Strengthening the interphase of thermoplastic sandwich composites by interleaving carbon nanotube yarns

The skin/core interphase area of sandwich composites is considered a shortcoming owing to its low debonding toughness. To address this issue, it is essential to establish an appropriate modification strategy to increase the debonding toughness of the skin/core interphase. In this study, we prepared carbon fiber-reinforced thermoplastic sandwich composites and modified the skin/core interphase using resin-coated CNT-yarn fillers. We induced 10-mm-long 30-g CNT yarns in the skin/core interphase area of sandwich composites. Compared with a non-modified sandwich composite, the Mode-I energy release rate, fracture toughness, and impact toughness at the fracture initiation stage were enhanced by 111.5 %, 36.1 %, and 248.6 %, respectively. Furthermore, an adequate interphase thickness (100-300 & mu;m) was also determined for this CNT-yarn modified sandwich composite using the DCB (double cantilever beam) elastic foundation model. This study provides a proper approach to address the low debonding toughness issue of the skin/core interphase area of sandwich composites with low weight gain.