1、Designation: D1720 03 (Reapproved 2012)Standard Test Method forDilution Ratio of Active Solvents in Cellulose NitrateSolutions1This standard is issued under the fixed designation D1720; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method cover
3、s the determination of the volumeratio of hydrocarbon diluent to active solvent required to causepersistent heterogeneity (precipitation) in a solution of cellu-lose nitrate.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.
4、3 The following applies to all specified limits in thisstandard; for purposes of determining conformance with thisstandard, an observed value or a calculated value shall berounded off “to the nearest unit” in the last right-hand digitused in expressing the specification limit, in accordance withthe
5、rounding-off method of Practice E29.1.4 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 regulatory limi
6、tations prior to use. For specific hazardstatements, see Section 6.1.5 For hazard information and guidance, see the suppliersMaterial Safety Data Sheet.2. Referenced Documents2.1 ASTM Standards:2D301 Test Methods for Soluble Cellulose Nitrate (With-drawn 2011)3D841 Specification for Nitration Grade
7、TolueneD4615 Specification forn-Butyl Acetate (All Grades)E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 dilution ratio, nthe maximum number of unit vol-umes of a diluent that ca
8、n be added to a unit volume of solventto cause the first persistent heterogeneity (precipitation) in thesolution at a concentration of 8 g cellulose nitrate per 100 mLof combined solvent plus diluent and at a temperature of 25 63C.NOTE 1The dilution ratio decreases as the cellulose nitrate concen-tr
9、ation at the end point increases. It is, therefore, necessary to set anarbitrary concentration of cellulose nitrate as part of the dilution ratioterm. For this purpose 8.0 g of cellulose nitrate per 100 mL of solvent plusdiluent has been adopted.4. Significance and Use4.1 By use of standard or refer
10、ence grade materials for anytwo of the three components, namely, oxygenated solvent,diluent, or cellulose nitrate, the effect of different batches ordifferent types of the third component can be determined.4.2 This test method is applicable for the determination ofthe following:4.2.1 The dilution ra
11、tio of toluene as the standard diluent toan oxygenated solvent under test, using as the solute standardcellulose nitrate as defined in 5.2.4.2.2 The dilution ratio of a hydrocarbon diluent under testto n-butyl acetate as the standard solvent, using as a solutestandard cellulose nitrate as defined in
12、 5.2.4.2.3 The dilution ratio of toluene, as the standard diluent, ton-butyl acetate as the standard solvent, using as the solutecellulose nitrate of varying solubility characteristics.4.3 The information developed through this test may beuseful in the formulation of cellulose-based lacquers andadhe
13、sives.5. Materials5.1 n-Butyl Acetate (90 to 92 %), conforming to Specifica-tion D4615.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.35 on Solvents, Plasticizers, and Che
14、mical Intermediates.Current edition approved Nov. 1, 2012. Published November 2012. Originallyapproved in 1960. Last previous edition approved in 2008 as D1720 03 (2008).DOI: 10.1520/D1720-03R12.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
15、serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM In
16、ternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1NOTE 2This grade of n-butyl acetate contains 8 to 10 % n-butylalcohol.5.2 Cellulose Nitrate, conforming to the Sampling section(Appearance,Ash, and Stability requirements) of Test MethodsD301 and of such
