INTRODUCTION: Spongin is a naturally occurring renewable biopolymer originating from marine sponges. In cultivated bath sponges, spongin-based 3D skeletal constructs are characterised by thermostability up to 360 °C, elasticity, durability, porosity, flexibility, and compressibility. This unique biomaterial can be carbonised at temperatures over 1000 °C and transformed into graphite without losing its 3D architecture [1]. The aim of this study was to investigate the melting behaviour of steel and copper on the surface of carbonised spongin scaffolds.

METHODS: Diverse types of steel in the form of shavings or powders as well as copper powder were melted on selected carbonised spongin templates in a furnace at temperatures of 1450 ^oC/1600 ^oC in an argon atmosphere for 90 min. The obtained phases were analysed using digital optical microscopy, SEM /EDS, and elemental mapping techniques.

RESULTS: Due to the reaction of carbonised spongin with steel or copper during melting, novel, never before reported 3D composite materials were developed and characterised (Figure 1, 2).

CONCLUSIONS: Due to the nanocrystalline metallic phase which is homogenously distributed on the surface of carbonised spongin, microfibres separated from the metallised 3D constructs show the appearance of magnetic properties only in the case of iron–spongin composites.

Figure 1.Stainless-steel 316 L powder after melting on carbonised spongin scaffold at 1450 ^oC for 90 min in an argon atmosphere.

Figure 2. Construction steel EN S235JRG2 (AISI 1015) after melting on carbonized spongin scaffold at 1450 ^oC for 90 min in an argon atmosphere.

ACKNOWLEDGMENTS: This research was funded by the National Science Centre (Maestro No. 2020/38/A/ST5/00151).

REFERENCES:

[1] Petrenko et al., (2019), Sci. Adv. 5(10): eaax2805., doi: 10.1126/sciadv.