Deformation dynamics of h-BN reinforced polyethylene nanocomposite under shock/impact loading

The aim of this article was to reveal the dynamic and structural response of hexagonal boron nitride (h-BN) reinforced polyethylene (PE) nanocomposites under shock/impact loading. Micro and nano scale deformation dynamics of h-BN reinforced PE nanocomposites were captured using experimental and atomistic-based combined approaches. The experimental approach was adopted to investigate the effect of fabrication techniques and the concentration of boron nitride nanoplatelets (BNNP) on the impact behavior of PE-based nanocomposites. The impact strength of nanocomposites was studied with the help of differential scanning calorimetry in conjunction with the plastic deformation governing mechanism captured using the micrographs of scanning electron microscopy (SEM). It was reported from the experiments that the crystallinity of BNNP/PE nanocomposites is significantly affected by the fabrication technique. The BNNP/PE nanocomposites fabricated with the solvent blending method show superior impact strength as compared to samples fabricated using the colloidal solution method at the same BNNP weight concentration of 5%. It was also revealed from the SEM observations that the addition of BNNP to the PE matrix shifts the plastic deformation mechanism from a combination of craze and drawing of fibrils in pure PE to brittle failure in BNNP/PE nanocomposites. To complement the experimental observations, molecular dynamics-based simulations were performed to study the effect of orientation and distribution of boron nitride nanosheets (BNNS) on shock mitigation capabilities of BNNS/PE nanocomposite. It was predicted from MD simulations that a parallel oriented nanosheet remains longer in contact with the shock, which helps in dissipating energy from the shock wave. As compared to stacked, dispersed nanosheets have superior shock attenuation capabilities. These findings could be helpful to design a roadmap for shock wave mitigation through impedance mismatch and energy disruption across the multiple interfaces of BNNS and polymer matrix.

Automated summary

This article investigates the dynamic and structural response of h-BN reinforced PE nanocomposites under shock loading, revealing the importance of fabrication techniques and BNNP concentration in impacting the impact strength and plastic deformation mechanisms. Additionally, molecular dynamics simulations show that the orientation and distribution of BNNS play a crucial role in shock mitigation capabilities.