Estudo com aditivos impermeabilizantes aplicados em embalagens de polpa moldada a partir de resíduos da cajucultura

Abstract

Renovation, restoration, and reuse are the principles of the circular economy, an economic model that aims for the maximum utilization of a material or product, countering the environmental impacts caused by excessive use and improper disposal of plastic. The generation of plastic waste is a global concern, as it can affect water, soil, and especially the marine ecosystem. In this regard, the study tested different formulations for the production of molded pulp packaging derivated from cashew cultivation waste, with the addition of waterproofing additives to enhance their barrier properties, aiming to reduce the use of plastic packaging from the food industry. Seven compositions were tested for the production of molded pulp, one of which served as the reference containing 80% cashew wood fiber and 20% cashew pulp fiber, while the others contained the same composition plus some waterproofing agent, either alky ketene dimer (AKD) at concentrations of 1%, 2%, and 3% (w/v), or carnauba wax (CC) at concentrations of 10%, 15%, and 20% (w/w). The fibers underwent alkaline treatment and then a suspension was made with 0.4% (w/v) of dry matter and distilled water, which was subsequently drained to form the molded pulp. Shortly thereafter, a cold pressing process was carried out, followed by 24-hour drying period, which preceded a hot pressing with a pressure of 8.87 MPa. The wood fiber and the bagasse fiber were characterized through lignocellulosic analysis, assessing the contents of lignin and hemicellulose in their compositions. Then, the quality of the molded fibers was assessed through tensile and bending tests, which revealed greater mechanical strength and better malleability for the samples containing the additives. In order to verify the hydrophobic character, contact angle, swelling and water absorption, and water vapor permeability analyses were conducted, showing a favorable result for food packaging with high water activity. In addition, a qualitative colorimetry analysis was conducted that allowed for the understanding of the color trends of the material Therefore, the work obtained materials of waterproof molded pulp, composed of cashew cultivation waste, with greater mechanical resistance and hydrophobic character compared to the reference material due to the interaction mechanisms between the fibers and the additives.