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Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer
Polymer characteristics such as Melt Flow Rate, Melt Volume Rate
and Melt Density all give clues as to how a material will process
and flow. Additionally, significant changes in any of the three
values post-molding or post-extrusion may mean that polymer
degradation has taken place.
Possible reasons why a company might test for melt flow rate, melt volume rate
and/or melt density include:
- Checking for Polymer Degradation During Processing
Below you will find a brief description of the ASTM Test Method related to the topics covered above:
1. Scope
1.1 This test method covers measurement of the rate of extrusion of molten resins through a die of a specified length and diameter under prescribed conditions of temperature, load, and piston position in the barrel as the timed measurement is being made.
1.2 Procedure A is a manual cutoff operation based on time used for materials having flow rates that fall generally between 0.15 and 50 g/10 min. Procedure B is an automatically timed flow rate measurement used for materials having flows from 0.50 to 900 g/10 min. By both procedures, the piston travel is generally the same during the timed measurement; the piston foot is about 46 and 20.6 mm above the die. Comparable flow rates have been obtained by these procedures in interlaboratory round-robin measurements of several materials described in . Provision is made for calculation of melt volume-flow rate as well as melt mass-flow rate.
Note 1 -- Round-robin testing indicates this test method may be suitable at flow rates up to 1500 g/10 min if the timing clock resolves the elapsed time to the nearest 0.01 s.
Note 2 -- This test method and ISO 1133-1991 are technically equivalent.
This standard does not purport to address 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 precautionary statements are given in 5.7, 10.2.12, and 15.1.2.
2. Referenced Documents
ASTM Standards
- D3364 Test Method for Flow Rates for Poly Vinyl Chloride with Molecular Structural Implications
- D618 Practice for Conditioning Plastics for Testing
- D883 Terminology Relating to Plastics
- E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
ANSI Standard
ISO Standard
- ISO1133-1991 Determination of the Melt-Mass Flow Rate (MFR) and the Melt Volume-Flow Rate (MVR) of Thermoplastics
Index Terms
melt flow rate; melt index; volume flow rate; ICS Number Code 83.080.20 (Thermoplastic materials)
DOI:
10.1520/D1238-04C
( Download ASTM D1238 From www.ASTM.org )
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