Rheological and Mechanical Properties of Thermoplastic Crystallizable Polyimide-Based Nanocomposites Filled with Carbon Nanotubes: Computer Simulations and Experiments

Abstract

Recently, a strong structural ordering of thermoplastic semi-crystalline polyimides near single-walled carbon nanotubes (SWCNTs) was found that can enhance their mechanical properties. In this study, a comparative analysis of the results of microsecond-scale all-atom computer simulations and experimental measurements of thermoplastic semi-crystalline polyimide R-BAPB synthesized on the basis of dianhydride R (1,3-bis-(3′,4-dicarboxyphenoxy) benzene) and diamine BAPB (4,4′-bis-(4″-aminophenoxy) biphenyl) near the SWCNTs on the rheological properties of nanocomposites was performed. We observe the viscosity increase in the SWCNT-filled R-BAPB in the melt state both in computer simulations and experiments. For the first time, it is proven by computer simulation that this viscosity change is related to the structural ordering of the R-BAPB in the vicinity of SWCNT but not to the formation of interchain linkage. Additionally, strong anisotropy of the rheological properties of the R-BAPB near the SWCNT surface was detected due to the polyimide chain orientation. The increase in the viscosity of the polymer in the viscous-flow state and an increase in the values of the mechanical characteristics (Young’s modulus and yield peak) of the SWCNT-R-BAPB nanocomposites in the glassy state are stronger in the directions along the ordering of polymer chains close to the carbon nanofiller surface. Thus, the new experimental data obtained on the R-BAPB-based nanocomposites filled with SWCNT, being extensively compared with simulation results, confirm the idea of the influence of macromolecular ordering near the carbon nanotube on the mechanical characteristics of the composite material.

Preparation and Characterization of High-Density Polyethylene with Alternating Lamellar Stems Using Molecular Dynamics Simulations

“…Molecular simulation requires an appropriate semi-crystalline model that mimics bulk behavior through which numerical analysis and analytically solving the equations of motion can be carried out. In addition to this, advancements in MD simulation, which can document the molecular chain behavior over a millisecond time scale provided for polymers represented either as a united atom (UA) or as coarse-grained (CG) models, are indispensable for preparing a simple, more affordable HDPE semi-crystalline model structure comprising random or zigzag amorphous regions and ordered crystalline lamellar segments [ 6 , 7 , 8 , 9 , 10 , 11 ]. By taking advancements of UA or CG modeling in MD simulations, the macroscopic mechanical recycling methods would be simulated to predict the microstructure–mechanical property behavior [ 6 ].…”

Comparison of properties of carbon reinforced plastic obtained on the basis of semicrystalline polyimideR‐BAPBand other high‐temperature‐resistant thermoplastic matrices

“…The higher interlaminar fracture toughness values observed for CFRP based on R‐BAPB as compared to CFRPs based on PEEK or PEI may be because of a higher level of intermolecular interactions, which are largely due to the presence of a biphenyl fragment in the BAPB diamine (see Figure 8a). Intermolecular interactions in this kind of polyimides are usually associated with π–π interactions 37,38 . Strong intermolecular interactions can lead to both strengthening of the matrix and improvement of the relationship at the matrix‐fiber interface.…”

“…Intermolecular interactions in this kind of polyimides are usually associated with π-π interactions. 37,38 Strong intermolecular interactions can lead to both strengthening of the matrix and improvement of the relationship at the matrix-fiber interface. The most significant change in the parameter G 1C with increasing temperature is observed for CFRPs based on PEEK (Figure 7).…”

Effects of Hygrothermal Aging and Cyclic Compressive Loading on the Mechanical and Electrical Properties of Conductive Composites

“…Finally, the composites maintained good sensitivity after hygrothermal ageing and cyclic loading, indicating their greater potential for application in the field of monitoring in complex environments. Alternatively, a combination with dynamic computer simulations [ 33 , 34 ] can be used to evaluate the effect of fillers on composite properties.…”