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

Author(s)

Barbosa, Rafael ; Goncalves, Roger ; Tozzi, Kaique Afonso ; Saccardo, Matheus Colovati ; Zuquello, Ariel Gustavo ; Scuracchio, Carlos Henrique

• Document type: Journal article
• Source: Journal of Applied Polymer Science; v. 139, n. 23, p. 13-pg., 2022-03-10.

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. (AU)

• FAPESP's process: 18/07001-6 - Study and characterization of ionic conductive polymers used as artificial muscles: proposals for performance improvement
• Grantee: Carlos Henrique Scuracchio
• Support Opportunities: Regular Research Grants
• FAPESP's process: 20/02696-6 - Synthesis and characterization of artificial muscles based on SBS block copolymers with selective sulfonation of the phases
• Grantee: Matheus Colovati Saccardo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 20/10839-1 - Study of the influence of the cation and relative humidity of the air in the electrical response of deformation sensors based on IPMC
• Grantee: Iago Cordeiro Santa Bárbara
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 18/09761-8 - Study and development of ionic polymer/metal composites for application in actuators and sensors aiming low cost and high performance
• Grantee: Roger Gonçalves
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 20/10588-9 - Effect of metal electrode degradation on the electromechanical performance of actuators based on ionomeric polymer and metal composites
• Grantee: Marina de Sousa de Paula
• Support Opportunities: Scholarships in Brazil - Scientific Initiation