Shock compression of polyvinyl chloride

Abstract

This study presents shock compression simulation of atactic polyvinyl chloride (PVC) using ab-initio and classical molecular dynamics. The manuscript also identifies the limits of applicability of classical molecular dynamics based shock compression simulation for PVC. The mechanism of bond dissociation under shock loading and its progression is demonstrated in this manuscript using the density functional theory based molecular dynamics simulations. The rate of dissociation of different bonds at different shock velocities is also presented in this manuscript.

Average and Local Tg Shifts of Plasticized PVC from Simulations

“…Some other all-atom force fields have been used previously for MD simulations on PVC melts, such as customized force fields derived from experimental data or ab initio quantum chemistry calculation, , classic (first-generation) force field CVFF, and second-generation force fields, such as CFF91, PCFF, and COMPASS. , …”

“…A more coarse-grained approach is not suitable for polar PVC monomers because of the distinct partial charges on each atomic species that would be amalgamated into a single united atom. Some other all-atom force fields have been used previously for MD simulations on PVC melts, such as customized force fields derived from experimental data 11 or ab initio quantum chemistry calculation, 12,13 classic (first-generation) force field CVFF, 14 and second-generation force fields, such as CFF91, 14 PCFF, 15 and COMPASS. 15,16 Since our main focus in the present work is to explore the relation between the global and local T g shifts and short-time dynamics, we simply adopt the vanilla OPLS-AA force field for its ease of use in GROMACS, rather than fine-tuning a force field to accurately reproduce the properties measured in experiments.…”

“…Some other all-atom force fields have been used previously for MD simulations on PVC melts, such as customized force fields derived from experimental data 11 or ab initio quantum chemistry calculation, 12,13 classic (first-generation) force field CVFF, 14 and second-generation force fields, such as CFF91, 14 PCFF, 15 and COMPASS. 15,16 Since our main focus in the present work is to explore the relation between the global and local T g shifts and short-time dynamics, we simply adopt the vanilla OPLS-AA force field for its ease of use in GROMACS, rather than fine-tuning a force field to accurately reproduce the properties measured in experiments. The OPLS-AA force field provides a complete set of bonded and nonbonded interaction parameters for both PVC and DEHP and does not involve complicated cross terms as in some force fields mentioned above.…”

Noncovalent Interactions in Mechanical Response of Thermoset Epoxy Resin

“…However, only low shock intensities have been considered in this simulation such that the shock equilibrated temperature is below the polymer’s glass transition temperature (≤400 K). It can also be anticipated (based on previous experience) that covalent bonds will not experience dissociation at these low shock intensities. Shock studies at very low intensities do not produce significant compression of the specimen, so for this study, the range of shock speeds between 2 and 4.5 km/s has been investigated.…”

“…This paper presents a detailed study of the noncovalent force interaction within these free volumes, which accounts for reported variations in the mechanical performance of these thermoset polymer resins. It should be mentioned that apart from thermoset polymers, these free volumes also influence the response of thermoplastic polymers (as exemplified in energy curves for different other systems considered previously by the author , ).…”