Poly(isosorbide carbonate) (PIC) was synthesized by melt polycondensation of dimethyl carbonate (DMC) and isosorbide using lithium acetylacetonate (LiAcac) as the catalyst. The reaction conditions were optimized to achieve PIC with relatively high number‐average molecular weight (Mn) of 28,800 g/mol and isosorbide conversion of 95.2%. A series of poly(aliphatic diol‐co‐isosorbide carbonate)s (PAICs) were also synthesized by melt polycondensation of DMC with isosorbide and equimolar amounts of aliphatic diols (1,4‐butanediol, 1,5‐pentanediol, 1,6‐hexanediol, and 1,4‐cyclohexane dimethanol) in the presence of LiAcac and the TiO2/SiO2‐based catalyst (TSP‐44). PAICs with Mn values ranging from 18,700 to 34,400 g/mol and polydispersities between 1.64 and 1.69 were obtained. The 13C NMR analysis revealed the random microstructure of PAICs. The differential scanning calorimetry results demonstrated that all the PAICs were amorphous with a unique Tg ranging from 46 to 88 °C. The dynamic analysis results showed that the incorporation of linear or cyclohexane structure changed the dynamic mechanical properties of PIC drastically. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

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The structural evolution of poly(butylene succinate) (PBS) during tensile deformation was investigated by in situ synchrotron X-ray scattering. Crystal transition during stretching was identified at 30–90 °C. An increase of long period was observed during the α–β crystal transition, which was attributed to the increase of both amorphous layer thickness and crystalline layer thickness (lamellar thickness). The reversibility of crystal transition and correlation of lamellar thickening with crystal transition were confirmed by a “step-cycle” deformation measurement. The variation of the amorphous layer was partially recoverable, while the variation of lamellar thickness was nearly fully recoverable. The different repeating length in unit cell along the chain axis in different crystal forms resulted in the variation of the lamellar thickness. The different recoverability of structural parameters was interpreted by the different dynamics of the amorphous and crystalline phase.

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Multiblock copolymers consisting of crystalline poly(butylene succinate) and amorphous poly(1,2-propylene succinate) (PBS-co-PPS) are synthesized. The microstructure of the materials is investigated by the combination of thermal analysis and wide-angle/small-angle X-ray scattering (WAXS/SAXS). The noncrystalline PPS blocks are found to locate predominately in the amorphous phase between crystalline lamellae of PBS. By means of in situ WAXS coupled with optical-assisted strain measurement, the deformation process of PBS-co-PPS is studied. The stiffness and strength of PBS-co-PPS decrease with increasing PPS fraction, while the strain recovery behavior of PBS-co-PPS is similar to PBS homopolymer. Transition from α crystal to β crystal is observed for all the PBS-co-PPS samples. The critical stress for α–β transition of PBS-co-PPS is determined, which is found to be independent of PPS blocks. The universal critical stress for crystal transition is interpreted through a single-microfibril-stretching mechanism.

A new family of high-molecular-weight poly(isosorbide carbonate-co-butylene terephthalate)s (PICBTs) partially based on renewable isosorbide (Is) were prepared by incorporating 1,4-butanediol (BD) and dimethyl terephthalate (DMT) into poly(isosorbide carbonate) (PIC), via a two-step bulk condensation polymerization. The incorporation of BD and DMT was developed to compensate for the low reactivity of Is and improve the molecular weight and processability of PIC, while retaining the rigidity and hence high glass transition temperature (T g ) of PIC. The resulting copolymers showed high number-average molecular weights ranging from 30 600 to 52 300 g mol −1 and tunable T g values from 69 to 146°C. The molecular structure of the novel poly(ester carbonate)s was confirmed using 1 H, 13 C, 2D-COSY and 2D-HSQC NMR techniques. 1 H NMR analysis revealed the random sequence distributions of the PICBTs. A systematic study on the structure-property relationship revealed that the thermal, dynamic mechanical and mechanical properties of the PICBTs strongly depended on their composition, which would enable molecular design of material properties with the desired balance of material rigidity, ductility, and biobased content. † Electronic supplementary information (ESI) available: 1 H NMR spectra of the PICBT copolymers; transmittance of PICBTs with varied feed content of Is; DSC heating traces of the PICBT copolymers; 1 H NMR spectra of PI 80 CBT 20 under isothermal degradation at 370°C; stress-strain curves of the PICBT copolymers. See

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In order to lower the capital and operational cost of desalination and wastewater treatment processes, nanofiltration (NF) membranes need to have a high water permeation and ionic rejection, while also maintaining a stable performance through antifouling resistance. Recently, Turing-type reaction conditions [Science 2018, 360, 518–521] and sacrificed metal organic frame (MOF) nanoparticles [Nat. Commun. 2018, 9, 2004] have been reported to introduce nanovoids into thin-film composite (TFC) polyamide (PA) NF membranes for an improved performance. Herein, we report a one-step fabrication of thin-film nanocomposite membranes (TFNM) with controllable nanovoids in the polyamide layer by introducing hollow zwitterionic nanocapsules (HZNCs) during interfacial polymerization. It was found that embedding HZNCs increases the membrane internal free volume, external surface area, and hydrophilicity, thus enhancing the water permeation and antifouling resistance without trading off the rejection of multivalent ions. For example, water permeation of the NF membranes embedded with about 19.0 wt % of HZNCs (73 L m–2 h–1) increased by 70% relative to the value of the control TFC NF membrane without HZNCs (43 L m–2 h–1). This increase comes while also maintaining 95% rejection of Na2SO4. Further, we also determined the effect of the mass loading of HZNCs on the top surface of the TFC NF membranes on the membrane performance. This work provided a direct and simple route to fabricate advanced desalination membranes with a superior separation performance.