Improving the swelling, mechanical, and electrical properties in natural rubber latex/carbon nanotubes nanocomposites: Effect of the sonication method

Abstract

Conductive polymeric composites are exciting for future electronic applications given the possibility to ally electrical conductivity and flexibility. However, the high viscosity of plasticized elastomers difficult the dispersion of conductive fillers in an elastomeric matrix is difficult. This research aimed to compare the use of bath or probe sonication to disperse multi-walled carbon nanotubes (MWCNT) in the lower-viscosity natural rubber latex. The MWCNT concentration varied from 0.5 to 2.5 wt%, and the coagulated compounds were vulcanized after compounding in a two-roll mill. Nanocomposite's swelling behavior was determined by Flory-Rehner crosslink density and Kraus theory, indicating better dispersion in probe sonication, which also was conducted in lesser time and applied lower energy than bath sonication. This result is evidenced through tensile strength and hardness tests, as the better MWCNT dispersion improved the reinforcement due to greater filler-matrix interaction. The electrical response was obtained by impedance spectroscopy, with higher conductivities also found in tip-sonicated samples.In addition, cyclic strain fatigue test was realized from 20% to 100% strain during 20,000 cycles with simultaneous impedance measurement, reinforcing the better distribution of MWCNT in the probe-sonicated nanocomposites with higher tensile stress (Payne's effect) and conductivity retention than bath sonicated.

Novel IP2C sensors with flexible electrodes based on plasma-treated conductive elastomeric nanocomposites

“…The central advantage is the very low viscosity of latex compared to rubber mixing in the plasticized state, which facilitates fillers dispersion. Another great advantage is the possibility of using high-power sonication to disperse fillers without damage due to the damping effect of ultrasonic waves by the latex viscous medium, as evidenced by previous research by this group [42,43].…”

Enhanced rheological properties of carbon nanotubes reinforced natural rubber/butadiene rubber nanocomposites

“…[8][9][10] It is well known that the application potential of CNT has been gravely limited due to the difficulties correlated with the dispersion of CNT in polymer matrix resulting from the strong van der Waals attractions and poor interfacial interaction between CNT and polymer. 11,12 In recent years, a variety of approaches have been proposed to improve the dispersion of CNT and to enhance the interfacial interaction between CNT and rubber matrix, such as chemical functionalization, 13 ultrasonic dispersion, 14 latex blending, 15 solution mixing, 16 and melt/mechanical compounding. 17,18 It is worth noting that most of these strategies are complicated and costly, which hinders the industrial application of CNT.…”

PI Controller for IPMC Actuators Based on Nafion®/PT Using Machine Vision for Feedback Response at Different Relative Humidities

“…The main characteristics are low density, noiselessness, miniaturization capacity, and biocompatibility 2 . For this reason, they are promising materials for a wide range of technological applications in strategic areas, such as conductive rubber composites (CRC) 3 , actuators 4,5 , sensors [6][7][8] , artificial muscles 9 , robotics 10,11 , aerospatial industry 12 , energy harvesting 13 , biomimicry 14,15 , and oil exploration 16 .…”