Carbonized polybenzoxazine for electromagnetic interference shielding

• Published in: Materials chemistry and physics 2019-10, Vol.236, p.121806, Article 121806
• Main Authors: Zhang, Shuai, Ran, Qichao, Fu, Qiang, Gu, Yi
• Format: Article
• Language: English
• Subjects: Aldehydes; Carbonization; Conductivity; Electrical resistivity; Electromagnetic shielding; EMI shielding; Heat treatment; Ketones; Organic chemistry; Polybenzoxazine; Polybenzoxazines; Pyrolysis; Raman spectroscopy; Superhigh frequencies; Thermal stability; X ray photoelectron spectroscopy
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2019.121806

A kind of highly thermally stable polybenzoxazine prepared from the monomer bearing both acetenyl and aldehyde groups was treated at different temperatures till 1000 °C. The evolution of the chemical structures of the products during the heat treatment process was studied by FTIR, EA, XRD, XPS and Raman spectroscopy. It is learned that the pyrolysis process dominates below 600 °C while the carbonization plays a leading role when the temperature rises above 800 °C. Polybenzoxazine can rapidly carbonize and form N-containing heterocyclic structures such as pyridine, pyridinium and O-containing structures like cyclic ketones and ether groups at high temperatures (>800 °C). The resultant carbonaceous material treated at 1000 °C shows the electrical conductivity as high as 2.36 S/m, which is nine orders of magnitude higher than that of polybenzoxazine. Consequently, a 1 mm thick carbonaceous material shows an electromagnetic interference shielding effectiveness (EMI SE) more than 24 dB over the range of X-band, which means 93.7% of incident electromagnetic energy can be blocked. [Display omitted] •Systematic study of carbonization process of a highly thermally stable polybenzoxazine.•Electrical conductivity of 2.36 S/m and thermal conductivity of 0.6367 W/mK were obtained for the carbonized material.•The carbonized material electromagnetic interference shielding effectiveness more than 24 dB.