Functionalized sepiolite intercalated graphene nanostructure reinforced polypropylene composites

The present work developed hybrid polypropylene (PP) ternary composites using PP with different contents of amine-functionalized sepiolite intercalated graphene (f-Sep-Gr) nanofillers through the melt blending method. The amine functionalization on sepiolite intercalated graphene (Sep-Gr) nanostructure was carried out using 3amino propyl triethoxyl silane. Fourier Transform-Infra Red (FT-IR), X-ray Photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis confirmed the successful functionalization of the amine group into Sep-Gr. Transmission Electron Microscopy (TEM) analysis also confirmed that the amine functionalization didn't disturb the Sep-Gr morphology. Maleic anhydride graft polypropylene (PP-g-MA) was employed as an interfacial compatibilizer to enhance the dispersion of f-Sep-Gr into the continuous PP phase via a perfect covalent bond interaction. X-ray diffraction (XRD) analysis showed a complete distribution of f-Sep-Gr into the PP/PP-g-MA blend matrix, and the intercalated structure of f-Sep-Gr was not adversely disturbed in the composite. Melt rheological analysis revealed that the composite consisting of the lower content of f-Sep-Gr (0.5 wt%), resulting in a viscous behavior, and a further increase in the content of f-Sep-Gr into the PP/PP-g-MA blend showed viscoelastic solid-like behavior. Differential scanning calorimetry (DSC) analysis revealed that the f-Sep-Gr did not accelerate the melt-crystallization process of PP. In addition, thermogravimetry analysis (TGA) showed that the thermal stability of PP/PP-g-MA/f-Sep-Gr composites improved as a function of f-Sep-Gr content. A small amount of f-Sep-Gr (0.5 wt%) increased Young's modulus and impact strength of the PP matrix, which is about 123% and 266%, respectively, compared to pure PP. TEM analysis ensured the incorporation of a small fraction of f-Sep-Gr into the blend matrix, forming a three-dimensional network structure in the composite.

Automated summary

In this study, hybrid polypropylene ternary composites were developed using amine-functionalized sepiolite intercalated graphene nanofillers. The functionalization process did not affect the morphology of the filler, and the use of an interfacial compatibilizer improved the dispersion of the filler in the polypropylene matrix. Thermal analysis showed that the addition of a small amount of filler enhanced the thermal stability and mechanical properties of the composites.