Biodegradação em solo e em água doce de membranas de diferentes bases biopoliméricas

Abstract

This work aims to produce and characterize biopolymer films based on chitosan, agar and their blends, with an emphasis on biodegradability analysis. For this purpose, films and blends were prepared by the casting method, using three different formulations. The materials were characterized through physical, chemical, barrier, mechanical and morphological analyses. Afterwards, biodegradability analyses were performed in soil and freshwater. The agar film presented a thickness of 0.07±0.01 mm, grammage of 0,75±0,20 g/cm2 , swelling from 57,12±2,08% to 73,87±1,39%, water solubility of 28,29±0,55%, contact angle of 43,46±6,74°, water vapor permeability of 2.18 x 10 -122.26x10-15 kg. m-1 .s-1 .Pa-1 , maximum tensile strength of 10.84±0.81 MPa, elongation of 24.44±4.55%, a biodegradation rate in soil of 62.82% in 112 days and in fresh water showed fragmentation after 90 days. The blend had a thickness of 0.07±0.00 mm, a weight of 0.83±0.03 g/cm2 , a swelling of 47.61±2.89% to 106.74±2.76%, a water solubility of 30.93±0.86%, a contact angle of 38.56±6.58°, a water vapor permeability of 5.23 x 10 -14±7.89x10-16 kg. m-1 .s-1 .Pa-1 , maximum tensile strength of 9.61±0.57 MPa, elongation of 19.63±2.26%, a biodegradation rate in soil of 43.18% in 112 days and showed no fragmentation on degradation in fresh water. Chitosan film showed thickness of 0.07±0.01 mm, grammage of 0.98±0.13 g/cm2 , swelling from 320.84±8.87% to 440.32±2.76%, water solubility of 34.03±0.90%, contact angle of 36.07±2.56°, water vapor permeability of 6.07 x 10 - 14±4.57x10-15 kg. m-1 .s-1 .Pa-1 , maximum tensile strength of 4.99±0.38 MPa, elongation of 45.97±5.76%, being completely degraded in 112 days in soil and showing no fragmentation on degradation in water. Scanning electron microscopy and atomic force microscopy analyses showed that there were changes in the surfaces of the samples, which was also highlighted by EDS analysis. In conclusion, the three films studied present satisfactory characteristics for use as packaging, and the chitosan films is biodegradable according to EN 13432.