Sustainable 3D printing with alkali-treated hemp fiber-reinforced polycarbonate composites

Abstract

The study investigated the properties of alkali-treated hemp fiber-reinforced polycarbonate (PC) composites that can be formed by 3D printers for architectural applications. To determine the optimum alkali treatment to be applied to the fibers, the properties of the samples treated with 5% and 7% sodium hydroxide (NaOH) at both ambient temperature (AT) and 120 °C (HT) were determined by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). It was determined that the alkali treatment that gave the optimum result was 5% HT. Composite specimens with fiber/matrix ratios of 10/90, 20/80, and 30/70 were prepared in filament form to be printed in a 3D printer as alkali-treated and untreated. These composites were characterized by conducting tensile strength, FTIR, differential scanning calorimetry (DSC), TGA, and scanning electron microscopy (SEM) analyses. Tensile strength results revealed the highest mechanical performance for 5% NaOH alkali-treated and 10 wt.% hemp fiber-reinforced PC composites. DSC results showed that slight changes occurred in the glass transition temperature values. Furthermore, SEM analysis showed that 5% NaOH-treated hemp fibers have better interfacial bonding with the PC matrix than untreated fibers. As a result, more natural and sustainable materials have been obtained for architectural applications without significantly decreasing in PC properties.