Novel hydroxyl‐containing and thermo‐dehydrocyclizable polycondensation polymers for multifunctional materials: Synthesis, properties, application

Novel poly(amide‐imide)s and poly(amide‐o‐hydroxy‐imide)s were synthesized in the process of low‐temperature polycondensation of diacid chloride of 2‐(4‐carboxyphenyl)‐1,3‐dioxoisoindoline‐5‐carboxylic acid with a single diamine of 5,5′‐methylenebis(2‐aminophenol (DADHyDPhM) or of 4,4′‐methylenebis(benzeneamine) (DADPhМ), and also with a mixture of named diamines (molar ratios of DADHyDPhM to DADPhМ being equal to 7:3, 1:1, and 3:7). The influence of hydroxy‐imide modifying units (fragments) introduced into the basic poly(amide‐imide) on its thermal stability (the processes of polymers destruction proceed intensively in the temperature range from 400 to 600°C and has a complex character); parameters of pervaporation through heat‐resistant films prepared from polymer solutions were analyzed. Polymer films are rigid materials (modulus of elasticity–3 to 4 GPa) with a strength above 100 MPa. Heating up to 300°C leads for all three compositions to a noticeable increase in the elastic modulus and to a pronounced tendency to increase the strength characteristics.