Role of natural rubber structure in the electrical conductivity and strain sensor performance of natural rubber/carbon nanotube nanocomposites stabilized by sodium alginate

Strain-sensitive sensors utilizing nanocomposites of natural rubber (NR) were produced through latex mixing technology, employing different varieties of NR, namely, unmodified NR and epoxidized NR with 25 and 50 mol % epoxidized natural rubber (ENR25 and ENR50) respectively. A linear polysaccharide, sodium alginate (Alg), was used as an effective dispersing agent. This work revealed that the polar functional group on the rubber structure showed a positive impact on the dispersion state of carbon nanotubes (CNTs) in the nanocomposite suspensions. The incorporation of Alg as a dispersing agent in rubber nanocomposites remarkably improved the uniformity and overall performance of the nanocomposite suspensions. The results demonstrated the critical role of the polar functional group on the NR molecules in achieving an outstanding electrical conductivity of 102 S/ cm. In addition, the mechanical properties were dramatically improved with the introduction of Alg into NR, ENR25, and ENR50 filled with CNTs. Alg improved the electrical conductivity and strain sensitivity of the rubber nanocomposites and the variation of R/R0, demonstrating its beneficial effect on the strain sensor.