Flexible nanocellulose-graphene composite membrane and preparation method thereof

Abstract

The invention discloses a flexible nano-cellulose-graphene composite film and a preparation method thereof. The mass fraction of the composite film is composed of: graphene 0.1%-90%, nano-cellulose 10%-99.9%, and the preparation steps are as follows: : (1) Prepare a graphene oxide dispersion with a concentration of 0.05-5 mg / ml and a nano-cellulose dispersion with a concentration of 0.05-5 mg / ml, ultrasonically disperse for 1-2 hours, and mix to obtain a concentration of 0.05-5 mg / ml The first dispersion liquid of nanocellulose-graphene oxide; (2) add reducing agent in the first dispersion liquid, heat up, stir, stir evenly, obtain the second dispersion liquid of nanocellulose-graphene; (3) The above-mentioned second dispersion liquid is subjected to centrifugal degassing, and then vacuum-filtered to form a composite film, and the composite film is transferred to an oven, and vacuum-dried to obtain a flexible nanocellulose-graphene composite film. There will be no agglomeration between the graphene sheets in the composite film, and its thermal conductivity in the parallel direction is ≥2W·m ‑1 ·K ‑1 , vertical thermal conductivity ≤0.3W·m ‑1 ·K ‑1 , Thermal conductivity anisotropy ratio ≥ 5.

Description

technical field [0001] The invention relates to a heat-conducting composite film, in particular to a flexible nanocellulose-graphene composite film and a preparation method thereof, belonging to the field of heat-conducting composite materials. Background technique [0002] As a new type of two-dimensional carbon nanomaterial, graphene has high thermal conductivity, high specific surface area and Young's modulus. The thermal conductivity of single-layer graphene at room temperature is as high as 5300 W m -1 •K -1 , is currently known as the material with the highest thermal conductivity, and is a very ideal thermal conductivity filler. [0003] The two-dimensional planar structure of graphene determines the regular arrangement of carbon along the plane, which can endow the composite with anisotropic properties. Anisotropic thermally conductive materials prepared by traditional polymer matrix, such as polyamide-graphene composite materials, silicone rubber-graphene composi...

AI Technical Summary

Problems solved by technology

[0004] Research on anisotropic thermally conductive materials at home and abroad, in the existing technology, the Chinese patent publication number CN103740110A, the publication date is 2014.04.23, the title of the invention is "a kind of directional flexible thermally conductive material and its molding process and application", the invention Disclosed is an oriented flexible thermally conductive material, the main components of which are silicone rubber and anisotropic thermally conductive fillers. The thermally conductive material has good thermal conductivity in a specific direction, but due to poor compatibility between graphene and silicone rubber, graphene Easy to form irreversible agglomerates in silicone rubber products

Chinese Patent Publication No. CN101407322A, publication date 2009.04.15, the title of the invention is "A Preparation Method of Anisotropic Graphite Heat-conducting Heat Sink", the method is to wash the acid-treated graphite, after high-temperature expansion, with a flexible Graphite coil production equipment is processed and formed, and the thermal conductivity of the product is significantly improved. However, due to the poor mechanical properties such as strength and toughness of pure graphite film, its popularization and application is limited.

Images