Influência morfológica nas propriedades da celulose nanocristalina hidrolisada com ácido sulfúrico e cloreto de ferro e seu uso como matriz de hidrogel

Abstract

Cellulose, when it comes to being one of the most abundant biopolymers on our planet, is being explored and studied a lot more the past few years, specially to obtain nanocellulose, a sustainable process that makes a non-harmful material for the environment, which can be used as a reinforcement/load (or even as a matrix), when it comes to inducing better properties on a certain material. This process involves, among other possibilities, acid hydrolysis, which can be done using different chemical reagents (such as sulfuric acid or inorganic salts [Lewis’ acids]), knowing that this change directly affects the morphology of the obtained nanocellulose, as well as their physicochemical properties. Nanocellulose has also been studied as a lower toxicity option to obtain hydrogel matrixes, which are tridimensional polymeric structures with high capacity to store loads of different liquids, being able to be applied in different industries, such as biotechnology and medicine.

By combining nanocellulose with crosslinking agents and ultrasonication, a three- dimensional matrix, the hydrogel, is obtained, capable of swelling and storing different

liquids within itself. This capacity (known as Swelling Index) is directly proportional to the intensity of the hydrolysis applied. The S.I. is directly related to the properties of the cellulosic matrix, being considerably high in the case of microcrystalline cellulose. However, when cellulose undergoes hydrolysis, this index decreases significantly, due to the acidic nature of the attacks. Nevertheless, the use of iron chloride greatly improves de S.I., potentially reaching values around half of those of microcrystalline cellulose, enabling various applications.