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Melt acidolysis polymerization of hydroquinone with a kinked monomer, biphenyl 3,4′-bibenzoate, afforded a novel liquid crystalline polymer (LCP), poly( p -phenylene 3,4′-bibenzoate) (poly(HQ-3,4′BB)). Selection of hydroquinone diacetate (HQ a ) or hydroquinone dipivilate (HQ p ) facilitated either a tan or white final polymer, respectively. 1 H NMR spectroscopy confirmed consistent polymer backbone structure for polymers synthesized with either derivative of hydroquinone. Poly(HQ-3,4′BB) exhibited the onset of weight loss at about 480 °C, similar to commercially available Vectra® LCP. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) revealed a glass transition temperature ( T g ) of 190 °C and an isotropic temperature ( T i ) near 330 °C. The observation of a melting temperature ( T m ) depended upon the thermal history of the polymer. Wide-angle X-ray scattering (WAXS) and polarized optical microscopy (POM) confirmed the formation of a nematic glass morphology after quench-cooling from the isotropic state. Subsequent annealing at 280 °C or mechanical deformation induced crystallization of the polymer. Rheological studies demonstrated similar shear thinning behavior for poly(HQ-3,4′BB) and Vectra® RD501 in the power law region at 340 °C. Zero-shear viscosity measurements indicated that HQ a afforded higher melt viscosities after identical polymerization conditions relative to HQ p , suggesting higher molecular weights. 

In recent years, nonconjugated, fluorophore‐free organic polymers have emerged as potentially useful light‐emitting materials. The fluorescence properties of a novel class of nonconjugated,tert‐butyl carboxylate functionalized stilbene‐containing alternating copolymers are investigated in this work. These sterically crowded, semi‐rigid copolymers exhibit very strong blue fluorescence in organic solvents upon irradiation. The origin of the fluorescent band with high quantum yield is attributed to the “through space” π–π interactions between the phenyl rings from the stilbene and CO groups from the anhydride groups. To the best of our knowledge, the di‐tert‐butyl group‐containing stilbene and maleic anhydride alternating copolymer showed one of the highest fluorescent intensities among all fluorophore‐free polymers. The excellent linearity of the luminescence property of this copolymer is an important attribute for future potential quantitative applications. The fluorescence is maintained when thetert‐butyl groups are removed and the resulting carboxylic acid‐functionalized copolymer is dissolved in water at neutral pH, which can render these copolymers as attractive candidates for diagnostic and therapeutic applications.