Optical spectroscopy, thermal analysis, and dynamic mechanical properties of graphene nano-platelets reinforced polyvinylchloride

Nanocomposites of graphene nano-platelets (GnPs) with different ratios were embedded in polyvinyl chloride (PVC) by a simple casting technique. DSC and TGA analysis proved that PVC/GnPs (0.5 wt% of GnPs) showed the highest thermal stability. The effects of Gnps on PVC were discussed through studying some important optical parameters besides the thermal properties. Increasing GnPs content increased the thermal stability of the nanocomposites as the residue increased from 1.9% for PVC to 9.3% upon addition of 0.5 wt% of GnPs. The penetration depth (δ), the steepness parameter (S) and the group velocity dispersion (GVD) decreased as the content of GnPs increased. Solar skin protection factor (SSPF) of PVC/GnPs (2.5 wt% of GnPs) nanocomposite improved to be 95% compared with 26% for pure PVC. The optical oscillator strengths (f) increased from 7.97 (eV)² for PVC to 90.8 (eV)² for PVC/GnPs (2.5 wt%). The dispersion energy E_d, the single oscillator energy E_o, the static refractive index (n_o), the oscillator length strength (S_o), the average interband oscillator wavelength (λ_o) were GnPs content dependent. The enhancement in the optical (σ_optical) conductivity, by increasing the content of GnPs is due to increasing the absorbance of the nanocomposite films. DMA results showed that the storage modulus was increased by 21% upon addition of 0.25 wt% of GnPs while decreased by ~ 31% upon increasing GnPs ratio up to 2.5 wt%.