Trinh Anh Truc

Tensile, rheological properties, thermal stability, and morphology of ethylene vinyl acetate copolymer/silica nanocomposites using EVA-g-maleic anhydride

In this article, we present a study on the properties of ethylene vinyl acetate copolymer/silica nanocomposites prepared in absence and presence of EVA-g-maleic anhydride as a compatibilizer between silica nanoparticles and ethylene vinyl acetate matrix. A series of ethylene vinyl acetate/silica nanocomposites with different contents of silica nanoparticles were prepared by solution method. EVA-g-maleic anhydride with 0.5 wt% maleic anhydride groups was added to all ethylene vinyl acetate/silica nanocomposites. Fourier transform infrared, field emission scanning electron microscopy, rheology behavior, and thermogravimetry analysis were used to characterize the structure, morphology, rheological, and thermal properties of the nanocomposites, respectively. The Fourier transform infrared spectra and field emission scanning electron microscopy micrographs showed that the hydroxyl groups on the surface of silica nanoparticles interact with maleic anhydride groups in EVA-g-maleic anhydride and lead to a finer dispersion of individual silica nanoparticles in the ethylene vinyl acetate matrix. The rheological properties and thermal stability of ethylene vinyl acetate/silica nanocomposites were significantly increased after adding EVA-g-maleic anhydride into the nanocomposites. Mechanical properties including tensile strength and elongation at break of the nanocomposites were mainly affected by the content of silica nanoparticles. For the tensile strength as well as elongation at break of the nanocomposites, a maximum value was observed at the content of 0.5 wt% of silica nanoparticles. The addition of EVA-g-maleic anhydride into ethylene vinyl acetate/silica nanocomposites resulted in a further improvement of mechanical properties of the nanocomposites.

Improvement of Mechanical and Dielectric Properties of Epoxy Resin Using CNTs/ZnO Nanocomposite

In this study, carbon nanotubes (CNTs)/ZnO composites had been prepared using the sol-gel method and then incorporated into an epoxy resin for reinforcement of mechanical and electrical properties. Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) Field Emission Scanning Electron Microscope (FE-SEM) analyses show that the ZnO nanoparticles deposited on CNTs were crystallized in a hexagonal wurtzite structure. Average particle size of ZnO deposited on the CNT was about 8 nm. The mechanical and dielectric properties of epoxy containing CNTs/ZnO were investigated in comparison to epoxy resin and epoxy resin containing only CNT or ZnO nanoparticles. The results indicated that tensile strength and elongation at break of the nanocomposite were substantially improved with the presence of CNTs/ZnO at the equal volume. The DSC analysis associate with the dielectric results shows that the behavior of epoxy/CNTs/ZnO is identical to epoxy/ZnO composite, and the CNTs is essential to the distributed arrangement of ZnO in the epoxy resin.

Study on preparation, morphology, and some properties of EVA/silica nanocomposites

The effect of Silica Nanoparticles (SNP) on the structural, morphologial mechanical, rheological and thermal properties of ethylene vinyl acetate copolymer (EVA) containing 18 wt.% vinyl acetate has been investigated. The EVA/silica nanocomposites (ENCs) were prepared by in–situ synthesis method from tetraethoxysilane (TEOS). The obtained samples have been characterised by Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA). The optimal conditions for ENC preparation (e.g. mixing temperature and mixing time and pH value) were found. FT–IR and FESEM techniques were used for monitoring the formation and the dispersion of SNP in EVA matrix. With SNP presence, the mechanical, rheological and thermal properties of EVA are significantly improved. Among the tested ENCs, the sample 15 wt.% TEOS has the best properties.