Standards Development

Scope

This document specifies a test method for determining the bulk electrical conductivity and volume resistivity of compressed rCF specimens prepared from milled recycled carbon fibres (rCF) using a four-probe powder resistivity measurement system. This document also provides procedures for determining appropriate sample preparation conditions, including sample amount and thermal pretreatment, for recycled carbon fibre products.

This document specifies:

a) the apparatus required for preparing compressed rCF specimens;

b) procedures for determining appropriate sample preparation conditions, including sample amount, thermal pretreatment and specimen preparation;

c) the measurement procedure for determining electrical conductivity and volume resistivity; and

d) the calculation and reporting of the test results.

Purpose

Carbon fibre reinforced polymer (CFRP) composites are increasingly used in aerospace, automotive, wind energy and other advanced industries because of their high specific strength and lightweight characteristics. Consequently, the demand for recycled carbon fibres (rCF) is steadily increasing to support resource efficiency, circular economy initiatives and carbon neutrality. Recycled carbon fibres intended for electrical conductivity evaluation are generally supplied in milled form rather than as continuous filaments. Their physical characteristics differ significantly from those of continuous carbon fibres, making conventional electrical conductivity test methods unsuitable for direct application. Therefore, a standardized test method specifically designed for milled recycled carbon fibres is required to obtain reliable and reproducible measurement results. In addition, because the characteristics of recycled carbon fibre products can vary depending on the recycling process and product type, appropriate sample preparation conditions should be determined for each product. This document specifies a standardized four-probe test method for determining the bulk electrical conductivity and volume resistivity of compressed specimens prepared from milled recycled carbon fibres. The proposed method includes procedures for determining appropriate sample preparation conditions, including sample amount and thermal pretreatment, as well as standardized procedures for specimen preparation, measurement and data analysis to improve the reliability and reproducibility of test results.