Tuning Thermal and Mechanical Properties of Polydimethylsiloxane with Carbon Fibers

Abstract

In order to meet the needs of constantly advancing technologies, fabricating materials with improved properties and predictable behavior has become vital. To that end, we have prepared polydimethylsiloxane (PDMS) polymer samples filled with carbon nanofibers (CFs) at 0, 0.5, 1.0, 2.0, and 4.0 CF loadings (w/w) to investigate and optimize the amount of filler needed for fabrication with improved mechanical properties. Samples were prepared using easy, cost-efficient mechanical mixing to combine the PDMS and CF filler and were then characterized by chemical (FTIR), mechanical (hardness and tension), and physical (swelling, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and coefficient of thermal expansion) analyses to determine the material properties. We found that hardness and thermal stability increased predictably, while the ultimate strength and toughness both decreased. Repeated tension caused the CF-filled PDMS samples to lose significant toughness with increasing CF loadings. The hardness and thermal degradation temperature with 4 wt.% CF loading in PDMS increased more than 40% and 25 °C, respectively, compared with the pristine PDMS sample. Additionally, dilatometer measurements showed a 20% decrease in the coefficient of thermal expansion (CTE) with a small amount of CF filler in PDMS. In this study, we were able to show the mechanical and thermal properties of PDMS can be tuned with good confidence using CFs.

Understanding How Metal-Ligand Coordination Enables Solvent Free Ionic Conductivity in PDMS

“…First, PDMS has a low glass transition temperature (T g ≈ −123 ℃), yielding dynamic chain motion at room temperature, which facilitates the transport of ions. 35,36 Second, PDMS has low inherent ion impurity content and low dielectric constant (κ ≈ 2.3−2.8), which serves as a non-conductive baseline and creates a clear contrast in the ionic conductivity of the polymer before and after introducing metal-ligand coordination. 37,38 Furthermore, ion interaction in the system is mainly mediated by the metal-ligand coordination rather than the solvation of polymer backbone, which offers us a good model to decouple the effect of metal-ligand coordination from other factors that contribute to the ionic conductivity.…”

Thermal, Mechanical, and Acoustic Properties of Polydimethylsiloxane Filled with Hollow Glass Microspheres

“…In certain applications of PDMS, enhancement of TC is needed, for instance to improve heat dissipation when PDMS is used as a sealant in electronics. Carbon-based fillers are considered as the most promising filler candidate [ 8 , 9 , 10 , 11 ]. Addition of 4.2 wt% of aligned graphene tubes results in 1082.14% higher TC compared to pure PDMS [ 7 ].…”

Ultrasonic photoacoustic emitter of graphene-nanocomposites film on a flexible substrate

“…The c p has been shown to decrease by introducing carbon inclusion up to 10 wt% [29] , as well as β parameter also undergoes a reduction due to the network of the filler that blocks the volume expansion. The latter is supposed to be on the order of 20 % and 30 % smaller in carbon nanofiber and tubular graphene PDMS-based structures [30] , [31] . An estimation of c p is given in Section 4 of the suppl.…”