Three-dimensional printing of PLA and PLA/PHA dumbbell-shaped specimens of crisscross and transverse patterns as promising materials in emerging application areas: Prediction study

Abstract

This paper presents ex-ante examination of advanced polymer materials to detect defects and define and minimize the potential failure of novel polymer products before they arise. The effect of build directions on the properties of dumbbell-shaped specimens obtained by three-dimensional printing from polylactide and polylactide/polyhydroxyalkanoate commercial filaments was investigated, as well as the hydrolytic degradation of these specimens at 50 ºC and 70 ºC. Taking into account previous studies, we have found further dependences of the properties of 3D printed species before and during abiotic degradation from the orientation of printing. The initial assumption that only the contact time with the 3D printer platform leads to an increase in the crystalline phase during printing turned out to be insufficient. Further investigations of individual parts of the dumbbell-shaped specimens showed that the size of the specimens' surface in contact with the platform also affected the structural ordering of the material.

Morpho-Structural, Thermal and Mechanical Properties of PLA/PHB/Cellulose Biodegradable Nanocomposites Obtained by Compression Molding, Extrusion, and 3D Printing

“…FDM is based on the heating of a thermoplastic filament up to its melting point and the extrusion of the material followed by layer by layer deposition on a substrate to create a three-dimensional model [35,36]. Ausejo et al [37] studied the influence of 3D printing conditions (horizontal or vertical direction, contact time) and specimen size on the crystallinity, thermal and mechanical properties of PLA and PLA/polyhydroxyalkanoate (PHA) blends. A drawback in the 3D printing process is represented by the lack of strength and thermal stability when dealing with biopolymers.…”

Three-Dimensional Printed PLA and PLA/PHA Dumbbell-Shaped Specimens: Material Defects and Their Impact on Degradation Behavior

“…3D printed PLA and PLA/PHA dumbbell-shaped specimens type 1BA (specimen geometries according ISO 527 standard [14]) were obtained using a fused deposition modelling printer (FLASHFORGE Dreamer dual extrusion 3D printer, FlashForge Corporation, Jinhua, China). Specimens with unexpected shrinkage phenomena after post-processing heat treatment were prepared according to [4,15] with two different processing build directions, one with a horizontal (flat, XY plane) processing build direction and with raster angle (45 • /−45 • ) and a second with a vertical (upright, ZX plane) processing build direction and with raster angle (90 • /0 • ). The detailed characteristics of the specimens without shrinkage phenomena, including molar masses and mechanical properties before and after degradation, was described in [4,15].…”

“…Specimens with unexpected shrinkage phenomena after post-processing heat treatment were prepared according to [4,15] with two different processing build directions, one with a horizontal (flat, XY plane) processing build direction and with raster angle (45 • /−45 • ) and a second with a vertical (upright, ZX plane) processing build direction and with raster angle (90 • /0 • ). The detailed characteristics of the specimens without shrinkage phenomena, including molar masses and mechanical properties before and after degradation, was described in [4,15]. Specimens for investigating the impact of conditioning and various printer working platform and nozzle temperatures on shrinkage phenomena were printed in a horizontal processing build direction (flat, XY plane) with 7 perimeter layers and with oblique infill with raster angle (45 • /−45 • ) in a wide section for better specimens strength.…”

“…Specimens were cut in half to check for differences in material degradation, as a mechanical break in its continuity could cause changes in degradation progress. The detailed study on the degradation experiment (without shrinkage phenomena) was described in [4,15]. (ii) For additional degradation experiments in which an attempt was made to find out the reasons for the shrinkage phenomena after post-processing heat treatment, the dumbbell-shaped specimens (whole and cut specimen) were incubated in the same conditions as before for a period of 7 days only, since the shrinkage had to occur in the initial stage of degradation after applying the elevated temperature.…”

Scanning Electron Microscopy and Atomic Force Microscopy: Topographic and Dynamical Surface Studies of Blends, Composites, and Hybrid Functional Materials for Sustainable Future

“…e extrusion head deposits the material layer by layer in the Z-axis. e process is continued to produce the desired element [34][35][36]. e upper layer is the furthest from the platform (see Figure 6, UH layer).…”