Composite material for electric heating and overheat protection and prepn. thereof

Abstract

This invention discloses a kind of composite materials for electroheating and thermal-overload protection, which comprises 4~7wt% carbon nanotubes and 96~93wt% high-density polyethylene. In this invention, melting blending is adopted and the steps are as follows: carbon nanotube powders and high-density polyethylene particles are weighed according to the ratio above and put into a mould after mixing to homogeneity at a temperature of 140~170 deg. C. The mixture is first preheated at a temperature of 165~180 deg. C for 5~20 minutes and compressed under a pressure of 5~20MPa and 10~30MPa for 5~20 minutes, respectively. It is then demoulded and cooled to room temperature. The composite materials in this invention adopt high-density polyethylene as matrix and carbon nanotubes as additives and have the advantages of lower additive amount compared to carbon black and no damnification to matrix continuity. This kind of materials has good PTC properties which promise both electroheating and thermal-overload protection functions and self-limited temperatures. Besides, this invention also has the advantages of simple technique, easy operation and considerable repeatability and is thus suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a composite material for electric heating and overheating protection and a preparation method thereof. Background technique [0002] Carbon nanotubes are a new material discovered in the early 1990s. They are rolled up from graphite layers in a certain way. According to the number of layers formed, they can be divided into single-walled carbon nanotubes and multi-walled carbon nanotubes. It is a typical representative of one-dimensional nanomaterials that has attracted widespread attention in the field of nanomaterials research. Due to their excellent electrical, mechanical and thermal properties, carbon nanotubes have good application prospects in many fields such as field emission, microwave absorption, electrode materials, and general-purpose polymer materials. All countries in the world have increased their further application research. Devotion. [0003] Polymer materials generally have advantages such as easy molding, b...

AI Technical Summary

Problems solved by technology

Materials with PTC effect basically used PTC ceramics in the past, and now there are carbon black-polymer composite materials, but due to the poor conductivity of carbon black, it not only requires a large amount of addition, but also reduces the continuity of the polymer matrix material, resulting in Its strength is destroyed and its performance decreases

Images