17、 quality that, when used in determining thetoluene dilution ratios of n-butyl acetate and methyl n-propylketone, it will give results between the following limits:Toluene Dilution Ration-butyl acetatemethyl n-propyl ketone2.73 to 2.833.80 to 3.905.3 Toluene (Toluol), conforming to Specification D841
18、.6. Hazards6.1 Soluble cellulose nitrate is a flammable material, thedegree of flammability varying with the extent and nature ofthe wetting medium. Cellulose nitrate is always wet with wateror alcohol in commercial handling, shipping, and storage, inwhich condition it presents no unusual hazard. Dr
19、y cellulosenitrate, if ignited by fire, spark, or static electricity, burns veryrapidly. Do not store samples of dry cellulose nitrate at anytime. Dry only that portion required for immediate test. Wear aface shield when the oven is opened after samples have beenheated. Wet excess material and the s
20、amples left after testingwith water and dispose of properly.7. Drying Cellulose Nitrate7.1 Dry not more than 20 g of cellulose nitrate at a time byspreading in a thin layer on a tray at room temperature for 12to 16 h, or on top of a 100C oven where the temperature is 35to 40C for about8h(Warning, se
21、e 6.1). Alternatively, use asteam or hot water-heated oven maintained at 45 to 50C to dryspecimens in about 8 h. For safety reasons, the oven shouldhave the latch removed.7.2 Another simple way to dry small quantities of cellulosenitrate is to use a drier assembled from common laboratoryapparatus. T
22、he assembled drier is shown in Fig. 1. Hot air froma laboratory electric oven is drawn through wet cellulosenitrate contained in a brass tube hooked up through a thistletube, or small funnel, and suction flask to a water aspirator orother vacuum source. The brass pipe should be about 40 mm indiamete
23、r and 200 mm long, these relative dimensions havingbeen found to give efficient results. Such a tube will hold about25 g, dry weight, of wet cellulose nitrate. The pipe is insulatedto conserve heat. The suction flask end of the brass tube is fittedwith a thistle tube, or a small funnel, over the mou
24、th of whichis tied a silk cloth screen. An indentation made in the funneledge allows insertion of the thermometer. The funnel andthermometer are held in place by means of a rubber stopper.When using an oven temperature of 85C and vacuum suppliedby a water aspirator or other vacuum source, the alcoho
25、l-wetcellulose nitrate will be dried in about 4 h.7.3 If larger quantities of cellulose nitrate are required, thedrying equipment described in the Procedure section of DryingSamples of Test Methods D301 may be used.8. Preparation of Solution8.1 When testing either a solvent or diluent, first estimat
26、ethe probable dilution ratio for the unknown component inrelation to the other to determine the amount of solventrequired to dissolve the cellulose nitrate (Table 1). This volumeof solvent should be such that there will be approximately 10g of cellulose nitrate present per 100 mL of solvent plus dil
27、uentat the end point.NOTE 3Reference to published data on similar types of solvents ordiluents will provide a good approximation of the amount of solventrequired. If data are not available, several solutions with varying amountsof solvents may be required to arrive at a suitable volume to use.8.2 On
28、 an analytical balance, weigh 5 6 0.01 g of thecellulose nitrate into a 125-mL cork-stoppered, preweighedErlenmeyer flask, or other suitable container. From a buret addthe volume of solvent indicated in Table 1. Swirl the flask untilthe cellulose nitrate is completely dissolved. When a highconcentra
29、tion of cellulose nitrate in solvent is required, disper-sion may be more quickly accomplished by adding a measuredportion of the diluent to the flask. This reduces the solidsconcentration and thus lowers the viscosity of the solution,making it easier to dissolve the cellulose nitrate.9. Procedure9.
