Effect of networked hybridized nanoparticle reinforcement on the thermal conductivity and mechanical properties of natural rubber composites

J M A R B Jayasinghe; R T De Silva; Rohini M de Silva; K M Nalin de Silva; M M M G P G Mantilaka; Vinod Asantha Silva

doi:10.1039/c8ra08543a

Effect of networked hybridized nanoparticle reinforcement on the thermal conductivity and mechanical properties of natural rubber composites

RSC Adv. 2019 Jan 2;9(2):636-644. doi: 10.1039/c8ra08543a.

Authors

J M A R B Jayasinghe^{1

2}, R T De Silva², Rohini M de Silva¹, K M Nalin de Silva^{1

2}, M M M G P G Mantilaka², Vinod Asantha Silva^{3

4}

Affiliations

¹ Department of Chemistry, University of Colombo Colombo 00300 Sri Lanka rohini@chem.cmb.ac.lk.
² Sri Lanka Institute of Nanotechnology (SLINTEC), Nanotechnology and Science Park Pitipana Homagama 10200 Sri Lanka.
³ University of Moratuwa Bandaranayake Mawatha, Katubedda, Moratuwa 10400 Sri Lanka.
⁴ Global Rubber Industries Perawala Estate, Badalgama 11538 Sri Lanka.

Abstract

Thermal conductivity of natural rubber (NR) was enhanced by incorporating novel conductive hybrid nanofillers, namely polyaniline grafted carbon black (PANI/CB) nanoparticles and carbon black nanoparticles linked with carbon microfiber (CF/CB) composites. The PANI/CB hybrid fillers were synthesized using an in situ method, where aniline monomers were initially adsorbed onto carbon black spherical domains and, afterwards, it was polymerized in the presence of an oxidizer. Final rubber composites were prepared through melt mixing, where PANI/CB and CF/CB filler loading was kept at 40 parts per hundred of rubber (phr). The thermal conductivity values of the rubber composites with CF/CB (20 : 20) and PANI/CB (20 : 20) yield were 0.45 W m^-1 K^-1 and 0.31 W m^-1 K^-1, respectively and the thermal conductivity improved significantly compared to the control (0.25 W m^-1 K^-1) sample. The higher thermal conductivity values of CF/CB and PANI/CB incorporated composites suggest that the generated networked structure of CF and PANI nanofibers with CB nanoparticles has immensely contributed to enhancing the heat dissipation compared to that of the neat CB rubber composite. Scanning electron micrographs (SEM) confirmed the attachment of the synthesized PANI onto the spherical CB nanoparticles and interconnected morphology of CF/CB and PANI/CB hybrid fillers. The synthesized PANI/CB hybrid filler was further characterized using Fourier-transform infrared (FTIR) spectroscopy to evaluate the chemical properties. Furthermore, thermogravimetric analysis revealed the higher thermal stability of CF/CB (20 : 20) and PANI/CB (20 : 20) composites compared to the control. Moreover, the addition of CF/CB (20 : 20) and PANI/CB (20 : 20) improved the mechanical properties such as ultimate tensile strength, modulus at break, resilience and abrasion resistance significantly and well above the minimum required standard mechanical parameters in the tyre industry. These reinforced composites show great potential to be used as heat dissipating rubber composites in the tyre industry.