Oligomeric aliphatic/aromatic poly(amides) containing silicon in the main chain and phthalimide or tetrahalophthalimide moieties as side groups

Abstract

Oligomeric aliphatic poly(amides) (PAs) with phthalimide or tetrahalophthalimide were obtained from aspartic and glutamic acids which reacted previously with phthalic or tetrahalophtalic anhydrides, and the diamine bis(4-aminophenyl)-diphenylsilane, by direct polycondensation according to the Yamazaki method. PAs were characterized by IR and 1H, 13C and 29Si NMR, inherent viscosity measurements and optical activity. The results showed low ηinh values due to the insolubility of the PAs in the reaction media. All PAs were soluble in aprotic polar solvents and partially soluble in other common solvents as CHCl3 and THF. The Tg values for the PAs derived from aspartic acid showed an increase when the size of the halogen atom is increased due to the more rigidity of the imide group. For those PAs derived from glutamic acid the influence of the side groups was less important due probably to the higher influence of the longer aliphatic main chain. The thermal degradation analysis showed that PAs have good TDT values with the exception of PA-7. The temperature for 50 % of weight loss for both PAs series was dependent on the nature of the halogen, showing an increase when the halogen was more electronegative. PAs do not showed good optical properties, with the exception of PA-1 and PA-6 without halogen atoms in the side chain, due to the increase of the volume of the side group which affects their mobility increasing their packing. It is possible to see a low increase of the transmittance when the aliphatic chain is increased from aspartic to glutamic acid due to an increase of the flexibility of the main chain.