30、1 Add the diluent, maintained at 25 6 3.0C, to the flaskfrom a buret in small additions. Five-millilitre increments maybe added at first, but these shall be decreased to about 0.5 mLas the end point is approached. After each addition, stopper theflask and swirl vigorously to disperse any gel or prec
31、ipitatethrown down by local overconcentration of diluent (Note 4).When precipitation persists after at least 2 min of vigorousswirling, the initial end point has been reached, as indicated bythe presence of gel particles in the solution or on the sides ofthe flask (Note 5). Determine the total volum
32、e of diluent addedto the flask at this point.NOTE 4Take care to prevent loss of volatile components by evapo-ration. Avoid contact of the solution with the stopper.NOTE 5Presence of a uniform fine haze that is usually formed whenaliphatic hydrocarbons are used as diluents must not be confused with t
33、hegel end point.FIG. 1 Assembled DrierD1720 03 (2012)29.2 Determine a second end point using the same solution.This requires addition of solvent to redissolve the cellulosenitrate. The amount of solvent to add depends upon the amountof diluent used in the initial titration. The volume of solvent tob
34、e added is obtained directly from Fig. 2 and the volume ofdiluent used to reach the initial end point.9.3 After addition of the required volume of solvent, swirlthe flask to redisperse the cellulose nitrate. Then, continue thetitration with diluent to the second end point, at which pointthere should
35、 be approximately8gofcellulose nitrate presentper 100 mL of solvent plus diluent.10. Calculation10.1 Calculate the dilution ratio and cellulose nitrate con-centration at both the initial and the second end points asfollows:Dilution ratio 5 A/B (1)Cellulose nitrate concentration per 100 mL of volatil
36、e matter5C/A1B!where:A = diluent for the titration, mL,B = solvent used, mL, andC = cellulose nitrate used, g.10.2 Construct a graph for dilution ratio versus cellulosenitrate concentration. Plot as two points on the graph (Fig. 3)the two sets of values calculated as described in 10.1. One ofthe poi
37、nts will be very close to 8 g/100 mL of volatile matter.The correct value at exactly 8 g/100 mL of volatile matter maybe interpolated by drawing a straight line connecting the twoexperimentally determined points. While the curve showingthe relationship between the dilution ratio and cellulose nitrat
38、econcentration is not necessarily a straight line, the error madeby interpolating or extrapolating from the straight line connect-ing the two points is negligible in the proximity of 8 6 1 g/100mL of volatile matter.NOTE 6Example: Assuming a probable dilution ratio of approxi-mately 3, the following
39、 results are obtained:SolventInitial Added SecondEnd (from EndPoint Fig. 2) PointCellulose nitrate, g 5.00 . 5.00Solvent, mL 12.5 3 15.5Diluent, mL 35.0 . 49.6Solvent plus diluent, mL 47.5 . 65.1Dilution ratio 35/12.5 = 2.8 . 49.6/15.5=3.2Cellulose nitrate per 100 mL ofvolatile matter, g10.5 . 7.7Fr
40、om Fig. 3 the dilution ratio at 8.0 g of cellulose nitrate = 3.1611. Report11.1 When testing solvents, report the ratio of the volume oftoluene to the volume of solvent at8gofcellulose nitrate per100 mL of volatile matter.11.2 When testing diluents, report the ratio of the volume ofdiluent to the vo
41、lume of n-butyl acetate at8gofcellulosenitrate per 100 mL of volatile matter.11.3 When testing cellulose nitrate, report the ratio of thevolume of toluene to the volume of n-butyl acetate at8gofcellulose nitrate per 100 mL of volatile matter.12. Precision and Bias12.1 PrecisionThe following criteria
42、 should be used forjudging the acceptability of results at the 95 % confidencelevel.12.1.1 RepeatabilityTwo results obtained by the sameoperator should be considered suspect if they differ by morethan 0.1.12.1.2 ReproducibilityTwo results obtained by operatorsin different laboratories should be cons
43、idered suspect if theydiffer by more than 0.2.12.2 BiasThis test method has no bias because the valueof the test result is defined only in terms of the test method.TABLE 1 Volume of Solvent Required to Dissolve CelluloseNitrateProbable Dilution Ratio, volume ofdiluent:volume of solventmL of Solvent
44、per 5 g of CelluloseNitrate at 25C1 25.02 16.73 12.54 10.058.3FIG. 2 Volume of Solvent to Be Added to Complete Titration ver-sus Volume of Diluent Used to Reach Initial End PointFIG. 3 Grams of Cellulose Nitrate per 100 mL of Volatile Matterversus Dilution RatioD1720 03 (2012)313. Keywords13.1 activ
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