Biogenic Composite Filaments Based on Polylactide and Diatomaceous Earth for 3D Printing

Abstract

New composites containing a natural filler made of diatom shells (frustules), permitting the modification of polylactide matrix, were produced by Fused Deposition Modelling (3D printing) and were thoroughly examined. Two mesh fractions of the filler were used, one of <40 µm and the other of 40−63 µm, in order to check the effect of the filler particle size on the composite properties. The composites obtained contained diatom shells in the concentrations from 0% to 5% wt. (0−27.5% vol.) and were subjected to rheological analysis. The composites obtained as filaments of 1.75 mm in diameter were used for 3D printing. The printed samples were characterized as to hydrophilic–hydrophobic, thermal and mechanical properties. The functional parameters of the printed objects, e.g., mechanical characteristics, stability on contact with water and water contact angle, were measured. The results revealed differences in the processing behavior of the samples as well as the effect of secondary granulation of the filler on the parameters of the printing and mechanical properties of the composites.

A New Method of Diatomaceous Earth Fractionation—A Bio-Raw Material Source for Epoxy-Based Composites

“…According to our previous research, for the species of diatoms used for this study, the particles smaller than 6 µm can be attributed to broken frustules (pieces thereof), while particles larger than approx. 40 µm are mostly agglomerates or colonies of frustules, as well as some single specimens of a bigger size [ 22 ]. It was observed that fraction 3 obtained by sedimentation of diatomaceous earth shows much narrower distribution of particle size, ranging from approx.…”

“…We also observed an additional band at a wavelength of 797 cm −1 , which is caused by symmetric bending vibrations of Si–O–Si bonds [ 27 ]. The band at 1646 cm −1 is due to bending vibrations of H–O–H bonds of bound molecular water [ 22 ]. We additionally observed bands at a wavelength of 1015 cm −1 , which could be attributed to the asymmetric stretching of Si–O–Si bond, while the 661 cm −1 belong to symmetric stretching [ 28 ].…”

A New Method of Diatomaceous Earth Fractionation - A Bio-Raw Material Source for Epoxy-Based Composites

“…According to our previous research, for the species of diatoms used for this study, the particles smaller than 6 µm can be attributed to broken frustules (pieces thereof), while particles larger than approx. 40 µm are mostly agglomerates or colonies of frustules, as well as some single specimens of a bigger size [15].…”

Change in Pull-Out Force during Resorption of Magnesium Compression Screws for Osteosynthesis of Mandibular Condylar Fractures

“…Currently, two other groups of fixing materials are available for resorbable osteosynthesis in mandibular condylar fractures: polymers and metal alloys. Because of the promising chemical properties [ 20 ], a series of polylactide fixing materials [ 21 , 22 ] dedicated for that purpose (pins, screws, and meshes) have been developed in the last two decades. Their physical properties require some compromise in bone fragment fixation.…”