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In a Fourier transform infrared (IR) spectrometer, the Michelson interference signal extrapolation method based on linear prediction is often used to improve spectral resolution. In this method, an autoregressive (AR) model is established for the Michelson interference signal in the spectrometer. Once the AR model parameters are determined, the AR process is predictable. The interference signal can be used to figure out the AR model's parameters. Based on this, the AR model can be used to extrapolate the interference signal to improve the spectral resolution. In this paper, the forward–backward linear prediction total least squares (FB-TLS) method is proposed to estimate the parameters of the AR model. The parameters that are estimated are used to improve the IR spectral resolution. By simulating different order and signal-to-noise ratio situations, the effects of the Burg, the least square, and the FB-TLS parameter estimation methods on spectral resolution enhancement are studied. The simulation results demonstrate that the FB-TLS parameter estimation method can effectively suppress noise and avoid spurious peaks. The experimental results demonstrate that the FB-TLS parameter estimation method is effective for spectral resolution enhancement technology based on linear prediction. When the FB-TLS method is used to enhance NH3 IR spectral resolution from 2 cm−1 to 1 cm−1, the spectral prediction error in the NH3 characteristic band is only 0.21% compared with the measured NH3 spectrum, whose spectral resolution is 1 cm−1. Graphical Abstract This is a visual representation of the abstract. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydrophilic-hydrophobic microphase separation is an important mechanism to promote aqueous polymer self-assembly. However, it is rarely used in the construction of magneto-dielectric absorbers in the interdisciplinary research involving organic polymer and inorganic hybrid material. Herein, a novel metal-coordination-driven self-assembly strategy is proposed for fabricating organic–inorganic composite co-assemblies by combining resorcinol–formaldehyde resin as carbon precursor and iron-containing polymer self-assemblies as soft template. Co-assemblies are then transformed into porous iron/carbon (Fe/C) composites with spherical Fe nanoparticles and micro-mesopores that form in graphited carbon matrix through high-temperature pyrolysis. The minimum reflection loss of Fe/C-800 composite in paraffin matrix with 10% filler loading can reach −57.8 dB, while the effective absorption bandwidth of 5.3 GHz can cover the whole X band. It is considered that the co-assemblies-derived microstructure and magneto-dielectric composition contribute to the multiple reflection, polarization loss, conductive loss, ferromagnetic resonance and eddy current loss for high-efficiency electromagnetic wave absorption. In general, this work opens up new prospects for designing and preparing high-performance magneto-dielectric absorbers via a novel metal-coordination-driven self-assembly strategy. [ABSTRACT FROM AUTHOR]

• The Multi-step Linear Prediction Method is proposed to enhance spectral resolution. • The relative error of the spectrum enhanced by the MSLP method is only 0.28%. • The method successfully identified the NO spectral features in the 1880–1900 cm−1 band. Fourier Transform Infrared (FTIR) spectroscopy is a widely used technique for passive remote sensing applications, enabling the detection and quantification of various atmospheric constituents, including trace gases and pollutants. High-resolution solar spectra play a crucial role in research pertaining to atmospheric vertical profiles and analysis of atmospheric composition. However, the improvement of spectral resolution is subject to certain limitations due to hardware constraints. In this research, we propose a novel approach called the multi-step linear prediction (MSLP) method based on sliding windows to enhance the spectral resolution of passive remote sensing FTIR spectra, thereby improving the accuracy and reliability of atmospheric composition analysis. The MSLP method improves the spectral resolution of passive remote sensing FTIR spectra by using the linear prediction technique and iterative extrapolation of interference signals, which involves selecting an appropriate window length. In simulations, the MSLP method significantly enhanced the spectral resolution of passive remote sensing FTIR spectra, achieving spectral line separation for water vapor (H 2 O) and nitric oxide (NO), as well as the acquisition of low-concentration NO spectra. Experimental results demonstrate that compared to the measured high-resolution (0.2 cm−1) spectrum, the relative error of the spectrum enhanced by the MSLP method is only 0.28 %. Therefore, the MSLP method effectively achieves passive remote sensing FTIR spectral resolution enhancement, leading to more accurate identification and quantification of target compounds. [ABSTRACT FROM AUTHOR]

In this paper, a new type of Al-8Si-1.5Cu-1Ni-0.5Mg-0.5Mn-0.2Ti-0.2Zr-0.2V-0.06Sr alloy (Al-Si-Cu-Ni alloy for short) was prepared by combining micro-alloying and squeeze casting (SC) forming technology, and its microstructure and mechanical properties were investigated. The results show that the average diameter and secondary dendritic arm spacing of α-Al grains in Al-Si-Cu-Ni alloy prepared by SC are 63 µm and 12.8 µm respectively, and the internal pores of the alloy are basically eliminated. Moreover, the eutectic Si and complex second phases (i.e., AlSiMnFe, Al 3 CuNi and (Al,Si) 3 (Zr,Ti,V)) are greatly refined and more uniformly distributed in the SC alloy. In particular, the eutectic Si can even be refined to sub-micron or nanoscale, and its average F value (i.e., average shape factor) for eutectic Si in the SC alloy is 0.57, which is 29.5 % higher than that of GC alloy. The as-cast ultimate tensile strength (UTS), yield strength (YS) and elongation of the SC Al-Si-Cu-Ni alloy are 310 MPa, 169 MPa and 3.8 %, respectively. Interestingly, its UTS and ductility are much higher than those of most other Al-Si alloys formed by same method, especially its UTS can even be comparable to that of some T6 heat-treated alloys. The increase in strength and elongation is mainly attributed to a reduction in porosity, grain refinement and improvement in the morphology of the second phases. • Development of a novel Al-Si-Cu-Ni alloy through micro-alloying and SC. • The Al-Si-Cu-Ni alloy exhibits high strength and some ductility in as-cast state. • The SC alloy has fine grains and second phases (e.g., nanoscale eutectic Si). • Clarifying the mechanism for high strength of Al-Si-Cu-Ni alloy under SC. [ABSTRACT FROM AUTHOR]

• A Fourier spectral resolution enhancement algorithm based on linear prediction is proposed. • The spectral error of the NH 3 characteristic band is 0.16% (2 cm−1) and 0.26% (1 cm−1), respectively. • The accuracy of concentration inversion is improved by 2.13% (2 cm−1) and 4.06% (1 cm−1), respectively. Fourier transform infrared spectroscopy (FTIR) has been widely used for real-time monitoring of ambient gases, but for quantitative analysis of certain gases, higher spectral resolution is required to quantify more accurately. In this paper, a Fourier spectral resolution enhancement algorithm based on linear prediction is proposed. Firstly, the linear prediction model for interference signals is studied, utilizing the forward and backward linear prediction total least squares method for parameter estimation, minimum error criterion for determining the autoregressive (AR) model order, and sliding window technique for multi-step prediction. Then, the impact of the signal-to-noise ratio, enhancement factor, and initial resolution of the FTIR spectrum on the accuracy of the algorithm was studied through simulations. Finally, the algorithm is applied to spectral resolution enhancement and quantitative analysis of ammonia (NH 3). The experimental results show that when the spectral resolution of NH 3 is enhanced from 4 cm−1 to 2 cm−1 and 1 cm−1, the spectral error of the characteristic band is 0.16% and 0.26%, respectively. Additionally, the accuracy of concentration inversion is improved by 2.13% and 4.06%, respectively. The relative error of concentration inversion is 0.69% and 2.15%, respectively, when compared to the measured spectrum at corresponding resolutions. The algorithm proves effective in enhancing spectral resolution and improving the accuracy of quantitative analysis. [ABSTRACT FROM AUTHOR]

