accordance with the procedure setout in 9.2.4, 25 mL and manufactured from low expansionborosilicate glass.7, 69.2.1.6 Pycnometer, calibrated, 50-mL.9.2.1.7 Automatic 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 Bulb
25、s.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 SolutionDissolve sodiumdichromate
26、 Na2CrO72H2O, technical grade, in concentratedsulfuric acid (H2SO4, sp gr 1.84).9.2.2.3 m-Cresol,8, 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 additional require-ments:
27、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 OilsUse certified viscosityoils, which have been calibrated by a laboratory-accredited toISO 170259. S-3, S-20, K-50, S-60, and S-200. The approxi-mate kinematic viscosi
28、ties at 25C are 4.0, 35, 90, 120, and 480cSt, respectively.9.2.2.6 Stopcock Lubricant.10, 69.2.2.7 Analytical BalanceCapable of weighing 0.1 mg(four decimal place balance).9.2.3 Calibration of ASTM Ubbelohde (suspended level)-type viscometer (note that a kinetic energy correction factormay be requir
29、ed 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 determinenylon polymer-formic acid solutions.5The sole source of supply of the Brookfield viscometer known to the committeeat this time is
30、 Brookfield Engineering Laboratories, Inc., 240 Cushing St.,Stoughton, MA 02072.6If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which
31、you may attend.7The 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, NJ07003.8The compound m-cresol is used with n-alkoxyalkyl nylon 6:6 resin becauseformic acid tends to crosslink this nylon. It is us
32、ed with nylon 6:10 resin because ofthis nylons insolubility in formic acid. The sole source of supply of what is knownas No. 5072 is Matheson, Coleman, and Bell Co., East Rutherford, NJ 07073.9Suitable standard viscosity oils are available from a number of companies.10The sole source of supply of “C
33、ello-Grease” known to the committee at thistime is Fisher Scientific Co., 717 Forbes St., Pittsburgh, PA 15219.D789 07129.2.3.1 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 t
34、he 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 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
35、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 (to 0.2 seconds)required for the liquid to fall from the upper timing mark to thelower timing mark. Repeat until three successive values
36、 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 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 efflux
37、time as tf. Calculate the absolute viscosity of the 90 % formicacid as follows:hf5 ft3 df3 tf(2)where:hf= absolute viscosity of formic acid, kPa 3 s(E+6cP)ft= Size 1 viscometer tube factor, mm2/s(cSt)/s = h3/t3df= density of formic acid at 25C, g/mL = 1.1975tf= average efflux time for 90 % formic ac
38、id at 25C, sh3= kinematic viscosity of Oil S-3 mm2/s (cSt)h100= kinematic viscosity of Oil N-100, mm2/s (cSt)t3= average efflux time for oil S-3 at 25C, st100= average efflux time for oil N-100 at 25C, s9.2.4 Calibration of Pipet Viscometer(Note that a kineticenergy correction factor may be required
39、 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 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 a
40、t 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 a finger over the top of the pipet, andrelease the pressure by opening the system to air. Remove thefinger and allow pipet to
41、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.Determine the efflux time, t20, repeating until three successivevalues agree within 0.5 %, and record the average. Repeat theprocedu
42、re with Oil S-60 to obtain t60. Calculate the viscometertube factor as follows:tube factor 5 f201 f60!/2 (3)where:f20= kinematic viscosity of S-20 oil, mm2/s (cST)/t20,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 o
43、il, 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) Vis-cometer (Note that a kinetic energy correction factor may berequired on all flow times of less than 200 seconds, refer to 7.2of Specif
44、ication D446.)Add to the viscometer 10 mLof Oil S-3at approximately 25C from a volumetric pipet. Immerse theviscometer in the constant-temperature bath at 25 6 0.1C andallow it to remain at least 20 min. Apply air pressure to thelarge diameter leg by means of a rubber bulb until oil is abovethe uppe
45、r 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 0.2 s) required for the liquid to fall from the uppertiming mark to the lower timing mark. Repeat until threesuccessive va
46、lues 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 procedure, using 10 mL of 90 % formic acid. Record theaverage efflux time as tf. Calculate the absolute viscosity of the90 %
47、formic acid as follows:hf5 ftdftf(4)where:hf= absolute viscosity of formic acid, kPa s (E+6cP),ft= viscometer tube factor, mm2/s (cSt)/s = h3/t3,h3= 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=
48、 average efflux time for 90 % formic acid at 25C, s.9.2.6 Preparation of Solutions:9.2.6.1 Preparation of Nylon Polymer-Formic AcidSolutionsWeigh 11.00 g of nylon polymer into a clean, dry,250-mL, ground-glass stoppered Erlenmeyer flask (see Note2). Add, by means of the calibrated 100-mL automatic p
49、ipet,100 mL of 90 % formic acid at 25 6 1C. Slowly shake theflask while adding the acid to prevent the polymer fromforming a gelatinous mass. Set the flask in an oven 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).9.2.6.2 The procedure for the preparation of n-alkoxy-alkylnylon 6:6 and nylon 6:12 polymers in m-cresol is the same asfor
