Low velocity impact behaviour and mechanical properties of sandwich panels with cores made from Tetra Pak waste

Sandwich panels were fabricated with aluminium faces and two different types of cores: (i) the PAC (high- and low-density polyethylene-aluminium-cellulose) core made from recycled Tetra Pak and high-density polyethylene (HDPE) containers, and (ii) the PAL (low-density polyethylene-aluminium) core produced with only recycled Tetra Pak containers. The tensile and compression tests showed that the PAC core had higher stiffness and lower ductility than the PAL core. The PAC core sandwich panel and the PAL core sandwich panel had similar tensile stiffness; however, the PALS panel exhibited higher ductility. Both sandwich panels had a similar flexural response, dominated by the aluminium sheet behaviour. The PAC core had lower thermal conductivity than the PAL core, attributed to the high cellulose content in the PAC core. The impact test results showed that for impact energies of 10 J and higher, where more extensive core deformation was observed, the peak force of the PALS panels was larger than that of the PACS panels for any given level of absorbed energy. This behaviour demonstrated the higher load-carrying capacity of the PALS panels, attributed to the higher ductility of the PAL core. In addition, the PALS panel exhibited higher penetration threshold energy than the PACS panel.