Effects of pyromellitidiimide pattern on thermomechanical properties and thermal stability of silicone networks. (December 2022)

• Record Type: Journal Article
• Authors: De Monléon, Quentin; Banet, Philippe; Chikh, Linda; Fichet, Odile
• Is Part Of: Polymer degradation and stability. Volume 206(2022)
• Publication Date: 2022-12
• Subjects: Cold crystallization -- Fragmentation -- Depolymerization; Polymers -- Deterioration -- Periodicals; Stabilizing agents -- Periodicals; Polymères -- Dégradation -- Périodiques; Stabilisants -- Périodiques; 668.9
• DOI: 10.1016/j.polymdegradstab.2022.110187
• Languages: English
• ISSNs: 0141-3910

Abstract

Highlights: 18 based-silicone networks containing up to 42 wt.% PYRO were synthesized solvent-free. The presence of PYRO reduces the cold crystallization phenomenon characteristic of PDMS. The cracking of PDMS materials disappears during thermal ageing. The functional temperature range of PDMS increases with a well-chosen PYRO proportion. Abstract: Silicones are widely used in many industrial fields because of their operating temperature ranging from -40°C to 200°C. This range is limited at low temperature by a cold crystallization of high molar weight polydimethylsiloxane, and at high temperature their thermal degradation. To widen this operating temperature range, silicones have been associated with pyromellitidiimide (PYRO) patterns, commonly used for the synthesis of polyimides known for their high thermal stability. This unit has been introduced via hydrosilylation reactions up to 42 wt.% into silicone networks whose cross-linking node concentration varied from 1.36 10 −4 to 22.42 10 −4 mol/g. Thermal and thermomechanical properties of these materials were then characterized by DSC, TGA and DMTA, before and after isothermal ageing at 250°C in air. While the presence of PYRO units reduced the cold crystallization phenomenon, surprisingly, the introduction of more than 10 wt.% PYRO units proportionally increased the mass loss of materials during their thermal ageing. However, the presence of PYRO patterns prevented the appearance of cracks and thus the breaking of the materials.