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The thermodynamic effect of octyl-β-D-glucopyranoside (OGP) on the formation of methane-1,3-dimethylcyclohexane (DMCH) hydrate was studied in this work. The thermodynamic equilibrium hydrate formation pressures between 275.15 K and 283.15 K were measured by the isothermal pressure search method. Different OGP aqueous solutions (0, 0.1, and 1 wt%) were used in this work. The experimental results show that OGP had no obvious thermodynamic inhibition on methane-DMCH hydrate formation when its concentration was low (0.1 wt%), whereas it had an inhibition on methane-DMCH hydrate formation when its concentration was high (1 wt%). The phase equilibrium hydrate formation pressure of the methane-DMCH-OGP system is about 0.1 MPa higher than that of the methane-DMCH system. The dissociation enthalpies of methane hydrate in different solutions remained uniform, which indicates that OGP was not involved in methane-DMCH hydrate formation. This phenomenon is explained from the perspective of the molecular structure of OGP. As a renewable and biological nonionic surfactant, the concentration of OGP in the liquid phase is low, so OGP can be added to the methane-DMCH system without significant thermodynamic inhibition. [ABSTRACT FROM AUTHOR]

Luban locks with mortise and tenon structure have structural diversity and architectural stability, and it is extremely challenging to synthesize Luban lock‐like structures at the molecular level. In this work, we report the cocrystallization of two structurally related atom‐precise fcc silver nanoclusters Ag110(SPhF)48(PPh3)12 (Ag110) and Ag14(μ6‐S)(SPhF)12(PPh3)8 (Ag14). It is worth noting that the Ag110 cluster is the first compound to simulate the complex Luban lock structure at the molecular level. Meanwhile, Ag110 is the largest known fcc‐based silver nanocluster, so far, there is no precedent for fcc silver nanocluster with more than 100 silver atoms. DFT calculations show that Ag110 is a 58‐electron superatom with an electronically closed shell1S21P61D102S21F142P61G18. Ag110⋅Ag14 can rapidly catalyze the reduction of 4‐nitrophenol within 4 minutes. In addition, Ag110 presents clear structural evidence to reveal the critical size and mechanism of the transformation of metal core from fcc stacking to quasi‐spherical superatom. This research work provides an important structural model for studying the nucleation mechanism and structural assembly of silver nanoclusters. [ABSTRACT FROM AUTHOR]

A systematic density functional theory study including 17 exchange-correlation functionals was performed on different types of superhalogens with high level coupled-cluster single double including perturbative triple excitations (CCSD(T)) results as the reference. The superhalogens selected here cover the ranges from mononuclear to polynuclear structures and from structures with halogen-atom ligands to those with non-halogen ligands, e.g., [MgX3]-, [Mg2X5]-, and [Mg3X7]- (X = F, Cl, CN). It is clearly indicated that three double-hybrid functionals B2T-PLYP, B2GP-PLYP, B2K-PLYP as well as the range-separated hybrid functional ωB97X are capable of providing results which approach the accuracy at the CCSD(T) level. The basis set effect is usually moderate and, in most cases, it is enough to utilize the basis set of triple-ξ quality, e.g., Def2-TZVP. In addition, the results of the HF and MP2 method are also acceptable here, especially for polynuclear superhalogens where CCSD(T) is probably unpractical. [ABSTRACT FROM AUTHOR]

Two types of new [Fe]-H2ase models were synthesized using well-designed synthetic methods. The first type of trisubstituted pyridine ligand-containing models [2-MeOCH2-4-O2P(OPh)2-6-COCH2C5H2N]Fe(CO)2R (1, R = I; 2, R = EtS, 3, R = MeCOS), [2-MeOCH2-4-O2P(OPh)2-6-COCH2C5H2N]Fe(CO)2(MeCN)BF4 (4) and [2-MeOCH2-4-O2P(OPh)2-6-COCH2C5H2N]Fe(CO)(PPh3)I (5) were synthesized on the basis of preparing the new trisubstituted pyridine precursors L1–L6, whereas the second type of pentasubstituted pyridine ligand-containing model [2-MeO-3,5-Me2-4-OP＝O(OPh)O-5′-(N2-iPrCO-2′,3′-O-CMe2-guanosine)-6-COCH2C5N]Fe(CO)2(η2-6-Me-2-SC5H3N) (6) was synthesized via the esterification reaction of a new phosphatoguanosine derivative L7 with the corresponding pentasubstituted pyridine ligand-containing precursor (2-MeO-4-HO-3,5-Me2-6-COCH2C5N)Fe(CO)2(η2-6-Me-2-SCH5H3N) (D) in the presence of the dehydrating agent DCC. While all the new precursors L1–L7 and models 1–6 were fully characterized via elemental analysis and various spectroscopic techniques, the molecular structures of model 5 and precursor D were confirmed via X-ray crystallography. In addition, model 1 has been found to be a catalyst for proton reduction to H2 from TFA under CV conditions. [ABSTRACT FROM AUTHOR]

Red-emissive carbon dots (R-CDs), as a novel type of carbon nanomaterial, have attracted extensive attention in various fields due to their unique properties and physicochemical characteristics. However, most of the reported R-CDs have mainly shown fluorescence in solution, which seriously limits their practical applications, especially in anticounterfeiting and optoelectronic device fields. In recent years, significant efforts have been devoted to achieving solid-state red fluorescence of CDs and exploring their potential applications. In this review, we analyzed the key issues in the synthesis of solid-state red carbon dots (SSR-CDs), elucidated the possible mechanisms of anti-quenching, and introduced their applications. Finally, we discuss the current challenges and opportunities of SSR-CDs. • We summarize the existing research and emerging advances of such CDs from a particular angle to guide their synthesis with desirable optical properties. • We focus on their solid-state fluorescent (SSF) mechanism from the molecular structure design to achieve AIE, R-CDs in such a solid-state matrix and CEE. • The applications of SSR-CDs, especially in photoelectric device applications and anti-counterfeiting applications, are summarized to determine their potential value. [ABSTRACT FROM AUTHOR]

Two new ent-clerodane diterpenoids, named isoscoparins R and S (1 and 2), were isolated from the aerial parts of Isodon scoparius. Their structures were characterized mainly by analyzing the NMR and HRESIMS data, and the relative configuration of compound 1 was determined by single-crystal X-ray diffraction. Compound 2 showed weak activity as an autophagic inhibitor. [ABSTRACT FROM AUTHOR]

The EtOH extract of the roots of Platycodon grandiflorum afforded two new triterpene saponins platycoside P (1) and platycoside Q (2). Their structures were elucidated based on spectroscopic means and hydrolysis products. These compounds were evaluated for inhibitory activity against LPS-induced TNF-α production in RAW 246.7 macrophages. Compounds 1 and 2 showed inhibitory activity with the inhibition ratios (%) of 38.6 and 44.1 at 50 μM, respectively. [ABSTRACT FROM AUTHOR]

The accidental overcharging is emulated in fully charged LiCoO2/mesocarbon microbeads (MCMB) batteries through initial one-off overcharging and successive long-term normal cycling. The aging mechanism and effect of accidental overcharging on the performance of LiCoO2/MCMB battery is studied by the electrochemical tests and physical characterizations. The result clearly shows that not all accidentally overcharged batteries should be discarded and the extent of the degradation is highly dependent on the overcharging cutoff voltages. Compared with the blank batteries, low overcharging cutoff voltages have almost no influence on the performance degradation during successive long-term normal cycling. Under this condition, the aging is primarily due to the consumption of active lithium. However, high overcharging cutoff voltages, even just one time, decay the battery. Furthermore, further cycling accelerates the aging and changes the aging mechanism of battery under normal operation condition. Under this condition, the surface structure destruction of the LiCoO2 is revealed as the primary contributor to battery degradation, which is related to the dissolution and reduction of cobalt ions after overcharging at high cutoff voltages and successive long-term normal cycling. [ABSTRACT FROM AUTHOR]

The EtOH extract of the roots and rhizomes of Clematis chinensis afforded two new macrocyclic glucosides clemochinenosides C (1) and D (2). Their structures were elucidated on the basis of spectroscopic means and hydrolysis products. These compounds were evaluated for inhibitory activity against lipopolysaccharides-induced TNF-α production in RAW 246.7 macrophages. Compounds 1 and 2 showed moderate inhibitory activity with IC50 values of 12.9 ± 2.3 and 18.4 ± 2.7 μM, respectively. In addition, a proliferation study was used to evaluate the anti-angiogenic effects of these compounds in vitro (VEGF-induced human umbilical vein endothelial cell proliferation). Compounds 1 and 2 displayed weak inhibitory effects with inhibition rates of 26.3 ± 1.8 and 19.2 ± 2.6% at 50 μM, respectively. [ABSTRACT FROM AUTHOR]

Abstract: A novel composite membrane consisting of an interconnected MOF scaffold coated with cross‐linked poly(ethylene glycol) (PEG) has been developed. As a result of its unique structure, the membrane shows an exceptional 18‐fold permeability enhancement as compared to pristine PEG membranes, without compromising the selectivity. This performance is unattainable with current mixed‐matrix membranes (MMMs). Our optimized membrane has a permeability of 2700 Barrer with a CO2/N2 selectivity of 35, which surpasses the latest Robeson upper bound. [ABSTRACT FROM AUTHOR]

