Strategies to improve segregated polymer composites for electronics
Tailored processing and advanced predictive models can reportedly enhance electrical, thermal and mechanical properties.
Researchers at Jeonbuk National University, South Korea, have found a way to suppress this micro-void formation, by incorporating a lower-melting-point polymer.
Segregated conductive polymer composites (S-CPCs) are said to have potential for managing electrical interference and dissipating heat in portable and wearable electronic devices.
Integrated high-performance components and wireless communication technologies can increase the risk of electromagnetic interference (EMI), heat accumulation and device degradation.
The S-CPCs contain conductive filler networks, concentrated along polymer boundaries, that enable high electrical and thermal conductivity even with low amounts of filler. However, microscopic voids that form during processing restrict the amount of filler that can be added, weakening mechanical strength.
Advanced percolation models incorporating excluded volume effects in segregated composites via nano-interconnection and micro-void structure optimization, published in Advanced Composites and Hybrid Materials, explains how the team blended polypropylene (PP), which melts at 150°C, with PP terpolymer that melts at 130°C.
They produced two-types of S-CPCs – one using graphite nanoplatelet (GNP) conductive fillers (G-SCs) and the other with hexagonal boron nitride (h-BN) fillers (B-SCs).
By analysing the composites’ internal structures using micro-computed tomography, the researchers reportedly identified excluded volume – regions inaccessible to fillers – and micro-voids as key structural features influencing performance.
They also found G-SCs and B-SCs were able to incorporate up to 4.93% and 12.15% more filler material respectively. The G-SCs exhibited up to 124.07% and 68.11% increase in electrical and thermal conductivity respectively, while the B-SCs achieved up to a 53.54% improvement in thermal conductivity.
The team also incorporated the excluded volume and micro-void effects into conventional percolation theory to create new segregated percolation models for future materials design.
They claim their models accurately predicted the composites’ conductive behaviour, showing strong agreement with experimental results.
‘The materials developed…can be immediately utilised as next-generation EMI shielding and thermal management solutions,’ claims Professor Seong Yun Kim.
