Designation:D789–07
Standard Test Methods for
Determination of Solution Viscosities of Polyamide(PA)1,2 This standard is issued under thefixed designation D789;the number immediately following the designation indicates the year of original adoption or,in the ca of revision,the year of last revision.A number in parenthes indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
1.Scope*
uniqueness
1.1The test methods cover the determination of solution viscosities as they apply to polyamide(PA).
1.2The values stated in SI units are to be regarded as standard.The values given in brackets are for information only.
1.3This standard does not purport to address all of the safety concerns,if any,associated with its u.It is the responsibility of the ur of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to u.
onair是什么意思N OTE1—This standard and ISO307address the same subject,but the technical content is different.
2.Referenced Documents
2.1ASTM Standards:3
D446Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers
D883Terminology Relating to Plastics
D4000Classification System for Specifying Plastic Mate-rials
D6779Classification System for Polyamide Molding and Extrusion Materials(PA)被增长
2.2ISO Standards:4
ISO307Determination of Viscosity Number of Polyamides in Dilute Solutions
ISO17025General Requirements for the Competence of Testing and Calibration Laboratories
3.Terminology
3.1Definitions—The definitions ud in the test methods are in accordance with Terminology D883.
4.Significance and U
4.1The test methods are intended for u as control and acceptance tests.They are also applicable in the partial evaluation of materials for specific end us and as a means for detecting changes in materials due to specific deteriorating caus.
4.2Since some materials require special treatment,refer to the ASTM test methods applicable to the
material being tested. Classification System D4000lists materials that would be applicable to the tests contained in the test methods.
4.3The steps involved in running this method are:
4.3.1Calibration of the viscometers,
4.3.2Preparation of solutions,
4.3.3Determination of efflux time,
4.3.4Calculation of relative viscosity(which requires the following),
4.3.4.1Determining the density of the polymer/formic acid solution,and
4.3.4.2Determining the absolute viscosity of the formic acid ud.
4.4Viscosity for groups03,04,and05(PA11,PA12,and PA6,12)in Classification System D6779shall be measured using solvents other than formic acid.Relative viscosities for Groups03and04shall be measured using0.5g of polymer dissolved in99.5g of m-cresol at2
5.060.1°C in a Cannon-Fenske No.200viscometer.Inherent viscosity of Group05shall be measured using0.5g of polymer dissolved in100mL of m-cresol at25.060.1°C in a Cannon-Fenske No. 200viscometer.The inherent viscosity is calculated as follows:
Inherent viscosity5
ln~t s/t c!
C(1) where:
t s=average efflux time for sample solution,
t c=average efflux time for solvent,and
C=concentration in g/100mL
5.Test Specimen
5.1Test specimens for the various tests shall conform to the requirements prescribed herein.
1This test method is under the jurisdiction of ASTM Committee D20on Plastics
and is the direct responsibility of Subcommittee D20.15on Thermoplastic Materials
(Section D20.15.09).
Current edition approved Sept.1,2007.Published September2007.Originally
approved in1944.Last previous edition approved in2006as D789-06a.
2There is no similar or equivalent ISO standard.
3For referenced ASTM standards,visit the ASTM website,www.astm,or
contact ASTM Customer Service at rvice@astm.For Annual Book of ASTM
Standards volume information,refer to the standard’s Document Summary page on
the ASTM website.reren
4Available from American National Standards Institute(ANSI),25W.43rd St.,
新东方图书网4th Floor,New York,NY10036.
*A Summary of Changes ction appears at the end of this standard. Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
6.Number of Tests
6.1One determination shall be considered sufficient for testing each molding powder batch or resin lot.Table1gives repeatability and reproducibility statistics for relative viscosity testing.
7.Sampling
7.1The material shall be sampled statistically or the sample shall come from a process that is in statistical control.
7.2Samples in many forms,such as molded powder, molded shapes,or re-grind are permitted.It is recommended that molded specimens be cut into smaller parts prior to testing.
8.Conditioning
8.1Test Conditions—Do not remove samples from aled, airtight containers until ready for testing.
TEST METHOD
9.Relative Viscosity
9.1General—Determine the relative viscosity of the nylon polymer by ASTM Ubbelohde(Suspended-Level)-type vis-cometer.The ASTM Ubbelohde-type viscometer is the refer-ence and referee method.Ostwald-type viscometers,pipet viscometer,and rotational viscometer5,6are acceptable as an alternative method.
