Silicon-containing poly(esters) with halogenated bulky side groups. Synthesis, characterization and thermal studies

Abstract

Poly(esters) (PEs) derived from diacids containing bulky side groups, which have an halogenated (Cl, Br) imide ring, an aminoacidic residue (glycine, L-alanine, L-valine) and an amide group were obtained with a silicon-containing diphenol. Also PEs without the aminoacidic residue were obtained. PEs were characterized by IR and NMR spectroscopy, and the results were in agreement with the proposed structures. PEs were obtained with good yields and moderate or high η_inh values. PEs were soluble in aprotic polar solvents and were swollen in other solvents like m-cresol and THF. The T_g values were determined and it was possible to see a tendency in the sense that when the size of the atom (Cl, Br) bonded to the imidic ring is increased, the T_g values decreased, also for those PEs obtained without the aminoacidic residue. The thermal decomposition temperatures showed that only two PEs can be considered as thermostable, considering TDT values above 400 °C at 10% of weight lost. The other PEs showed good thermal stability, showing in general a decrease of the TDT values when the volume of the side group, is increased. PEs showed UV-vis transparency at 400 nm lower than 20%, but between 500 and 600 nm, showed 80% transparency. PEs containing halogen atoms showed flame retardancy in a simple essay, with respect to PEs without halogen atoms in which the combustion was complete.