Mechanical and thermal properties of cellulose nanofiber composites with nanodiamond as nanocarbon filler

Takashi Kato,Takuya Matsumoto,Chizuru Hongo,Takashi Nishino

doi:10.1080/20550324.2018.1550924

Abstract

Cellulose nanofibers are green nanomaterials because of their biodegradability and sustainability, they are also attractive structural materials because of their high mechanical performance. For further expansion of their application and acquisition of their reliability, mechanical reinforcement and functionalization of cellulose nanofiber materials are required. In this work, we focused on the mechanical properties and thermal conductivities of composites of cellulose nanofibers and a nanodiamond (ND). Compared with graphene oxides, which are conventional two-dimensional nanocarbon fillers in aqueous media, natural diamond possesses a much larger modulus. It also has the highest thermal conductivity among all the elemental substances. The ND possesses hydrophilic oxygen functional groups at the surface, following a high dispersion in aqueous media and the rigid diamond structure at the core. In this work, the ND resulted in an increased mechanical reinforcement and enhancement of the thermal conductivity of the cellulose nanofiber, while keeping the high visible light transmittance originating from the latter. In particular, 2,2,6,6-tetramethylpiperidine 1-oxyl-oxidized cellulose nanofibers were reinforced more effectively than quaternary ammonium cellulose nanofibers because of the stronger interaction with the ND and higher dispersibility of the ND. Accordingly, it was proved that the cellulose nanofiber/ND composite was a promising high-strength and high-thermal-conductive material.

Highlights

Cellulose nanofiber is a prominent research topic as a ‘green’ and ‘nano’ material owing to its robust mechanical properties [10,11]
The purified kenaf fibers were reacted with glycidyltrimethylammonium chloride (GMAC), and quaternary ammonium cellulose nanofibers (QCN) were prepared as per the reported method
1615 cm1 were observed, which indicated that the hydroxyl groups at the 6-position of cellulose were translated to carboxyl groups [59]

Summary

Introduction

Cellulose is one of principal components in cell walls [1,2] and has been accepted as an architectural material and hull material since ancient times. For achieving an increased material performance, various bio-based polymers have been composited with diverse nanofillers [3,5,11,12,13] Nanocarbon materials, such as fullerene [14,15], carbon nanotube [16,17,18,19], graphene [20,21,22,23,24], graphene oxide (GO) [25,26,27,28,29,30] and nanodiamond (ND). ND is accepted as a mechanical- and thermal-reinforcement filler in composites owing to their large modulus and thermal stability [28,36,37,39,40] For this decade, cellulose nanofiber is a prominent research topic as a ‘green’ and ‘nano’ material owing to its robust mechanical properties [10,11]. The effects of GO fillers on the mechanical and thermal properties of the cellulose nanofiber composites were evaluated and compared with the results of the ND loading

Materials and methods

Results and discussion

Conclusions