9.2ASTM Ubbelohde(Suspended Level)-type Viscometer—To determine the viscosity of formic acid u an ASTM Ubbelohde viscometer Size1with an inside diameter of 0.58mm62%.For u to determine the viscosity of the polyamide solutions u the appropriate ASTM Ubbelohde viscometer as defined in Specification D446,Fig.A2.1for the polyamide viscosity range.
9.2.1Apparatus:
9.2.1.1Constant-Temperature Liquid Bath,t to operate at 2560.1°C.
9.2.1.2Precision Thermometer,calibrated,for u in the liquid bath(ASTMS45C(non-mercury),and ASTM45C (mercury-filled)).(Warning—Mercury has been designated by EPA and many state agenci
es as a hazardous material that can cau central nervous system,kidney and liver damage.Mer-cury,or its vapor,may be hazardous to health and corrosive to materials.Caution should be taken when handling mercury and mercury containing products.See the applicable product Ma-terial Safety Data Sheet(MSDS)for details and EPA’s website—v/mercury/faq.htm—for addi-tional information.Urs should be aware that lling mercury and/or mercury containing products into your state may be prohibited by state law.)
9.2.1.3Ubbelohde(Suspended Level)-type Viscometer), calibrated by an ISO17025-accredited laboratory or in accor-dance with the procedure t out in9.2.3and manufactured from low-expansion borosilicate glass.
9.2.1.4Ostwald-type Viscometer,calibrated by an ISO17025-accredited laboratory or in accordance with the procedure t out in9.2.5and manufactured from low-expansion borosilicate glass.
9.2.1.5Pipet Viscometer,calibrated by an ISO17025-accredited laboratory or in accordance with the procedure t out in9.2.4,25mL and manufactured from low expansion borosilicate glass.7,6
9.2.1.6Pycnometer,calibrated,50-mL.
9.2.1.7Automatic Pipet,calibrated,100-mL.
9.2.1.8Erlenmeyer Flasks,250-mL,heat-resistant glass. 9.2.1.9Shaking Machine.
9.2.1.10Rubber Bulbs.
9.2.1.11Timer,accurate to0.2s.
9.2.1.12With the exception of the pipet,Ostwald,and Ubbelohde viscometers,apparatus capable of equivalent accu-racy may be substituted.
9.2.2Reagents and Materials:
9.2.2.1Acetone,commercial grade.
9.2.2.2Chromic Acid Cleaning Solution—Dissolve sodium dichromate Na2CrO7·2H2O,technical grade,in concentrated sulfuric acid(H2SO4,sp gr1.84).
9.2.2.3m-Cresol,8,6having a viscosity of12.83cP at25°C and a density of1.02960.0011g/mL at25°C.
9.2.2.4Formic Acid(9060.2%)—Clear,water-white. ACS-grade formic acid with the following additional require-ments:Methyl formate content0.2%maximum;density 1.198560.001g/mL at25°C;viscosity1.56°60.02cP at 25°C.
9.2.2.5Standard Viscosity Oils—U certified viscosity oils,which have been calibrated by a laboratory-accredited to ISO170259.S-3,S-20,K-50,S-60,and S-200.The approxi-mate kinematic viscosities at25°C are4.0,35,90,120,and480 cSt,respectively.
9.2.2.6Stopcock Lubricant.10,6
9.2.2.7Analytical Balance—Capable of weighing0.1mg (four decimal place balance).
9.2.3Calibration of ASTM Ubbelohde(suspended level)-type viscometer(note that a kinetic energy correction factor may be required on allflow times less than200conds,refer to7.2of Specification D446)—Size1type ud to determine absolute viscosity of formic acid.Size3type ud to determine nylon polymer-formic acid solutions.
9.2.3.1Add to the viscometer10-18mL of viscosity oil standard from a volumetric pipet.U S-3for Size1viscom-eter and N-100for Size3viscometers.Immer the viscometer in the constant temperature bath at2560.02°C and allow it to
5The sole source of supply of the Brookfield viscometer known to the committee at this time is Brookfield Engineering Laboratories,Inc.,240Cushing St., Stoughton,MA02072.
