TY - JOUR
T1 - An investigation of the influence of matrix properties and fibre–matrix interface behaviour on the mechanical performance of carbon fibre-reinforced PEKK and PEEK composites
AU - Ramaswamy, Karthik
AU - Modi, Vedant
AU - Rao, Pavan S.
AU - Martin, Pedro P.
AU - McCarthy, Conor T.
AU - O'Higgins, Ronan M.
N1 - Publisher Copyright:
© 2022
PY - 2023/2
Y1 - 2023/2
N2 - Poly-ether-ketone-ketone (PEKK) is an emerging alternative to poly-ether-ether-ketone (PEEK) as a matrix for high-performance carbon fibre (CF) reinforced composites. Herein, the results of an experimental investigation to examine the influence of matrix properties and fibre–matrix interface behaviour on the mechanical performances of CF/PEKK and CF/PEEK composites are presented. CF/PEKK presents superior strength under longitudinal tension, longitudinal and transverse compression, as well as in-plane shear. It also exhibits better interfacial shear strength (IFSS) than CF/PEEK, which contributes to its superior strength, as damage typically initiates at the fibre–matrix interface under in-plane loading. Predictions of different analytical models adopted from the literature, which assess the influence of fibre–matrix adhesion on the in-plane strength, compare favourably to the experiments. Under cyclic shear tests, CF/PEKK exhibited more gradual stiffness reductions and low shear plasticity until 5% shear strain, indicating a more damage tolerant matrix. Relative to CF/PEEK, CF/PEKK presents superior interlaminar shear strength (ILSS) and mode I fracture toughness (GIC), but similar mode II fracture toughness (GIIC). High GIC is due to a synergistic interaction between its inherently ductile matrix and high IFSS, while ILSS strongly correlates with IFSS. Overall, CF/PEKK offers a better combination of strength and toughness, exceeding CF/PEEK.
AB - Poly-ether-ketone-ketone (PEKK) is an emerging alternative to poly-ether-ether-ketone (PEEK) as a matrix for high-performance carbon fibre (CF) reinforced composites. Herein, the results of an experimental investigation to examine the influence of matrix properties and fibre–matrix interface behaviour on the mechanical performances of CF/PEKK and CF/PEEK composites are presented. CF/PEKK presents superior strength under longitudinal tension, longitudinal and transverse compression, as well as in-plane shear. It also exhibits better interfacial shear strength (IFSS) than CF/PEEK, which contributes to its superior strength, as damage typically initiates at the fibre–matrix interface under in-plane loading. Predictions of different analytical models adopted from the literature, which assess the influence of fibre–matrix adhesion on the in-plane strength, compare favourably to the experiments. Under cyclic shear tests, CF/PEKK exhibited more gradual stiffness reductions and low shear plasticity until 5% shear strain, indicating a more damage tolerant matrix. Relative to CF/PEEK, CF/PEKK presents superior interlaminar shear strength (ILSS) and mode I fracture toughness (GIC), but similar mode II fracture toughness (GIIC). High GIC is due to a synergistic interaction between its inherently ductile matrix and high IFSS, while ILSS strongly correlates with IFSS. Overall, CF/PEKK offers a better combination of strength and toughness, exceeding CF/PEEK.
KW - Carbon-fibre
KW - Crystallinity
KW - Fibre-matrix adhesion
KW - Fractography analysis
KW - In-plane tests
KW - Interlaminar tests
KW - Poly-ether-ether-ketone (PEEK)
KW - Poly-ether-ketone-ketone (PEKK)
UR - http://www.scopus.com/inward/record.url?scp=85143798736&partnerID=8YFLogxK
U2 - 10.1016/j.compositesa.2022.107359
DO - 10.1016/j.compositesa.2022.107359
M3 - Article
AN - SCOPUS:85143798736
SN - 1359-835X
VL - 165
JO - Composites Part A: Applied Science and Manufacturing
JF - Composites Part A: Applied Science and Manufacturing
M1 - 107359
ER -