Preparation and characterization of novel PA6/SiO2 composite microsphere applied for selective laser sintering

Abstract

Abstract. The high cost and less variety of raw materials has greatly restricted the wide application of selective laser sintering (SLS) technology. In order to make the material cheaper and more diverse, PA6 is the most preferable material. In this work, a new PA6/SiO 2 composite microsphere used for SLS was designed and fabricated. To construct the material, PA6 porous microspheres with diameters of 20-80 µm and a certain pore volume were firstly prepared by the dissolution precipitation method. Then, SiO 2 was generated in situ in the PA6 porous microsphere framework, thus achieving a special structured PA6/SiO 2 composite microsphere. These microspheres with much well dispersed SiO 2 in PA6 matrices formed a powder with high bulk density and good electron conductivity. The particle size and weight fraction of the two components can be well controlled by adjusting the experimental conditions. Differential scanning calorimetry (DSC) data showed that the composite powder had a larger sintering window, which would be beneficial for SLS processing. The introduction of SiO 2 reduced the rate of water absorption in the composite powder, which could improve the accuracy of SLS forming. This work has certain significance as a reference for the design and development of SLS polymer-based composite materials.

Production of polyamide 11 microparticles for Additive Manufacturing by liquid-liquid phase separation and precipitation

“…While several solvents for the manufacturing of PA11 and PA12 membranes via thermally induced phase separation are known [36], the literature on utilization of LLPS for the production of well-defined PA particles is virtually limited to patents [21][22][23]37]. One approach for PA12 SLS particle formation is based on the dissolution of the polymer in hot formic acid and subsequent anti-solvent precipitation with ethanol, but application of these powders in industrial SLS machines is lacking [13,38]. Furthermore, the LLPS process with PA12 in a mixture of ethanol, butanone and water was used to coat metal powders for SLS green part manufacturing [39] and to coat carbon fibers for SLS composite part manufacturing [40].…”

Enhancing the tensile properties of PA6/CNT nanocomposite in selective laser sintering process

“…[ 9 ] One of the most important polymers used in the SLS process is polyamide 6 (PA6) due to its excellent abrasion resistance, easy processing, heat resistance, and high tensile strength. [ 4,10,11 ] PA6 has been widely applied in cable manufacturing industry, mechanical parts and automotive industry. The parts produced in these industry are usually under tensile loading, so it is required to improve their tensile properties.…”

Controllable preparation of polyamide 12@SiO2 composite powders

“…Thus, a clear thermal stabilization effect due to the addition of SiO 2 to PA12 is observed. The silicon hydroxyl on SiO 2 and the amide groups on the PA12 polymer chain can form stable intermolecular interactions, thereby significantly improving the thermal stability . Residues which can be attributed to SiO 2 and heat stabilizer or other auxiliaries are present at the end of thermal degradation.…”