6If you are aware of alternative suppliers,plea provide this information to ASTM International Headquarters.Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.
7The sole source of supply of the Drawing No.66-1644known to the committee at this time is Scientific Glass Apparatus Co.,51Ackerman St.,Bloomfield,NJ 07003.
8The compound m-cresol is ud with n-alkoxyalkyl nylon6:6resin becau formic acid tends to crosslink this nylon.It is ud with nylon6:10resin becau of this nylon’s insolubility in formic acid.The sole source of supply of what is known as No.5072is Matheson,Coleman,and Bell Co.,East Rutherford,NJ07073.
9Suitable standard viscosity oils are available from a number of companies.
10The sole source of supply of“Cello-Grea”known to the committee at this time is Fisher Scientific Co.,717Forbes St.,Pittsburgh,PA
15219.
remain at least20minutes.Block off the air arm(not the capillary)and apply air pressure to the large diameter(filling) tube by means of a rubber bulb so that oil pass into the capillary until oil is above the upper timing mark.Un-block the air arm and simultaneously allow the oil toflow down.This ensures that the viscometer is wet.Again,force oil above the upper timing mark,and obrve the time(to0.2conds) required for the liquid to fall from the upper timing mark to the lower timing mark.Repeat until three successive values agree within0.5%,and record the average for the viscosity oil standard at25°C as t3(S-3)or t100(N-100).Remove the viscometer from the bath,clean and dry the inside surfaces thoroughly.
9.2.3.2Repeat the above procedure,using10-18mL of 90%formic acid in a Size1tube.Record the average efflux time as t f.Calculate the absolute viscosity of the90%formic acid as follows:
东南大学自考专业h f5f t3d f3t f(2) where:
h f=absolute viscosity of formic acid,kPa3s(E+6cP) f t=Size1viscometer tube factor,mm2/s(cSt)/s=h3/t3 d f=density of formic acid at25°C,g/mL=1.1975
t f=average efflux time for90%formic acid at25°C,s h3=kinematic viscosity of Oil S-3mm2/s(cSt)
h100=kinematic viscosity of Oil N-100,mm2/s(cSt)
t3=average efflux time for oil S-3at25°C,s
t100=average efflux time for oil N-100at25°C,s
9.2.4Calibration of Pipet Viscometer—(Note that a kinetic energy correction factor may be required on allflow times of less than200conds,refer to7.2of Specification D446.)U Oil S-20.Asmble the pipet viscometer so that the lowest mark on the pipet aligns with the50-mL mark on the rervoir to the pipet.Place the asmbly in the water bath adjusted to a temperature of2560.1°C.After at least20min,apply air pressure to the rervoir or vacuum to the capillary,by means of a rubber bulb,to drive the oil up into the pipet above the upper timing mark.Place afinger over the top of the pipet,and relea the pressure by opening the system to air.Remove the finger and allow pipet to drain.Repeat at least three times to wet the pipet thoroughly,and then record the time(to0.2s)for the liquid level to fall from the upper timing level to the lower. Determine the efflux time,t20,repeating until three successive values agree within0.5%,and record the average.Repeat the procedure with Oil S-60to obtain t60.Calculate the viscometer tube factor as follows:
tube factor5~f201f60!/2(3) where:
f20=kinematic viscosity of S-20oil,mm2/s(cST)/t20,
f60=kinematic viscosity of S-60oil,mm2/s(cST)/t60,
t20=average efflux time of S-20oil,s,and
t60=average efflux time of S-60oil,s.
This value shall be ud in calculating the relative viscosity of a polymer solution,as shown in9.2.8.
prius
9.2.5Calibration of Ostwald(Cannon-Fenske Routine)Vis-cometer—(Note that a kinetic energy correction factor may be required on allflow times of less than200conds,refer to7.2 of Specification D446.)Add to the viscometer10mL of Oil S-3at approximately25°C from a volumetric pipet.Immer the viscometer in the constant-temperature bath at2560.1°C and allow it to remain at least20min.Apply air pressure to the large diameter leg by means of a rubber bulb until oil is above the upper timing mark.Allow the oil toflow down.Repeat veral times to ensure thorough wetting of the viscometer. Again,force oil above the upper timing mark,and obrve the time(to0.2s)required for the liquid to fall from the upper timing mark to the lower timing mark.Repeat until three successive values agree within0.5%,and record the average for Oil S-3at25°C as t3.Remove the viscometer fro
m the bath, clean and dry the inside surfaces thoroughly,and repeat the above procedure,using10mL of90%formic acid.Record the average efflux time as t f.Calculate the absolute viscosity of the 90%formic acid as follows:
h f5f t·d f·t f(4) where:
h f=absolute viscosity of formic acid,kPa·s(E+6cP),
f t=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-3at25°C,s,
d f=density of90%formic acid at25°C,g/mL,=1.1975,
and
t f=average efflux time for90%formic acid at25°C,s.