Abstract In the past decade, poly(carbonate ether)polyols, or CO 2 -polyols, have been synthesized by the copolymerization of CO 2 and propylene oxide (PO) with a double metal cyanide (DMC) catalyst in the presence of various chain transfer agents. CO 2 -polyols show great potential use as substitutes for polyols derived from fossil feedstock in the polyurethane industry. Brookfield viscosity tests have revealed the importance of primary hydroxyl (1° OH) content in the reactivity of CO 2 -polyols; in particular, the low 1° OH content of CO 2 -polyols severely limits their application in foam materials. Incorporation of more carbonate linkages has proven to be only moderately efficient for preparing CO 2 -polyols with high 1° OH content, e.g., 19F NMR spectroscopy indicates that the 1° OH content of a CO 2 -polyol can increase from 13% to 39% when the carbonate content in the CO 2 -polyol is increased from 26.1% to 80.0%. In this study, the PO end-capping route was developed using a strong Lewis acid, such as tris(pentafluorophenyl)borane (FAB) as a catalyst, and a CO 2 -polyol with 1° OH content of 60% was synthesized. Graphical abstract Image Highlights • 19F NMR spectroscopy was used to analyze the 1° OH contents of CO 2 -polyols. • Insertion of CO 2 was helpful for increasing 1° OH% of CO 2 -polyols by regulating the ring-opening mode of PO. • Brookfield viscosity tests revealed the importance of 1° OH content in the reactivity of CO 2 -polyols. • CO 2 -polyol with 1° OH content of 60% was synthesized by PO end-capping using a strong Lewis acid as a catalyst. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of soybean oil-based terminal epoxides (SOTE) through the saponification of soybean oil followed by epoxidation and their application for the production of new biodegradable polycarbonates via the intergration of CO 2 . Three processes for the production of soap from soybean oil were compared. Epoxidation reaction parameters, including the molar ratio of epichlorohydrin (EPCH) to soap, phase transfer catalyst (cetyltrimethylammonium bromide, CTAB) loading, and reaction time, were optimized based on the response surface methodology via a Box-Behnken experimental design. The optimal reaction parameters for the production of soybean oil-based terminal epoxide were a molar ratio of EPCH to soap at 17.3:1 with 2.4% CTAB based on 1 mol of soap under refluxing for 28.4 min. Epoxidation yields of 94.3% were obtained with these optimized reaction parameters. The synthesized SOTE were then polymerized with CO 2 for the production of new biodegradable polycarbonates, which had a molecular weight of 5100 g/mol with a dispersity of 1.22. [ABSTRACT FROM AUTHOR]

Current methods of administering busulfan to remove the endogenous germ cells cause hematopoietic toxicity, require special instruments and a narrow transplantation time. We use a direct testicular injection of busulfan method for preparing recipients for SSC transplantation. Male ICR mice (recipients) were divided into four groups, and two experimental groups were treated with a bilateral testicular injection of 4 or 6 mg/kg/side busulfan (n = 60 per concentration group). Mice received an intraperitoneal injection (i.p.) of 40 mg/kg busulfan (n = 60, positive control) and bilateral testicular injections of 50% DMSO (n = 60, negative control). Donor SSCs from RFP-transgenic C57BL/6J mice were introduced into the seminiferous tubules of each recipient testis via efferent duct injection on day 16–17 after busulfan treatment. Recipient mice mated with mature female ICR mice and the number of progeny was recorded. The index detected at day 14, 21, 28, 35 and 70 after busulfan treatment. Blood analysis shows that the toxicity of busulfan treated groups was much lower than i.p. injection groups. Fertility was restored in mice treated with busulfan and donor-derived offspring were obtained after SSC transplantation. Our study indicated that intratesticular injection busulfan for the preparation of recipients in mice is safe and feasible. [ABSTRACT FROM AUTHOR]

An aluminum porphyrin complex with a quaternary ammonium salt cocatalyst exhibits high activity (i.e., a turnover frequency as high as 1.85 × 105 h−1) and selectivity (＞99%) for cyclic carbonates synthesis from CO2 and epoxides; the catalyst can be reused at least 4 times with only a slight loss in activity. [ABSTRACT FROM AUTHOR]

Simple Summary: The mechanism of follicular cyst formation is largely unknown but changes in follicular composition are known to be involved. In particular, there is abnormal hormone secretion in cystic follicles. Here, we found there was disruption of hormone secretion in the fluid of cystic follicles in sows. The glucocorticoid receptor was highly expressed, and the melatonin receptor was weakly expressed in cystic follicles compared with control follicles. Thus, secretion of steroid hormones in cystic follicles is disrupted and disturbances in signaling via cortisol and melatonin are involved in the development of follicular cysts in sows. (1) Background: Cortisol and melatonin (MT) act in regulating follicular development. We hypothesized that abnormal levels of cortisol, MT, and steroids in theca interna cells might be involved in the development of follicular cysts in sows. (2) Methods: To test this hypothesis, we measured the mRNA levels of enzymes involved in steroid hormone synthesis, the glucocorticoid receptor (GR), and melatonin receptors (MTRs) in theca interna cells of cystic and normal porcine follicles. (3) Results: The concentrations of estradiol, progesterone, and cortisol were greater in cystic follicles than in control ones (p = 0.034, p = 0.020, p = 0.000), but the concentration of MT was significantly lower (p = 0.045). The levels of GR, 11β-HSD1, and 11β-HSD2 were higher in cystic follicles than in control l follicles. MT types 1 and 2 were significantly lower in cystic follicles (p < 0.05). The mRNA expression levels of genes encoding the steroid hormone synthesis enzymes, steroidogenic acute regulatory protein (StAR), recombinant cytochrome P45011A1 (CYP11A1), and 3β-hydroxysteroid dehydrogenase (3β-HSD) in theca interna cells of cystic follicles were significantly higher than in control follicles. Thus, there was disruption of hormone secretion in the fluid of cystic follicles in sows. (4) Conclusions: The levels of steroid hormones, cortisol and MT are disrupted in porcine cystic follicles. [ABSTRACT FROM AUTHOR]

ABSTRACT Common CO2-based biodegradable polycarbonates like poly(propylene carbonate) or poly(cyclohexene carbonate) are generally hydrophobic, leading to slow biodegradation rate and poor cell adhesion, which limit their applications in the biomedical field. Here hydrophilic polycarbonates were prepared by one-pot terpolymerization of CO2, propylene oxide (PO), and 2-((2-(2-(2-methoxyethoxy)ethoxy)ethoxy)methyl)oxirane (ME3MO) using binary Salen Co(III)-Cl/PPNCl catalyst system. The resultant terpolymers showed one glass transition temperature ( Tg), which decreased with the increase of ME3MO units in the terpolymers ( FME3MO). Water contact angles of the resultant terpolymers with FME3MO of 4.2−23.6% were 68−25°, while that of poly(propylene carbonate) was 90°, indicating that the terpolymers became hydrophlilic. Furthermore, the terpolymers with FME3MO more than 25.8% exhibited reversible and rapid thermo-responsive property in water, and the lower critical solution temperature (LCST) was highly sensitive to FME3MO. In particular, aqueous solution of the terpolymer with FME3MO of 72.6% showed a LCST around 35.2 °C, close to body temperature, which was promising for biomedical applications, especially for in vivo applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2834-2840. [ABSTRACT FROM AUTHOR]

A novel bifunctional cobalt ‐ porphyrin catalyst which contains a Lewis acidic metal cENter and a quaternary ammonium salt unit in a molecule has beEN developed. This new catalyst system exhibits superior copolymerization activity in comparison to a traditional binary system. [ABSTRACT FROM AUTHOR]

A convenient one-pot terpolymerization of CO2, propylene oxide (PO), and L-lactide ( L-LA) in short polymerization time (10 h or shorter) to afford poly(propylene carbonate-lactide) with excellent mechanical property and thermal stability using Y(CCl3COO)3-ZnEt2-glycerin rare-earth ternary catalyst is reported. The yield of the copolymerization was between 69.7 and 111.7 g/(g Zn), corresponding to L-LA/PO molar feed ratio varying from 0 to 0.1, and the number average molecular weight was between 5.5×104 and 11.9×104. The L-LA content in the terpolymer increased from 1.1% to 34.7% when L-LA/PO molar feed ratio changed from 0.01 to 0.1. Introducing L-LA as the third comonomer could significantly improve the mechanical strength and thermal stability of PPC. For the terpolymer obtained from L-LA/PO molar feed ratio of 1:50, the elongation at break reached 40.5%, which is 3 times of that of pure PPC, and the thermal decomposition temperature increased by 32°C compared with pure PPC. [ABSTRACT FROM AUTHOR]

