# Multifunctional Biocomposites based on Polyhydroxyalkanoate and Graphene/Carbon-Nanofiber Hybrids for Electrical and Thermal Applications

**Authors:** Pietro Cataldi, Pietro Steiner, Thomas Raine, Kailing Lin, Coskun Kocabas, Robert J. Young, Mark Bissett, Ian A. Kinloch, Dimitrios G. Papageorgiou  
**arXiv:** [2005.08525](https://arxiv.org/abs/2005.08525)  
**Date:** 2020-05-18  
**Summary page:** https://www.summarizepaper.com/en/paper/2005.08525v1/

## Key points

- Bio-based and biodegradable plastics, such as polyhydroxyalkanoate (PHA), are being explored as sustainable alternatives to traditional fossil fuel-derived plastics.
- PHA has potential in various applications but is limited to packaging, cosmetics, and tissue engineering due to its subpar physical properties.
- Researchers are developing nanocomposites using PHAs as the polymer matrix to expand their applications.
- Incorporating graphene nanoplatelets (GNPs) and carbon nanofibers (CNFs) into a PHA biopolyester matrix through melt blending results in hybrid nanocomposites with enhanced thermal stability and increased Young's modulus.
- The hybrid nanocomposites show improved electrical conductivity at lower nanofiller loadings compared to systems with only GNPs.
- The hybrid material demonstrates superior electromagnetic interference shielding performance and thermal conductivity compared to pure GNPs nanocomposites.
- These multifunctional bio-nanocomposites offer promise for expanding the application range of PHAs and enhancing environmental sustainability in the plastic industry.

## Summary

In the quest for more sustainable alternatives to traditional plastics derived from fossil fuels, bio-based and biodegradable plastics have emerged as promising options. Among these alternatives, polyhydroxyalkanoate (PHA) stands out for its potential in various applications. However, its use has been limited primarily to packaging, cosmetics, and tissue engineering due to its subpar physical properties. To expand the range of applications for PHA, researchers have turned to developing nanocomposites where PHAs serve as the polymer matrix. In a recent study published in ACS Applied Polymer Materials, researchers investigated the incorporation of graphene nanoplatelets (GNPs) and carbon nanofibers (CNFs) into a PHA biopolyester matrix through melt blending. The resulting hybrid nanocomposites exhibited enhanced thermal stability and a significant increase in Young's modulus compared to pure PHA. Notably, the hybrid nanocomposites showed improved electrical conductivity at lower nanofiller loadings compared to systems with only GNPs. At a 15 wt.% loading, the electrical conductivity was approximately six times higher than that of GNP-based samples. Moreover, the hybrid material demonstrated superior electromagnetic interference shielding performance compared to pure GNPs nanocomposites, with a shielding effectiveness exceeding 20 dB – a threshold suitable for common commercial applications. The thermal conductivity of both types of bio-nanocomposites also saw a substantial increase, reaching values around 5 W K-1 m-1. The hybrid-based material displayed the best performance in terms of thermal conductivity. The proposed multifunctional materials offer promise for expanding the application range of PHAs and enhancing the environmental sustainability of the plastic and plastic electronics industry. With their solvent-free production method and compatibility with industrial processes, these bio-nanocomposites represent an innovative step towards more eco-friendly materials with diverse functionalities and applications.