Polymerization Formula:
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Definition: The Number-Average Degree of Polymerization is a weighted mean of the degrees of polymerization of polymer species, weighted by the mole fractions (or the number of molecules) of the species.
Purpose: It helps polymer scientists and engineers understand the average size of polymer molecules in a sample.
The calculator uses the formula:
Where:
Explanation: The formula calculates the average number of monomer units per polymer chain in the sample.
Details: The degree of polymerization affects material properties like strength, viscosity, and melting point.
Tips: Enter the number of original molecules and the number of molecules at specific time. All values must be > 0.
Q1: What does a higher degree of polymerization indicate?
A: Higher DPN indicates longer polymer chains, which typically means higher molecular weight and different material properties.
Q2: How is this different from weight-average degree of polymerization?
A: Number-average gives equal weight to each molecule, while weight-average gives more weight to heavier molecules.
Q3: What are typical DPN values for common polymers?
A: This varies widely - from hundreds for some plastics to thousands for high-performance polymers.
Q4: How do I determine the number of molecules?
A: This is typically measured using techniques like gel permeation chromatography or light scattering.
Q5: Can DPN be less than 1?
A: No, since it represents the average number of monomer units per chain, it must be ≥ 1.