Polypropylene Copolymers Designed for Fused Filament Fabrication 3D‐Printing

Abstract

Several chemical properties which influence the printability for fused filament fabrication 3D‐printing are derived from analyses of commercially available filaments. In preliminary experiments, polymerization conditions are optimized and suitable monomers and selectivity control agents (donors) are selected. An experimental series in which propene is copolymerized with the comonomers 1‐butene and 1‐hexene with an industrial Ziegler–Natta catalyst will be discussed here. The experiments are planned using design of experiments. Based on a split‐plot design, the design is adapted for mixtures and the combination of homo‐ and copolymerization. The observed factors, besides the mixture composition, are hydrogen partial pressure and the amount of donor. The obtained polymers are analyzed by means of high‐temperature size exclusion chromatography, differential scanning calorimetry, and rheology. 1‐Butene copolymers show good printing results and promising properties almost matching the desired ones. The targeted polymer properties are achieved within certain limits. 1‐Hexene copolymers result in lower molecular masses while crystallinity remains slightly higher, which does not match with the desired profile. Beneficial properties are likely to be achieved within a wider factor range, for example, higher comonomer amount and lower hydrogen partial pressure.

Fused Filament Fabrication of a Dynamically Crosslinked Network Derived from Commodity Thermoplastics

“…Over the years, melt compounders have emerged in various forms that have been coupled to other postprocessing steps, such as melt blowing and injection molding. Additive manufacturing has added another dimension to material design, when functional polymeric materials are extruded as a continuous filament from a melt compounder, and then served to a three-dimensional (3D) printer in the fused filament fabrication (FFF) mode to produce digitally encoded structure on demand. , Here, to demonstrate this process, the vitrimer derived from commodity plastics was manufactured into complex objects with high-dimensional precession. After that, we verified whether the material properties were preserved after the FFF 3D-printing process.…”

Large Scale 3D Printing: Influence of Fillers on Warp Deformation and on Mechanical Properties of Printed Polypropylene Components

“…[21] Another strategy to make PP printable as filament is to modify the material by fillers and additives to reduce shrinkage and warpage. For example, PP reinforced with carbon fibers, [20] glass fibers, [22,23] natural fibers such as hemp fibers, [24,25] glass spheres, [13,14] cellulose, [15,16,26] talc, [27] expanded perlite, [28] or PP copolymers [29] show a reduced warpage. Other approaches have investigated blending polypropylene/ethylene random copolymers with several amorphous polypropylene (aPP) grades leading to less warp deformation and still adequate mechanical properties.…”

Branched Comonomers in LLDPE—Influence of Short Chain Branch Shape on Crystallinity

“…A detailed description of the reactor setup can be found in previous publication. [21] In order to minimize possible contaminant interference, the reactor was cleaned before each experiment, using three cycles of nitrogen purging followed by evacuation of the reactor. To remove remaining traces of moisture, 80 g propane was filled into the reactor, which was then heated to >90 °C for at least 30 min to ensure that the impurities could be purged with the propane at the end of the purification process.…”