Information on the most widely used ASTM standards within the materials testing industry
ASTM D3364: Standard Test Method for Flow Rates for Poly(Vinyl Chloride) with Molecular Structural Implications
ASTM D3364 test method is an extension of Test Method D1238 specific to the measurement of flow rates of poly(vinyl chloride) (PVC) compounds while detecting and controlling various polymer instabilities associated with the flow rate. it is useful for quality-control tests on PVC compounds having a wide range of melt viscosities. Measurements are made at shear rates close to 1 s−1.
This testing method is widely used for quality control testing of PVC compounds with a wide range of melt viscosity. It is specifically designed to measure the melt flow rate (MFR or MFI) of polyvinyl chloride compounds, while detecting and controlling various polymer instabilities related to flow rate. The sensitivity of this testing method makes it useful as an aid in correlating with processing conditions and predicting processing changes. This test is capable of detecting and tracking profound changes that occur during extrusion, injection molding, milling, or mixing processes due to three types of measured polymer instability, including thermal instability caused by temperature effects, shear instability caused by polymer chain breakage, and rheological instability caused by uneven distribution of viscosity or molecular weight elements.Test a PVC sample at 175 ° C.
Due to the corrosiveness of PVC material, the melt flow index tester need equip with a special corrosion-resistant kit to prevent any interaction between the material and metal during testing.
Under standard configuration, measurements are taken at a temperature of 175 ° C and a load of 20kg.
For rigid PVC, using a larger test load of approximately 50kg may be more advantageous. Semi hard or soft PVC is measured at 150 ° C/50kg.
The mold is 25.43mm (1 inch) long, with a diameter of 2.095mm compared to the standard mold, and has a conical feeding port.
Compared to standard molds, this mold reduces MVR by approximately 10 times. The filling volume is 2.15 grams and must be strictly followed.
The MFR value is calculated in milligrams per minute, and the instability of the molten material is expressed as a percentage.
Through the testing method of ASTM D3364, it is possible to detect polymer bond breakage caused by temperature effects, shear, or instability caused by rheological effects (such as uneven distribution of viscosity or molecular weight).
Related Standard
ISO 1133: Plastics -- Determination of the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) of thermoplastics.
ISO 1133 standard specifies two procedures for the determination of the melt mass-flow rate (MFR) and the melt volume-flow rate (MVR) of thermoplastic materials under specified conditions of temperature and load. One is a mass-measurement method. The other is a displacement-measurement method. Normally, the test conditions for measurement of melt flow rate are specified in the material standard with a reference to ISO 1133. The test conditions normally used for thermoplastics are listed in annexes.
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