Colorless oligo(carbonate-ether) diols were selectively synthesized in high efficiency from copolymerization of CO and propylene oxide (PO) using Zn[Co(CN)]-based double metal cyanide complex (DMC) as catalyst and different molecular weight polypropylene glycols (PPGs) as chain transfer agent. The catalytic activity was related to carbonate unit content and molecular weight of target oligo(carbonate-ether) diols, for oligo(carbonate-ether) diol with number average molecular weight of 6.4 kg/mol and carbonate unit content of 34.3 %, it reached 10.0 kg oligomer/g DMC catalyst during 10 h of copolymerization. Generally, the number average molecular weight of the oligo(carbonate-ether) diol was tunable between 1.8 kg/mol and 6.4 kg/mol, and the molecular weight distribution was controllable between 1.14 and 1.83. Moreover, the carbonate unit content in the oligo-diols can be adjusted between 15.3 % and 62.5 %, lower temperature and higher CO pressure were favorable for higher carbonate content. Better selectivity of oligo(carbonate-ether)diol over propylene carbonate(PC) was realized, where the weight ratio of PC (W) was controlled less than 8.0 wt%. We also found that the alkali metal ion residue may play an important role in PC formation, in some cases this effect may be more significant than backbiting process, removing the residual alkali metal ion should be meaningful in the future to further reduce the PC formation. [ABSTRACT FROM AUTHOR]

2-Furyloxirane(FO) with purity of over 99% was prepared in 80% yield by epoxidation of furfural with trimethylsulfonium chloride and potassium hydroxide in acetonitrile/water solution. Polymerization of FO was realized using tri-isobutyl aluminum (Al( i-Bu)) as catalyst, when Al( i-Bu) concentration was 0.009 mol/L, poly(2-furyloxirane)(PFO) with M of 3.4 kg/mol and a polydispersity index of 1.5 was obtained in yield of 88% after polymerization at 25 °C for 48 h. The corresponding PFO showed glass transition temperature ( T) of Ca. 1 °C and 5 wt% thermal decomposition temperature( T) of 260 °C. The obtained PFO was almost 100% head-to-tail structure, and it was a good plasticizer and thermal stabilizer for poly(propylene carbonate)(PPC), an alternate copolymer of propylene oxide and carbon dioxide. For PFO/PPC polyblend with PFO loading of 2 wt%, its T increased by 50 °C from 214 °C of pure PPC to 264 °C, while its elongation at break increased from 13% of pure PPC to 29%. [ABSTRACT FROM AUTHOR]

Abstract: High-molecular-weight poly(propylene carbonate) (PPC) was synthesized using a Zndouble metal cyanide (Co-DMC) catalyst. The catalytic activity reached as high as 60.6kg polymer/g Co-DMC after 10h when the low-molecular-weight polyether polyol initiator was not used. In contrast, production of the by-product propylene carbonate (PC) significantly decreased to below 1.0wt%. Considering the carbonate content in the alternative copolymer as 100%, the carbonate content of the obtained PPC ranged between 34% and 49%. The carbonate content was highly important for the air stability of PPC. The number average molecular weight of the as-polymerized PPC with a carbonate content of 48% reached 130kg/mol. However, it decreased to ca. 60kg/mol after 24h of storage at 70°C, and further dropped to ca. 40kg/mol after 7d. This result confirmed that severe oxidative degradation occurred for the low-carbonate-content PPC. Air stability significantly improved by adding antioxidant 1010 (tetrakis[methylene(3,5-di-(tert-butyl)-4-hydroxy-hydro cinnamate)] methane). Similarly, a more air stable PPC was also prepared by raising its carbonate content. Our work provided a new explanation on the wide existence of low-molecular-weight PPC in DMC catalyst literature. Strategies for obtaining high-molecular-weight PPC were also disclosed. [Copyright &y& Elsevier]

Abstract: Poly(propylene carbonate) (PPC), a biodegradable plastic produced by alternating copolymerization of carbon dioxide and propylene oxide, is amorphous at glass-transition temperature of ∼35 °C; therefore, it becomes brittle at temperatures <20 °C. This article reports on the synthesis of low molecular weight urethanes, such as 1,6-bis(hydroxyethyl urethane)hexane (BEU), 1,6-bis(hydroxyisopropyl urethane)hexane (BPU), and 1,6-bis(methyl urethane)hexane (HDU) bearing rich NH and Cby a non-isocyannate method and their use as plasticizers for PPC. The hydrogen-bonding interaction between BPU and PPC was found to be significantly more effective as compared with BEU and HDU, and the highest hydrogen-bonding interaction fraction reached 5.2% in a PPC/BPU blend with 15 wt% BPU loading. Solubility parameters calculated from Hoy’s method, in combination with differential scanning calorimetric analysis, indicated that HDU and BPU were miscible with PPC at a molecular scale, while BEU was immiscible with PPC. Usually, plasticizing is generally accompanied by sacrificing of tensile strength; however, it was encouraging to observe that the elongation at break for PPC/HDU blend with 10 wt% of HDU loading reached 727% – an increase 53 times that of pure PPC – while the tensile strength was maintained at 30 MPa, which was comparable with that of linear low-density polyethylene. The hydrogen-bonding interaction generated a remarkable improvement in the mechanical performance of PPC; it not only confined the migration of the plasticizer to the surface and thus ensured stability of the blending material over time, but it also maintained the mechanical strength of the plasticized PPC. [Copyright &y& Elsevier]

Recently, rare earth ternary coordination catalyst represented as Y(CCl3OO)3-Glycerin-ZnEt2 has been used for producing poly(propylene carbonate) (PPC, an alternating copolymer of carbon dioxide and propylene oxide) in industry scale, but its catalytic activity needs further improvement. One reason for the relatively low catalytic activity lied in that only 11.7% of active center was efficient due to possible embedding of active center in the heterogeneous catalyst. In this report, supporting strategy was developed, where Y(CCl3OO)3-Glycerin-ZnEt2 was supported on various inorganic oxides. Two supporting methods were carried out. One way was to mix Y(CCl3OO)3-Glycerin with inorganic oxide first and then ZnEt2 was dropped to form the supported catalyst, and the other was to make Y(CCl3OO)3-Glycerin-ZnEt2 at first and then mixing with inorganic oxides. The former showed decreasing catalytic activity compared with corresponding unsupported rare earth ternary catalyst, while an improvement of 16-36% in catalytic activity was realized in the latter. PPC with an average number molecular weight ( Mn) of over 100 kg/mol and carbonate unit (CU) content of higher than 96% was prepared by both supported catalysts. The catalytic activity of the supported catalyst depended significantly on the supports, which increased in the following order: α-Al2O3 < MgO < ZnO ≈ SiO2 <γ-Al2O3. γ-Al2O3 was the best support for rare earth ternary catalyst, which showed a remarkable 36% increase in catalytic activity, corresponding to the utilization of 17% of active center. Although MgO supported catalyst gave only an 8% increase in catalytic activity, the Mn and CU content of PPC were raised to about 143 kg/mol and 99%, whereas the PPC from common rare earth ternary catalyst was about 108 kg/mol and 97%, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 [ABSTRACT FROM AUTHOR]

Poly(cyclohexene carbonate) (PCHC) is an alternative copolymer of carbon dioxide and cyclohexene oxide. Severe thermal decomposition occurs during melt processing of PCHC, thus, it is important to find the reason for thermal decomposition and raise its thermal stability. In this report, as-polymerized PCHC was obtained under Y(CClCOO)-ZnEt-glycerin rare earth coordination ternary catalyst. The pyrolysis gas chromatography with mass spectrometry analysis disclosed that chain unzipping depolymerization dominated the thermal decomposition process. The residue metal (mainly ZnO in this catalyst system) was important in PCHC degradation, and the onset decomposition temperature of PCHC containing 5 ppm zinc was 56 °C higher than that of PCHC containing 4,400 ppm Zn, corresponding to apparent activation energy change from 190 KJ/mol to 146 KJ/mol. When PCHC was subjected to melt processing, its average molecular weight decreased more rapidly, as it contained more catalyst residue, indicating metal residue in PCHC could accelerate the decomposition process, and removing the metal residue should be effective in raising its thermal stability. [ABSTRACT FROM AUTHOR]

2-Furyloxirane (FO), a monomer usually obtained from a nonpetroleum route, was prepared from the epoxidation reaction of furfural and trimethylsulfonium chloride. About 200-300 g FO can be obtained in each preparation process. Although anionic polymerization of FO generally gives low- molecular-weight polymers even after long periods of polymerization, the reaction was greatly improved when macrocyclic ether was used as a cocatalyst to potassium tert-butoxide. When 18-crown-6 was used as a cocatalyst, poly(2-furyloxirane) (PFO) with a number-average molecular weight ( Mn) of 41.5 kg/mol and a polydispersity index of 1.3 was obtained at 94% yield after polymerization at 40 °C for 72 h. The PFO obtained contained a 61.7% head-to-tail (H-T) structure in the absence of the macrocyclic ether, and it reached 70.6% when cryptand[2,2,2] was used as a cocatalyst. PFO with higher regioregular structures showed improved thermal properties. For PFO with Mn of around 20.0 kg/mol, its glass transition temperature ( Tg) increased from −3 to 6 °C when the H-T content was increased from 61.7 to 70.6%. Raising the Mn of PFO also raised Tg. For PFO with 68.9% H-T structure, its Tg could reach 7 °C when Mn was increased to 40 kg/mol. This study shows two effective ways to improve the thermal and mechanical performances of the polymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 [ABSTRACT FROM AUTHOR]

Abstract: Biodegradable poly(propylene carbonate) (PPC) was blended with o-lauroyl chitosan (OCS) by solution casting using chloroform as common solvent. FTIR and XPS confirmed hydrogen bonding interaction between PPC and OCS, which was saturated when OCS loading reached 20wt%. Because of the hydrogen bonding interaction, a 2–3°C increase in glass transition temperature and a 5% improvement (46–53°C) in weight loss temperature (T 5%) were observed in the PPC/OCS blend with OCS loading of 10–20wt%. The interaction was beneficial to improving the mechanical performance of PPC. The tensile strength, elongation at break, and Young''s modulus of the pure PPC film were 31MPa, 3.8%, and 392MPa, respectively. For the blend with 10wt% OCS loading, the effect of toughening was so substantial that the maximum elongation at break increased twofold to 8.1% and Young''s modulus increased nearly threefold to 1014MPa; the tensile strength and stress at break remained unchanged. [Copyright &y& Elsevier]

[Display omitted] The rational regulation of the magnetic-dielectric composition and microstructures of the absorber is considered an important approach to optimize both the impedance matching and the electromagnetic microwave attenuation ability. Along these lines, a novel architecture-controlled large-caliber carbon nanotube/mesoporous carbon/Fe 3 C nanoparticle-based hybrid nanocomposites (CNT/C/Fe 3 C), which were derived from the CNT/polyimide (PI) assemblies anchoring ferric oxide hydrate nanoprecipitates, are presented in this work. The proposed configurations were prepared by applying a cooperative co-assembly strategy and high-temperature pyrolysis procedure for the development of an ultra-lightweight electromagnetic microwave absorber. The employed hierarchically tubular heterogeneous architecture is composed of a highly graphited CNT supporting skeleton, polyimide assemblies-converted carbon interlayer with mesopores, and uniformly distributed magnetic Fe 3 C nanoparticles. This unique hierarchical structure can not only induce multiple reflection and scattering effects of the incident electromagnetic microwave but also trigger dipole/interfacial polarization, ferromagnetic resonance and eddy current loss that are beneficial for the synergistic dielectric and magnetic loss. Moreover, the large-caliber CNT and mesoporous carbon interlayer can endow the as-prepared absorber with lightweight characteristics. Hence, the proposed CNT/C-EDA/Fe 3 C-900 hybrid nanocomposite exhibits a minimum reflection loss (RL) of −48.4 dB at a matching thickness of 3.2 mm, and the effective absorption bandwidth (RL ≤ -10 dB) almost covers the whole X-band only with a 5 wt% filler loading. Undoubtedly, these encouraging outcomes will promote the development of hierarchical engineering techniques of novel magnetic-dielectric nanocomposite absorbers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synergistic etching-assembly strategy toward hierarchical Fe-based microspheres engineering. • Successive regulation of magnetic-dielectric components and microstructure for balanced magnetic-dielectric synergy. • Fe@C-1/NC exhibits minimum reflection loss of-70.7 dB and effective absorption bandwidth of 3.75 GHz at 2.3 mm. Hierarchical engineering of magnetic-dielectric composite microspheres has attracted increasing attention owing to its potential to enhance electromagnetic wave absorption (EMA) through magnetic-dielectric synergy. However, optimizing magnetic-dielectric balance in composite microspheres at the nanoscale remains a formidable task due to their limited component optimization and microstructural regulation. Herein, a novel approach is proposed to modify conventional carbonyl iron powder (CIP) microspheres via synergistic etching-assembly strategy. By applying a polydopamine coating, successive tannic acid (TA) etching-assembly, and pyrolysis, hierarchical iron@carbon-1/ N -doped carbon (Fe@C-1/NC) composite microspheres are obtained. This overcomes the drawbacks of CIP microspheres, including their high density and poor impedance matching, which hinder EMA performance. Hierarchical carbon layer engineering can introduce abundant dipole centers, heterogeneous interfaces, and conductive networks to induce dielectric loss, while magnetic components contribute to magnetic resonance and eddy current loss, as demonstrated by the results. Accordingly, Fe@C-1/NC composite microspheres demonstrate a minimum reflection loss (RL min) of −70.7 dB and an effective absorption bandwidth of 3.75 GHz at a matching thickness of 2.3 mm. Generally, this work paves the way towards CIP engineering to provide guidance to the future exploration of hierarchical magnetic-dielectric EMA materials. [ABSTRACT FROM AUTHOR]

A novel functional polycarbonate (PAGC), characterized by the presence of double bonds within its side chain, was successfully synthesized through a ternary copolymerization of propylene oxide (PO), allyl glycidyl ether (AGE), and carbon dioxide (CO2). Polyhedral oligomeric silsesquioxanes octamercaptopropyl (POSS-SH) was employed as a crosslinking agent, contributing to the formation of organic–inorganic hybrid materials. This incorporation was facilitated through thiol-ene click reactions, enabling effective interactions between the POSS molecules and the double bonds in the side chains of the polycarbonate. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) confirmed a homogeneous distribution of silicon (Si) and sulfur (S) in the polycarbonate matrix. The thiol-ene click reaction between POSS-SH and the polycarbonate led to a micro-crosslinked structure. This enhancement significantly increased the tensile strength of the polycarbonate to 42 MPa, a notable improvement over traditional poly (propylene carbonate) (PPC). Moreover, the cross-linked structure exhibited enhanced solvent resistance, expanding the potential applications of these polycarbonates in various plastic materials. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is a major food and feed contaminant that threaten public health. Previous studies indicate that AFB1 exposure disrupted oocyte maturation. However, an effective and feasible method is unavailable for protecting oocytes against toxicity of AFB1. In the present study, using in vitro matured porcine oocytes and parthenogenetic embryos as model, we confirmed that AFB1 exposure during in vitro oocyte maturation (IVM) significantly impaired both nuclear and cytoplasmic maturation in a dose‐ and time‐dependent manner. The different concentrations of melatonin were also tested for their protective effects on oocytes against the AFB1‐induced toxicity. Our results showed that supplementation of a relative high concentration of melatonin (10−3mol/L) during IVM efficiently reversed the impaired development rate and blastocyst quality, to the levels comparable to those of the control group. Further analysis indicated that melatonin application efficiently alleviated reactive oxygen species accumulation and initiation of apoptosis induced by AFB1 exposure. In addition, disrupted GSH/GPX system, as well as inhibited mitochondrial DNA (mtDNA) replication and mitochondrial biogenesis in AFB1‐treated oocytes, can be notably reversed by melatonin application. Furthermore, cumulus cells may be important in mediating the toxicity of AFB1 to oocytes, and the metabolism of AFB1 in cumulus cells can be depressed by melatonin. To the best of our knowledge, this is the first report to confirm that melatonin application can efficiently protect oocytes from AFB1‐induced toxicity. Our study provides a promising and practical strategy for alleviating or reversing AFB1‐induced female reproductive toxicity in both clinical treatment and domestic reproductive management. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical FeCo/Co@NC nanocomposites were prepared by polymer self-assembly guided fabrication strategy. • Interfaces generated from FeCo-Co, FeCo/Co-carbon and amorphous-graphitic carbon contribute to interfacial polarization. • Enhanced natural resonance plays a crucial role for low frequency electromagnetic wave absorption. • The optimal RL min and maximum EAB are −59.61 dB at 5.4 GHz and 6.27 GHz at 11.84 GHz, respectively. Magnetic-dielectric synergy is currently regarded as among the most effective approaches to achieve low-frequency electromagnetic wave absorption (EMA). However, designing and fabricating EMA materials with tunable magnetic-dielectric balance towards high-performance low-frequency EMA remains challenging. Herein, a polymer self-assembly guided heterogeneous structure engineering strategy is proposed to fabricate hierarchical magnetic-dielectric nanocomposite. Polymer assemblies not only can be employed as intermediates to encapsulate metal-organic frameworks and load metal hydroxide, but also that they play a crucial role for the in-situ formation of polycrystalline FeCo/Co composite nanoparticles. As a result, the minimum reflection loss (RL min) can reach −59.61 dB at 5.4 GHz (4.8 mm) with a 20 wt% filler loading, while the effective absorption bandwidth (EAB, RL min ≤ −10 dB) is 2.16 GHz, exhibiting excellent low-frequency EMA performance. Systematic investigations demonstrate that hierarchical mesoporous carbon matrix that supports FeCo/Co composite nanoparticles is beneficial for optimizing impedance matching and increasing attenuation capacity. In general, this study opens up new prospects for developing magnetic-dielectric EMA materials using a polymer self-assembly guided heterogeneous structure engineering strategy, which may receive significant attention in future research. [ABSTRACT FROM AUTHOR]

Simple Summary: Ovarian follicular cysts are one of the most common reproductive disturbances in dairy cows. However, the exact mechanism underlying this disorder is not clear enough and remains difficult to identify. Here, we found that there was a disrupted secretion of hormone and abnormal mRNA expression of corresponding receptors in bovine cystic follicles compared with control follicles. Further KEGG enrichment analyses of transcriptome indicated that the differential expressed genes were significantly enriched in the ovarian steroidogenesis pathway. Based on the findings of the study, metabolic and endocrine disorders were associated with bovine ovarian follicular cysts. After estrus, when mature follicles fail to ovulate, they may further develop to form follicular cysts, affecting the normal function of ovaries, reducing the reproductive efficiency of dairy cows and causing economic losses to cattle farms. However, the key points of ovarian follicular cysts pathogenesis remain largely unclear. The purpose of the current research was to analyze the formation mechanism of ovarian follicular cysts from hormone and gene expression profiles. The concentrations of progesterone (P4), estradiol (E2), insulin, insulin-like growth factor 1 (IGF1), leptin, adrenocorticotropic hormone (ACTH) and ghrelin in follicle fluid from bovine follicular cysts and normal follicles were examined using enzyme-linked immunosorbent assay (ELISA) or 125I-labeled radioimmunoassay (RIA); the corresponding receptors' expression of theca interna cells was tested via quantitative reverse transcription polymerase chain reaction (RT-qPCR), and the mRNA expression profiling was analyzed via RNA sequencing (RNA-seq). The results showed that the follicular cysts were characterized by significant lower E2, insulin, IGF1 and leptin levels but elevated ACTH and ghrelin levels compared with normal follicles (p < 0.05). The mRNA expressions of corresponding receptors, PGR, ESR1, ESR2, IGF1R, LEPR, IGFBP6 and GHSR, were similarly altered significantly (p < 0.05). RNA-seq identified 2514 differential expressed genes between normal follicles and follicular cysts. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis linked the ovarian steroidogenesis pathway, especially the STAR, 3β-HSD, CYP11A1 and CYP17A1 genes, to the formation of follicular cysts (p < 0.01). These results indicated that hormone metabolic disorders and abnormal expression levels of hormone synthesis pathway genes are associated with the formation of bovine ovarian follicular cysts. [ABSTRACT FROM AUTHOR]

The inside cover picture shows a temperature controllable porphyrin aluminum catalyst using 5,10,15,20‐tetra(1,2,3,4,5,6,7,8‐octahydro‐1,4:5,8‐dimethanoanthracen‐9‐yl)porphyrin as ligand, which showed significantly temperature‐responsive selectivity in the coupling reaction of CO2 and PO. Only cycloaddition reaction happened at temperature above 75 °C to produce 100% CPC, whereas copolymerization became dominant to afford PPC with selectivity over 91% at temperature below 50 °C. More details are discussed in the article by Wang et al. on page 299–305. [ABSTRACT FROM AUTHOR]

The selective synthesis of polypropylene carbonate (PPC) and cyclic propylene carbonate (CPC) from coupling reaction of CO2 and propylene oxide (PO) is a long term pursuing target. Here we report that a temperature controllable porphyrin aluminum catalyst using 5,10,15,20‐tetra(1,2,3,4,5,6, 7,8‐octahydro‐1,4:5,8‐dimethanoanthracen‐9‐yl)porphyrin as ligand, once in conjunction with suitable onium salt, achieved single cycloaddition or copolymerization reaction. Only cycloaddition reaction happened at temperature above 75 °C to produce 100% CPC, whereas copolymerization became dominant to afford PPC with selectivity over 99% at 25 °C, and the obtained PPC showed over 99% carbonate linkage and 92% head‐to‐tail structure. Based on systematic analysis of the electronic and steric feature in the porphyrin ligand, it was found that the electronic feature of the substituent in porphyrin ligand was decisive for PPC selectivity, porphyrin ligand bearing strong electron‐donating substituents displayed a significantly reduced tolerance towards increased temperature with respect to PPC formation. Therefore, temperature‐responsive catalyst could be designed by suitable modification in porphyrin ligand, and such accurate synthesis of target product by one catalyst may create a useful and facile platform for selective PPC or CPC production. [ABSTRACT FROM AUTHOR]

Corpus luteum cysts are a serious reproductive disorder that affects the reproductive performance of sows. In this study, transcriptome and metabolome datasets of porcine normal and cyst luteal granulosa cells were generated to explore the molecular mechanism of luteal cyst formation. We obtained 28.9 Gb of high−quality transcriptome data from luteum tissue samples and identified 1048 significantly differentially expressed genes between the cyst and normal corpus luteum samples. Most of the differentially expressed genes were involved in cancer and immune signaling pathways. Furthermore, 22,622 information-containing positive and negative ions were obtained through gas chromatography−mass spectrometry, and 1106 metabolites were successfully annotated. Important differentially abundant metabolites and pathways were identified, among which abnormal lipid and choline metabolism were involved in the formation of luteal cysts. The relationships between granulosa cells of luteal cysts and cancer, immune-related signaling pathways, and abnormalities of lipid and choline metabolism were elaborated, providing new entry points for studying the pathogenesis of porcine luteal cysts. [ABSTRACT FROM AUTHOR]

from epoxides and CO2 [ABSTRACT FROM AUTHOR]

Crystallization kinetics of the Zr 70-x Ni 14+x Al 16 (x = 0, 5, 10, 15, and 20 at.%) metallic glasses (MGs) was investigated using the non-isothermal and isothermal methods, respectively. The crystallization of the Zr 70-x Ni 14+x Al 16 (x = 15 and 20 at.%) MGs proceeds by the nucleation and growth of Zr 2 Ni 3 Al 5 and Zr 6 NiAl 2 crystals. The crystallization sequence of the Zr 70-x Ni 14+x Al 16 (x = 0, 5, and 10 at.%) MGs can be concluded as follows: amorphous phase → amorphous phase + Zr 2 Ni 3 Al 5 + ZrNiAl crystals → Zr 6 NiAl 2 crystals. The crystallization kinetics of the initial and intermediate stages for the present system changes from the diffusion-controlled one-dimensional growth to two- and three-dimensional growth. Compared with the Zr 70-x Ni 14+x Al 16 (x = 15 and 20 at.%) MGs, the nucleation and growth during the initial crystallization of the Zr 70-x Ni 14+x Al 16 (x = 0, 5, and 10 at.%) MGs are relatively faster, which should be contributed to their lower activation energies for initial crystallization. The subsequent crystallization proceeds by a slower nucleation and growth compared with the Zr 70-x Ni 14+x Al 16 (x = 15 and 20 at.%) MGs, which should be suppressed by the endothermic phase transition from Zr 2 Ni 3 Al 5 and ZrNiAl crystals to Zr 6 NiAl 2 crystals. The present studies could give a complementary understanding on crystallization behaviors of metastable alloys. [ABSTRACT FROM AUTHOR]

As a powerful protocol for the preparation of common polymers, such as polyolefins, polyesters, and polycarbonates, late-transition-metal-catalyzed polymerization can be carried out by controlling the reaction conditions or developing dynamic catalytic systems that use external stimuli to influence the performance of the active sites, resulting in well-defined polymeric materials. In particularly, under the latter conditions, 'one catalyst' can provide more than one kind of polymer with a controlled sequence from the monomer mixture, making full use of the prepared catalyst. In this review, tunable modes, including reaction conditions, redox, light or electrochemical properties, Lewis acids, and alkali metal cations, of late-transition-metal-complex (especially iron, cobalt, and nickel)-catalyzed polymerization were collected and thoroughly discussed. [ABSTRACT FROM AUTHOR]

The copolymerization of carbon dioxide (CO2) with epoxides demonstrates promise as a new synthetic method for low-carbon polymer materials, such as aliphatic polycarbonate materials. In this study, a binary Schiff base cobalt system was successfully used to catalyze the copolymerization of 1,2-butylene oxide (BO) and CO2 and its terpolymerization with other epoxides such as propylene oxide (PO) and cyclohexene oxide (CHO). 1H nuclear magnetic resonance (1H NMR), diffusion-ordered spectroscopy (DOSY), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) confirmed the successful synthesis of the alternating terpolymer. In addition, the effects of the polymerization reaction conditions and copolymerization monomer composition on the polymer structure and properties were examined systematically. By regulating the epoxide feed ratio, polycarbonates with an adjustable glass transition temperature (Tg) (11.2–67.8 °C) and hydrophilicity (water contact angle: 85.2–95.2°) were prepared. Thus, this ternary polymerization method provides an effective method of modulating the surface hydrophobicity of CO2-based polymers and their biodegradation properties. [ABSTRACT FROM AUTHOR]

Graphitic carbon materials are considered to be an important category of dielectric absorbers, but these materials are typically accompanied with poor impedance matching and unsatisfactory electromagnetic wave absorption (EMA) performance. Herein, engineered amorphous carbon is developed to produce hierarchical carbonaceous nanocomposites (HCNs) via crystallization-induced interfacial polymer self-assembly and carbonization, which is aimed at boosting dielectric polarization for enhancing EMA capability. By optimizing the polymer precursor species, graphitic carbon matrix, and carbonization temperature, the hierarchical architecture and N-bonding configurations, containing pyridinic N, pyrrolic N, and graphitic N, can be regulated for polarization relaxation loss and conductive loss. In addition, multiple reflection and scattering behavior are also beneficial for increasing EMA capability. Compared with those of the pure graphitic carbon matrix and related HCNs, the minimum reflection loss (RL min) of MWCNTs coated with polyimide-derived amorphous carbon at 700 °C (MWCNT/C(PI-EDA)-700) is −45.7 dB at a matched thickness of 3.6 mm with a filler loading of only 5 wt%, and its effective absorption bandwidth (EAB, RL min < −10 dB) is 3.9 GHz. In summary, based on the systematic analysis of 16 carbonaceous absorbers, in this study, not only the intrinsic EMA mechanism of HCNs is revealed, but also new avenues for designing and fabricating high-efficiency dielectric absorbers are opened. [Display omitted] [ABSTRACT FROM AUTHOR]

Simple Summary: Larger litter size (born alive) and higher uniformity of piglets' birth weight are the most desired characteristics in pig production. Application of N-carbamylglutamate (NCG) was shown to increase litter size and decrease the coefficient of variation of piglets' birth weight from sows after conventional artificial insemination. In this study, we report that, in sows after fixed-time artificial insemination (FTAI), NCG improved the number of piglets born alive and the coefficient of variation of birth weight through direct effects (increased serum NCG levels) and indirect effects (altered intestinal microbiome and serum metabolites). These findings indicate that NCG can improve reproductive performance by improving both the number of piglets born alive and the uniformity of piglets' birth weight in sows after FTAI. N-carbamylglutamate (NCG) supplementation during gestation improves reproductive performance in sows after conventional artificial insemination. However, whether NCG can improve reproductive performance and change fecal microbiota and serum metabolite levels during pregnancy in sows after fixed-time artificial insemination (FTAI) remains unclear. Two hundred multiparous sows were assigned a diet from mating until farrowing: control (corn–soybean meal) or NCG supplementation (0.05% NCG). At days 30, 70, and 110 of gestation and after farrowing, maternal microbial diversity and serum metabolites were studied. Supplementation of NCG increased the number of piglets born alive and the litter weight (all p < 0.05) and altered the fetal microbial community during gestation. Some genera were particularly abundant at different time points during gestation and after farrowing, but none were commonly abundant across all four time points. Metabolic analysis revealed that NCG supplementation significantly increased the serum concentrations of NCG, ferulic acid, cinnamoylglycine, 3-phenyllactic acid, and gamma-glutamylglutamic acid in the NCG group compared with levels in the control group. Our results reveal that NCG supplementation during gestation improves reproductive performance in sows after FTAI, exerting both direct (increased serum NCG levels) and indirect effects (altered intestinal microbiome and serum metabolites) on sow reproduction and, ultimately, improving placental and fetal development. [ABSTRACT FROM AUTHOR]

To overcome the brittleness of poly(propylene carbonate) (PPC), rubbery non-isocyanate polyurethane (NIPU) with rich hydrogen bonding moiety was synthesized for toughening PPC. Debonding phenomenon of NIPU was observed during the impact process of PPC/NIPU blends, which was beneficial for toughening PPC. When the NIPU loading increased to 10 wt%, the unnotched impact strength increased 3 times compared with neat PPC. The NIPU dispersed uniformly and a transition from brittle to marginally tough occurred when L / d reached a critical value, 1.74, where L and d were center-to-center distance and the diameter of the particle, respectively. The debonding of NIPU accounted for the increase of toughness, and shear yielding of the matrix was limited around the microvoids. When the NIPU loading reached 13 wt%, NIPU flocculated in the matrix leading to decline in toughness. The equilibrium between self-associating hydrogen bonding and intermolecular one formed between PPC and NIPU affected their miscibility and thereby the morphology of the blends. [ABSTRACT FROM AUTHOR]

ABSTRACT Due to the concern on residue toxic metal in biodegradable poly(propylene carbonate) (PPC), soil tolerant and heavy metal free aluminum complexes, that is, bifunctional aluminum porphyrin catalysts bearing quaternary ammonium salts on the ligand framework were prepared. Variation of the quaternary ammonium anion and the axial ligand had dramatic effects on the catalytic activity of resultant complex, among which complex 3b yielded perfectly alternative PPC with high molecular weight and relatively narrow polydispersity, and its TOF reached 3,407 h−1 at [PO]/[cat.] ratio of 20,000 at 110 °C, although the PPC selectivity was 71%. By introducing specific substituent on the ligand framework, the electronic environment at the active center can be changed, among which complex 5b bearing tertiary butyl-functionalized aryl substituents exhibited a TOF of 449 h−1 at [PO]/[cat.] ratio of 5,000 at 70 °C, with PPC selectivity of 92% and number average molecular weight of 36 kg mol−1. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2346-2355 [ABSTRACT FROM AUTHOR]

Inspired by the cooperative multi-metallic activation in metalloenzyme catalysis, artificial enzymes as multi-metallic catalysts have been developed for improved kinetics and higher selectivity. Previous models about multi-metallic catalysts, such as cross-linked polymer-supported catalysts, failed to precisely control the number and location of their active sites, leading to low activity and selectivity. In recent years, metallopolymers with metals in the sidechain, also named as sidechain metallopolymers (SMPs), have attracted much attention because of their combination of the catalytic, magnetic, and electronic properties of metals with desirable mechanical and processing properties of polymeric backbones. Living and controlled polymerization techniques provide access to SMPs with precisely controlled structures, for example, controlled degree of polymerization (DP) and molecular weight dispersity (Đ), which may have excellent performance as multi-metallic catalysts in a variety of catalytic reactions. This review will cover the recent advances about SMPs, especially on their synthesis and application in catalysis. These tailor-made SMPs with metallic catalytic centers can precisely control the number and location of their active sites, exhibiting high catalytic efficiency. [ABSTRACT FROM AUTHOR]

The novel iron complexes [N,N′-bis-2-pyridinylmethylene-cyclohexane-1,2- diamine]iron(II) chloride (1) and [N,N′-bis-2-pyridinylmethyl-cyclohexane-1,2-diamine]iron(II) chloride (2) were designed, and they showed excellent activity for the coupling reaction epoxides and CO2 to generate the corresponding cyclic carbonates. When complex 2 was used alone as a catalyst for the cycloaddition of propylene oxide (PO) and CO2, the PO conversion was 95% at 130°C and 4MPa CO2 pressure in 4h. Once a co-catalyst like tetrabutylammonium bromide (TBAB) was added, the conversion could reach 100% with nearly 100% selectivity for propylene carbonate (PC), with a turnover number (TON) of 1000 at 100°C and 4MPa CO2 pressure in 6h, i.e. the quantitative synthesis of propylene carbonate can be realized. Moreover, in combination with TBAB, the iron complex can also catalyze the cycloaddition of cyclohexene oxide (CHO) and epichlorohydrin (ECH) with CO2 to produce the corresponding cyclic carbonates, and the cyclohexene carbonate obtained was mainly the cis-isomer. [ABSTRACT FROM AUTHOR]

The incorporation of diverse macromolecular blocks into CO 2 -based polycarbonates offers a promising approach for tailoring the properties of polycarbonates for special needs. In this work, we report for the first time the synthesis and characterization of an ABA triblock copolymer polycarbonate- b -polyalkenamer- b -polycarbonate in combination of ROCOP and ROMP via a one-pot route from CO 2 , epoxides and cycloalkenes. Cis -2-butene-1,4-diol as the bifunctional chain transfer agent was used as a "bridge" for the combination of different blocks as well as an effective regulator for the molecular weight of the polymers. In the one-pot reaction, the conversion of cycloalkenes reached 99.9% within 0.5 h, while the conversion of CHO was initially marginal at 0.5% but gradually increased to 99.7% after 24 h. The significant discrepancy in reaction rates between the two processes enables efficient synergistic reactions within the one-pot system. Specifically, hydroxyl-telechelic polyalkenamer is initially formed via ROMP and subsequently acts as an active species for ROCOP when coordinated with the porphyrin Al catalyst. This one-pot strategy provides a unique and simple method for controllably constructing functional polycarbonates with single-modal molecular weight distributions. By integrating the advantages of polyalkenamers and polycarbonates, this approach proves to be a viable solution for addressing the unsatisfactory thermal properties of aliphatic polycarbonates. [Display omitted] • CO 2 -based functional polycarbonate prepared via one pot reaction in combination of ROCOP and ROMP. • Bifunctional chain transfer agent as a bridge for polycarbonate and polyalkenamer to achieve block copolymer. • ABA block structure confirmed by 1H NMR, DOSY and MALDI-TOF analysis. [ABSTRACT FROM AUTHOR]

Novel biodegradable poly(carbonate-ether)s (PCEs) with lower critical solution temperature (LCST) at body temperature were synthesized by copolymerization of CO2 and ethylene oxide (EO) under double metal cyanide (DMC) catalyst. The PCEs showed carbonate unit (CU) content of 1.0-42.4 mol % and molecular weight of 2.7-247 kg/mol, which exhibited reversible thermoresponsive feature in deionized water with LCST in a broad window from 21.5 to 84.1 °C. The LCST was highly sensitive to the CU content and the molecular weight of PCEs, and it showed a linear relation with CU content for PCEs with similar molecular weight. In particular, aqueous solution of PCE with a 26.0 mol % of CU showed an LCST around 36.1 °C, which was very close to the body temperature. Interestingly, it was found that the phase transition behavior changed with PCE concentration. For PCE with Mn of 2.7 kg/mol and CU content of 30.0 mol %, the LCST increased from 21.5 to 36.7 °C when the PCE concentration changed from 10 to 1 g/L. Dynamic light scattering indicated that the phase transition was possibly due to a coil-to-globule transition. The thermoresponsive biodegradable PCE with LCST at body temperature is promising for biomedical applications, especially for in vivo applications. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 [ABSTRACT FROM AUTHOR]

Low-molecular weight oligo(carbonate-ether) diols are important raw materials for polyurethane formation, which with tunable carbonate unit content (CU) may endow new thermal and mechanical performances to polyurethane. Herein, facile synthesis of oligo(carbonate-ether) diols with number average molecular weight ( Mn) below 2000 g mol−1 and CU tunable between 40% and 75% are realized in high activity by immortal copolymerization of CO2/propylene oxide (PO) using zinc-cobalt double metal cyanide complex (Zn-Co-DMCC) in the presence of sebacic acid (SA). Mn of the oligomer is in good linear relationship to the mole ratio of PO and SA (PO/SA) and hence can be precisely controlled by adjusting PO/SA. Besides, the molecular weight distribution is quite narrow due to the rapid reversible chain transfer in the immortal copolymerization. High pressure and low temperature are favorable for raising CU. In all the reactions, the weight fraction of propylene carbonate ( WPC) can even be controlled as low as 2.0 wt %, and the catalytic activity of Zn-Co-DMCC is above 1.0 kgg−1 cat. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

Mesoporous nanospheres are of great importance in the cutting-edge fields of energy, catalysis and sensor technology, mainly because of their multilevel architectures, tunable meso-structures, specific compositions and soft-templated synthesis approaches. In this review, the control mechanisms of aqueous polymer self-assembly are first elaborated based on the correlated driving forces, methods, and initial conditions. Then, recent advances of co-assembly-driven nanocomposite formation techniques toward mesoporous nanosphere engineering using amphiphilic block copolymers and low-molecular-weight surfactants as soft templates are systematically reviewed. Here, soft templates and organic or inorganic precursor species as well as their co-assembly processes and formation mechanisms are elaborated to thoroughly understand co-assembly-driven nanocomposite formation techniques. After soft template removal through high-temperature pyrolysis or solvent extraction, mesoporous nanospheres can be obtained. Generally, this review presents insights and a guideline to co-assembly-driven engineering of mesoporous nanospheres and promotes the development of this emerging interdisciplinary research field at the frontier between organic polymer co-assembly and inorganic nanomaterial fabrication. Co-assembly-driven nanocomposite formation techniques show great potential in manufacturing mesoporous nanospheres with multilevel architectures, in which the controllable soft template self-assemblies, precursor species and their nanocomposite formation techniques enable mesoporous nanospheres with tunable meso-structures and compositions, soft-templated synthesis approaches and functional applications. [Display omitted] • A systematic summary of soft template-directed co-assembly techniques. • In-depth analysis on mesoporous nanospheres with controllable meso-structures. • Perspectives on the opportunities and challenges of mesoporous nanospheres. [ABSTRACT FROM AUTHOR]

A m +B n +C 1 hyperbranched star copolymers with multidodal molecular weight distribution produced from one-pot one-batch process exhibit an increased influence of number of maromolecules and decreased influence of intramolecular cyclization on the number raito of monomeric structural units contrast A m +B n hyperbranched polymers so as to regulate hyperbranched star topology for an unexpected aqueous self-assembly. [Display omitted] • One-pot one-batch synthesis of Am+Bn+C1 hyperbranched star copolymers. • A convenient expression of N A /N B for the analysis of intramolecular cyclization. • Effect of intramolecular cyclization and number of macromolecules on topology. Hyperbranched star copolymers are important soft materials that have been employed for aqueous self-assembly and bioapplication, but their one-pot one-batch synthesis strategy and relevant topology are rarely discussed. In this contribution, we produce hyperbranched star poly(vinyl ether ester)s (mPEG- hb -PVEEs) amphiphiles with multimodal molecular weight distribution via one-pot one-batch Am+Bn+C1 (m ≥ 2, n ≥ 3) step-growth polymerization. Based on the topological analysis of these hyperbranched star copolymers, a convenient expression of the number ratio of monomeric structural units (N A /N B) is deduced to describe the cyclic defect of intramolecular cyclization only by using proton nuclear magnetic resonance spectroscopy. The introduction of long-chain terminators and the change in the molar feed ratio of A 2 :B 3 :C 1 considerably affect the N A /N B so as to give rise to increased influence of number of macromolecules and decreased influence of intramolecular cyclization, which are then responsible for an aqueous self-assembly behavior of mPEG- hb -PVEEs amphiphiles. Overall, this study opens new possibilities for the precise description of intramolecular cyclization and controllable synthesis of hyperbranched star copolymers via one-pot Am+Bn+C1 step-growth polymerization. [ABSTRACT FROM AUTHOR]

Hollow engineering is an effective approach to optimize impedance matching and modify magnetic-dielectric synergy for enhanced wave absorption capability, but the composition and microstructure manipulation of metal-organic frameworks (MOFs)-derived absorbers remains a challenge. Herein, a novel and facile polymerization-induced assembly-etching strategy is proposed for the manufacture of wrinkled zeolitic imidazolate framework-67@polypyrrole (ZIF-67@PPy) microcages using ammonium persulfate catalyzed pyrrole polymerization and concomitant acid etching. Then, hollow cobalt@N-doped carbon microcages (Co@NCMs) with distorted carbon shells, rich core-shell heterojunctions, highly dispersive Co nanoparticles, and abundant heterogeneous interfaces are produced via high-temperature pyrolysis process, which eliminates the need for additional templates and etching agents. Moreover, the hollow microcage structure with interior cavities and mesopores provides superior impedance matching and lightweight characteristics to the absorbers. Therefore, the hollow absorbers demonstrate a minimum reflection loss of −50.4 dB and an effective absorption bandwidth (EAB) of 3.85 GHz at 2.7 mm with a 10 wt% filler loading. In general, the polymerization-indued assembly-etching strategy inspires the hollow engineering of MOF derivatives, and facilitates the development of superior electromagnetic wave absorption (EMA) materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Due to the axial group initiation in traditional (salen)CoX/quaternary ammonium catalyst system, it is difficult to construct single active center propagating polycarbonates for copolymerization of CO2/epoxides. Here a redox-responsive poly(vinyl cyclohexene carbonate) (PVCHC) with detachable disulfide-bond backbone is synthesized in a controllable manner using (salen)CoTFA/[bis(triphenylphosphine)iminium, [PPN]TFA binary catalyst, where the axial group initiation is depressed by judiciously choosing 3,3′-dithiodipropionic acid as starter. While for those comonomers failing to obtain polycarbonate with unimodal gel permeation chromatography (GPC) curve, a versatile method is developed by combination of immortal copolymerization and prereaction approach, and functional aliphatic polycarbonates having well-defined architecture and narrow polydispersity can be prepared. The resulting PVCHC can be further functionalized with alkenes by versatile cross-metathesis reaction to tune the physicochemical properties. The combination of immortal polymerization and prereaction approach creates a powerful platform for controllable synthesis of functional CO2-based polycarbonates. [ABSTRACT FROM AUTHOR]

CO 2 -based polycarbonates are among the most promising eco-friendly polymers with excellent biodegradability and biocompatibility. However, the poor performance of conventional CO 2 -based polycarbonates such as poly(propylene carbonate) (PPC) and poly(cyclohexene oxide) (PCHC) limits their application. Herein, a series of siloxane functionalized CO 2 -based polycarbonates were obtained via terpolymerization of carbon dioxide (CO 2), propylene oxide (PO), and [2-(3, 4-epoxycyclohexyl)-ethyl] trimethoxysilane (TMSO) using a SalenCoCl/PPNCl catalyst system. A systematic study of these polycarbonate's thermal, mechanical, and surface properties was conducted by tuning the ratio between TMSO and PO. The siloxane units offered polycarbonate with a higher surface energy, resulting in a water contact angle of 110° and a significant improvement in glass transition temperature (T g) and decomposition temperature (T d). Additionally, the micro-crosslinked structure formed by the hydrolysis and condensation of methoxysilane groups provided to the polycarbonate's remarkable mechanical strength, with a high tensile strength of 46 MPa. As a result, a novel CO 2 -based polycarbonate derived from cost-efficient silane coupling agents and CO 2 has shown promising results as an alternative to rigid plastics used in industry. [Display omitted] • Siloxane functionalized polycarbonates were prepared from carbon dioxide and epoxides. • Micro-crosslinked structure of polycarbonate endows its excellent mechanical properties. • Methoxysilane groups increase surface energy and permit post-modification. [ABSTRACT FROM AUTHOR]

One-pot synthesis of well-defined bio-renewable polyesters and cyclic carbonates in high yields was successfully realized for the first time by way of a tandem reaction using metal salen complexes as catalysts. This tandem process offered unprecedented opportunities for the atom-efficient production of two relevant compounds. [ABSTRACT FROM AUTHOR]

Integrating organic multiple-carbonyl polymers and inorganic mesoporous metal oxides on highly conductive carbon nanotubes is a promising strategy to manufacture high-performance lithium-ion battery anodes; however, developing multicomponent nanocomposites with a hierarchical architecture still remain challenging. Herein, we design and produce hierarchically nanostructured carbon nanotube (CNT)/polyimide (PI)/mesoporous Fe 2 O 3 (meso-Fe 2 O 3 /PI/CNT) ternary nanocomposite materials via a sequential assembly and high-temperature dehydration strategy, aiming to fabricate flexible PI-supported meso-Fe 2 O 3 stacked on a conductive CNT supporting skeleton. By controlling the linear PI mainchain through the comonomer composition, different PI assemblies can grow on the surface of CNT to anchor meso-Fe 2 O 3 nanoparticles as well as alleviate the structural strain resulting from the volume expansion of meso-Fe 2 O 3 in its phase conversion reaction. Considering the porosity and cavity, the mesoporous Fe 2 O 3 architecture can not only buffer its volume expansion but also accommodate a large number of electrolytes to promote Li + transport. In addition, the hierarchical architecture endows the meso-Fe 2 O 3 /PI/CNT nanocomposite materials with a high structural stability during the electrochemical process. Benefiting from these structural advantages, Li-ion batteries assembled with meso-Fe 2 O 3 /PI-EDA/CNT electrodes deliver high capacities of 708.9, 608.2, and 454.5 mAh g−1 at 0.1, 0.3, and 0.5 A g−1, respectively. Even at a high current density of 1 A g−1, a discharge capacity of 95.6 mAh g−1 is still obtained after 3000 cycles. This work provides a promising route to integrate multiple-carbonyl polymers and mesoporous metal oxides with the aim of developing multicomponent organic-inorganic composite anode for Li-ion battery. [Display omitted] • Hierarchically tubular organic-inorganic nanocomposite anode from self-assembly-assisted fabrication technique is reported. • Polyimide assemblies with controllable architecture for organic anode material and strain buffer interlayer. • Fe 2 O 3 nanoparticle with mesoporous structures for inorganic anode material. • The organic-inorganic nanocomposite anode shows desirable lithium-ion battery performance. [ABSTRACT FROM AUTHOR]