Polyamide foams prepared by solution foaming approach and their adsorption property towards bisphenol A

Solution foaming technique was adopted to fabricate polyamide-610 (PA610) foams, in which anhydrous formic acid and sodium carbonate were selected as the acid/base for performing neutralization reaction to in situ produce CO2 working as foaming agent. The major affecting parameters were investigated to adjust the cellular structure and diameter distribution, such as controlling the polyamide concentration, the sodium carbonate concentration and mixing rate (the rate to add carbonate solution into polyamide-610 solution) to tune the generation rate of CO2. The best foaming parameters were determined as 16 wt% PA concentration and 7 wt% sodium carbonate concentration, while the mixing rate was 1 mL/min. The resulting foams were subjected to diverse characterizations. SEM micrographs show that the foams have hierarchical open cell structures. The foaming process has effects on crystallization of the foams, further affecting foams’ thermal performance. The adsorption capacities of the foams towards bisphenol A (BPA) were tested, and the maximum adsorption quantity can be up to 94.84 mg/g. The adsorption isotherm fits better with Freundlich isotherm, indicating multilayer adsorption of the foams towards BPA. The adsorption kinetic follows the pseudo-second order model. After 3 adsorption-desorption cycles, the foams still have medium adsorption level towards BPA. [Display omitted] •PA610 foams were prepared by solution foaming based on acid/base reaction.•The foaming process has advantages, particular the mild preparation conditions.•Cellular structure was easily adjusted by tuning experimental parameters.•The foams have good adsorption capacity towards bisphenol A.