Preparation of new optically active and thermally stable poly(amide-imide) containing bicyclo segment and ether group in the main chain by direct polycondensation in two different media

Abstract

A new series of optically active and thermally stable poly(amide-imide)s (PAIs) with good inherent viscosities based on bicyclo diacids and etheric diamine in the main chain were synthesized from the direct polycondensation reaction of N,N?-(bicyclo[2,2,2]oct-7-ene-tetracarboxylic)-bis-L-amino acids 3a-g with 1,2-Bis[4-aminophenoxy]ethane 7 by direct polycondensatios with two different media such as direct polycondensation in a medium consisting of N-methyl-2- pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride (CaCl2)/pyridine (Py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (Py)/N,Ndimethylformamide (DMF) system. Also 3a-g were synthesized by the condensation reaction of bicyclo[2,2,2]oct-7-ene-2,3,5,6- tetracarboxylic dianhydride 1 with two equimolars of various amino acids such as L-alanine 2a, L-valine 2b, L-leucine 2c, L-isoleucine 2d, L-phenylalanine 2e, L-2-aminobutyric acid 2f and L-histidine 2g in an acetic acid solution. The polymerization reactions produced a series of thermally stable and optically active organosoluble PAIs. The resulting polymers were fully characterized by means of FT-IR and 1H-NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation, solubility tests and differential scanning calorimeter (DSC). Also thermal properties of the PAIs 8a-g were investigated using thermal gravimetric analysis (TGA) and derivative of thermaogravimetric (DTG) analysis.