Synthesis and characterization of new derivates of poly(ether imide) from acylation of Friedel-Crafts

Full text: In this work was performed the synthesis of four derivatives of polymer poly(ether imide) (PEI) from Friedel Crafts Acylation reaction. The derivatives were synthesized from PEI and different acyl chlorides in the presence of aluminum chloride as catalyst. The acyl chloride used were acetyl chloride, butyryl chloride, hexanoyl chloride and decanoyl chloride, from which was possible to obtain the derivatives named as PEI-A, PEI-B, PEI-H and PEI-D, respectively. The obtained derivatives were characterized by Fourier Transform infrared spectrometry (FTIR) and by nuclear magnetic resonance of hydrogen (¹H NMR). By these analyses was possible to identify the modification percentage for each derivative, from the changes in the ¹H NMR spectrum and the presence of a new carbonyl signal at FTIR spectrum. The substitution degree (GS) for each derivative was 44% (PEI-A), 41% (PEI-B), 36% (PEIH) and 58% (PEI-D). The derivatives T_g values were 216°C (PEI), 198°C (PEI-A), 175°C (PEI-B), 162°C (PEI-H), 72°C (PEID). It was possible to identify that this change of Tg show a linear comportment with the number of carbons added and the percentage of modification of polymer, being verified by the plotting . The linear equation obtained for this graphic was T_g = -25,059(NC x DG) + 217,12; where NC is the number of carbon of lateral group added and DG is the substitution degree. Determinations were performed in UV-Vis spectrometry where an increase of the absorption coefficient of the derivatives with respect to the polymer was observed. Tests were also carried out for film formation, where the brittleness of the films that were very brittle was verified. (author)