Enhanced mechanical properties of functionalized BN nanosheets-polymer composites

Abstract

Liquid exfoliated, hydroxylated functionalized hexagonal boron nitride nanosheets (h-BNNSs-OH) are prepared for improved dispersion in polymers. Polymer nanocomposites are fabricated using (0–0.03 Vf) hydroxyl (OH) functionalized and non-functionalized BNNSs with poly methyl methacrylate, PMMA, by solution mixing for comparative study. Mechanical properties of the composites are improved considerably. The maximum ultimate tensile strength of the functionalized BN/PMMA (0.003 Vf BN) reached to ~ 26 MPa as compared to non-functionalized composites maximum value of ~ 19 MPa while the base polymer value remained at ~ 15 MPa. The Young’s modulus enhanced as well from 1.45 GPa (PMMA) to 2.01 GPa and 2.19 GPa both for non-functionalized and functionalized composites respectively. The degree of reinforcement validated with the Halpin–Tsai Model is in close agreement for functionalized polymer nanocomposites. Structural and morphological characteristics are analyzed using X-ray Diffraction (XRD) and scanning electron microscopy (SEM) respectively, confirming the composites formation. The lateral dimension of the synthesized nanosheets is estimated with SEM as well. Dimensional analysis of nanosheets is carried out using atomic force microscopy (AFM). The estimated thickness of functionalized hBN flakes was around 5–10 nm. Fourier transform infra-red spectroscopy (FTIR) is used to confirm the presence of functional groups on h-BN. Differential scanning calorimeter (DSC) is used to study the polymer and nanosheets interactions.