Influence of the solvent sorption, additivation, and chemical modification on the molecular mobility dynamics of Polyamide 6,6 amorphous phase and its consequences on the tensile and impact strength properties of this polymer

• Main Author: Rios de Anda, Agustin
• Language: English
• Published: Université Claude Bernard - Lyon I 2012
• Subjects: [CHIM:OTHE] Chemical Sciences/Other; [CHIM:OTHE] Chimie/Autre; Polyamide; Amorphous phase; Molecular mobility; Polymer-solvent interaction; Shock and mechanical properties; Glass transition
• Online Access: http://tel.archives-ouvertes.fr/tel-00933978; http://tel.archives-ouvertes.fr/docs/00/93/39/78/PDF/TH2012Rios-deAndaAgustin.pdf

This work forms part of a project aimed to develop Polyamide 6,6(PA6,6)-based automotive fuel tanks. PA6,6 is a good candidate for technical applications since it possesses good thermo-mechanical properties compared to its weight. These formulations must exhibit good impermeable properties to classic gasoline, to biofuels (gasoline containing ethanol), and to water which is found in the atmosphere, while keeping good impact behavior.The scientific issues are the better understanding of PA6,6-solvent interactions in the case of a series of solvents having different sizes and polarities and also for a set of ternary mixtures composed of ethanol, toluene, and isooctane at various concentrations that model biofuels. The effect of these solvents on the glass transition temperature Tg (molecular mobility signature) was assessed. The effect of additivating or chemically-modifying PA6,6 on the impact and barrier properties of the polymer was studied.In this work, it was described how the nature of a solvent conditions its sorption and its plasticizing effect on PA6,6. It was also observed that the PA6,6 inter-chain interactions also condition the solvent sorption. Moreover, a thermodynamic approach describing the sorption and plasticizing effects of ternary mixtures in PA6,6 was considered and developed. It was also observed that PA6,6 mechanical properties depend or are related to the amorphous phase molecular mobility state.