Biodegradable multiphase poly(lactic acid)/biochar/graphite composites for electromagnetic interference shielding

High performance electromagnetic interference (EMI) shielding materials that are of lightweight, thin, and easy-to-design are extremely important for future portable and wearable electronic and telecommunication devices. Achieving such functionalities using environmentally friendly and biodegradable materials is becoming increasingly important and adds on even more value. Herein, we demonstrate two- and three-phase composites of poly(lactic acid), graphite and biochar that can be produced in large quantities and practically in any shape or form by applying facile twin-screw extrusion and subsequent hot-pressing methods. The developed conducting polymer composites with a wide range of filler loading level enable excellent shielding with an effectiveness beyond 30 dB at K-band frequency range (18–26.5 GHz) using very thin films (0.25 mm). The corresponding specific shielding effectiveness 890 dB cm2 g−1 is particularly high among biodegradable shielding materials. The outstanding performance is due to scattering and thus increased propagation distance of electromagnetic waves in the multiphase composite medium. The presented novel environmentally friendly and biodegradable materials are not only promising for wearables and portable devices but also for other applications, where size and weight matters such as in aeronautics, astronautics and robotics.

Authors:
Tolvanen Jarkko, Hannu Jari, Hietala Maiju, Kordas Krisztian, Jantunen Heli

Publication type:
A1 Journal article – refereed

Place of publication:

Keywords:
A: biochar, A: polymers, B: electrical properties, E: extrusion

Published:
28 July 2018

Full citation:
Jarkko Tolvanen, Jari Hannu, Maiju Hietala, Krisztian Kordas, Heli Jantunen, Biodegradable multiphase poly(lactic acid)/biochar/graphite composites for electromagnetic interference shielding, Composites Science and Technology,
Volume 181, 2019, 107704, ISSN 0266-3538, https://doi.org/10.1016/j.compscitech.2019.107704

DOI:
https://doi.org/10.1016/j.compscitech.2019.107704

Read the publication here:
http://urn.fi/urn:nbn:fi-fe2019070822869