Significance and Use
The inherent viscosity is relatable to the composition and molecular weight of a polyester resin. It must be controlled so that the processability and end properties of the resin remain in a desired range.
1.1 This test method is for the determination of the inherent viscosity of poly(ethylene terephthalate) (PET) soluble at 0.50 % concentration in a 60/40 phenol/1,1,2,2-tetrachloroethane solution by means of a glass capillary viscometer. Highly crystalline forms of PET that are not soluble in this solvent mixture will require a different procedure.
1.2 The inherent viscosity values obtained by this test method are comparable with those obtained using differential viscometry described in Test Method D5225.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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 and health practices and determine the applicability of regulatory limitations prior to use. Specific hazards statements are given in Section 8.
Note 1—This test method and ISO 1628-5 are similar but not technically equivalent. This ISO standard gives an option of solvents for PET. Solvent specified in this ASTM test method is one of the options in the ISO method. ISO also uses Type 1C Ubbelohde viscometer, rather than the 1B, and reports viscosity number, rather than inherent viscosity.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
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
D1972 Practice for Generic Marking of Plastic Products
D5225 Test Method for Measuring Solution Viscosity of Polymers with a Differential Viscometer
E1 Specification for ASTM Liquid-in-Glass Thermometers
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
IEEE/ASTM SI-10 Practice for Use of the International System of Units (SI)
C 602 Testing of Glass Volumetric Apparatus Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
ISO 1628-5 Determination of the Viscosity of Polymers in Dilute Solution Using Capillary Viscometers--Part 5: Thermoplastic Polyester (TP) homopolymers and Copolymers. Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
glass capillary viscometer; inherent viscosity; poly(ethylene terephthalate); PET; solution viscosity; Flow and flow rate--thermoplastics; Glass capillary viscometer; PET (poly(ethylene terephthalate)); Polymer content; Viscosity--plastics
ICS Number Code 83.080.20 (Thermoplastic materials)
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Citing ASTM Standards
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