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

## TL;DR

This study uses simulations to compare the thermal conductivity of cellulose and cellulose acetate, showing they can match synthetic polymers, making them viable eco-friendly alternatives.

## Contribution

Quantum-corrected thermal conductivity estimates for amorphous and semi-crystalline cellulose derivatives using molecular dynamics simulations.

## Key findings

- Amorphous cellulose has thermal conductivity of 0.14–0.26 Wm⁻¹ K⁻¹, comparable to synthetic polymers.
- Semi-crystalline cellulose shows 20–35% higher thermal conductivity at 20% crystallinity.
- Cellulose acetate has slightly lower thermal conductivity than cellulose in amorphous forms.

## Abstract

Polymers are essential
in our everyday life due to their versatility
and tunable properties, but common synthetic polymers pose significant
environmental challenges. This has led to growing interest in natural,
biodegradable alternatives such as cellulose. For cellulose to serve
as a viable alternative, it must match or ideally exceed materials
properties of synthetic polymers. Thermal conductivity, κ, is
one such critical property that often determines the suitability of
polymers for a wide range of applications. In this study, we employ
large–scale molecular dynamics simulations to investigate heat
transport in dense, solvent–free cellulose and cellulose acetate
systems. Our focus is on the amorphous phases of both materials, as
well as the semi–crystalline phase of pure cellulose. By analyzing
the vibrational density of states, g(ν), we
report quantum–corrected estimates of the heat capacity, c, and consequently κ, enabling reasonable comparison
with experimental data. Our results show that, over the temperature, T, range of 280–400 K, κ of amorphous cellulose
varies between approximately 0.14 and 0.26 Wm–1 K–1, while slightly lower values, around 0.12 to 0.22
Wm–1 K–1, are observed for amorphous
cellulose acetate. Within a similar temperature range, our experimental
data for amorphous cellulose acetate give κ ≃ 0.15–0.21
Wm–1 K–1. In semi–crystalline
cellulose samples, depending on T, κ can increase
by approximately 20–35% when the degree of crystallinity reaches d ≃ 20%. These values are comparable to those of
standard synthetic polymers, highlighting cellulose as a promising
alternative. This study demonstrates that cellulose offers a natural,
sustainable alternative to common synthetic polymers, while also providing
insight into the thermal behavior of cellulose–based materials.