Evaluation of the effect of triphenyl phosphate on hemp fiber‐reinforced polycarbonate composites for 3D printing applications

Abstract This study examined the effects of adding plasticizer to 3D printable hemp fiber‐reinforced polycarbonate (PCH) composites to improve composite properties and facilitate the 3D printing process. The plasticizer or flame retardant, triphenyl phosphate (TPP), was added to the PCH composite at three different ratios (5%, 10%, and 20%). The characterization of composites was realized with Fourier‐transformed infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), rheological analysis, tensile testing, limiting oxygen index (LOI), and scanning electron microscope (SEM) analyses. According to DSC results, while the glass transition temperature of pure PC was 148.44°C, it was reduced to 93.74°C with the addition of TPP. TGA analysis showed that PC has the best thermal resistance. The tensile test demonstrated that 20%TPP‐containing samples exhibited a value of 59.52 MPa, representing a 38% increase compared to pure PC. Additionally, the LOI value of this sample is 32.4, increased by 12% compared to pure PC. Furthermore, SEM analysis showed that TPP reduced the gaps between the matrix and fiber. In general, the properties improved with an increase in TPP content. A composite was developed from a partially natural and more sustainable material, with improved properties and 3D printing processability compared to pure polycarbonate. Highlights 10%TPP‐added composite has demonstrated the best thermal resistance 20% TPP‐added composite has 32.4 LOI and 59.52 MPa tensile strength values Adding hemp fiber to PC did not significantly change the T_g value 20% TPP addition to the composite reduced the T_g value by 63%. The 3D printing process has become easier with the increasing TPP ratio.