Síntese e Aplicação de Acrilatos de Glicerila como Agentes de Reticulação para Hidrogéis Superabsorventes de Base Acrílica

Abstract

About 70% of the fresh water consumed on Earth is destined for agriculture, but much of it is wasted. To minimize this problem, the use of superabsorbent polymers is essential, as it provides better water management. The present work aims at the synthesis of glyceryl acrylates (GA), which are esters from the reaction of glycerin and acrylic acid, and their use as crosslinking agents in the production of superabsorbent hydrogels. In addition to the formation of new crosslinking agents, the study presents a new use for glycerin that still remains as a surplus in the production of biodiesel. The synthesis of glyceryl acrylates (GA) was carried out by varying the temperature and time and keeping the proportion in moles of reactants and catalyst constant, in order to obtain an optimal reaction condition. Acrylic acid (AAc), glycerin (G) and glyceryl acrylates (GA) were characterized by FTIR, 1H and 13C NMR. The formation of several possibilities of glyceryl acrylates was found. Four superabsorbent hydrogels of poly(acrylamide-co-potassium acrylate) were synthesized by varying the percentage in moles of the crosslinking agents glyceryl acrylates (GA), corresponding to 1.0, 1.5, 2.0 and 3.0%, respectively. For comparison purposes, another poly(acrylamide-co-potassium acrylate) hydrogel was synthesized, but with another crosslinking agent, N,N-methylene bisacrylamide (MBA), which is the most used in the synthesis of superabsorbent hydrogels. The hydrogels were characterized by FTIR, SEM, swelling in distilled water, in saline solution, swelling/drying cycles and in vitro cytotoxicity test in non-tumor cells of murine fibroblasts (L929). The gels synthesized using glyceryl acrylates (GA) as crosslinking agents showed excellent cell viability, significant capacity for reuse, water absorption, with potential for application in agriculture. The application of glyceryl acrylates (GA) as crosslinking agents is promising, because even not being in its purified state, it provides not only the crosslinking of hydrogels, but also less toxicity and adds value to glycerin.