Data for “Crosslinker-dependent effective network topology and property responses of SSBR revealed by molecular dynamics simulations”
Description
This dataset supports the article entitled “Crosslinker-dependent effective network topology and property responses of SSBR revealed by molecular dynamics simulations”. It contains molecular models, crosslink-topology statistics, mean-squared displacement data, free-volume and density results, density-temperature data used for glass-transition-temperature determination, reverse non-equilibrium molecular dynamics results for thermal conductivity, elastic-modulus results, figure source data, and analysis scripts for neat and crosslinked solution-polymerized styrene-butadiene rubber systems. The investigated crosslinking systems include sulfur, HVA-2, TMPTMA and TAIC. The files are organized according to the corresponding analyses and figures in the associated manuscript. Please consult 00_README.txt for file descriptions, units and instructions for reuse.
Files
Steps to reproduce
1. Open the supplied XSD/XTD molecular models using Materials Studio 2019. 2. Use the COMPASS force field for all geometry optimization and molecular dynamics calculations. Apply Ewald electrostatics with an accuracy of 1.0 × 10−4 and a van der Waals cutoff of 15.5 Å. 3. Construct the crosslinked SSBR models using Rubber_crosslinking.pl. The initial reaction cutoff is 4.0 Å and is increased in 1.0 Å increments to a maximum of 10.0 Å. Remove unreacted free crosslinker molecules after crosslinking. 4. Perform geometry optimization, followed by five 100 ps NVT annealing cycles between 200 and 500 K. Equilibrate each model for 1.2 ns under NVT conditions at 298 K, followed by 1.2 ns under NPT conditions at 298 K and 101 kPa. Use a time step of 1 fs. 5. Run count_crosslink_connections.pl to determine N1, N2, N3 and direct C-C connections. Calculate the effective connection number as Neff = N2 + 2N3 + NC-C. Historical and final model names are listed in model_name_mapping.csv. 6. Calculate mean-squared displacement from the equilibrated trajectories. Calculate free volume using the Atom Volumes & Surfaces module with a Connolly surface, a van der Waals scale factor of 1.000, a probe radius of 1.000 Å and a grid interval of 0.750 Å. 7. Determine glass-transition temperature from NPT simulations between 100 and 400 K at 25 K intervals. Fit the glassy and rubbery density-temperature regions separately and use their intersection as Tg. 8. Calculate thermal conductivity using thermal_conductivity_RNEMD.pl. Divide the periodic cell into 40 slabs along the z direction and use slabs 0 and 20 as the heat-exchange regions. Exchange velocities every 250 time steps. Perform 500 exchanges under NVT conditions to establish the temperature profile, followed by 1,000 exchanges under NVE conditions for production analysis. 9. Calculate the elastic properties using the Forcite Mechanical Properties task with the constant-strain method, four strain steps and a maximum strain amplitude of 3.0 × 10−3. Report the Hill-averaged bulk, shear and Young’s moduli. 10. Use the supplied raw outputs, source tables and analysis scripts to reproduce the reported topology statistics, MSD, free-volume fraction, density, Tg, thermal conductivity and elastic-modulus results. File integrity can be checked using upload_archive_checksums.csv.
Institutions
- Qingdao University of Science and TechnologyShandong, Qingdao