Multinuclear solid‐state NMR investigation of the moisture distribution in PEEK‐PBI and PEKK‐PBI blends. Issue 6 (4th September 2014) - Pope, Jacqueline C.
ABSTRACT Blends of polyaryletherketones (PAEK), such as polyetheretherketones (PEEK) and polyetherketoneketones (PEKK), with polybenzimidazole (PBI) are of commercial interest due to their improved high‐temperature stability and wear properties. The changes of PBI and its PEEK‐ and PEKK‐blends (50 : 50 wt %) after immersing them in liquid H2O and D2O, and exposing them to D2O steam at elevated temperatures and pressures are investigated by multinuclear solid‐state NMR and IR spectroscopy. Macroscopic morphological and chemical changes on the molecular scale, which take place upon high‐temperature steam‐treatment and the extent and reversibility of moisture uptake have been investigated. Interactions and reactions of water, steam, and aqueous solutions of LiCl and ZnBr2 with the functional groups of the polymer components have been studied using D2O in combination with IR, 1H wideline, 2H, 7Li, and 79Br MAS, as well as 13C and 15N CP/MAS NMR spectroscopy. Different locations and types of water and protons in the blends have been described and PBI has been proven to be mainly responsible for water and salt uptake into the blends. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41421.