This work investigated the interfacial adhesion between carbon fibers grafted with liquid-crystalline compounds and an epoxy matrix using the "single-fiber tensile test". The liquid-crystalline monomer and its side-chain liquid-crystalline polymer contain phenolic groups and can therefore bond covalently to both carbon fibers and epoxy matrices. Their mesogenic nature also offers the possibility of forming highly ordered interfacial structures. Epoxy specimens containing a single carbon fiber embedded along their length were loaded in tension and observed in transmission by polarized light microscopy. Both stress birefringence due to plastic shear deformation of the epoxy and the fiber's critical fragmentation length, lc, were measured. Relative to specimens with ungrafted fibers or monomer-grafted fibers, those containing fibers grafted with the self-ordering polymer revealed the greatest plastic deformation in the matrix possibly caused by strong interfacial adhesion. Measurements of critical fragmentation lengths suggest the grafted liquid-crystal polymer causes toughening of the carbon fiber/epoxy interface.
|Number of pages||4|
|Journal||Chemistry of Materials|
|Publication status||Published - 1994|
ASJC Scopus subject areas
- Materials Chemistry
- Materials Science(all)