The development of wood-based thermoplastic polymers
that can replace
synthetic plastics is of high environmental importance, and previous
studies have indicated that cellulose-rich fiber containing dialcohol
cellulose (ring-opened cellulose) is a very promising candidate material.
In this study, molecular dynamics simulations, complemented with experiments,
were used to investigate how and why the degree of ring opening influences
the properties of dialcohol cellulose, and how temperature and presence
of water affect the material properties. Mechanical tensile properties,
diffusion/mobility-related properties, densities, glass-transition
temperatures, potential energies, hydrogen bonds, and free volumes
were simulated for amorphous cellulosic materials with 0–100%
ring opening, at ambient and high (150 °C) temperatures, with
and without water. The simulations showed that the impact of ring
openings, with respect to providing molecular mobility, was higher
at high temperatures. This was also observed experimentally. Hence,
the ring opening had the strongest beneficial effect on “processability”
(reduced stiffness and strength) above the glass-transition temperature
and in wet conditions. It also had the effect of lowering the glass-transition
temperature. The results here showed that molecular dynamics is a
valuable tool in the development of wood-based materials with optimal
thermoplastic properties.