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.

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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.

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.