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Abstract Polyimides (PIs), known for their thermal resistance, chemical stability, and mechanical properties, are often considered challenging materials to process, resulting in limited commercial availability of PIs for melt extrusion, injection molding, and fused filament fabrication (FFF). Currently, material and knowledge gaps prevent the ability to rapidly produce parts from PIs that can be used in high strength and elevated temperature applications. To address this, a novel, fully aromatic PI with thermotropic liquid crystalline properties (LCPI) is successfully synthesized. The synthesized LCPI exhibits better solvent tolerance and thermal stability than commercially available counterparts. The LC phase is confirmed by thermal analysis, wide angle X‐ray scattering, and polarized optical microscopy. Rheological behavior clearly demonstrates that the LC phase reduces melt viscosity. These properties enable the LCPI to be processed into both drawn fibers and filaments for FFF, which is demonstrated alongside an injection molding process. The properties of the printed parts rivaled those made with Ultem 1000, exhibiting an average elastic modulus of 4.16 GPa. The injection molding process resulted in tensile moduli as high as 8.59 GPa and tensile strengths as high as 124.70 MPa. The LCPI polymer demonstrates the desired properties required for aerospace applications via melt processing techniques. 

Many recent studies have highlighted the timescale for stress relaxation of biomaterials on the microscale as an important factor in regulating a number of cell-material interactions, including cell spreading, proliferation, and differentiation. Relevant timescales on the order of 0.1–100 s have been suggested by several studies. While such timescales are accessible through conventional mechanical rheology, several biomaterials have heterogeneous structures, and stress relaxation mechanisms of the bulk material may not correspond to that experienced in the cellular microenvironment. Here we employ X-ray photon correlation spectroscopy (XPCS) to explore the temperature-dependent dynamics, relaxation time, and microrheology of multicomponent hydrogels comprising of commercial poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer F127 and alginate. Previous studies on this system have shown thermoreversible behavior in the bulk oscillatory shear rheology. At physiological temperatures, bulk rheology of these samples shows behavior characteristic of a soft solid, with G ′ > G ′′ and no crossover between G ′ and G ′′ over the measurable frequency range, indicating a relaxation time >125 s. By contrast, XPCS-based microrheology shows viscoelastic behavior at low frequencies, and XPCS-derived correlation functions show relaxation times ranging from 10–45 s on smaller length scales. Thus, we are able to use XPCS to effectively probe the viscoelasticity and relaxation behavior within the material microenvironments.