Physical properties of polymers with strong interactions

Most of the polymers developed and commercialized by Solvay exhibit strong intermolecular interactions consisting in H-bonds or dipole-dipole interactions (see figure below). The fact is that these intermolecular interactions are essential regarding polymer properties at the solid state (mechanical properties, barrier properties) and at the molten state (processability), but so far, the way to tailor intermolecular interactions to enhance applicative properties is still an open and challenging issue. The applicative objective of this research axis is precisely to identify how fine-tuning intermolecular interactions can help to enhance Solvay polymers performances, or develop new materials exhibiting a non-usual properties compromise.

The amorphous phase of polymers consists in long range disordered macromolecular chains that can present different levels of intermolecular interactions depending on the nature of the chemical functions present on the chain. It is known that these intermolecular interactions drive some important characteristics of the polymer such as the glass transition temperature. For instance, weak Van der Waals intermolecular interactions in polyethylene lead to a glass transition temperature (Tg) close to -120°C, whereas the presence of H-bonds in polar polymers such as polyamides lead to a Tg greater than 50°C. The current research thematic aims at understanding in what extent intermolecular interactions in H-bonded polymers drive polymer physical properties in the molten and in the solid state, and the importance of intermolecular interactions is studied regarding other microstructural parameters that are molecular weight or chains entanglements and polymer crystallinity. Among the different studied properties, a particular interest is paid to polymers relaxations including the main relaxation associated to Tg, polymer rheology, stiffness, tenacity, fatigue lifetime, brittle-tough transition temperature, and diffusion of polar and apolar solvents in polymers. The industrial objective of this research is to develop new polymeric materials satisfying unmet needs such as for instance tenacity/barrier or tenacity/fluidity compromises.