NUST Institutions Library Catalogue

This study focuses on preparing pure polylactic acid (PLA) and polybutylene adipate –coterephthalate (PBAT)-reinforced PLA filaments. PLA and PBAT are biodegradable aliphatic
polyesters and have recently received considerable attentions. Due to its brittle nature, PLA has
limited application in various fields. To overcome this challenge, numerous efforts have been made
to incorporate various additives to enhance its performance. In this work, pure PLA filament and
PBAT-reinforced PLA filament with diameter 1.75 ± 0.02 mm were prepared in the lab. Their
thermal and mechanical properties were analyzed and compared with the commercial PLA
filament bought from the market. Following the previous research works and suggestions of
incorporating no more than 10 wt.% PBAT, we have mixed 8 wt.% PBAT into the PLA mixture.
We then proceeded to extrude pure PLA and PBAT-reinforced PLA filaments at a temperature
range of 170 oC to 180 oC, utilizing single screw extruder. Next, we printed tensile and flexural
specimens using an FDM 3D printer, in accordance with Taguchi L9 OA. Due to PBAT’s high
ductility, 92-8 wt.% PLA-PBAT filament demonstrated a significant increase in elongation at
break, reaching up to 12%. Likewise, the PLA-PBAT filament displayed tensile and flexural
strengths of up to 48.34 MPa and 107.295 MPa respectively. These values are comparable to the
tensile and flexural strengths of pure PLA, which is a great indication that the addition of 8 wt.%
PBAT did not cause any unacceptable reduction in the tensile and flexural strengths. Additionally,
it was found through DSC analysis that PLA-PBAT filament exhibited a higher degree of
crystallinity (Xc) of up to 38.7%, which is significantly higher than that of pure extruded PLA.
Furthermore, the TGA curve indicated that thermal stability of PLA-PBAT filament was improved
by adding 8 wt.% PBAT. Moreover, digital microscopy results revealed that PLA-PBAT filament
had a ductile fracture after necking, whereas pure PLA had a brittle fracture. Lastly, statistical
analysis showed that both material type and layer thickness had significant impact on the results.
The addition of this new PLA-PBAT filament provides an additional alternative to the current
FDM filaments, and it will aid in reducing the constraints of the materials when it comes to additive
manufacturing (AM) progress.