resumo
Cork is a renewable and sustainable material, highly porous and lightweight. We valorised waste cork and recycled wine stoppers to make pyrolysed/carbonised solid cork, for use as economic and sustainable microwave (MW) absorbers at the microwave X-band (8-12 GHz), without binder or additives. Although cork is already a very lightweight material (0.16 g cm-3), the pyrolysed cork is five-times less dense at 0.031 g cm-3, was amorphous graphitic carbon, and had an excellent shielding effectiveness (SET) of -18 to -38 dB, depending on thickness, with attenuation of the electromagnetic energy through internal reflection within the cellular cork structure. Furthermore, this ultra-light-weight material has an extremely high MW specific shielding effectiveness or efficiency (SSE), between -640 to -1235 dB g-1 cm3 over the entire X-band range, depending on thickness (3.0-8.6 mm), one of the highest reported for any pure carbon material, this upper value being more than twice that of any previously reported graphite-based foams. Pyrolysed solid cork as un ultra light-weight MW absorber material in the X-band-extremely high SSE of -640 to -1235 dB g-1 cm3.
palavras-chave
CARBON FOAM; GRAPHENE FOAM; COMPOSITES; WASTE; PERFORMANCE; ADSORPTION; POWDER; FABRICATION; GRAPHITE
categoria
Chemistry; Science & Technology - Other Topics; Materials Science; Physics
autores
Pullar, RC; Novais, RM; Caetano, APF; Krishnakumar, KA; Surendran, KP
nossos autores
Projectos
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Solar thermochemical production of hydrogen based on cork Ecoceramics (H2CORK)
agradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. R. C. Pullar wishes to thank FCT grant IF/00681/2015 for supporting this work. R. M. Novais wishes to thank FCT project H2CORK (PTDC/CTM-ENE/6762/2014) and FCT grant CEECIND/00335/2017. A. P. F. Caetano thanks FCT project "Bio4MURAL" PTDC/HAR-ARQ/29157/2017. K. P. Surendran and R. C. Pullar wish to acknowledge the FCT-DST Indo-Portuguese bilateral project (INT/Portugal/P-09/2013) for supporting this work.