Síntese e caracterização de membrana de acetato de celulose obtida a partir da polpa acetossolve da madeira de Schizolobium parahyba (Vell.) Blake

Abstract

Non-biodegradable polymers are produced on a large scale and cause several environmental problems, mostly because of their resistance to decomposition. Cellulose acetate is a non-toxic and a cheap polymer, representing a environmental importance. The objective of this work was the synthesis of cellulose acetate from the wood of Schizolobium parahyba (guapuruvu) with 20 and 60 mesh granulometries from experimental planting, with 38 months of age, for the preparation of membranes.The materials were chemically characterized and the samples obtained at each stage of the processing were characterized by Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM) Absorption Spectroscopy to evaluate the chemical and morphological changes of the samples and verify if the processes were successful. The materials were subjected to the pulping of acetose, bleaching and acetylation. The yields found for each process and the degree of polymerization and substitution of the acetates were analyzed. The membranes were also characterized by molecular absorption spectroscopy in the ultraviolet and visible region (UV-Vis). It was possible to make the acetates with the wood of both granulometries. The FTIR spectra showed changes in the bands of the samples indicating that the processes were efficient and the SEM images showed the morphological changes that occurred in the steps of the procedures. The cellulose acetate obtained from the 60 mesh material had a higher degree of substitution (2.74 ± 0.12) when compared to the 20 mesh acetate (2.59 ± 0.13), indicating that the grain size of the material influenced the acetylation efficiency. Despite, the DMA analysis showed that the 20 mesh membrane had higher strength than the 60 mesh membrane, the transmittance of the 60 mesh membrane at 550 nm was approximately 80%, showing to be superior than the 20 mesh membrane, especially when the purpose of the membrane requires transparency.