9.2.6Preparation of Solutions:
9.2.6.1Preparation of Nylon Polymer-Formic Acid Solutions—Weigh11.00g of nylon polymer into a clean,dry, 250-mL,ground-glass stoppered Erlenmeyerflask(e Note 2).Add,by means of the calibrated100-mL automatic pipet, 100mL of90%formic acid at2561°C.Slowly shake the flask while adding the acid to prevent the polymer from forming a gelatinous mass.Set theflask in an oven at50°C for 15min,if needed,to obtain complete solutions.Then put stopcock lubricant on the glass stopper,inrt it tightly into the flask,and place theflask and contents on a shaking machine. Agitate until the solution is complete(e Note3).
9.2.6.2The procedure for the preparation of n-alkoxy-alkyl nylon6:6and nylon6:12polymers in m-cresol is the same as for the preparation of formic acid solutions,except that the quantity of nylon polymer shall be9.44g instead of11.00g, and the m-cresol shall be specified as the solvent instead of formic acid.
N OTE2—The polymer should contain less than0.28%moisture.If it contains more than0.28%,the polymer should be dried.Normally,drying at70°C in a vacuum for4to6h or90°C for20min is adequate.
N OTE3—Heating may be continued for a maximum of2h while shaking at a temperature not exceeding50°C.
9.2.7Procedure—Pipet or pour10mL of the nylon polymer-formic acid solution into the viscometer.Determine the efflux time,t p,as described in9.2.3,9.2.4,or9.2.5.
9.2.8Calculation of Relative Viscosity—The relative vis-cosity,h r,is the ratio of the absolute viscosity of the polymer solution to that of the formic acid:
h r5~h p/h f!5~f t·d p·t p!/h f(5)
where:
d p=density of formic acid-polymer solution at25°C(e
9.2.9),and
t p=average efflux time for formic acid-polymer solution, s.
h f=absolute viscosity of formic acid,kPa3s(E+6cP)
f t=viscometer tube factor,mm2/s(cSt)/s=h3/t3 Calculate the relative viscosity of n-alkoxyalkyl nylon6:6 and nylon6:12resins usin
g m-cresol as the comparison ba, not formic acid.Substitution of proper constants in the calcu-lation formulas will then be necessary.
9.2.9Density of Nylon Polymer-Formic Acid Solution: 9.2.9.1Prepare the nylon polymer-formic acid solution as described in9.2.6.1.
N OTE4—Calibration of the pycnometer ud to determine density is made by repeating the procedure specified in9.2.9.2and9.2.9.3,using distilled water in place of the nylon polymer-formic acid solution.
9.2.9.2Weigh(to60.1mg)a clean,dry,calibrated50-mL pycnometer,andfill it with the nylon polymer-formic acid solution at a temperature slightly below(1to2°C)the test temperature.Stopper or cap the pycnometer,leaving the overflow orifice open.Take care to prevent the formation of bubbles in the pycnometer.Immer thefilled pycnometer(the neck of the pycnometer shall be above the water line)into a constant-temperature liquid bath,maintained at2560.1°C. Allow20to30min for temperature equilibrium to be reached.
9.2.9.3Remove the pycnometer from the liquid bath,and wipe away any overflow with paper towels or other absorbent material,taking care not to remove any subquent overflow that may be caud in this step.Dry the pycnometer thor-oughly,and weigh immediately(60.1mg).
9.2.9.4The density of the nylon polymer-formic acid solu-tion,in grams per cubic centimetre,is calculated by the following formulas:
d p5m p2m o
V(6)
and
V5m w2m o
d w(7)
where:
m p=mass of pycnometer and nylon polymer-formic acid solution,g,
m o=mass of empty pycnometer,g,撒切尔基因
V=volume of water at25°C,cm3,
m w=mass of pycnometer and water,g,and
my dream英语作文d w=density of water at25°C(0.9970),g/cm3.
