Structure formation of a polyamido-imide with asparaginimide links in dimethylformamide

Abstract

The turbidity spectrum method has been used to study the formation of supermolecular order (SMO) in the system polyamido-imide (with asparaginimide links)-DMF in the range of polymer concentrations, c=5–20 g/dl at 20°C and in the temperature range 0–60°C with c=20 g/dl. The SMO level has been characterized by the turbidity of the system, τ, and the mean equivalent radius of the supermolecular particles, rdash. On going from c=5 g/dl to 20 g/dl, the rate of SMO formation increases by 2 orders of magnitude. The temperature dependence of the rate of formation has extremal characteristics. The kinetic curves for SMO formation exhibit two-stage characteristics: a basic brocess, after which a slow increase in the SMO level follows. SMO formation occurs at the same temperature at which the polymer was initially dissolved. Supermolecular particles formed at 20°C melt when the system is subsequently heated. The temperature, Tm, at which the minimum SMO level is reached, increases as the polymer concentration is increased. The collection of data obtained points to the crystalline nature of SMO in the system studied.