Effect ofEffect of Chitosan and Alginate-Based Biopolymers on Controlled Release of Urea Fertilizer Chitosan and Alginate-Based Biopolymers on Controlled Release of Urea Fertilizer

Resumo

Este trabalho descreve os efeitos de diferentes plastificantes — glicerol, triacetina e acetato de 1-etil-3-metilimidazólio — sobre a estrutura e propriedades de materiais termomecanicamente processados à base de quitosana e quitosana/alginato. Os dados mecânicos mostram que, na matriz de quitosana, glicerol e acetato de imidazólio foram eficazes na redução das forças intra e intermoleculares entre as cadeias de biopolímeros, aumentando a ductilidade. A triacetina, embora menos eficaz como plastificante, suprimiu a recristalização dos biopolímeros. Na matriz de quitosana/alginato, a triacetina promoveu maior recristalização, estabilidade térmica e propriedades mecânicas. Já o acetato de imidazólio causou separação de fases e propriedades mecânicas inferiores. O estudo revela como diferentes plastificantes afetam as interações de hidrogênio e eletrostáticas em sistemas complexados por polieletrolitos, com potencial para aplicações biomédicas e agrícolas.

Abstract

This work describes the effects of different plasticizers, namely, glycerol, triacetin, and 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), on the structure and properties of thermomechanically processed, bulk chitosan and chitosan/alginate materials. Mechanical data shows that, for the chitosan matrix, glycerol and [C2mim][OAc] were highly effective at reducing intra- and intermolecular forces between biopolymer chains, leading to increased ductility, while the plasticization effect of triacetin was minor. Nonetheless, this triester effectively suppressed biopolymer recrystallization, whereas [C2mim][OAc] promoted it. In contrast, for the chitosan/alginate matrix, inclusion of triacetin resulted in increased recrystallization, higher thermal stability, and excellent mechanical properties. The triacetin assisted the interactions between biopolymer chains in this polyelectrolyte complexed system. In contrast, the chitosan/alginate material plasticized by [C2mim][OAc] displayed the most apparent phase separation, poorest mechanical properties, and highest surface hydrophilicity, behavior associated with the disruption of polyelectrolyte complexation and hydrogen bonding between biopolymer chains.