Improvement of delamination resistance in laminated composites with electrospun nanointerlayers

초록

Nano-interlayers were fabricated with polycarbonate by using an electrospinning process to improve delamination resistance in laminated composites. The laminates were laid up without and with the nano-interlayers having the stacking sequence of [30/-30/90]s and tested under uniaxial tensile loading. Five nano-interlayers in the form of the electrospun nanofiber mats were placed at every ply interfaces. A mixture ratio of THF/DMF solvent at 6:4 yields the optimal nanofiber formation for the polycarbonate. With this solvent ratio, average diameters of the nanofibers for the 16 wt.-% and 18 wt.-% of the polycarbonate are 250 nm and 350 nm, respectively. Thickness difference of the laminates without and with five nano-interlayers is less than 0.001 mm. First-ply-failure stress, delamination stress and ultimate strength increased 8.4%, 8.1% and 9.8% with the addition of the nano-interlayers as compared with the pristine specimens. The number of microcracks at the delamination stress decreases significantly by 21.6% with the addition of the nano-interlayers. Therefore, the ultra thin electrospun nano-interlayer cannot only suppress the microcracking and delamination damage by reducing the interlaminar stress concentration at the free edges in the laminated composites, but increase the ultimate strength property as well.