ASTM D3591-22

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Designation: D3591 − 17 D3591 − 22
Standard Test Method for
Determining Logarithmic Viscosity Number of Poly(Vinyl
Chloride) (PVC) in Formulated Compounds
This standard is issued under the fixed designation D3591; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the determination of the logarithmic viscosity number of poly(vinyl chloride) (PVC) homopolymers
after compounding or processing.
1.2 It is the basic assumption of this technique that the formulation of the compounded resin is known and that any additives
present can be separated from the resin by extraction with diethyl ether. This is necessary to permit adjustment of the amount of
sample used in the test to give a resin concentration in cyclohexanone of 0.2 6 0.002 g/100 mL.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use. Specific precautionary statements are given in 7.3 and 8.4.1.
NOTE 1—This test method and ISO 1628-2 are not equivalent.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity)
D446 Specifications and Operating Instructions for Glass Capillary Kinematic Viscometers
D883 Terminology Relating to Plastics
D1243 Test Method for Dilute Solution Viscosity of Vinyl Chloride Polymers
D2124D1600 Test Method for Analysis of Components in Poly(Vinyl Chloride) Compounds Using an Infrared Spectrophoto-
metric TechniqueTerminology for Abbreviated Terms Relating to Plastics (Withdrawn 2020)
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
E2935 Practice for Evaluating Equivalence of Two Testing Processes
IEEE/ASTM SI-10 Standard for the Use of International System of Units (SI)
This test method is under the jurisdiction of ASTM Committee D20 on Plastics and is the direct responsibility of Subcommittee D20.70 on Analytical Methods.
Current edition approved Dec. 1, 2017Sept. 1, 2022. Published January 2018September 2022. Originally approved in 1977. Last previous edition approved in 20112017
as D3591 – 97D3591 – 17.(2011). DOI: 10.1520/D3591-17.10.1520/D3591-22.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3591 − 22
2.2 ISO Standard:
1628-2 Plastics—Determination of Viscosity Number and Limiting Viscosity Number—Part 2: Poly (Vinyl Chloride) Resins
3. Terminology
3.1 Units and symbols used in this test method are those recommended in IEEE/ASTM SI-10.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 The term logarithmic viscosity number is defined by the equation is 9.1.
3.2 Definitions—For definitions of terms pertaining to plastics used in this test method, refer to Terminology D883. For definitions
of abbreviations used in this test method, refer to Terminology D1600, unless otherwise indicated. For definitions of terms that
appear in this test method relating to quality and statistics, refer to Terminology E456.
3.2.1 The term logarithmic viscosity number is defined by the equation is 9.1.
4. Summary of Test Method
4.1 The sample is pressed into a thin film and extracted to remove the plasticizer.
4.2 The plasticizer-free film is dissolved in cyclohexanone and centrifuged to remove insoluble matter.
4.3 The viscosity of the cyclohexanone solution is measured in accordance with Test Method D1243.
5. Significance and Use
5.1 The logarithmic viscosity number provides information on the effect of compounding or processing of PVC.
5.2 Exposure of PVC compositions to shear or to high temperatures can result in a change in the logarithmic viscosity number
of the resin.
6. Apparatus
6.1 Centrifuge, capable of 2500 rpm with 100-mL sample container.
6.2 Heated Hydraulic Press, capable of 620-kN ram force and a temperature of 165°C.
6.3 Soxhlet Extraction Apparatus with a 150-mL flask and a 27 by 100-mm thimble.
6.4 Volumetric Flasks, 100-mL.
6.5 Viscometers.
6.6 Infrared Spectrophotometer,Spectrophotometer. see 5.4 of Method D2124.
6.7 Filter Funnel, funnel, Hirsch-Type; borosilicate glass; with coarse fritted disc, pore size: 40–60 μm.
6.8 Thermometer, standard, in accordance with Test Method E2251.
7. Reagents
7.1 Cyclohexanone, high-purity (see Annex A1).
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
ASTM Ubbelohde Size 1 or Cannon-Ubbelohde No. 75 have been found satisfactory for this purpose.
D3591 − 22
7.2 Diethyl Ether, anhydrous, reagent grade.
7.3 (Warning—Safety precautions should be taken to avoid personal contact, to eliminate toxic vapors, and to guard against
explosive hazards in accordance with the hazardous nature of the particular reagent being used.)
8. Procedure
8.1 Prepare the PVC sample for extraction by pressing a film. The film should be 0.02 to 0.5 mm (1 to 2 mil) thick. Prepare two
films in order to make duplicate runs.
8.1.1 Heat the hydraulic press to 165°C (330°F).
8.1.2 Place 2 g of sample between two sheets of aluminum foil and insert into the press.
8.1.3 Allow the sample to come to temperature for 2.5 min. During the next 0.5 min, increase the force on the sample to 620 kN.
Maintain the force for 3 min, then cool while maintaining the force.
8.2 Weigh, to 60.2 mg, approximately 1 g of pressed film into a 27 by 100-mm extraction thimble.
8.3 Place the thimble in a Soxhlet extraction apparatus fitted with a tared 150-mL flask, and extract with 120 mL of diethyl ether
for 20 h.
8.4 Remove the tared 150-mL flask containing the diethyl ether and extracted plasticizer from the extraction apparatus, and gently
heat to boil off the ether.
8.4.1 (Warning—When evaporating a quantity of ether to near dryness, precautions should be taken to guard against an explosive
hazard, due to peroxides which may be in the ether or which may have been formed during use.)
8.5 Place the flask in an evacuated desiccator for a minimum of 1 h to remove the last traces of ether.
8.6 Weigh, to 60.2 mg, the flask containing the extracted plasticizer.
8.7 Calculate the percentage plasticizer as follows:
Plasticizer,%5 A 3100 /B (1)
~ !
where:
A = weight of extracted plasticizer (7.6), and
B = sample weight (7.2).
8.8 Dry the film to remove all solvent.
8.8.1 The extracted film must be free of plasticizer. Errors in excess of 10 % will result from small residual amounts of plasticizer.
Examine the extracted film by infrared spectroscopy to ascertain that the plasticizer level is less than 0.05 % in order to obtain
satisfactory results. An example for a carbonyl containing plasticizer is shown in Fig. 1 and Fig. 2.
8.9 Determine the sample size of the extracted film that will yield 0.02 6 0.002 g of PVC resin as follows:
100 2 P
F 5 30.2 (2)
R
where:
F = weight of extracted film, g,
P = plasticizer, %, and
...