Relation structure propriétés dans les composites et les nanocomposites à base d’un polymère thermoplastique/silice

Abstract

The primary objective of this thesis is to develop and evaluate the performance of nanocomposites based on a thermoplastic matrix of polypropylene (PP) and high density polyethylene (HDPE) filled with fumed silica, by incorporating different contents of unmodified silica (3% and 5%) and silica modified by a coupling agent of hexadecyltrimethoxysilane type (HDTMS in 1% and 2% rate) in the presence or absence of an interface modifier such as stearic acid AS (1% and 5%). The compounds produced through melt blending in an internal mixer. An improvement in mechanical and thermal properties was observed for some formulations, particularly with the addition of 1% AS to PP/ unmodified SiO2 nanocomposites compared to HDPE/SiO2 systems. The functionalization of the silica surface by silane was effective and allowed to strengthen the interfacial interactions between silica and the PP matrix. A significant improvement in thermal stability, tensile modulus, impact resistance and dispersion of the nanoparticles was confirmed in this context by FTIR, TGA, DTG, MFI, tensile and impact tests, as well as by scanning electron microscopy (SEM) for PP/SiO2 nanocomposites in the presence of silane. All the experimental results demonstrated that the joint use of a silane coupling agent, AS interface agent and an optimal loading rate makes it possible to obtain nanocomposites with reinforced properties to offer the most efficient formulation according to the desired mechanical and thermal criteria.