University of Oulu

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,

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

Saved in:
Author: Tolvanen, Jarkko1; Hannu, Jari1; Hietala, Maiju2;
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, Finland
2Fibre and Particle Engineering Research Unit, Faculty of Technology, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.5 MB)
Persistent link:
Language: English
Published: Elsevier, 2019
Publish Date: 2019-07-08


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.

see all

Series: Composites science and technology
ISSN: 0266-3538
ISSN-E: 1879-1050
ISSN-L: 0266-3538
Volume: 181
Pages: 1 - 6
Article number: 107704
DOI: 10.1016/j.compscitech.2019.107704
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: The research was funded by the projects Grelectronics (1569/31/2017, Business Finland) and 6Genesis Flagship (grant no. 318927, Academy of Finland).
Academy of Finland Grant Number: 318927
Detailed Information: 318927 (Academy of Finland Funding decision)
Copyright information: © 2019 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (