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Although triblock polycarbonate thermoplastic elastomers (TPEs) have recently attracted great interests due to their biodegradability, insufficient attentions have been paid to improving the elastomeric properties. Through a tandem reaction strategy involving CO 2 / allyl glycidyl ether (AGE) / cyclohexene oxide (CHO), poly(cyclohexene carbonate)-b-poly(allyl glycidyl ether carbonate)-b-poly(cyclohexene carbonate) (PCAC) is successfully synthesized using a metal-free Lewis acid-base pair catalyst. The synthesized PCACs are pure well-defined ABA triblock all-polycarbonate, which is supported by 1H NMR, gel permeation chromatography (GPC), and diffusion-ordered spectroscopy (DOSY). A simple modification by grafting alkylthiol chains to PCAC results in excellent TPEs named PCAC-g-S-C a H 2a+1 (PCASaC). The synthesized TPEs are characterized by atomic force microscopy (AFM), thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and mechanical test. They demonstrate a semi-network and semi-domain phase separation structure, wide service temperature range, good strength, high elongation, and extremely high elastic recovery properties. This low-cost, biodegradable, high-performance TPE shows great potential for applications in biomedical, wearable products, sports equipment, and other fields. ● Synthesis of ABA triblock polycarbonate with double bonds in B block followed by grafting long alkyl chain via facile thiol-ene click reaction. ● Investigating the influence of the M n , hard segment content and length of grafted alkyl chain on the mechanical properties of the TPEs. ● CO 2 -based TPEs with well-balanced combination of essential properties, including high strength and elongation, excellent elastic recovery, biodegradability. [ABSTRACT FROM AUTHOR]

A completely new poly(carbonate-ester) macrodiol (PPCP-mDL), derived from direct copolymerization of carbon dioxide (CO 2), propylene oxide (PO), phthalic anhydride (PA) and 1, 4-butanediol (BDO) catalyzed by metal-free triethylborine (TEB)/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) pairs has been developed. The molecular weight of PPCP-mDL produced varying from 1.1–2.3 kg mol−1 can be easily controlled through the regulation of reaction conditions. For the formulation of non-toxic, phthalate-free flexible PVC, novel and biodegradable ec-PPCP-mDL with high molecular weight may be obtained through end-capping the PPCP-mDL using benzoyl chloride. The ec-PPCP-mDL/PVC blends display better comprehensive plasticization performance than do comparable blends with commercial DEHP plasticizers. These blends exhibit high thermal stability, mechanical properies, plasticizer migration resistance and transmittance. The interaction between ec-PPCP-mDL and PVC has been characterized using FTIR spectroscopy. A possible mode of plasticization has been suggested. The rich ester groups in the structure of ec-PPCP-mDLs interact well with PVC via hydrogen bonding, resulting in excellent compatiblity with PVC. Overall, the novel ec-PPCP-mDL material, respects an attractive alternative to plasticizers as a green, non-toxic, biodegradable, partially sustainable for the preparation of flexible PVC formulations. • CO2-based poly(carbonate-ester) macrodiols (PPCP-mDLs) were developed. • green, novel and biodegradable ec-PPCP-mDLs were obtained through end-capping the PPCP-mDL. • ec-PPCP-mDLs display better comprehensive plasticization performance than commercial DEHP plasticizers. [ABSTRACT FROM AUTHOR]

Pseudocapacitive Na+ storage based on the fast absorption/desorption kinetics is a new alternative to realize the high rate capability, which rely on increasing the surface area and creating surface vacancies. This means low Na+ capacity because of low dielectric constant for the reported pseudocapacitive Na+ storage materials. According to the capacitance formula, we find increasing the dielectric constant is a new path to improve the Na+ capacity. This dielectricity (other than surface engineering) based pseudocapacitance can be called more real pseudocapacitance. The superparaelectric 2-dimensional (2D) Sn 2 P 2 S 6 has much higher dielectric constant than the bulk counterpart. The identical polaron direction triggered superparaelectricity and high dielectric constant of 2D Sn 2 P 2 S 6 are well verified. And 2D assembly between the 2D Sn 2 P 2 S 6 and graphene construct the compact network for conductivity of electron and Na+. As results, the 2D Sn 2 P 2 S 6 battery based on more real pseudocapacitance delivers alloy-like capacity and long cycle stability. Image 1 • Increasing the dielectric constant is a new path to improve the battery capacity. • Superparaelectric 2D Sn 2 P 2 S 6 have higher dielectric constant than ferroelectric bulk Sn 2 P 2 S 6. • High pseudocapacitance percentage in the superparaelectric Sn 2 P 2 S 6 contribute to long cycle stability. [ABSTRACT FROM AUTHOR]

Oligocarbonate diols (PPCDL) with carbonate content higher than 90% were successfully synthesized by the direct copolymerization of propylene oxide (PO) and carbon dioxide (CO 2) using metal-free Lewis acid-base catalysts in the presence of 1,4-butanediol (BDO) as proton exchange agent (PEA). The effects of molar ratio of PO to BDO, temperature, pressure and reaction time on the copolymerization were systematically investigated. The molecular weight of the prepared oligocarbonate diols is in good linear relationship to PO/BDO feeding ratio and can be easily and precisely controlled in the range of 1000–4000 g mol−1. The detailed structures of the oligocarbonate diols were fully investigated by 1H NMR, 13C NMR, MALDI-TOF analysis. The rheological properties of synthesized PPCDL were also studied using a rheometer. Finally, polycarbonate urethanes were designed and successfully prepared using the PPCDLs as soft segment and 4,4′-diphenylmethane diisocyanate (MDI) and BDO as hard segment. The comprehensive evaluation of thermal and mechanical properties of the synthesized poly(carbonate urethane)s (PCUs) demonstrates their complete feasibility in the application of polyurethane industry. [Display omitted] • Synthesis of oligocarbonate diols catalyzed by metal-free Lewis acid-base catalysts at the first time. • The molecular weight of the oligocarbonate diols can be easily and precisely controlled in the range of 1000–4000 g mol−1. • Polycarbonate urethanes（PUs） were successfully prepared using the oligocarbonate diols. [ABSTRACT FROM AUTHOR]

Poly(propylene carbonate phthalate) (PPC-P) is a new biodegradable polymer which displays improved thermal and mechanical properties compared with poly(propylene carbonate) (PPC). However, PPC-P suffers from low melt viscosity at high temperature, restraining its applications in foaming and blowing materials. To address this issue, crosslinkable PPC-P is designed and synthesized by introducing vinyl moieties into PPC-P backbone. Later, the crosslinking conditions are optimized and the influences on the crosslinking density is investigated. The crosslinked PPC-P possesses tailorable melt flow rates, basically unchanged thermal properties and improved tensile performances as well as satisfactory transparency, laying a foundation for PPC-P to be applied as foaming and blowing materials. [Display omitted] • Synthesis of the functional CO 2 -based polymers via PO/PA/NA/CO 2 bulk copolymerization using robust metal-free Lewis pairs. • Crosslinked polymers with tunable MFR values are constructed in situ at high temperature. • Crosslinked polymers display improved tensile properties and excellent transparency. • A methodology is developed to broaden the practical application and boost the commercialization of CO 2 -based polymer. [ABSTRACT FROM AUTHOR]

Random and gradient terpolymers are successfully synthesized by one-pot copolymerization of epoxides/ethylene oxide (EO)/CO 2 and phthalic anhydride (PA)/EO/CO 2 via triethylborane (TEB)-activated catalysis, respectively. The random terpolymer of cyclohexene oxide (CHO)/EO/CO 2 exhibits one glass transition temperature (T g), which can be adjusted in the range of 26–126 °C by simply varying CHO content. The PA/EO/CO 2 terpolymers are proved to be gradient structure and show two separated T g s. To synthesize polycarbonate-type triblock copolymers, a tandem strategy is employed to copolymerize CHO/CO 2 for preparing poly(cyclohexene carbonate) (PCHC) as di-functional macroinitiator first, and then trigger the EO/CO 2 copolymerization to afford poly(ethylene carbonate) (PEC) as two external blocks. A series of high-molecular-weight PEC-PCHC-PEC triblock copolymers are obtained with phase separation microstructures (M n = 126–275 kg mol−1). All obtained copolymers are characterized by 1H NMR, diffusion-ordered spectroscopy (DOSY), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). Thermogravimetric analysis (TG) and mechanical test show that the obtained terpolymers exhibit superior and tailorable performances compared with PEC. [Display omitted] • Synthesis of high-molecular-weight EO/CO 2 -based copolymers catalyzed by metal-free catalyst at the first time. • The mechanical and thermal performances of EO/CO 2 copolymer were improved by the introduction of rigid CHO or PA. • PCHC-PEC-PCHC triblock copolymers were synthesized via tandem strategy. [ABSTRACT FROM AUTHOR]

Abstract: Sulfonated poly(fluorenyl ether ketone)s with inherent viscosity ranging from 0.68 to 0.93dL/g were directly synthesized by aromatic nucleophilic polycondensation of bisphenol fluorene with various ratios of sulfonated difluorobenzophenone to difluorobenzophenone. The synthesized polymers were characterized by 1H NMR method and elemental analysis. The polymers were tested to be soluble in dipolar aprotic solvents such as DMAc, DMF and DMSO and can be readily cast into tough films. These films showed highly thermal degradation temperature, glass transition temperature and excellent water affinity as well as excellent proton conductivity. The polymers showed a promising proton membrane material for PEM fuel cell application. [Copyright &y& Elsevier]

Abstract: Various heterogeneously supported PbO catalysts were prepared for the synthesis of diphenyl carbonate (DPC) by transesterification of dimethyl carbonate (DMC) with phenol. MgO was found to be the best support, and the modification by oxygen further enhanced the catalytic activities of PbO/MgO catalysts. Several parameters affecting the transesterification were investigated. The yields of methylphenyl carbonate (MPC) and DPC reached 10% and 26.6%, respectively, over 10wt% O2-promoted PbO/MgO catalyst which was prepared by impregnation method. X-ray diffraction (XRD), differential thermal analysis (DTA) and Brunauer–Emmet–Teller (BET) technique were employed for the characterization of prepared catalysts. It was discovered that the structure and the oxidation states of lead species in PbO/MgO catalysts changed after the promotion by oxygen. [Copyright &y& Elsevier]

[Display omitted] • PO/PA/CO 2 bulk terpolymerization using robust metal-free Lewis pairs as catalysts. • Tunable architectures by simply applying different Lewis pairs as catalysts. • Improved properties and reduced production cost by incorporation of PA. • Tailorable and satisfactory biodegradability of the terpolymers. Bulk terpolymerization of carbon dioxide and phthalic anhydride with propylene oxide is successfully carried out using metal-free and economical Lewis pairs under mild conditions. A series of commercial organic bases are coupled with triethyl borane (TEB) as Lewis pairs to optimize the activity and the results show that the TEB/ bis(triphenylphosphine)iminium chloride (PPNCl) pair exhibits relatively high activity and selectivity. The impact of the molar ratio of TEB to organic bases, reaction temperature and CO 2 pressure as well as the catalyst loading on the activity and selectivity of the copolymerization are investigated. Particularly, the turnover frequency reaches 164 h−1 with a TEB/PPNCl molar ratio of 2/1 at 80 °C. To our delight, the poly(ester- co -carbonate)s with random or block structures can be simply tuned by choosing different organic bases coupled with TEB. In these cases, the resultant terpolymers with comprehensive properties can be readily synthesized. As expected, the incorporation of phthalic anhydride effectively modifies the thermal and mechanical properties of commercial poly(propylene carbonate) (PPC). Terpolymers named as PPC-P with 43 mol% aromatic polyester moieties displays a glass transition temperature (T g) of 47 °C, about 9 °C higher than that of commercial PPC, and gives a tensile strength higher than 37.6 MPa. To our delight, the synthesized PPC-P exhibits satisfactory degradation speed under standard composting condition compared with commercial PBAT and PPC. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pd x Au y /C binary catalysts were prepared by a pulse microwave assisted polyol method. [•] Pd x Au y /C exploits the high activity of Pd and high poison tolerance of Au for glucose oxidation. [•] Pd30Au70/C shows a desirable activity and poison tolerance for glucose oxidation. [•] Pd30Au70/C exhibits a very sensitive amperometric response for glucose molecules. [ABSTRACT FROM AUTHOR]

Abstract: Novel poly(arylene ether ketone) with fluorene pendants were synthesized and then sulfonated into a series of poly(arylene ether ketone)s with sulfonated fluorene pendants using chlorosulfonic acid. The sulfonated polymers were thereafter cast into membranes from their solutions. The properties of the ionic exchange capacity, sulfonation degree, water uptake, mechanical properties, thermal and oxidative stabilities as well as proton conductivities of the membranes were fully investigated. It was found that their proton conductivities increased continuously with increasing testing temperature up to 130°C at 100% relative humidity. The membrane exhibited a higher proton conductivity and other comprehensive properties for proton exchange membrane than Nafion®-117 at 130°C under same testing conditions. [Copyright &y& Elsevier]

Abstract: Poly(propylene carbonate)/MgAl layered double hydroxide (PPC/MgAl-LDH) exfoliated nanocomposites were synthesized by solution intercalation of PPC into the galleries of organic modified MgAl-LDH (OMgAl-LDH) in cyclohexanone. The crystal morphological structures, thermal degradation behavior, and mechanical properties have been studied by Fourier transform infrared spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction, and thermogravimetric analysis (TGA). The nanoscale dispersion of OMgAl-LDH layers in the PPC matrix has been verified by the disappearance of d 001 XRD diffraction peak of OMgAl-LDH and the observation of TEM image. The TGA data give evince that the thermal degradation temperature of the exfoliated PPC/MgAl-LDH nanocomposites with 1% OMgAl-LDH is 10°C higher than that of pure PPC resin when 20% weight loss was selected as a point of comparison. The data from the mechanical test show that the tensile strength of the PPC/MgAl-LDH nanocomposites with 5% LDH is 36.9MPa, which is 72% and 30% higher than those of pure PPC resin and simple mixed sample with the same content of LDH, and its Young’s modulus is 1303MPa, which is 57% and 21% higher than those of the same two samples, respectively. [Copyright &y& Elsevier]

A systematic and extensible framework for quantification of structural hierarchy is indispensable to understand the structure–property correlation of SiC ceramics. Microstructural hierarchy descriptor (μ SHD) is constructed and used to quantify experimental microstructures reported in the literature. Despite a variation nature of microstructures and the scatterness in measured properties, μ SHD–property correlations have been identified. The μ SHD curves with less hierarchical levels suggest a high strength, while more hierarchical levels are related to a high toughness. The μ SHD curve exhibiting a homogeneous distribution across all the scales and one exhibiting a gradual decrease from the smaller to larger scales can both stand for a high thermal conductivity. A quick drop from the smaller to larger scales on the μ SHD curve is a characteristic of a high electrical resistivity, and a reverse trend, showing a gradual increase from smaller to larger scales and maintaining larger μ SHDs at larger scales, characterizes a low resistivity. [ABSTRACT FROM AUTHOR]

Porous composite membrane of polyvinylidene fluoride (PVDF)/sulfonic silica with high vanadium ions selectivity was fabricated for vanadium redox flow battery (VRFB) application. The porous PVDF membranes were first prepared as matrix via phase transfer method, followed by introducing sulfonic silica into the matrix via sol-gel process. The sulfonic silica filled in the pores can not only provide proton transfer carriers but also suppress the permeation of vanadium ions through the membrane. Moreover, the organic/inorganic composite can enhance the durability of the membrane. The morphologies of composite membranes (PVDF/SiO 2 –SO 3 H) were characterized by SEM technique. Finally, the fabricated composite membrane shows one order of magnitude lower vanadium ion permeability (1.12✕10−7 cm2min−1) and 3 times higher ion selectivity compared with Nafion 115 at room temperature. The single cell assembled using the as-prepared composite membrane gives a Coulombic efficiency of 90.3% and an energy efficiency of 75.6% at a current density of 60 mA cm−2, which is comparable with Nafion 115 (89.7% and 78.2%, respectively). This strategy could provide a simple way to design and fabricate an organic/inorganic composite membrane with high durability for the application in VRFBs. • Porous composite membrane with sulfonic silica filled in the pores of PVDF matrix can not only provide proton transfer carriers but also suppress the permeation of vanadium ions. • The organic/inorganic composite can enhance the durability of the membrane. [ABSTRACT FROM AUTHOR]

The low electronic conductivity and poor Li+ diffusion coefficient of conventional LiFePO 4 (LFP) materials severely impede its high-rate applications for lithium-ion batteries (LIBs). To break these limits, one novel poly(1,3-diethynylbenzene) (PAB) acetylenic carbon-rich polymer with extremely high-carbon content (96.75 wt%) and good solubility has been prepared by an oxidative coupling reaction. One definite advantage is that this carbon-rich PAB polymer will release, upon pyrolysis, very low amounts of gas, forming therefore uniform and dense highly conductive carbon network. Besides, the specific resistivity of continuous PAB-C layer can be as low as ∼0.01 Ω cm, which can effectively improve electrical conductivity and maintain mechanical integrity of LFP cathode. As a result, the prepared LFP@PAB-C nanocomposites with approximately 3.8 wt% carbon content and 2.5 nm carbon layer exhibit an excellent high-rate capability, e.g. even at a considerable discharge rate of 50 C, while the capacity can still be remained at 129.6 mA h g−1. Moreover, the LFP@PAB-C nanocomposites also reveal a remarkable cycling stability with as high as 100.6% capacity retention at 20 C over 1000 cycles. This kind of LFP@PAB-C composite was demonstrated to be an ideal cathode material for high-power LIBs. Acetylenic carbon-rich polymer assisted LFP@PAB-C(700) nanocomposites have been prepared for significantly enhanced high-rate Li-storage performance. Image 1 [ABSTRACT FROM AUTHOR]