Composite films of ecofriendly lignocellulosic nanostructures in biodegradable polymeric matrix

Abstract

Cellulose nanostructures (CNS) are an alternative for reinforcement of biodegradable polymers. However, the usual process applied to obtain them is environmentally harmful, generating chemical wastes, mostly in the lignin removal process. In this work, bionanocomposites reinforced with CNS were obtained using a process with lower environmental impact, viz. enzymatic hydrolysis of Pinus wood, with or without alkaline pretreatment for lignin removal. They were then incorporated into poly(butylene adipate-co-terephthalate) (PBAT) at 1%, 3%, and 5% (wt./wt.) by a solvent casting process with a nonionic surfactant as surface modification agent. The properties of the obtained composites indicated that pretreatment for lignin removal was not necessary to improve the mechanical properties. The isolated nature of the CNS led to a better distribution in the casting process and similar mechanical properties, with an increase in the Young’s modulus by 16%. Addition of the surfactant helped improve the dispersion of the reinforcement but did not affect the mechanical properties. The interaction with water was affected by the addition of surfactant, which resulted in a hydrophilic composite and influenced its post-use degradation. The results of this work confirm that it is possible to produce CNS composites without excessive consumption of reagents and that their properties can be modified for use in different packaging applications.