Sager, Ryan James (2008-05). A characterization of the interfacial and interlaminar properties of carbon nanotube modified carbon fiber/epoxy composites. Master's Thesis.
The mechanical characterization of the interfacial shear strength (IFSS) of carbon
nanotube (CNT) coated carbon fibers and the interlaminar fracture toughness of woven fabric carbon fiber/epoxy composites toughened with CNT/epoxy interleave films
is presented. The deposition of multiwalled carbon nanotubes (MWCNT) onto the
surface of carbon fibers through thermal chemical vapor deposition (CVD) was used
in an effort to produce a graded, multifunctional interphase region used to improve
the interfacial strength between the matrix and the reinforcing fiber. Characterization of the IFSS was performed using the single-fiber fragmentation test. It is shown
that the application of a MWCNT coating improves the interfacial shear strength between the coated fiber and matrix when compared with uncoated fibers. The effect
of CNT/epoxy thin interleave films on the Mode I interlaminar fracture toughness of
woven fabric carbon/epoxy composites is examined using the double-cantilever beam
(DCB) test. Initiation fracture toughness, represented by critical strain energy release rate (GIC), is shown to improve over standard un-toughened composites using
amine-functionalized CNT/epoxy thin films. Propagation fracture toughness is shown
to remain unaffected using amine-functionalized CNT/epoxy thin films with respect
to standard un-toughened composites.