1、Designation:E240804(Reapproved 2009)Standard Test Method forRelative Extensional Viscosity of Agricultural Spray TankMixes1This standard is issued under the fixed designation E2408;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the
2、year 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.Scope1.1 This test method covers the determination of the relativeextensional viscosity or Screen Factor(SF)of dilute agricu
3、l-tural spray mixes.1.2 The test can be used for tank mixes containingdissolved,emulsified or dispersed materials,or mixtures.1.3 Results may be affected by the quality of the water used.Make-up water quality should therefore be specified in thepresentation of results.1.4 Proper safety and hygiene p
4、recautions must be takenwhen working with pesticide formulations to prevent skin oreye contact,vapor inhalation,and environmental contamina-tion.Read and follow all handling instructions for the specificformulation and conduct the test in accordance with goodlaboratory practice.NOTE1References to th
5、e development of extensional viscosity fromdissolved polymers,extensional viscosity effects on the droplet sizedistribution of sprays,and measurements of screen factor on recirculatedspray mixes containing polymers are available.2,31.5 The values stated in SI units are to be regarded asstandard.No o
6、ther units of measurement are included in thisstandard.1.6 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 and determine the applica-bility of
7、 regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:4D1193 Specification for Reagent WaterE609 Terminology Relating to PesticidesE1116 Test Method for Emulsification Characteristics ofPesticide Emulsifiable Concentrates2.2 CIPAC Documents:CIPAC Monograph 1(Instructions for
8、the preparation ofhard water)CIPAC Method MT 18.1.1 to 18.1.7(Instructions for thepreparation of standard waters)3.Terminology3.1 Definitions:3.1.1 screen factor,(SF)the ratio of the flow time of a testfluid(tp)to the flow time of water(tw)through the screenviscometer apparatus.3.1.2 extensional vis
9、cosity,(E)a measure of the resistanceof a fluid to distortion by a stretching force.4.Significance and Use4.1 Extensional viscosity is a measure of the resistance of aliquid to stretching forces,such as those occurring during thedisruption of liquid films and the formation of sprays used inagricultu
10、re and other purposes including painting operations ormetal working.This method for measurement of a ScreenFactor,gives a relative value for extensional viscosity,whichmay be used:4.1.1 To compare the potential for drift control of differentpolymers.4.1.2 To compare the relative extensional viscosit
11、y compo-nent of different spray tank mixtures.4.1.3 To determine the extent of breakdown of polymersolutions used as drift control additives during the recirculationof the solutions through pumps and screens.4.1.4 To use as a parameter in the Spray Drift Task ForceModels for droplet size prediction.
12、1This test method is under the jurisdiction of ASTM Committee E35 onPesticides,Antimicrobials,and Alternative Control Agentsand is the direct respon-sibility of Subcommittee E35.22 on Pesticide Formulations and Delivery Systems.Current edition approved Oct.1,2009.Published November 2009.Originallyap
13、proved in 2004.Last previous edition approved in 2004 as E2408 04.DOI:10.1520/E2408-04R09.2Dexter,R.W.,“Measurements of Extensional Viscosity of Polymer Solutionsand its Effect on Atomization from a Spray Nozzle,”Atomization and Sprays,Vol6,1996,pp.1671913Zhu,H.,Dexter,R.W.,Fox,R.D.,Reichard,D.L.,Br
14、azee,R.D.,and Okzan,H.E.,“Droplet Size and Viscosity Effects in Recirculated Polymer Spray Solutions,”J.Agric.Engr.Res.,Vol 67,1997,pp.35454For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume inf
15、ormation,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2 It should also be noted that many drift control polymersare irreversibly destroyed during the recirculation of sp
16、raymixes by pumping with high shear pumps such as gear orcentrifugal pumps.It is advisable to subject the test mixture tosimilar pumping regimes to simulate practical conditionsbefore carrying out the extensional viscosity test.Measure-ments of extensional viscosity are the only presently knownmethod of determining the extent of this breakdown propertiesof dilute polymer solutions.4.3 This method is intended to produce a relative value forextensional viscosity.The purpose of the method is to com