9.3Brookfield Viscometer:
9.3.1Apparatus:
9.3.1.1Constant-Temperature Liquid Bath,t to operate at 2560.1°C.
9.3.1.2Precision Thermometer,calibrated,for u in liquid bath.
9.3.1.3Brookfield Synchro-Lectric Viscometer,Model LVF.
9.3.1.4Viscometer,Cannon-Fenske type,Size75,uncali-brated.
9.3.1.5Automatic Pipet,200-mL.
9.3.1.6Shaking Machine,reciprocating type.
9.3.1.7Stopwatch,having divisions of at least0.1s or0.01 min and accuracy of at least0.05%.
9.3.1.8Bottles,8-oz,round,wide-mouth with caps contain-ing polyethylene liners.
9.3.1.9With the exception of the Brookfield and Cannon-Fenske viscometers,apparatus capable of equivalent accuracy may be substituted.
9.3.2Reagents and Materials—Same as described in9.2.2.
9.3.3Analytical Balance—Same as described in9.2.2.7.
9.3.4Determination of Absolute Viscosity of Formic Acid: 9.3.4.1Add10.0mL(pipet)of9060.2%formic acid(at 25.060.5°C)to a Size75Cannon-Fenske viscometer.The viscometer is calibrated as described in9.3.4.3.Suspend the viscometer from the lid of the constant-temperature liquid bath in a vertical position so that the upper bulb is well immerd in the bath at2560.1°C.Allow20to30min for temperature equilibrium to be reached.Apply suction(bulb or vacuum)to the small leg of the viscometer and draw the liquid above the upper timing mark.Allow to drain.Repeat twice to ensure complete wetting of the tube.Obrve and record the time required for the meniscus of liquid to fall fr
om the upper timing mark to the lower timing mark.Repeat until three successive readings agree within0.5%.Average the results;record the efflux time as t f.
9.3.4.2Calculation of Absolute Viscosity for Formic Acid:
h f5f t·d f·t f(8) where:
h f=viscosity of formic acid,kPa·s(E+6cP),
f t=tube factor,mm2/s(cSt)/s(9.3.4.3),
d f=density of formic acid at2560.1°C,g/cm3=1.1975,
and
t f=efflux time of formic acid,s.
9.3.4.3Calibration of Viscometer,Cannon-Fenske,Size 75—Determine the efflux time of the standard viscosity Oil S-3,following the procedures of9.3.4.1.Record the efflux time as t.
f t5h d/t d(9) where:
f t=tube factor,mm2/s(cSt)/s,
h d=viscosity of S-3oil,mm2/s(cSt),and
t d=efflux time of S-3oil,s.
9.3.5Determination of Relative Viscosity of Nylon-Formic Acid Solutions:
9.3.5.1Using an automatic pipet,add200mL of 9060.2%formic acid to an8-oz screw-cap bottle with a metal cap,containing a polyethylene liner.Weigh2260.01g of nylon polymer and add to the formic acid in the8-oz bottle. (U care to avoid splashing formic acid out of the bottle.) Allowing the cap to remain loo,heat the mixture to 5065°C,using any convenient method.
9.3.5.2Tighten the cap thoroughly,and place the sample in the shaker.Agitate until all the nylon is in solution.Then place the bottle in a constant-temperature liquid bath maintained at 2560.1°C for not less than1h.
9.3.5.3Some nylons that dissolve slowly may be subject to time-temperature effects.To avoid possible degradation,mate-rials having relative viscosities above200should not
be
heated.The supplier’s recommended procedures for dissolving should be followed in such cas.
9.3.5.4Select the spindle and speed according to the ex-pected viscosity of the solution by using the following table:
Spindle Number for Indicated
Speed,r/min
RV BVs603012
5–619–1001
61–122100–2001
122–305200–50021 Where a choice of two spindles is given,it is more convenient to u the smaller-
numbered spindle and change the speed than to change spindles.U the same spindle and speed for similar viscosity level polymers.
