1、Designation: E2408 04 (Reapproved 2015)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
2、, the 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
3、dilute agricul-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 safet
4、y and hygiene precautions 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.NOT
5、E 1References to the 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 reg
6、arded asstandard. No other 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 determ
7、ine the applica-bility of 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 Mon
8、ograph 1 (Instructions for 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 screenviscomet
9、er apparatus.3.1.2 extensional viscosity, (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
10、 formation of sprays used inagriculture 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 c
11、ompare the relative extensional viscosity 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
12、ForceModels for droplet size prediction.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.
13、1, 2015. Published February 2016. Originallyapproved in 2004. Last previous edition approved in 2009 as E2408 04(2009).DOI: 10.1520/E2408-04R15.2Dexter, R. W., “Measurements of Extensional Viscosity of Polymer Solutionsand its Effect on Atomization from a Spray Nozzle,” Atomization and Sprays,Vol6,
14、1996, pp. 1671913Zhu, H., Dexter, R. W., Fox, R. D., Reichard, D. L., Brazee, 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, orcontac
15、t ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, 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 States14.2 It should also be not
16、ed that many drift control polymersare irreversibly destroyed during the recirculation of spraymixes 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 extens
17、ional 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 comparet
18、he extensional viscosity produced by different polymer typesor concentrations of polymer in spray tank mixes.5. Apparatus5.1 List of Materials for Construction of Screen Viscometer:5.1.1 Item 1Fluorinated plastic14 in. (0.635 cm) straightunion, reference SKU-II4, P#D1O77019. Norton PerformancePlasti
19、cs, 150 Dey Road, Wayne, New Jersey, 07470, USA.5.1.2 Item 2Cut five (5)14 in. diameter discs (see 5.2)from 100 mesh (150 m aperture) USAStandard Testing Sieve,ASTM E11 specification, stainless steel plain weave screen, soas to fit tightly into the14 in. plastic union.5.1.3 Item 3Glass 25 mL pipette
20、, VWR catalog #7102(1999) or equivalent. External diameter of the tube below thebulb of the pipette = 0.82 cm. Cut off the lower part of thepipette at a point 2.5 cm below the bulb. Round off the sharpedges of the tube with a flame.5.1.4 Item 4Silicone rubber tubing, flexible, for use as asleeve to
21、join a glass tube (Item 5) to the lower end of thepipette (Item 3).5.1.5 Item 5Glass tube, cut froma2mLpipette, Kimax#37000, or equivalent (American Scientific catalog #P4140-2).Dimensions of tube are: length = 3 cm; outside diameter = 0.62cm. Round off the sharp ends of the tube in a flame.NOTE 2Ap
22、propriate safety precautions should be taken when using anopen flame for rounding the ends of the glass tubes.5.2 Assembly of Screen ViscometerRefer to Fig. 1, whichshows the arrangement of the separate items of equipment, andFig. 2, which shows the placement of the screen pack in theplastic union.5
23、.2.1 Push the five stainless screen discs, one at a time, intothe14 in. (0.635 cm) plastic union. Push each screen down tothe central lug in the union, using a piece of14 in. glass tubing.Ensure that the last of the 5 screens fits tightly into the plastictube to keep the pack of screens well compact
24、ed and fixed inplace.5.2.2 Push the silicone rubber sleeve (Item 4) on to thelower end of the pipette tube (Item 3). Leave approximately 0.8cm of the silicone tube projecting beyond the glass.5.2.3 Push the short glass tube (Item 5) into the plastic unionfirmly and press down on the pack of screens.
25、 Screw on the endcap of the union to retain the position of the screen pack.Ensure that the Teflon cone supplied with the union is fittedproperly, to provide a leak tight seal. About 0.6 cm of the glasstube should protrude from the end cap of the union.5.2.4 Push together the glass tube protruding f
26、rom the endcap, into the silicone rubber sleeve attached to the pipette.Check the alignment of the pipette and screen pack forstraightness.5.3 Other Accessories Required:5.3.1 Two 500 mL beakers.5.3.2 A stand and clamp to hold the pipette firmly in avertical position.5.3.3 A stopwatch, reading to 0.
