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

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. ARTICLE HISTORY

Highly Thermally Conductive Nanocomposites Prepared by the Ice-Templating Alignment of Nanodiamonds in the Thickness Direction

“…These results indicate that the ND content in the epoxy/ND composites can be controlled. In addition, in the XRD profiles of the epoxy/ND composites, the intensities of the diffraction peaks originating from the (111) plane of the NDs − increased with an increase in ND content, as shown in Figure S5 in the Supporting Information. However, no diffraction peaks of the PVA crystallites were observed because the amounts of PVA in their composites were small.…”

“…In particular, nanocarbon materials such as CNTs and nanographene are promising thermally conductive materials. Further, our group has investigated the use of composites, including nanodiamonds (NDs), for reinforcements of mechanical properties and enhancement of thermal conductivity in previous reports and developed the ND nanocomposites. − In particular, NDs are excellent electronic insulators having the diamond structure, − making them suitable as TIMs in electronic devices.…”

Surface and mechanical characterization of bionanocomposites for advanced applications: A review

“…The phase images showed that a good dispersion of CNC nanofillers was employed and no large aggregation was observed. Another study on cellulose nanofibre (CNF)/nanodiamond as nanofiller composite was reported by Kato et al 15 It was revealed that nanodiamonds prepared via detonation technique showed a spherical shape with a diameter of 10 nm and they were well dispersed in water due to their hydrophilic oxygen surface functional groups, as shown in Figure 7. It was reported that the nanodiamonds can be used as a nanofiller for improved mechanical and thermal properties of bionanocomposites.…”

Boron nitride nanosheet @ quantum‐sized diamond nanocrystal complex/epoxy nanocomposites with enhancing thermal conductivity and sufficient dielectric breakdown strength

“…The BNNS has obvious diffraction peaks at 26.7 , 41.6 , 43.7 , 50.1 , and 55.0 , consistent with their crystal planes of (002), (100), (101), (102), and (004). 47,48 DN only has a characteristic diffraction peak corresponding to a diamond crystal face of (111) at 43.8 . 49 Because the diffraction peak of DN was close to that of BNNS, there is no obvious diffraction peak of DN in the complex filler due to the its low content.…”