Rubber is one of the most important materials in our daily lives owing to its distinguishing elasticity. In the fabrication of rubber materials, the addition of reinforcement fillers is essential to improve poor mechanical properties of the original rubbers. One of the representative reinforcements for rubbers is Carbon black (CB). However, CB is not environmental-friendly, and generally loading of CB (~60%) is required to reinforce rubbers. To overcome these drawbacks of CB, we applied TEMPO-oxidized cellulose nanofibril (TOCN) as an alternative filler for rubbers. TOCN is a plant-derived nanomaterial with great properties such as high aspect ratios, high elastic moduli and large surface areas. In the present study, hydrogenated acrylonitrile butadiene rubber (H-NBR) was used as a rubber matrix to be reinforced with TOCNs, and we mainly focus on revealing the relationship between mechanical properties of TOCN/H-NBR composites and the TOCN nanostructures controlled by the preparation process and/or exchanging the couterions of the carboxylate groups on the TOCN surfaces. Three kinds of TOCN/H-NBR composite films with different TOCN nanostructures were prepared. The first film coded TOCN(Na+)/H-NBR(latex) was prepared by mixing an aqueous H-NBR latex and aqueous TOCN dispersions having sodium ions as couterions, casting into a glass Petri-dish and drying. The second one coded TOCN(QA+)/H-NBR(latex) was prepared by the same method as above, but TOCN had quaternary alkyl ammonium ions as substituent counterions. The last film coded TOCN(QA+)/H-NBR(solution) was prepared by mixing a H-NBR/ DMF solution and TOCN/DMF dispersions having quaternary alkyl ammonium ions. Tensile tests were conducted to investigate the effects of TOCN nanostructures on mechanical properties of the composites. The result showed that TOCN was able to greatly enhance the properties of the neat H-NBR film regardless of the nanostructures. However, the performances were remarkably different between them. For example, the TOCN(Na+)/H-NBR(latex) films showed higher Young’s modulus, while the TOCN(QA+)/H-NBR(latex) films showed larger elongation-at-break and the TOCN(QA+)/H-NBR(solution) films showed higher tensile strength. Mechanisms of these differences will be discussed in terms of different TOCN-TOCN interactions caused by the exchange of counterions or different TOCN distribution in the matrix induced by various morphologies of H-NBR and corresponding fracture behavior.

Significant effects of TEMPO-oxidized cellulose nanofibril (TOCN) nanostructures on mechanical properties of TOCN/rubber composites

251st National Meeting (2016)

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