Toughening of various PLA grades with natural rubber for 3D printing applications

Abstract

The aim of this present work was to study the toughening efficiency of natural rubber (NR) on various poly(lactic acid) (PLA) grades for 3D printing applications. For this purpose three different types of PLA with varying d-isomer content and average molecular weight were applied. Firstly, PLA-based filaments suitable for fused deposition modeling (FDM) were prepared with 10 wt% NR content using a twin-screw extruder. Subsequently, specimens were fabricated with a desktop FDM printer using two different infill patterns: i) a grid-like infill with an alternating raster angle of ±45° and ii) a unidirectional infill, parallel to the length of the specimens. The quasi-static and dynamic mechanical properties were determined by tensile tests and Charpy impact tests. The results indicated an outstanding toughening efficiency of NR, regardless of the PLA type, however, only for the samples prepared with the unidirectional infill.