Thermally Rearranged (TR) Polybenzoxazoles from o-Substituted Precursor Polyimides with Phenyl Pendant Groups: Synthesis, Properties, and Thermal Rearrangement Conditions.

ABSTRACT: A series of polyimides (PIs) was synthesized from 6FDA and two o-OH substituted diamines having bulky pendant phenyl, Ph, and trifluoromethyl, CF₃, groups as precursors for thermally rearranged polybenzoxazole, TR-PBO, membranes. One diamine had two pendant Ph substituents; in the other, the substituents were Ph and CF₃. Applying azeotropic and chemical cyclizations allowed the obtention of four o-hydroxy (o-OH) or/and o-acetoxy (o-OAc) substituted PIs depending on the imidization method. The PIs were labeled as 3Ph-OH, 4Ph-OH, or 3Ph-OAc and 4PH-OAc, respectively. Thermal rearrangements of all four precursors were investigated in the interval from 350 to 450 °C. The conversions to TR-PBO increased with temperature, and almost quanti

SUBMITTER: Rojas-Rodriguez M 

PROVIDER: S-EPMC11363616 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature