Melt Flow Index Formula:
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Definition: Melt Flow Index (MI) is a measure of the flow properties of a polymer when it is melted under specific conditions.
Purpose: It helps determine the viscosity and processability of thermoplastic materials.
The calculator uses the formula:
Where:
Explanation: The weight of polymer extruded in 10 minutes is divided by 10 to standardize the measurement.
Details: MI is crucial for quality control, material selection, and predicting polymer behavior during processing.
Tips: Enter the weight of polymer in grams collected during the standard 10-minute test. Value must be > 0.
Q1: What does a high Melt Flow Index indicate?
A: A high MI indicates lower viscosity and better flow characteristics under the test conditions.
Q2: What are standard test conditions?
A: ASTM D1238 and ISO 1133 specify standard temperatures and loads for different polymers.
Q3: How does temperature affect MI?
A: Higher temperatures generally increase flow rate and thus the MI value.
Q4: What's a typical MI range for common plastics?
A: It varies widely - from 0.1 g/10min for some engineering plastics to over 100 g/10min for certain polyethylenes.
Q5: Can MI predict mechanical properties?
A: Indirectly - higher MI polymers generally have lower molecular weight and thus different mechanical properties.