9.3.5.5Immer the spindle and guard of the calibrated Brookfield viscometer and adjust to the immersion mark.(See 9.3.8for calibration of the Brookfield viscometer.)(The temperature of the spindle and guard shall be maintained at 2560.1°C by keeping them immerd in a bottle of water in the bath between us and wiping them dry before using.) 9.3.5.6Obrve the spindle to e if air bubbles are clinging to it.Remove adhering air bubbles by removing and replacing spindle,or with a wire(avoid scratching spindle).Level the instrument.(Tilt the No.1spindle while immersing it to prevent trapping air on the bottom of the spindle.)Depress the clutch and turn on the motor.(Depressing the clutchfirst prevents unnecessary wear.)Adjust the proper spindle speed. (Set the speed regulator when the instrument is in motion,not when stopped.)Relea the clutch and allow the spindle to rotate until the pointer stabilizes at afixed position on the dial. (This requires about30s for50RV;it may require veral minutes for200-RV materials.)Depress the clutch,and when the pointer comes into view,stop the motor.(If the pointer goes to the full-scale limit,reduce the speed stepwi until the pointer stays on scale.If the pointer goes to full-scale limit at the lowest speed,change to the next higher-numbered spindle.)
9.3.5.7Read the position of the pointer on the dial,estimat-ing to the nearest0.1scale division.Take one reading if the RV is reported to the nearest whole number.Take four readings if the RV is reported to the nearest0.1unit,and report the average.(If additional readings are required,start the motor with the clutch still depresd,holding the original reading,and then relea the clutch.This will speed up readings by reducing oscillation of the pointer.)
9.3.6Calculation of Brookfield Viscosity of Nylon-Formic Acid Solution:
BV s5~IR,20.4!3F for60r/min(10) BV s5~IR!3F for30r/min or12r/min(11) where:
IR=instrument reading,
BV s=Brookfield viscosity of the solution,cP,and
F=spindle factor from the following table:
Speed,r/min
Spindle123060 1521
225105
31004020
4500200100
9.3.7Calculation of Relative Viscosity of the Nylon-Formic Acid Solution:
RV5~h s/h f!5[~BV s·C f!/h f#(12) where:
R V=relative viscosity of the nylon-formic acid solution, h f=absolute viscosity of formic acid,9.3.4.2,contrasting
h s=absolute viscosity of nylon-formic acid solutions, BV s=Brookfield viscosity of the solution,kPa·s(cP)
(9.3.6),and
C f=calibration factor(the instruments should be cali-
brated periodically against standard viscosity oils;
e9.3.8).
9.3.8Calibration of Brookfield Viscometer:
9.3.8.1Select the standard viscosity oil clost or within 10%of the absolute viscosity level of the nylon-formic acid solution to be tested.Make sure the height of the oil in the8-oz bottle is the same as that of the nylon-formic acid solutions. (The Brookfield viscometer is factory-adjusted to read viscosi-ties within1%of the absolute,provided that the measurements are made in a container that is at least76mm(3in.)in diameter and the spindle is properly centered in the container.The calibration must be performed in the same size container ud for testing the nylon-formic acid solution.Using the standard 8-oz bottle,the calibration factor(C f)will be about0.96for an instrument in good repair.)
9.3.8.2Determine the instrument reading of the oil follow-ing9.3.5.1.The calibration factor for the instrument is:
C f5TV o/BV o(13) where:
C f=calibration factor,
TV o=true viscosity of the oil,kPa·s(cP),and
BV o=Brookfield viscosity of the oil(instrument reading corrected for speed and spindle factors,kPa·s(cP);
e9.3.6).
9.3.9Precision—Relative viscosities by the Brookfield vis-cometer are comparable to tho obtained by the pipet viscom-eter,both instruments being calibrated against viscosity oil standards.In a laboratory test,a sample measured by the Brookfield method had an X of49.8with an Sd of0.53 covering192determinations made by24operators.The same sample measured by the pipet viscometer had an X of50.4with a Sd of0.46in a test of20determinations made byfive operators.Table1at the end of this test method gives repeatability and reproducibility statistics for relative viscosity testing.
10.Precision
10.1Precision,characterized by repeatability,S r,r,and reproducibility,S R,R,has been determined for the materials to be:
TABLE1Repeatability and Reproducibility for Relative Viscosity Material Average S r S R r R
Nylon6140.9 2.11 5.86 5.9016.41 Nylon6645.4 1.72 2.16 4.80
6.04
