Thermal catalytic depolymerization of polyamides

Summary The formation of cyclic diamides of polyamides 4,6 and 6,6 by thermal catalytic depolymerization of the corresponding polyamides was investigated. This method was optimized by changing external factors, like: concentration of catalyst; depolymerization temperature; — time; working under nitrogen flow and under a high vacuum (10^-5 mbar). The catalyst sodium-2-ethylhexanoate was used to accelerate the reaction. The different multi-component depolymerization products were analyzed by reversed phase HPLC. The formation of cyclic diamides of polyamides 4,6 and 6,6 was 10, respectively 20 wt.-%, under optimum conditions, which is not sufficient to be used as feed stock for new (co)polyamides.