Heat Flow in Solvent-Free, Dense Amorphous and Semi-Crystalline Cellulose Derivatives

Area of Science:

• Materials Science
• Polymer Science
• Computational Physics

Background:

• Synthetic polymers present environmental concerns, driving demand for sustainable alternatives like cellulose.
• Cellulose's viability as a replacement depends on matching or exceeding synthetic polymer properties, particularly thermal conductivity (κ).
• Thermal conductivity is crucial for polymer suitability across diverse applications.

Purpose of the Study:

• Investigate heat transport in dense, solvent-free cellulose and cellulose acetate.
• Analyze thermal properties in amorphous and semi-crystalline phases of these materials.
• Provide quantum-corrected estimates of thermal conductivity for comparison with experimental data.

Main Methods:

• Large-scale molecular dynamics simulations were employed.
• Analysis focused on the vibrational density of states, g(ν).
• Quantum corrections were applied to estimate heat capacity (c) and thermal conductivity (κ).

Main Results:

• Amorphous cellulose shows κ ranging from 0.14–0.26 Wm⁻¹K⁻¹ (280–400 K).
• Amorphous cellulose acetate exhibits slightly lower κ (0.12–0.22 Wm⁻¹K⁻¹).
• Experimental data for amorphous cellulose acetate align, showing κ ≃ 0.15–0.21 Wm⁻¹K⁻¹.
• Semi-crystalline cellulose demonstrates a 20–35% κ increase at ~20% crystallinity.

Conclusions:

• Cellulose-based materials possess thermal conductivity comparable to synthetic polymers.
• Cellulose is a promising sustainable alternative for various applications.
• The study offers insights into the thermal behavior of cellulose-based materials.