1. What is Free Volume in Polymer Systems?

The Free Volume is an inherent property of the polymer matrix that arises from the free spaces between entangled polymer chains. It represents the empty space available for molecular motion and plays a crucial role in determining various polymer properties.

2. How Does the Calculator Work?

The calculator uses the Free Volume formula:

Where:

• \( V_f \) — Free Volume (m³)
• \( V_{tot} \) — Total Volume of Polymer Sample (m³)
• \( V_{occ} \) — Volume Occupied by Polymer Molecules (m³)

Explanation: The free volume is calculated by subtracting the volume actually occupied by polymer molecules from the total volume of the polymer sample.

3. Importance of Free Volume Calculation

Details: Free volume is critical for understanding polymer properties such as diffusion, permeability, mechanical behavior, and glass transition temperature. It affects how polymers respond to stress, temperature changes, and chemical environments.

4. Using the Calculator

Tips: Enter the total volume of the polymer sample and the volume occupied by polymer molecules in cubic meters. Both values must be positive, and the occupied volume cannot exceed the total volume.

5. Frequently Asked Questions (FAQ)

Q1: Why is free volume important in polymer science?
A: Free volume determines many physical properties of polymers including diffusion rates, mechanical properties, and the glass transition temperature.

Q2: How is free volume typically measured experimentally?
A: Free volume can be measured using techniques such as positron annihilation lifetime spectroscopy (PALS), density measurements, or gas permeability studies.

Q3: Does free volume change with temperature?
A: Yes, free volume increases with temperature as polymer chains gain more thermal energy and create more space between molecules.

Q4: What factors affect free volume in polymers?
A: Factors include polymer structure, molecular weight, cross-linking density, temperature, and pressure.

Q5: How does free volume relate to polymer processing?
A: Free volume affects processing parameters such as melt viscosity, diffusion of additives, and solvent evaporation rates during various polymer processing operations.