Estudo das propriedades de misturas de triacetato de celulose e glicerol

Abstract

With environmental issues and society's demand for modes of production aimed at sustainability, this work aimed to use a residue of agribusiness origin, corn straw (PM), as a cellulose source for the synthesis of acetate. cellulose (CA), in order to verify the physical and chemical characteristics, acquired by films made of cellulose triacetate (TAC) with different concentrations of glycerol (0, 10, 20, 30% m/m), used as a plasticizer. The cellulose, after being extracted from the corn straw, was acetylated. The degree of substitution (DS) was determined chemically. The films were prepared using the casting method, dissolving the cellulose triacetate in dichloromethane. The films produced were characterized by the following methodologies: Differential Scanning Calorimetry (DSC), Thermal-thermogravimetry (TGA), X-ray diffraction, determination of functional groups was performed using Fourier transform infrared spectroscopy (FTIR), electron microscopy scanning (SEM), color, opacity, tensile and rupture tests, water flow transport with the Payne cup method, in terms of grammage and thickness. The cellulose acetate produced obtained a 2.77 degree of substitution, characterizing it as TAC. The molar mass determined was 127,175 g.mol-1. Electron microscopy images showed an increase in pores of the films, as the glycerol concentration increased. Tensile analysis revealed that the TAC 0% and TAC 10% films showed similarities while the TAC 20% and TAC 30% films showed similarities. In terms of color and opacity, it was found that the films with 0% TAC showed greater transparency, and the others did not show significant differences, but with less transparency than the film without glycerol. As for opacity, the 30% TAC film had the highest value (44.3 in Abs/600 nm -1). Glycerol influenced the mechanical behavior of the films in tensile and rupture forces, reducing from 23.99 Mpa to 8.99 Mpa in the tensile tests and from 2.52 N to 1.45 N for rupture. With the values observed, it is possible to give a better destination according to the physical, chemical, and mechanical characteristics that each produced film presents. The films produced showed potential for controlled release, for example, pharmaceuticals, desalination and water purification, food packaging, and electronic components, among others. It concluded then that the correct concentration for TAC films added with glycerol depends on the needs for each product to be packaged and its destination.