Natural and Synthetic Polymer Fillers for Applications in 3D Printing—FDM Technology Area

Abstract

This publication summarises the current state of knowledge and technology on the possibilities and limitations of using mineral and synthetic fillers in the field of 3D printing of thermoplastics. FDM technology can be perceived as a miniaturised variation of conventional extrusion processing (a microextrusion process). However, scaling the process down has an undoubtful drawback of significantly reducing the extrudate diameter (often by a factor of ≈20–30). Therefore, the results produced under conventional extrusion processing cannot be simply translated to processes run with the application of FDM technology. With that in mind, discussing the latest findings in composite materials preparation and application in FDM 3D printing was necessary.

Chemistry in light-induced 3D printing

“…cellulose), generally with an intrinsic fibrillar structure [127] and synthetic polymers (polyamide or polyester). Inorganic compounds include oxides and hydroxides (Al(OH) 3 , Mg(OH) 2 , TiO 2 , Fe 3 O 4 ), salts (CaCO 3 , BaSO 4 ), metals and silicates [125].…”

3D printed poly(lactic acid)-based nanocomposite scaffolds with bioactive coatings for tissue engineering applications

“…The mesoporous structure of the SrBG sample was also confirmed by XRD analysis. Indeed, in the low angle region, the XRD pattern of SrBG (Figure S1d) shows Bragg peaks/shoulders at 2h&2.4, 4.2 and 4.9°, revealing an ordered hexagonal network of mesopores (space group p6mm, d 10 = 3.65 nm, lattice parameter a 0 = 4.2 nm) [63][64][65][66][67]. On the other hand, the wide-angle XRD pattern of the calcined Sr-containing bioglass depicted in Figure S1e points to orthorhombic symmetry (Space Group: Pmcn) and is mainly related to the strontium carbonate (SrCO 3 ) strontianite phase [57,58] as observed upon comparing the powder profile with the expected peak positions (PDF No: 5-418).…”

“…Oftentimes, when preparing thermoplastic composite filaments with bioglass or HA, the composites are prepared beforehand using the solution mixing approach using organic solvents to ensure good filler dispersion [56,65,66], since the hydrophilic ceramics are incompatible with hydrophobic polymers. Additionally, adding a sufficient quantity of fillers in order to get enough particles on the surface of the filaments and obtaining the desired hydrophilicity can deteriorate printing quality [67,68]. With the coating approach, only water is used as a solvent and all the bioactive particles are located on the surface of the scaffolds, while when adding them in the filament only a handful of surface particles can be detected [69][70][71].…”

Micromechanical Dilution of PLA/PETG–Glass/Iron Nanocomposites: A More Efficient Molecular Dynamics Approach

“…The resulting polymer composites can be manufactured into production-ready 3D printing filaments. 15,22 Glass beads and iron particles have previously been used in 3D printing filaments with success. 23−27 Glass has been used as a mechanical reinforcement in polymers for decades as both fibers and hollow/solid glass beads.…”

“…Polylactic acid (PLA) and polyethylene terephthalate glycol (PETG) are popular thermoplastics used in additive manufacturing (3D printing) applications. − PLA is commonly used as a 3D printing filament due to its processability, biodegradability, compostability, and recyclability. − PETG is widely used in 3D printing due to its flexibility, processability, and good chemical, moisture, and UV resistance. ,,− The mechanical properties of PLA and PETG can be significantly improved by introducing fillers into the polymer matrix. The resulting polymer composites can be manufactured into production-ready 3D printing filaments. , Glass beads and iron particles have previously been used in 3D printing filaments with success. − …”