Desenvolvimento sustentável de filmes a partir da casca de Eucalyptus sp.

Abstract

Eucalyptus sp., native to Australia, New Guinea and Indonesia, is widely cultivated in various regions of the world due to its adaptability and rapid growth. This species has great economic relevance, providing timber for construction, cellulose for the paper industry and products with medicinal applications. However, during industrial processing, eucalyptus bark, which represents between 10% and 18% of the total volume of processed wood, is often discarded or used for energy generation. Due to its composition rich in cellulose, hemicellulose and lignin, this residue has emerged as a promising raw material for the production of biodegradable polymer films, with applications in packaging, pharmaceuticals and other sectors. In this context, this study investigates the sustainable use of Eucalyptus sp. bark in the production of biodegradable films, through different chemical (hydrothermal, acid, alkaline and bleaching) and physical (grinding) pretreatments. Eucalyptus bark, rich in cellulose, hemicellulose and lignin, is a promising biomass for the creation of sustainable materials, such as films. The chemical and physical treatments aimed to optimize the extraction of biomass constituents and improve the chemical, thermal, mechanical and optical properties of the resulting films. In general, the films showed excellent light barrier capacity, with transmittance below 1%. The crystallinity index (CI%) varied according to the pretreatment: 8.15% for hydrothermal, 7.01% for alkaline, 7.63% for acid and 10.80% for bleached. The increase in crystallinity observed during bleaching is due to the removal of amorphous components, such as lignin and hemicellulose. On the other hand, alkaline pretreatment resulted in films with greater mechanical strength, with a maximum stress of 88 MPa and Young's modulus of 3313 MPa, due to the retention of lignin and hemicellulose, which reinforced the structure of the material. It is concluded that the films have specific properties that make them suitable for different applications. Furthermore, the study contributes to sustainable development by valuing agro-industrial waste and promoting the circular economy. This work aligns with the Sustainable Development Goals (SDGs), especially SDG 9 (Industry, Innovation and Infrastructure), SDG 12 (Responsible Consumption and Production), SDG 13 (Climate Action) and SDG 15 (Life on Land), by promoting the conscious use of natural resources, technological innovation and the replacement of conventional materials with more sustainable alternatives.