1、Designation: D4243 99 (Reapproved 2009)D4243 16Standard Test Method forMeasurement of Average Viscometric Degree ofPolymerization of New and Aged Electrical Papers andBoards1This standard is issued under the fixed designation D4243; the number immediately following the designation indicates the year
2、 oforiginal adoption or, in the case of revision, 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 describes a standard procedure for dete
3、rmining the average viscometric degree of polymerization(abbreviated DPv) of new or aged electrical papers. The determination is made by measuring the intrinsic viscosity of a solutionof the paper in an appropriate solvent.1.2 The degree of polymerization (or the degree of condensation) of a particu
4、lar cellulose molecule is the number ofanhydro-glucose monomers, C6H10O5, in the cellulose molecule. Within a sample of paper, not all the cellulose molecules havethe same degree of polymerization so that the mean value measured by viscometric methods is not necessarily the same as thatwhich may be
5、are obtained by other methods.1.3 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address allof the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriatesafety and h
6、ealth practices and to determine the applicability of regulatory limitations prior to use. See Section 92. Referenced Documents2.1 ASTM Standards:2D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)D1711 Terminology Relating to Electrical
7、 Insulation1 This test method is under the jurisdiction of ASTM Committee D09 on Electrical and Electronic Insulating Materials and is the direct responsibility of SubcommitteeD09.01 on Electrical Insulating Products.Current edition approved Oct. 1, 2009Nov. 1, 2016. Published February 2010November
8、2016. Originally approved in 1983. Last previous edition approved in 20042009as D4243 99 (2004)(2009).1. DOI: 10.1520/D4243-99R09. 10.1520/D4243-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standar
9、dsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to
10、 adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Cons
11、hohocken, PA 19428-2959. United States12.2 Other Document:IEC 60450 Measurement of the Average Viscometric Degree of Polymerization of New and Aged Electrical Papers33. Terminology3.1 DefinitionsFor definitions of terms used in this test method, refer to Terminology D1711.4. Summary of Test Method4.
12、1 This test method measures the specific viscosity of a solution of the paper in cupriethylenediamine. From this measurementthe intrinsic viscosity of the solution is deduced, and from this the degree of polymerization is easily calculated.4.2 This test method follows very closely the procedures spe
13、cified in IEC 60450.5. Significance and Use5.1 This test method may be applied applies to all papers made from unmodified cellulose, as used in transformer, cable, orcapacitor manufacture. It applies to new or aged papers. For information, Appendix X1 shows an example of statistical distributionof D
14、Pv values for new papers intended for the insulation of transformers, together with information relative to cable and capacitorpapers. Nevertheless, where evaluating the decomposition stage of aged papers, take care to use, as a reference, the DPv value ofthe new paper of the very same origin; DPv o
15、f new papers being a function, among other factors, of their specific gravity and oftheir manufacturing process.5.2 This test method can also be used for the determination of the intrinsic viscosity of solutions of chemically modified papers,provided that these dissolve completely in the selection s
16、olvent. This Use this test method should be used with caution when itis applied to papers with mineral fillers.6. Interferences6.1 Lignins, that are present in measurable amounts in most papers and boards, may have an effect on the test results, dependingupon concentration and composition. For this
17、reason, it is important in aging studies to use as a reference samples of the unagedpaper as mentioned in 5.1.6.2 Under some conditions of heat and atmosphere, cross linking of cellulose molecules may occur, resulting in erratic testvalues. This effect has been observed for capacitor tissue in vacuu
18、m at temperatures as low as 110C and for other papers agedin air at higher temperatures.7. Apparatus7.1 Apparatus for Solution:7.1.1 Round-Bottomed 50-mL Flask, preferably with a short narrow neck, or a narrow-necked 50-mL Erlenmeyer flask.7.1.2 Rubber Stopper, fitting the neck of the flask, through
19、 which passes a capillary tube fitted with a small-bore cock glass cock;or a ground stopper, fitted with a small-bore cock may be used is suitable for use with a ground-neck flask.7.1.3 Glass Balls, 4 to 6-mm diameter, that shall not be able to enter the bore of the cock.7.1.4 Mechanical Stirrer, to
20、 rotate the solution flask with a uniform circular motion with a horizontal axis between 20 and 40r/min. The flask shall be mounted so that its axis is normal to the axis of rotation, and the radius of gyration shall not be greaterthan 200 mm.7.2 Apparatus for Measurement of Viscosity:7.2.1 Apparatu
