Poly(ether ester) Ionomers as Water-Soluble Polymers for Material Extrusion Additive Manufacturing Processes

Abstract

Water-soluble polymers as sacrificial supports for additive manufacturing (AM) facilitate complex features in printed objects. Few water-soluble polymers beyond poly(vinyl alcohol) enable material extrusion AM. In this work, charged poly(ether ester)s with tailored rheological and mechanical properties serve as novel materials for extrusion-based AM at low temperatures. Melt transesterification of poly(ethylene glycol) (PEG, 8k) and dimethyl 5-sulfoisophthalate afforded poly(ether ester)s of sufficient molecular weight to impart mechanical integrity. Quantitative ion exchange provided a library of poly(ether ester)s with varying counterions, including both monovalent and divalent cations. Dynamic mechanical and tensile analysis revealed an insignificant difference in mechanical properties for these polymers below the melting temperature, suggesting an insignificant change in final part properties. Rheological analysis, however, revealed the advantageous effect of divalent countercations (Ca, Mg, and Zn) in the melt state and exhibited an increase in viscosity of two orders of magnitude. Furthermore, time-temperature superposition identified an elevation in modulus, melt viscosity, and flow activation energy, suggesting intramolecular interactions between polymer chains and a higher apparent molecular weight. In particular, extrusion of poly(PEG-co-CaSIP) revealed vast opportunities for extrusion AM of well-defined parts. The unique melt rheological properties highlighted these poly(ether ester) ionomers as ideal candidates for low-temperature material extrusion additive manufacturing of water-soluble parts.

Quadruple Hydrogen Bond-Containing A-AB-A Triblock Copolymers: Probing the Influence of Hydrogen Bonding in the Central Block

“…In the second step, the chain extension of the macro-CTA with CyA monomer yielded the CyA-containing triblock copolymer. An optimized ratio of CTA and initiator allowed the reaction to achieve >60% conversion in 24 h. 1 H NMR spectroscopy of the reaction mixture yielded 65% monomer conversion, corresponding to an average of 49 CyA units for each external block, assuming an equal propagation rate on both chain ends. Dialysis of the reaction mixture in a CH 3 OH/CH 2 Cl 2 mixture afforded a purified CyA-containing triblock copolymer.…”

“…In contrast to chemically crosslinked thermoset rubbers, thermoplastic elastomers (TPEs) consist of thermoreversible physical crosslinks, which allow for recycling and reprocessing through melt-extrusion and injection-molding [1,2]. Poly(styrene-b-butadieneb-styrene) (SBS) triblock copolymers as well as isoprene analogs and hydrogenated versions collectively serve as prominent TPEs in the automotive industry and common consumer products such as asphalt additives.…”

Material extrusion‐based additive manufacturing of polypropylene: A review on how to improve dimensional inaccuracy and warpage

“…The evolving growth of scientific studies (displayed in purple in Figure ) on polystyrene (PS), poly(ether sulfone), poly(butylene terephthalate), and other polyesters, as well as poly(ε‐caprolactone) represent the expanding urge of widening the material portfolio. The fact that even niche materials, such as plant‐based polymers, biopolymers, silicone elastomers, recycled polymers, or highly filled polymers for the production of metals/ceramics, have been under investigation for the use in ME‐AM confirms the desired rapid growth in the process's material variety.…”

Semi‐Crystalline Polymer Blends for Material Extrusion Additive Manufacturing Printability: A Case Study with Poly(ethylene terephthalate) and Polypropylene

“…Though these are described in the patent, not all methods have been sufficiently investigated and reported in literature. An additional method of enabling printing of semi‐crystalline polymers is (iv) printing with a semi‐crystalline ionomer with a low melting temperature, as recently reported by Pekkanen and coauthors …”

“…An additional method of enabling printing of semi-crystalline polymers is (iv) printing with a semi-crystalline ionomer with a low melting temperature, as recently reported by Pekkanen and coauthors. [14] Fitzharris and coauthors report the coefficient of thermal expansion (CTE) as the most influential polymer property governing warping. They suggest the higher CTE of PPS, compared to their polypropylene reference, is responsible for successful, multi-layer parts manufactured via FFF.…”