High‐performance engineering polymers continually challenge existing boundaries of rapidly emerging research areas including electronics, transportation, energy, defense and aerospace. Significant research attention over the past decade highlights the exceptional performance of these polymers due to their superior thermomechanical properties and stability under extreme conditions. Unfortunately, inherent structure–property relationships of high‐performance engineering polymers, which predict this unique complement of physical properties, also describe high‐viscosity melts and high melting temperatures. These processing challenges have steered researchers towards advanced processing methods, such as additive manufacturing, that allow for unprecedented control over part geometry. In addition, additive manufacturing serves to advance application–cost relationships, as part optimization and 3D printing of previous monolithic components allow for less material consumption. Currently, the additive manufacturing materials toolbox only contains a fraction of commercially available high‐performance polymers due to unique processing constraints. This review discusses recent efforts towards the successful additive manufacturing of three high‐performance polymer families, i.e. polysulfones, poly(ether ether ketone)s and polyimides. © 2021 Society of Industrial Chemistry.
Vat photopolymerization (VP) is an advanced additive manufacturing (AM) platform that enables production of intricate 3D monoliths that are unattainable with conventional manufacturing methods. In this work, modification of amorphous poly(arylene ether sulfone)s (PSU) allows for VP printing. Post-polymerization telechelic functionalization with acrylate functionality yielded photocrosslinkable PSUs across a molecular weight range. 1 H NMR spectroscopy confirms chemical composition and quantitative acrylate functionalization. Addition of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) photoinitiator to 30 wt% PSU solutions in NMP provides a photocurable composition. However, subsequent photorheological studies elucidate rapid photodegradation of the polysulfone main chain, which is especially apparent in high M n (15 kg mol −1 ) PSU formulations. UV-light intensity and wavelength range are altered to reduce degradation while allowing for efficient crosslinking. The addition of 0.5 wt% of avobenzone photoblocker produces an ill-defined structure with 6 kg mol −1 PSU. For higher molecular weights (>12 kg mol −1 ), solutions with a low molar mass reactive diluent, i.e., trimethylolpropane triacrylate, enable the printing of an organogel with a storage modulus (>10 5 Pa) sufficient for vat photopolymerization. Employing multicomponent solutions provide well-defined parts with complex geometries through vat photopolymerization.
Additive manufacturing (AM), also known as 3D printing, is a promising technology to produce complex shapes with little waste material in a distributed fashion. AM can be implemented with various materials, but metal and polymer are dominant feedstocks. During the deposition process for polymeric AM, the polymer may encounter repetitive softening or melting, applied shear flow including multiple constrictions, cooling and solidification, solvent evaporation, polymerization and crosslinking, or coalescence across interfaces. This leads to the need to invoke polymer science principles to rationally predict the response of the polymeric feedstock to the shear fields, thermal gradients, and reaction fronts that they will encounter in the complex 3D printing process. Elucidating the fate of the macromolecules as they experience the 3D printing process provides a foundation to design new materials that are formulated to bias the formation of robust structures and interfaces. As such, polymers in AM offer a unique opportunity to apply polymer science principles to address shortcomings, offer potential solutions, and advance the technology. This article provides a focused discussion of how polymer science principles drive the growth of three common polymeric AM techniques, fused filament fabrication, direct‐ink write, and vat polymerization.
Melt polycondensation of dimethyl 3,3′‐bibenzoate (3,3'BB) with various linear and cycloaliphatic diols enabled the synthesis of a series of semi‐aromatic polyesters. Size exclusion chromatography analysis confirmed high molecular weight (Mn > 20 kg mol−1). Compression molding resulted in ductile films and further established molecular weights desirable for mechanical performance. 1H NMR spectroscopy confirmed polymer structure and retainment of the cis/trans ratios for the cyclohexyldimethylene‐based polyesters before and after polymerization. Thermogravimetric analysis revealed high onset of weight loss temperatures for the novel semi‐aromatic polymers (Td,5% > 380 °C). Differential scanning calorimetry and dynamic mechanical analysis were used to determine glass transition temperatures and melting temperatures. Further evaluation of these thermal transitions against previously synthesized 4,4'BB, 3,4'BB, and isophthalate‐based polymers elucidated the structure–property relationships of these systems. © 2023 Society of Industrial Chemistry.
Fully-renewable green composites are accessible when natural fibers are dispersed in a non-petroleum sourced polymeric matrix, which show promise for more sustainable composite materials and demand further research to expand their use.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.