Reactive Molecular Dynamics Study of the Thermal Decomposition of Phenolic Resins

Abstract

The thermal decomposition of polyphenolic resins was studied by reactive molecular dynamics (RMD) simulation at elevated temperatures. 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 those of the experimental values. Simulated densities approached a final density of 1.05-1.08 g/cm 3 which compared favorably with the experimental values of 1.16-1.21 g/cm 3 for phenol-formaldehyde resins. The RMD calculations were run using LAMMPS software at temperatures of 1250 K and 3000 K using the ReaxFF force field and employing an in-house routine for removal of products of condensation. The species produced during RMD correlated with those found experimentally for polyphenolic systems and rearrangements to form cyclopropane moieties were observed. At the end of the RMD simulations a glassy carbon char resulted. mixtures were also investigated by van Duin [13]. A new force field was derived for Pt-O systems by Fantauzzi et al. [14], and an organic mechanistic study was carried out on polymerization by Schoenfelder [15]. Adaptive accelerated RMD on hydrogen was published by Goddard et al. [16], and an implementation of RMD on GPU's was developed by Kylasa et al. [17]. The second generation of RMD methods were reviewed by Farah et al. in 2012 [18], which used empirical reactive force fields to generate the new species. Recently, a transferable reactive force field was developed by Xiao, Shi, Hao, Liao, Zhang, and Chen for phosphorous and hydrogen which showed a distinct improvement in predicting the mechanical properties of pristine-and defect-laden black phosphorous [19]. In this study we concentrate on phenol-formaldehyde resins (PFRs), also known as phenolic resins, which are a subclass of synthetically derived thermosetting polymers obtained from a reaction of phenol with formaldehyde ( Figure 1).

Synthesis and Thermal Degradation Study of Polyhedral Oligomeric Silsesquioxane (POSS) Modified Phenolic Resin

“…At present, the research work on phenolic resin mainly focuses on chemical modification and the synthesis process, while the thermal degradation study of modified phenolic resin has been less reported. As an important thermal protective ablation material substrate, the degradation properties of modified phenolic are closely related to its application under a high-temperature ablation environment [21]. On the other hand, the degradation study of the modified phenolic resin can provide rational feedback for the modification of the resin.…”

Molecular Simulations of Adsorption and Energy Storage of R1234yf, R1234ze(z), R134a, R32, and their Mixtures in M-MOF-74 (M = Mg, Ni) Nanoparticles

“…The MD and GCMC simulations in this paper were realized on the Materials Studio molecular simulation software 34,35 , which offers a rich set of features for materials modeling. In the simulation, MD and GCMC had adopted the COMPASS force field 36,37 to describe the inter-atom interactions, the Ewald method was employed to manage the long-range electrostatic interaction between particles, and the periodic boundary conditions were applied in the X, Y and Z directions of the simulation box [38][39][40] .…”

Simulating the complete pyrolysis and charring process of phenol–formaldehyde resins using reactive molecular dynamics

“…The structure was relaxed with a short period of MD between reaction steps. After many iterations, a cured polymer structure was obtained [43] (Fig. 3 is an example of the structures generated).…”