27、01 s.5.3.4 A 200 mesh USA Standard Testing (75 m aperture)stainless steel sieve, 4 in. diameter.5.3.5 A pipette bulb, or preferably, a low vacuum suctiondevice (see 7.2.2).FIG. 1 Diagram of ApparatusE2408 04 (2015)26. Test Materials6.1 Deionized Water, filtered through a 200 mesh (75 maperture) stai
28、nless steel screen, for use in rinsing the apparatusand as a standard fluid for calibrating the screen pack.6.2 Test Fluid(s), as required to be tested.7. Procedure7.1 Preparation of Test Fluids for use in Screen Viscometer:7.1.1 Dilute the formulation in the appropriate standardwater to the desired
29、 spray concentration. Pass approximately500 mL of the liquid so prepared through a 200 mesh USAStandard stainless steel sieve, to remove poorly dispersedaggregates or gels. The test can be run with as little as 200 mLof the test fluid. The temperature of the fluid should be kept atstandard temperatu
30、re, preferably in a constant temperatureroom.NOTE 3Dilute solutions of high molecular weight polymers oftenrequire prolonged dissolution to allow for complete swelling anddissolution, especially if provided as solids. Note also that excessivestirring or shearing by pumping can cause degradation of t
31、he polymermolecules resulting in a decrease in molecular weight and viscosity. If thesolution is drawn up into the screen viscometer too rapidly, it may bedegraded. It has been found useful to use a vacuum device that providesa low and consistent suction to the pipette.7.2 Calibration of Screen Visc
32、ometer:NOTE 4Water is used as the calibration fluid.7.2.1 Place 400 mL of deionized water in a 500 mL beakerand adjust to the required temperature. (A temperature of 23 to25C has been used, but any temperature at which the screenfactor is required may be used. The calibrating fluid (water)and the te
33、st fluid must be run at the same temperature).7.2.2 Lower the screen viscometer assembly into the water,clamp the pipette in a vertical position, and draw up water intothe pipette through the screen pack, by applying vacuum to thetop of the pipette. Draw the water up to a point about 2 in.above the
34、upper timing mark.7.2.3 Raise the pipette tip above the surface of the liquidabout 2 cm, and fix in position using the clamp, so that theliquid will fall freely from the pipette in air during draining.Then allow the water to run out of the pipette freely undergravity. Start the stopwatch as the meni
35、scus passes the uppertiming mark, and stop the watch when the meniscus passes thetop edge of the silicone rubber sleeve. The efflux time is shortand practice may be needed to obtain consistent results. Recordthe efflux time.7.2.4 Repeat the measurement a total of 5 times, andaverage the efflux times
36、. This is the efflux time for water (tw).Record the temperature of the room and fluid.7.3 Testing Spray Fluids:7.3.1 Completely drain the screen viscometer after calibra-tion with deionized water.7.3.2 Draw up the test fluid (as in 7.2.2) and record theefflux time for the fluid. Repeat the measureme
37、nts a total of 5times.7.3.3 Record the average time as the efflux time of the fluid(tp).7.3.4 If a second test fluid is to be run, then the screenviscometer should be thoroughly rinsed with filtered deionizedwater and drained between tests.NOTE 5If inconsistent results are obtained it is probably du
38、e totrapped air. Air bubbles can be released by tapping the pipette bulb andscreen pack.8. Report8.1 Report the following information:8.1.1 Average efflux time for water, tw.8.1.2 Average efflux time for the test fluid, tp.8.1.3 Calculate the average value of Screen Factor:FIG. 2 Diagram of Apparatu
39、sE2408 04 (2015)3Screen Factor SF!5 (1)average efflux time of the test fluidaverage efflux time for water at specified temperature5tptw8.1.4 In all cases the water quality should be specified, inparticular the concentration and chemistry of the dissolvedsolids content of the liquid. Any unusual trea
40、tment of the sprayliquid, for example pretreatment by pumping, should bereported.9. Precision and Bias9.1 PrecisionThe reproducibility of this test method asdetermined by statistical analysis of results obtained fromseveral laboratories in a round robin was as follows, averagedover single operators:
41、For water flow times (tw),Standard deviation of tw= 0.7 to 4 % for a single operatorFor polymer solution flow times (tp),Standard deviation of tp= 0.8 to 3 % for a single operatorFor Screen Factor values (SF),Standard deviation of SF = 1.5 to 6 % for a single operator9.1.1 Repeatability is expressed
42、 in terms of the standarddeviation from the mean in several tests. The existing data fromthe round robin indicate that the standard deviation of ScreenFactor for measurements of several different fluids conductedby all operators in aggregate is approximately 15 %.NOTE 6In the round robin procedure a
43、dopted, each operator wasrequired to construct his own apparatus, so that some differences in resultsfrom different operators would be expected, increasing the standarddeviation between operators.9.2 BiasThere exist other methods for the determinationof extensional viscosity. Extensional viscosity i
44、s dependentupon the strain rate for most polymer solutions, an differentmethods of measurement may give different extensional vis-cosity values, because of variations in the strain rate applied inthe equipment. This method may provide values for ScreenFactor that do not agree with the results of ext
45、ensionalviscosity from other methods. This method operates at rela-tively low extensional strain rates and may therefore be biasedtowards low extensional strains, so that the values of exten-sional viscosity may be relatively low, compared with, forexample, the Rheometrics RFX instrument. However, t
46、hemethod gives good comparisons between fluids and is moresensitive than other methods, especially at low polymer con-centrations. Reports of the use of this method and its relevanceto spray droplet size control are available (see Section 2,Referenced Documents).ASTM International takes no position
47、respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.Th
48、is standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Int
49、ernational Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the abovead
