Avaliação do ciclo de vida de plásticos biodegradáveis de amido reforçados com nanoceluloses

Abstract

This dissertation aimed to quantify the environmental impacts of starch packaging reinforced with cellulose nanofibrils (NFC) and nanocrystals (CNC) using life cycle assessment (LCA). The studies were carried out to evaluate the effect of eucalyptus pulp and cotton as cellulose sources, the NFC and CNC production methods and their contents (2.5% - 10%) on impact indicators of starch/nanocellulose nanocomposites. The LCA was conducted based on ISO 14044, establishing comparisons of nanocomposites with fossil-based and biobased LDPE (Bio-LDPE) using a 20 cm x 30 cm plastic bag as a flexible packaging model. A cradle to grave system boundary was adopted, assuming aerobic composting and landfill for the starch-based and LDPE-based packaging, respectively. The OpenLCA 2.2 software and the Ecoinvent 3.7.1 database were used for life cycle modeling and inventory (LCI) and for calculating impact indicators related to ecosystem vitality, human health and natural resource depletion. Uncertainty calculations were performed by Monte Carlo simulation with 10,000 iterations. The hypothesis that starch is an eco-friendly material in opposition to LDPE was confirmed. However, the use of nanocelluloses increases all the impact indicators of starch packaging, being such increases more critical with the use of CNC obtained by H2SO4-hydrolysis. Starch/NFC plastic packaging had lower impacts than LDPE packaging in terms of carbon footprint (15-53%), eutrophication (54-74%), freshwater ecotoxicity (23-43%), use of nonrenewable energy (50%) and the opposite effect for human toxicity. There are disadvantages in terms of acidification, aerosol emission, land use and water consumption. Therefore, to compete technically and environmentally with LDPE packaging, the development of starch/nanocellulose nanocomposites must seek the maximum reinforcing effect with the lowest possible nanomaterial content in association with nanocomposite production routes that minimize environmental impacts.