21、s for Measurement of Kinematic Viscosity, as described in Test Method D445. The viscometer shall have acalibration constant, C, of from 0.00010 or 0.00013 St/s (10 109 to 13 109 m2/s 2).7.2.2 This constant shall be determined by measuring the efflux-time T (seconds) of a liquid of known dynamic visc
22、osity(Ns/m2) and density (g/cm3). It is given by the formula:C 5 T (1)7.2.3 Constant-Temperature Water Bath, regulated at 20 6 0.1C.7.2.4 Stopwatch, with an accuracy of 0.1 s.7.3 Apparatus for Measurement of Water Content of Paper Sample:7.3.1 Weighing Containers, impermeable to water vapor, with ai
23、rtight lids.7.3.2 Ventilated Drying Oven, thermostatically controlled at 105 6 2C.7.3.3 Desiccator.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.D4243 1628. Reagents8.1 Cupriethylene-Diamine Solution:8.1.1 The formula
24、 ascribed to cupriethylene-diamine (CED) is:CuNH22CH22CH22NH2!2#OH!2 (2)This implies a molar ratio of 2 between the concentration of ethylene-diamine and the concentration of copper:CED/Ccu!52 (3)8.1.2 Cupriethylene-diamine solution may be purchased is available for purchase commercially at several
25、different concentra-tions. At a concentration greater than 1 M it may is suitable to be kept for one year in the dark. It is diluted to 1 M when requiredfor use. Alternatively the CED solution can be made in the laboratory at its working strength of 1 M by the methods described inAnnex A1.8.1.3 The
26、1 M solution will keep only for a limited time. As often as necessary check the solution should be checked by:8.1.3.1 Using the method described in Annex A2 to verify that the ratioCED/CCu52.060.1. (4)8.1.3.2 Verify that there is no precipitate in the solution.Any precipitate should be removed Remov
27、e any precipitate by filteringor by decanting.9. Preparation of Specimens9.1 Impregnated Papers:9.1.1 Using a Soxhlet extractor, degrease the paper with hexane or, if necessary, with chloroform. (WarningChloroform istoxic, and hexane is flammable. Adequate precautions must be taken to avoid exposure
28、 to vapors and to prevent fire.)9.1.2 Allow the solvent to evaporate in air at room temperature.9.1.3 Cut the sample into small pieces (1 or 2 mm2) with scissors, using gloves to avoid touching the paper.9.1.4 Keep the sample in a controlled-humidity atmosphere until it reaches equilibrium water con
29、tent before removing thematerial required for test purposes.9.2 Nonimpregnated Papers:9.2.1 Cut the sample into small pieces (1 or 2 mm2) with scissors, using gloves to avoid touching the paper.9.2.2 Keep the sample in a controlled-humidity atmosphere until it reaches equilibrium water content befor
30、e removing thematerial required for test purposes.10. Procedure10.1 Determination of Viscosity :10.1.1 Test SpecimenWeigh to the nearest 0.1 mg an amount (m) of paper, in equilibrium with the controlled atmosphere, ofabout:10.1.1.1 125 mg whenDPv lies between 100 and 300,10.1.1.2 50 mg when DPv lies
31、 between 300 and 700, and10.1.1.3 25 mg whenDPv lies between 700 and 1500.10.1.2 Solution:10.1.2.1 Put a few glass balls in the flask.10.1.2.2 Add the weighed test specimen.10.1.2.3 Carefully shake or stir by hand to ensure the small pieces of paper are separated and evenly distributed.10.1.2.4 Add
32、22.5 mL of distilled water.10.1.2.5 Again shake or stir by hand to disintegrate and wet all the paper completely.10.1.2.6 Leave for 12 h to allow thorough impregnation with water.10.1.2.7 Add 22.5 mL of 1 M solution of cupriethylene-diamine.10.1.2.8 Add a number of glass balls so that, when the stop
33、per with capillary tube, and so forth, is fitted, the liquid will entirelyfill the flask and reach the bore of the cock. Do not allow any pieces of paper to enter the capillary, for such paper will not bedissolved.10.1.2.9 Close the cock.10.1.2.10 Allow the specimen to dissolve with mechanical stirr
34、ing as described in 7.1.4. The preferred solution time is 2 h; 2 h;however, when the specimen is not satisfactorily dissolved, increase the solution time may be increased to a maximum of 18 h.For a specimen of an aged paper, there is little risk of further measurable degradation due to this increase
35、 of solution time.10.1.3 Measurement of Viscosity:10.1.3.1 After the period of stirring and before filling the viscometer, allow the solution to stand for 1 h at the temperature ofmeasurement, 20 6 0.1C.D4243 16310.1.3.2 Take the required volume of solution and transfer it to the viscometer reservoi
36、r.Assemble the viscometer and place theassembly in the thermostatic bath.10.1.3.3 Wait 15 min before beginning the measurements. Then raise the liquid level above the upper mark of the viscometereither by means of air pressure or slight vacuum. Measure the efflux time between the upper and lower mar
37、ks. Make threesuccessive measurements. The difference between the maximum and minimum time of flow shall be less than 0.5 s. If thisrepeatability is not achieved, clean the viscometer as described in 10.1.4. Take a second specimen of the solution that has beenkept at the measurement temperature and
38、make a further series of three measurements. If again the difference is not less than 0.5s, take a new specimen of paper and prepare a fresh solution.10.1.3.4 Under the same conditions, measure the flow time of the solvent. This shall be between 90 and 110 s for the viscometerconstant C stated in 6.
