|SILVA, MICHAEL - Sao Paulo State University (UNESP)|
|SANCHES, ALEX - Sao Paulo State University (UNESP)|
|MADEIROS, ELVIO - Paraiba University|
|MATTOSO, LUIZ - Embrapa National Research Center|
|MALMONGE, JOSE - Sao Paulo State University (UNESP)|
Submitted to: Journal of Thermal Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2014
Publication Date: 3/18/2014
Publication URL: http://dx.DOI.org/10.1007/s10973-014-3719-1
Citation: Silva, M.J., Sanches, A.O., Madeiros, E.S., Mattoso, L.H., Mcmahan, C.M., Malmonge, J.A. 2014. Nanocomposites of natural rubber and polyaniline-modified cellulose nanofibrils. Journal of Thermal Analysis and Calorimetry. 117:387-392.
Interpretive Summary: The use of materials from renewable sources in reinforcing polymers has attracted great attention by researchers not only due to sustainable development and environmental conservation but also for economic interests. Among these materials cellulose, one of the most abundant materials in nature, has been highlighted due to high crystallinity, good mechanical properties, light weight, and low cost. By coating with a conductive polymer it is possible to make cellulose nanofibers with both good mechanical properties and good electrical conductivity. Natural rubber is a biobased polymer has a wide range of commercial uses because of its superior elasticity, flexibility, and resilience. In this work, conductive composites of natural rubber reinforced with cellulose fibers were created; these materials might open up novel uses for biobased materials in wearable electronics, pressure sensors, and medical applications.
Technical Abstract: Cellulose nanofibrils (CNF) were isolated from cotton microfibrils (CM) by acid hydrolysis and coated with polyaniline (PANI) by in situ polymerization of aniline onto CNF in the presence of hydrochloride acid and ammonium peroxydisulfate to produce CNF/PANI. Nanocomposites of natural rubber (NR) reinforced with CNF and CNF/PANI were obtained by casting/evaporation method. TG analyses showed that coating CNF with PANI resulted in a material with better thermal stability since PANI acted as a protective barrier against cellulose degradation. Nanocomposites and natural rubber showed the same thermal profiles to 200 C, partly due to the relatively lower amount of CNF/PANI added as compared to conventional composites. On the other hand, mechanical properties of natural rubber were significantly improved with nanofibrils incorporation, i.e., Young’s modulus and tensile strength were higher for NR/CNF than NR/CNF/PANI nanocomposites. The electrical conductivity of natural rubber increased five orders of magnitude for NR with the addition of 10 mass% CNF/PANI. A partial PANI dedoping might be responsible for the low electrical conductivity of the nanocomposites.