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Gas separation performance of glassy polymers can be improved by enhancing the polymer backbone stiffness to decrease the chain packing and increase the free volume and gas permeabilities. In this work, two Tröger’s base (TB)-based polymers were prepared by polymerization from two spirobichroman-containing diamine monomers, MSBC and SBC. The obtained TB-based polymers show good solubility in polar aprotic solvents including DMF, DMAc, NMP, and DMSO, high molecular weight, and high thermal stability. Gas separation performance of TB-MSBC and TB-SBC are much better than those of the 6FDA-MSBC and 6FDA-SBC, especially for H2/N2and H2/CH4gas pairs. Furthermore, the CO2permeability of TB-MSBC is about 7.6 times higher than that of 6FDA-MSBC. The much-improved separation performance of TB-based polymers can be mainly attributed to the ineffective chain packing via the incorporation of the spriobichroman structure and a ladder-type bridged bicyclic TB unit.

Background: To evaluate the effects of correction in lumbar lordosis (LL) that have on full-body realignments in patients with degenerative lumbar scoliosis (DLS) who had undergone long sacroiliac fusion surgery. Methods: A multi-center retrospective study including 88 DLS patients underwent the surgical procedure of long sacroiliac fusion with instrumentations was performed. Comparisons of radiographic and quality-of-life (QoL) data among that at the pre-operation, the 3rd month and the final follow-up were performed. The correlations between the LL correction and the changes in other spinopelvic parameters were explored using Pearson-correlation linear analysis and linear regression analysis. The correlation coefficient (r) and the adjusted r2were calculated subsequently. Results: All radiographic and QoL data improved significantly (P< 0.001) after the surgical treatments. The LL correction correlated (P< 0.001) with the changes in the sacral slope (SS, r= 0.698), pelvic tilt (PT, r= -0.635), sagittal vertical axis (SVA, r= −0.591), T1 pelvic angle (TPA, r= −0.782), and the mismatch of pelvic incidence minus lumbar lordosis (PI–LL, r= −0.936), respectively. Moreover, LL increased by 1° for each of the following spinopelvic parameter changes (P< 0.001): 2.62° for SS (r2= 0.488), −4.01° for PT (r2= 0.404), −4.86° for TPA (r2= 0.612), −2.08° for the PI–LL (r2= 0.876) and -15.74 mm for SVA (r2= 0.349). Changes in the thoracic kyphosis (r= 0.259) and pelvic femur angle (r= 0.12) were independent of the LL correction, respectively. Conclusions: LL correction correlated significantly to the changes in spinopelvic parameters; however, those independent variables including the thoracic spine and hip variables probably be remodeled themselves to maintain the full-body balance in DLS patients underwent the correction surgery.