Process for the manufacture of polymerized materials that are suitable for incorporating and storing aqueous liquids, which comprises the following steps: i. radical cross-linking polymerization of a composition M of monomers, comprising a) at least one monomer A, which is chosen from among monoethylenically unsaturated C3-C8 monocarboxylic acids, mixtures and mixtures thereof of at least one monoethylenically C3-C8 monocarboxylic acid unsaturated with one or more monoethylenically unsaturated C4-C8 dicarboxylic acids, b) if necessary one or several B comonomers different from monomers A, which exhibit an ethylenic double bond, and c) 0.05 to 10% by weight, based on the total amount of monomers A and B, of at least one cross-linking agent C in the presence of at least one finely divided particulate cellulose material S, containing lignin, in an aqueous liquid, in which the ratio by weight of the composition M of monomers to substance S is in the range of 9: 1 to 1: 9； and ii. at least partial neutralization of the acid groups in the polymerized obtained in step i .； wherein the polymerization and / or neutralization are carried out in the presence of urea and at least 90% by weight of the particles of the cellulose material in the form of particles exhibits dimensions in the range of 1 μm to <；500 μm, determined by analysis of screening.Procedimiento para la fabricación de polimerizados que son adecuados para incorporar y almacenar líquidos acuosos, el cual comprende las siguientes etapas: i. polimerización que entrecruza por radicales, de una composición M de monómeros, que comprende a) al menos un monómero A, que es elegido de entre ácidos monocarboxílicos C3-C8 monoetilénicamente insaturados, sus mezclas y mezclas de al menos un ácido monocarboxílico C3-C8 monoetilénicamente insaturado con uno o varios ácidos dicarboxílicos C4-C8 monoetilénicamente insaturados, b) dado el caso uno o varios comonómeros B diferentes de los monómeros A, que exhiben un doble enlace
