Active Standard ASTM D4591 | Developed by Subcommittee: D20.15
Book of Standards Volume: 08.02
Historical (view previous versions of standard)
Significance and Use
DSC analysis may be used with fluoropolymers to achieve at least four different objectives as follows:
To measure transition temperatures to aid in the identification of the various fluoropolymers, individually or in mixtures;
To compare the relative levels of crystalline content of two or more specimens of a sample of a fluoropolymer relative to another sample by measuring the heat of fusion;
Note 2—Absolute values of crystalline content cannot be determined until values for heats of fusion of the completely crystalline polymers are available.
To characterize PTFE (DSC thermal curves determined on powders or products of PTFE that have never been melted convey appreciable information about details of morphology and molecular structure);
To supplement the test for standard specific gravity (SSG) described in Specifications D4894 and D4895 by using the heat of crystallization of pure PTFE homopolymer, depending on the relative molecular weight of the specimen. The scopes of these specifications, however, include PTFE resins modified with small amounts of comonomers, and many commercial PTFE resins are modified in this manner. These modifications can have profound effects on crystallization behavior. Published relationships between heat of crystallization and molecular weight refer to pure PTFE homopolymers and, therefore, cannot be applied to the modified resins.
1.1 This test method defines conditions for the use of differential scanning calorimetry (DSC) with fluoropolymers. It covers the use of DSC analyses with the fluoropolymers, PTFE, PVDF, PCTFE, and PVF and their copolymers PFA, MFA, FEP, ECTFE, EFEP, VDF/HFP, VDF/TFE/HFP, VDF/CTFE. The test method is applicable to the analysis of powders as well as samples taken from semi-finished or finished products. The nature of fluoropolymers is such that special procedures are needed for running DSC analysis and interpreting the results.
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 and health practices and determine the applicability of regulatory limitations prior to use. Note 1—There is currently no ISO standard that duplicates this test method. ISO 12086-1 and ISO 12086-2 cover similar testing and reference this test method for testing conditions.
Note 1—There is currently no ISO standard that duplicates this test method. ISO 12086-1 and ISO 12086-2 cover similar testing and reference this test method for testing conditions.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1600 Terminology for Abbreviated Terms Relating to Plastics
D3418 Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry
D4894 Specification for Polytetrafluoroethylene (PTFE) Granular Molding and Ram Extrusion Materials
D4895 Specification for Polytetrafluoroethylene (PTFE) Resin Produced From Dispersion
E473 Terminology Relating to Thermal Analysis and Rheology
E793 Test Method for Enthalpies of Fusion and Crystallization by Differential Scanning Calorimetry
âISO StandardsISO12086-2 Plastics--Fluoropolymer Dispersion and Molding and Extrusion Materials--Part 2: Preparation of Test Specimen and Determination of Properties
ICS Number Code 83.080.20 (Thermoplastic materials)
UNSPSC Code 13102008(Fluoropolymers PTFE)