Tribological Behavior of Polymers Simulated by Molecular Dynamics

Using molecular dynamics to simulate behavior of polymer surfaces during scratch testing, we report the first results of computer simulations of scratch behavior of noncrystals. A previously described procedure for creating realistic polymeric materials on the computer [W. Brostow, A.M. Cunha, and R. Simoes, Mater. Res. Innovat. 7, 19 (2003)] and used until now to simulate mechanical behavior of metals [S. Blonski, W. Brostow, and J. Kubat, Phys. Rev. B 49, 6494 (1994)] and one- and two-phase polymers [W. Brostow, A.M. Cunha, J. Quintanilla, and R. Simoes, Macromol. Theory Simul. 11, 308 (2002); W. Brostow, A.M. Cunha, and R. Simoes, Proc. Ann. Tech. Conf. Soc. Plastics Engrs. 60, 3105 (2002)] was applied. While experiments provide only the macroscopic penetration depth and the recovery (healing) depth, the simulations give the behavior of each macromolecular chain segment at each moment in time. We report results for one-phase polymers and also for systems with varying concentrations of a liquid crystalline (LC) second-phase that acts as a reinforcement. We relate the local structure to scratch resistance and recovery. The orientation of the chemical bonds is a major factor. The presence of a LC phase improves the tribological properties; however, the effect is not as significant as might have been expected.

[1]  M. Volkenstein,et al.  Statistical mechanics of chain molecules , 1969 .

[2]  V. Mom.  On the construction of self‐avoiding chains , 1981 .

[3]  W. Brostow,et al.  Transmission of mechanical energy through polymeric liquid crystals and their blends , 1988 .

[4]  B. Alder,et al.  Phase Transition for a Hard Sphere System , 1957 .

[5]  William D. Callister,et al.  Materials Science and Engineering: An Introduction , 1985 .

[6]  Y. Termonia.  Molecular modeling of spider silk elasticity , 1994 .

[7]  Witold Brostow,et al.  Failure of Plastics , 1986 .

[8]  Kenneth J. Tupper,et al.  Molecular dynamics simulations of friction in self-assembled monolayers , 1994 .

[9]  W. Brostow,et al.  Molecular dynamics simulations of chain relaxation and crack propagation in polymer liquid crystals , 1991 .

[10]  Y. Termonia.  Modeling of Polymer Processing and Properties , 2002 .

[11]  M. Marder,et al.  Friction and fracture , 2001, Nature.

[12]  Witold Brostow,et al.  Performance of Plastics , 2000 .

[13]  R. Daniel Mauldin,et al.  The Scottish book : mathematics from the Scottish Café , 1981 .

[14]  W. Brostow,et al.  Connection of surface tension with multiple tribological properties in epoxy + fluoropolymer systems , 2003 .

[15]  J. Quintanilla,et al.  Crack Formation and Propagation in Molecular Dynamics Simulations of Polymer Liquid Crystals , 2002 .

[16]  E. Rabinowicz,et al.  Friction and Wear of Materials , 1966 .

[17]  Ranga Komanduri,et al.  MD simulation of indentation and scratching of single crystal aluminum , 2000 .

[18]  K. Mittal.  Contact angle, wettability and adhesion. , 2003 .

[19]  A. Sarkar.  Friction and wear , 1980 .

[20]  W. Brostow,et al.  Graphical modeling and computer animation of tensile deformation in polymer liquid crystals (PLCs) , 2001 .

[21]  William D. Callister,et al.  Materials science and engineering : an introduction : student learning resources , 2003 .

[22]  S. Ulam,et al.  Adventures of a Mathematician , 2019, Mathematics: People · Problems · Results.

[23]  M. Yoneya,et al.  Molecular dynamics simulations of sliding friction of Langmuir–Blodgett monolayers , 1996 .

[24]  W. Brostow,et al.  Cure progress in epoxy systems: dependence on temperature and time , 2003 .

[25]  W. Brostow,et al.  Molecular-dynamics simulations of stress relaxation in metals and polymers. , 1994, Physical review. B, Condensed matter.

[26]  W. Brostow,et al.  Effects of fluoropolymer addition to an epoxy on scratch depth and recovery , 2002 .