Synergistic effect of carbon nanotubes and clay platelets in reinforcing properties of silicone rubber nanocomposites

Abstract

Fine powders of montmorillonite (MMT)/multiwalled carbon nanotube (MWCNT) hybrids have been prepared by simple grinding of MWCNT with MMT in different weight ratios of MMT to MWCNT (10 : 1, 6 : 1, 3 : 1, 1 : 1, and 1 : 3) and characterized by wide-angle X-ray diffraction, field emission scanning electron microscopy, and transmission electron microscopy. These studies have established the formation of the exfoliated structures of MMT/MWCNT (1 : 1) hybrid, in which MWCNTs exist in the state of single nanotubes that are adsorbed and intercalated on the surface and in between the MMT nanoplatelets. The hybrid has subsequently been used as reinforcing nanofiller in the development of high-performance silicone rubber (SR) nanocomposites, and a remarkably synergistic effect of MMT and MWCNT on SR properties has been observed. The tensile strength of SR containing 1% w/ w of the MMT/MWCNT (1 : 1) hybrid is improved by 215%, whereas the SR filled with MMT or MWCNT alone showed an improvement of 46 and 25%, respectively, over that of unfilled SR. In addition, SR/1 wt % MMT/MWCNT (1 : 1) nanocomposites also exhibit the maximum improvement in thermal stability corresponding to 10% weight loss by 70 C, crystallization and melting temperatures increased by 8 and 6 C as inferred from thermogravimetric analysis and differential scanning calorimetry, respectively. This approach is promising for the preparation of high-performance SR nanocomposites by using different dimension nanofillers together.

Multiwalled carbon nanotube/montmorillonite hybrid filled ethylene‐co‐vinyl acetate nanocomposites with enhanced mechanical properties, thermal stability, and dielectric response

“…Aggregated structure beyond this filler content indicates that presence of MMT is not enough to overcome strong interfiller attraction substantially. The observations match with the reported literatures on 3D hybrid filled polymer matrices .…”

“…Absence of characteristic (001) peak of MMT at 7.45° is probably due to its shift to below 5° (i.e., the lower limit of 2 θ of measurement) on account of extensive intercalation. Similarly absence of (002) peak of MWCNT at 25.88° indicates its uniform distribution in between MMT platelets with no aggregation in line with reported literatures . In other words, MMT really works as a dispersion promoter to substantially reduce the degree of aggregation of carbon nanotubes.…”

“…As can be clearly seen, carbon nanotubes are wrapped with aluminosilicate layers of MMT in different locations and aggregation has been prevented to a great extent. This can be attributed to significant interaction between the two fillers as previously reported by our research group based on shift in G‐band in Raman spectra, increase in intensity of C 1s peak in XPS . These work report the formation of a 3D network between MWCNT and MMT based on conclusions from tilted angle FESEM and surface profile AFM analysis.…”

“…Yang et al also demonstrated remarkable synergy between graphene platelets (MGPs) and multi walled carbon nano tubes (MWCNTs) in improving the mechanical and thermal conductivity of epoxy composites . This concept has been adopted by our research group for the preparation of a range of new generation 3D hybrid fillers such as MWCNT/MMT, MWCNT/LDH, MWCNT/graphene in the development of polymer nanocomposites of silicone rubber (SR) and thermoplastic polyurethane (TPU) . Dubois et al used polyethene coating on MWCNT in order to improve level of dispersion in EVA leading to substantial improvement in its mechanical properties and thermo‐oxidative stability .…”

Effects of Ultrasonication Time on Thermal Stability and Swelling Behaviour of The Commercial Organo-Montmorillonite (O-MMT)

“…It is clearly evident that the pristine O-MMT exists as platelets with a smooth surface and distinct bent edges [14]. The ultrasonicated O-MMT exhibits nanosize platelets with greater interlayer spacing.…”