Reactive Molecular Dynamics Study of the Thermal Decomposition of Phenolic Resins

The thermal decomposition of polyphenolic resins was studied by Reactive Molecular Dynamics (RMD) simulation at elevated temperature. Atomistic models of the polyphenolic resins to be used in the RMD were constructed using an automatic method which calls routines from the software package Materials Studio. In order to validate the models, simulated densities and heat capacities were compared with experimental values. The most suitable combination of force field and thermostat for this system was the Forcite force field with the Nosé-Hoover thermostat, which gave values of heat capacity closest to experiment. Simulated densities approached a final density of 1.05-1.08 g/cm3 which compares favorably with experimental values of 1.16-1.21 g/cm3 for phenol:formaldehyde resins. RMD calculations were run in LAMMPS at 1250K and 3000K using the ReaxFF force field and employing an in house routine for product removal. The species produced during RMD correlate with those found experimentally for polyphenolic systems and rearrangement to form cyclopropane moieties was observed. At the end of the RMD simulations a glassy carbon char results.