Compósitos de gesso reforçados com resíduos lignocelulósicos e micro/nanocelulose kraft

Abstract

Constructive gypsum elements are attractive in civil construction due to their rapid hardening, fire resistance, and acoustic and thermal efficiency. However, due to its porosity and low mechanical efficiency, gypsum use is generally limited to interiors. To improve these properties, reinforcement, such as fibers, is necessary. Reinforcing fibers can be obtained from various sources, including industrial waste, which aligns with the concept of reverse logistics. In this context, the general aim of this study was to evaluate the effect of adding industrial lignocellulosic waste and micro/nanocellulose fibrils derived from kraft paper tubes in gypsum- based composites. The design included incorporating the lignocellulosic material reinforcement in both raw and nanoscale forms at proportions of 0%, 2.5%, 5%, 7.5%, and 10% of the raw material and proportions of 0%, 0.25%, 0.5%, 0.75%, and 1% of the nanoscale material as a gypsum substitute. The specimens were evaluated for water absorption, apparent density, flexural mechanical strength, and thermal properties. A 10% increase in water absorption was observed in composites with residues and an 87% increase in nanocomposites, along with an increase in apparent density with higher reinforcement in the matrix. The composites with this incorporation were favorable for thermal conductivity. Flexural strength showed a decrease with reinforcement incorporation but remained within acceptable standards. The characterization of the micro/nanocellulose gel obtained from the tube waste assessed stability, rheology, and diameter distribution. The reuse of this kraft paper tube waste in gypsum composites proved to be a viable alternative for incorporation into the matrix, contributing to reverse logistics by reusing a material that would otherwise be improperly discarded in the environment, causing various negative impacts and demonstrating new potential applications for the material.