Uso de resíduos da cajucultura para a produção de embalagens de polpa moldada

Abstract

The generation of plastic waste is a global concern, as uncontrolled consumption and improper disposal cause numerous environmental problems across all ecosystems on the planet, impacting water, soil, climate, and various animal species. In this context, in line with the concepts of the circular economy, the study aimed to develop different formulations for the production of molded pulp packaging using waste from cashew cultivation, namely, the wood fiber from the cashew tree resulting from its periodic pruning and the raw cashew fiber, or pomace, obtained as a byproduct of the cashew nut processing industry. Three formulations for the production of molded pulp were tested: 100% cashew tree wood fiber; 10% raw cashew fiber and 90% cashew tree wood fiber; 20% raw cashew fiber and 80% cashew tree wood fiber. The fibers underwent alkaline treatment and then a suspension was made with 0.4% dry matter and distilled water, which was subsequently drained to form the molded pulp. A cold pressing process was then performed, followed by a 24-hour drying period, which preceded a hot-pressing process at a pressure of 8.87 MPa. To verify the effectiveness of the alkaline treatment, lignocellulosic analyses were conducted on the fibers, with and without treatment. To assess the quality of the molded fiber, mechanical tests for tension and bending were carried out. Aiming to examine the barrier properties, contact angle, swelling, water absorption, and water vapor permeability were analyzed, which showed that the presence of pomace in the formulation caused changes in the texture and density of the material, making the product less hydrophilic. Additionally, the PVA analysis revealed an unsuitable value for use in food packaging with high water activity. Therefore, a molded pulp material of good quality was obtained, classified as type 3 according to the IMFA, composed solely of waste (cashew tree wood and cashew pomace), which can be improved with the use of waxes or additives for waterproofing.