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Fully renewable oxygen barrier thermoplastic starch (TPS)/sugar alcohol blown films were innovatively prepared by blending proper loadings of Erythritol (ET), Sorbitol (ST), and Lactitol (LT) and supercritical carbon dioxide (scC[O.sub.2]) assistance. The oxygen transmission rate (OTR) values of the properly prepared scC[O.sub.2]TP[S.sub.x]ETy, scC[O.sub.2]TP[S.sub.x]S[T.sub.y], and scC[O.sub.2]TP[S.sub.x]L[T.sub.y] films reduced to 4.3, 6.6, and 12.5 [cm.sup.3]/[m.sup.2]*day*atm, which are about 5-28 times smaller than those of the conventional TPS films reported in the literature. The free-volume-cavity characteristics (FVCC) and OTR detected for TP[S.sub.x]E[T.sub.y] (or scC[O.sub.2]TP[S.sub.x]E[T.sub.y]), TP[S.sub.x]S[T.sub.y] (or scC[O.sub.2]TP[S.sub.x]S[T.sub.y]), and TP[S.sub.x]L[T.sub.y] (or scC[O.sub.2]TP[S.sub.x]L[T.sub.y]) films diminished to a minimum, as their ET, ST and LT loadings came near an optimal value. Slightly smaller OTR and FVCC values were detected for scC[O.sub.2]TP[S.sub.x]E[T.sub.y], scC[O.sub.2]TP[S.sub.x]S[T.sub.y] and scC[O.sub.2]TP[S.sub.x]L[T.sub.y] films than those of corresponding TP[S.sub.x]E[T.sub.y], TP[S.sub.x]S[T.sub.y], and TP[S.sub.x]L[T.sub.y] films prepared without scC[O.sub.2]-assistance. The smallest OTR and FVCC detected for the properly prepared TP[S.sub.x]E[T.sub.y] (or scC[O.sub.2]TP[S.sub.x]E[T.sub.y]), TP[S.sub.x]S[T.sub.y] (or scC[O.sub.2]TP[S.sub.x]S[T.sub.y]), and TP[S.sub.x]L[T.sub.y] (or scC[O.sub.2]TP[S.sub.x]L[T.sub.y]) films diminished with decreasing sugar alcohol's molecular weight. An essential result is that the OTR of the properly prepared scC[O.sub.2]TP[S.sub.x]E[T.sub.y] film was merely 4.3 [cm.sup.3]/[m.sup.2]*day*atm, which is small enough to meet the demand of high oxygen barrier packaging application. Dynamic molecular relaxations detected for these films disclosed that ET, ST, and LT were compatible with TPS, as their loads were [less than or equal to] the optimum value. The distinctly reduced OTR and FVCC for these properly prepared films are partially attributed to the reinforced molecular interactions between sugar alcohol and TPS's hydroxyl groups when they were prepared with scC[O.sub.2]assistance, optimal sugar alcohol loading, and/or smaller sugar alcohol's molecular weight. Highlights * High oxygen barrier thermoplastic starch/sugar alcohol blown films were prepared. * The lowest oxygen transmission rate of the renewable film was 4.3 [cm.sup.3]/ [m.sup.2]*day*atm. * This oxygen transmission rate is qualified for high oxygen barrier application. * Boosted oxygen barrier property was ascribed to the reduced free volume values. KEYWORDS erythritol, free-volume-cavity characteristics, lactitol, oxygen transmission rate, scC[O.sub.2]assisted thermoplastic starch, sorbitol, 1 | INTRODUCTION The contamination problem for nonbiodegradable petroleum-derived waste plastics has turned out to be a harsh challenge to our environment for the last tens of years. (1-7) Petroleum-derived [...]

Sandwich-type clusters with the planar fragment containing a heterometallic sheet have remained elusive. In this work, we introduce the [K(2,2,2-crypt)]4{(Ge9)2[η6-Ge(PdPPh3)3]} complex that contains a heterometallic sandwich fragment. The title compound is structurally characterized by means of single-crystal X-ray diffraction, which reveals the presence of an unusual heteroatomic metal planar fragment Ge@Pd3. The planar fragment contains a rare formal zerovalent germanium core and a peculiar bonding mode of sp2-Ge@(PdPPh3)3 trigonal planar structure, whereas the nonagermanide fragments act as capping ligands. The chemical bonding pattern of the planar fragment consists of three 2c-2e Pd-Ge σ-bonds attaching Pd atoms to the core Ge atom, while the binding between the planar fragment and the aromatic Ge9 ligands is provided by six 2c-2e Pd-Ge σ-bonds and two delocalized 4c-2e σ-bonds. The synthesized cluster represents a rare example of a sandwich compound with the heteroatomic metal planar fragment and inorganic aromatic capping ligands.

In order to solve the safety problems in the lithium ion batteries used nowadays,the researchers were increasingly attracted by the solid electrolytes. Allophane was prepared from Na2SiO3 and AlCl3·6H2O by sol-gel method. By mixing the allophane and the polyethylene oxide/lithium perchlorate(PEO/LiClO4)with the solution blending method,the composite solid polymer electrolyte was obtained. X-ray diffraction(XRD),fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry(DSC),transmission electron microscope(TEM),scanning electron microscope(SEM)and optical microscopy(OM)were used to characterize the microstructure and morphology of the samples. The results show that the noncovalent bonding interactions(complexation,hydrogen bonding,and Lewis acid-base interaction)among allophane,LiClO4 and PEO significantly inhibit the crystallization of PEO. The crystallinity of PEO decreases and then increases with the increase of allophone content. Moreover,the crystallinity of PEO decrease with the increase of LiClO4 content. When EO/Li+ molar ratio is 10:1 and the content of allophane is 5%(mass fraction),the crystallinity of PEO in the solid polymer electrolyte is only 4.12%.

Comprehensive Summary: Binary polyantimony clusters, namely [Cu2Sb14]4– and [Ag2Sb14]4–, containing coinage metals, were successfully synthesized and characterized, in which two homoatomic Sb73– subunits are bridged by two coinage metals in η4:η1 and η1:η1 coordination modes, respectively. In [Cu2Sb14]4–, two bridging Cu ions and two Sb atoms form a planar rhombic unit, which was revealed to have antiaromatic properties by theoretical calculations. Further electron structure and bonding analysis confirmed the presence of delocalized bonds in the rhombic unit and the metallophilic interaction between two formal M+ ions. [ABSTRACT FROM AUTHOR]

Sustainable oxygen barrier thermoplastic starch (TPS)/polyvinyl alcohol (PVA) blown films were successfully prepared by blending proper PVA loads during NaOH-treating and supercritical carbon dioxide (scCO2) assisted processing. The NaOH-treated TPS or scCO2TPS films showed smaller free-volume-cavity characteristics (FVCC) and oxygen transmission rate (OTR) than those of TPS (or scCO2TPS) prepared without proper alkali-treatment. Smaller OTR and FVCC values were detected for NaOH-treated scCO2TPS films than those of NaOH-treated TPS films prepared without scCO2-assistance. All OTR and FVCC values detected for proper alkali-treated scCO2TPSyPVAz films diminished distinctly to a smallest value, when their PVA loads came near a solubility limit value of 27.5 wt%. An essential result is that the OTR of the optimal NaOH-treated scCO2TPSyPVAz film is merely 3.1 cm3/m2 day atm, which meets the requirement of high oxygen barrier plastics. Dynamic molecular relaxations and WAXD patterns detected for proper NaOH-treated scCO2TPSyPVAz films disclosed that PVA was compatible with TPS, as PVA loads were ≤ the solubility limit value. The distinctly reduced OTR and FVCC detected for optimal NaOH-treated scCO2TPSyPVAz films are partially attributed to the reinforced molecular interactions between hydroxyl groups of TPS and PVA, as they were blended with proper PVA loads during their alkali-treating and scCO2-aid processing. [ABSTRACT FROM AUTHOR]

In this paper, we report the synthesis and structural characterisation of two hetero-metallic clusters, [(CO)3CrSn5Cr(CO)3]4− and [(CO)3MoSn5Mo(CO)3]4−, both of which have a pentagonal bipyramidal core. The structures are similar to that of previously reported [(CO)3MoPb5Mo(CO)3]4− and our analysis of the bonding suggests that they are best formulated as containing Sn54− rings bridging two zerovalent M(CO)3 fragments. The electronic structure is compared to two isolobal M2E5 clusters, [CpCrP5CrCp]− and Tl77−, both of which show clear evidence for trans-annular bonds between the apical atoms that is not immediately obvious in the title clusters. Our analysis shows that the balance between E-E and M-M bonding is a delicate one, and shifts in the relative energies of the orbitals on the E5 and M2 fragments generate a continuum of bonding situations linked by the degree of localisation of the cluster LUMO. [ABSTRACT FROM AUTHOR]

In this work, we report the synthesis and characterization of two novel Ru-containing Zintl clusters: [Sn19{Ru(COD)(en)}2]4− and [Sn20{Ru(COD)}2]6−. The synthesized compounds not only expand the family of Ru-Sn cluster systems but also shed light on the structure of heterometallic complexes in a previously unknown range of tin atoms. The single-crystal X-ray diffraction (XRD) analysis reveals the dimeric nature of the clusters. Two different assembly patterns of the formal [Sn(η3−Sn9)] monomer were observed: the dimerization through the vertex fusion process and the direct dimerization through the formation of 2c–2e Sn-Sn σ-bond. For both clusters, the density functional theory calculations reveal the locally σ-aromatic nature of the [Sn(η3−Sn9)] monomer resulting in two independent magnetic shielding cones. We believe that our findings will help the community to further explore the fascinating chemistry of polystannide clusters. [ABSTRACT FROM AUTHOR]

In this work, we synthesize naked tin cluster anion Sn368−, representing the first example of pure Sn nanowire assembled through oxidative coupling reactions of a super atomic cluster Sn94−. Theoretical analysis confirm the presence of aromaticity for each Sn9 unit showing four adjacent aromatic subunits bridged by parallel Sn–Sn bonds. [ABSTRACT FROM AUTHOR]