Enhanced electromagnetic shielding and thermal performance of GNP and boron nitride infused carbon fiber/PDMS composites through magnetic field-induced GNP alignment

The present work is focused on the development of magnetic field-assisted graphene nanoplatelets (GNP) alignment in boron nitride (BN) graded short carbon fiber/ PDMS composites for the enhancement of thermal, electrical properties and electromagnetic interference (EMI) shielding effectiveness in X-band (8-12 GHz) frequency which can be used as a gasket material. A rotating magnetic field is used for the alignment of GNP in the polymer matrix while the sample is in the curing stage. Initially, BN filler is optimized using morphological study viz., x-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. It has been validated that BN with 3 wt% is an optimum filler loading having a better filler dispersion and higher filler orientation. Extending the study further on this optimized BN filler (3 wt%) in the composite, the paper also analyzes the influence of filler orientation. Electrical properties by I-V characteristics, thermal properties by performing laser flash analysis, and thermography analysis are carried out. It is observed that the electrical and thermal conductivities are greatly influenced by the alignment of filler. The lateral alignment of filler (RMF-L) samples has a uniform heat distribution and better heat transfer all over the sample. In addition, the RMF-L sample has an enhancement of EMI shielding of 53.3 dB (i.e., 99.9995% attenuation) compared to the non-oriented NMF sample with 45.3 dB. In summary, the lateral alignment of filler in the RMF-L sample led to the efficient use of nanofiller in the application of EMI shielding with better thermal and electrical properties.