39、2 (0.00010 C 0.00013).10.1.4 Cleaning the Viscometer:10.1.4.1 By aspiration, fill the tube with chromic-acid mixture and immediately empty it again.10.1.4.2 Rinse thoroughly with distilled water.10.1.4.3 Rinse twice with acetone or alcohol.10.1.4.4 Dry by means of compressed gas from a cylinder or d
40、ust-and-oil-free compressed air.10.1.5 Make all tests in duplicate, making up two separate solutions from separately weighed specimens.10.2 Determination of Water Content of Paper:10.2.1 Test Specimen:10.2.1.1 Weigh to the nearest milligram approximately 2 g of paper in equilibrium with the controll
41、ed-humidity atmosphere, andin a closed weighing container that has been dried and tared.10.2.1.2 If the paper sample is too small for 2 g to be reserved for determining its water content, use a smaller specimen.However, if the amount of paper is only sufficient for the viscometric measurements, its
42、water content may be is deduced fromthe moisture equilibrium curves and the relative humidity of the conditioning atmosphere with which the paper was in equilibrium.If equilibrium curves are not available for the particular paper tested, the following average values may be are used as a firstapproxi
43、mation for temperatures between 20 and 27C.Relative Humidity of Air, % Water Content of Air, %50656810.2.2 Measurement of Water Content:10.2.2.1 After weighing, open the container and place it, with the weighed test specimen and its cap, in the oven and heat at105 6 2C until it reaches constant mass
44、. This will normally require from 4 to 18 h.10.2.2.2 After drying, replace the cap on the container and allow it to cool in a desiccator for about 45 min. After cooling,equalize the air pressures inside and outside the container by raising and lowering the cap quickly. Weigh the container with thesp
45、ecimen.10.2.3 Alternative procedures may be used are suitable for use to determine the water content of the paper sample provided thatit can be verified that the procedure used will give results that differ from the results used in 10.2.2 by no more than 0.5 %.11. Calculation11.1 Concentration, c, o
46、f Dry Paper in the Solution:11.1.1 The water content H of the paper, as a proportion of the dry weight, is as follows:H 5M 2M0/M0! (5)where:M = mass of the test sample used for determining the water content before drying, g andM0 = mass of this sample after drying, g.11.1.2 Knowing the mass, m, in g
47、rams of the test specimen and its water content, H, the concentration c (g/100 mL), of drypaper in the solution is given by:c 5m100/45!1/11H! (6)11.2 Specific Viscosity, sThe densities of the solvent and of the solution are practically identical. Thus, the specific viscositys as defined in 4.2 is gi
48、ven by: s 5Ts 2T0T0(7)where:T0 = mean efflux time of the solvent, andTs = mean efflux time of the solution.11.3 Intrinsic Viscosity :D4243 16411.3.1 The intrinsic viscosity is calculated using Martins formula from the specific viscosity s and the concentration c (g/100mL), of dry paper.11.3.2 As Mar
49、tins formula does not readily lend itself to calculation of , use Table 1, which contains values of the product c as a function of s.11.3.3 In Table 1, k = 0.14, which value has been found experimentally for the operating conditions described.11.4 Degree of Polymerization DPvThe average viscometric degree of polymerization DPv is given by the equation:DPv5#/K (8)where: = 1, andK = 7.5 10 3.12. Validity of Results12.1 Two conditions should be metMeet the following two conditions if the results are to be
