Carbon fibres type
HM (high modulus) are
carbon fibres with a value of
Young's modulus (tensile modulus) larger than
(nearly 30% of the
elastic constant of a
graphite single crystal).
Note:
The level of the tensile modulus of carbon fibres is controlled by the degree of preferred orientation of the layer planes in the direction parallel to the fibre axis.
, the elastic constant of
graphite single crystals in the direction of the layer planes, is
. In general, the ratio of tensile strength to tensile modulus is smaller than
for carbon fibres type
HM (but the tensile strength is influenced by flaws in the fibres and may be improved in the future). Carbon fibres type
UHM (ultra-high modulus) have moduli of elasticity in excess of
,
surpassing 50% of the theoretical
number. Such high values of
Young's modulus can be achieved most readily in
mesophase pitch-based carbon fibres (
MPP-based carbon fibres).
Source:
PAC, 1995, 67, 473
(Recommended terminology for the description of carbon as a solid (IUPAC Recommendations 1995))
on page 481
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
doi:10.1351/goldbook.
