composites 2 Flashcards
1
Q
why are fibres strong?
A
molecular/crystallographic alignment. elimination of flaws. development of fine structure.
2
Q
why are glass fibres used?
A
strength is increased but NOT the stiffness
3
Q
how are glass fibres produced?
A
melt spinning
4
Q
what are the two main types of carbon fibre?
A
PAN carbon fibre (polymeric precursor) and PITCH carbon fibre (petroleum or coal tar precursor)
5
Q
how is PAN carbon fibre produced?
A
fibres wet/dry spun, heated, oxidised, cooled
6
Q
why are PAN carbon fibres used?
A
generally most cost-effective range of properties for many different applications
7
Q
why are PITCH carbon fibres used?
A
very negative thermal coefficients of expansion. high electrical conductivity. thermal conductivity up to 4 times copper.
