Autoria: FARIA, D. L.; MESQUITA JUNIOR, L.; LAGO, R. C. do; SORIANO, J.; GUIMARÃES JUNIOR, M.; PIRES, N. J.; Augusto Cesar da Silva Bezerra; OLIVEIRA, J. E. de

Resumo: Cardboard has been widely used in various applications and industry sectors, such as in civil construction as a formwork for concreting circular columns. In addition to the versatility of the product, a vast amount of waste is generated by the manufacturing process. The objective of this work was to determine the properties of green polyurethane matrix thermosetting composites reinforced with cardboard tube waste for application as thermal insulation in buildings. Preliminarily, alkaline solutions of NaOH and Ca(OH)2 were applied to the residues to remove oils and waxes that affect the polymerization of vegetable polyurethane. The cardboard tube waste was characterized according to its chemical composition, basic density, infrared spectra, atomic force microscopy, Xray diffraction, and surface SEM images. The composites were produced with 10 % (wt%) treated cardboard waste and without surface treatment to replace vegetable polyurethane through the hand lay-up method. Specimens were obtained from the composites to perform tensile tests, determine the bulk density, water absorption, and thermal conductivity, and visualize the matrix–reinforcement interface via SEM. The data indicated that surface NaOH and Ca(OH)2 treatments significantly increased the tensile strength of the composites by 76 and 187 %, respectively, compared with that of the polymer. For the composites, the use of cardboard waste significantly increased the thermal insulation, as proven by the thermal conductivity varying from 0.0607 to 0.0632 W/(m. K) and compatible with other insulating materials used in civil construction. Thus, composite polymers generated from cardboard tube waste are potential sustainable alternative construction materials.

Ano de publicação: 2025

Tipo de publicação: Artigo de periódico

Unidade: Embrapa Instrumentação

Palavras-chave: Cardboard waste valorization, Lignocellulosic fiber, Natural fiber-reinforced composites, Polymeric composites, Vegetal polyurethane resin