Method for obtaining superabsorbent polymers via alkaline hydrolysis with pressurized water vapour, using polyacrylonitrile and acrylic fibres and fabrics

Abstract

A method for producing superabsorbent polymers from polyacrylonitrile (PAN) virgin or recycled from acrylic fibre manufacturing waste and discarded fabrics subjecting the PAN to alkaline hydrolysis with pressurized water vapour of up to 5 kgf/cm2 and a PAN:OH− molar ratio of 1:0.5 to 0.95, to obtain a cross-linked poly(acrylic acid-co-acrylamide) salt without using mechanical agitation, graphitizing agents with starch or cross-linking agents, and without precipitating the superabsorbent polymer obtained from the reaction medium with solvents or through pH adjustment with acids, the polymer obtained with recycled PAN leaves the autoclave already having a moisture content of 20% to 35% and a swelling capacity of >150 g H2O/g.

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