The equilibrium structures, stabilities, magnetic, and spectroscopic properties of small-sized Al xZr y () alloy clusters have been systematically investigated within the framework of density functional theory. We found that the structures of bimetallic clusters prefer to form the same motif as their corresponding pure Al or Zr clusters and chirality turns up in mixed clusters with and 9. Computations of VCD and VROA spectra confirmed the chirality of these clusters. For a given cluster size, the most favorable mixing occurs when the ratio of Al:Zr is approximatively equal to 1. The total magnetic moments depend not only on the configuration but also on the composition of the clusters. [ABSTRACT FROM AUTHOR]

The EtOH extract of the roots ofPaeonia veitchiiafforded two new monoterpene glycosides paeonidanin I (1)and paeonidanin J (2), and a new dimeric monoterpene glycoside paeonidanin K (3). Their structures were elucidated on the basis of spectroscopic means and hydrolysis products. [ABSTRACT FROM PUBLISHER]

The EtOH extract of the roots ofPaeonia lactifloraafforded a new phenolic glycoside paenoside A (1) and a new monoterpene glycoside paeonin D (2), and five known monoterpene glycosides. Their structures were elucidated on the basis of spectroscopic means and hydrolysis products. All compounds displayed inhibitory potential against enzyme lipoxygenase. [ABSTRACT FROM PUBLISHER]

Three new monoterpene glycosides, 2′-O-benzoylpaeoniflorin, albiflorin R2, and albiflorin R3 (1–3) were isolated from the roots of Paeonia lactiflora. Their structures were elucidated on the basis of spectroscopic means including one- and two-dimensional NMR experiments. [ABSTRACT FROM AUTHOR]

Three new triterpene saponins, clematochinenosides H–J (1–3), were isolated from the roots and rhizomes ofClematis chinensis. Their structures were elucidated on the basis of spectroscopic means including 1D and 2D NMR experiments and hydrolysis products. [ABSTRACT FROM PUBLISHER]

The formation of multilayer structures in the high-speed thin wall injection-molded samples of high-density polyethylene/isotactic polypropylene blends is reported. Based on the morphology development in injection runner and mold, a possible formation mechanism of multilayer structure was proposed in this study. Injection molding could be used as a simple and an effective method for the fabrication of multifunctional multilayer structure. This work is interesting and important for scientific research as well as several potential applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

Abstract: The growth of metal-free carbon nanotube (CNT) arrays on SiC surface was investigated systematically by using high temperature annealing of 6H–SiC(000 ) crystals under various atmospheres, including inert, hydrogen-containing, and oxygen-containing gaseous environments. Carbon nanowall structure consisting of graphene sheets standing vertically on the substrate forms under the inert and hydrogen-containing atmospheres, while vertically aligned CNT arrays can be obtained in oxygen-containing atmospheres, such as H2O. The comparative studies reveal that oxygen-containing species play a critical role in the formation of CNTs on SiC. Transient SiO nanoclusters formed at the C/SiC interface are proposed to be the active sites for CNT growth on SiC. [Copyright &y& Elsevier]

Abstract: Peripherally tetraimido-substituted phthalocyaninato zinc compounds 1–3 were synthesized through the reaction of tetraamino-substituted phthalocyaninato zinc with 4-Br-1,8-naphthalic anhydride, 4-hexahydropyridine-1,8-naphthalic anhydride and 4-morpholine-1,8-naphthalic anhydride, respectively. The compounds were characterized by MS, 1H NMR, UV–vis, IR and elemental analysis, the results of which were consistent with the proposed structures. The effects of substitutes, acid/base and solvents on the UV–vis spectra of the new complexes were discussed in detail. [Copyright &y& Elsevier]

Abstract  The structure and stability of neutral polyoxometalate cages (Mo2O6) m (m=1–13) have been computed systematically. These neutral cages can be viewed topologically as polyhedra containing triangles (f 3) and squares (f 4). The relative stability of these polyhedra is associated with the location and separation of the f 3. The initial stable isomers were preselected by the number of shared triangle edges (N 33), and the predicted stability was validated further at the GGA-PW91/DND level of density function theory with the fine quality of mesh size. For large clusters, the square neighbor signature (P 4444), which is similar to the hexagon neighbor rule for fullerene, becomes more applicable. The calculated disproportionation energies indicate that Mo6O18 (O h, Lindqvist), Mo12O36 (O h, α Keggin), Mo18O54 (D 3h, Wells–Dawson) and Mo24O72 (O h) cages have enhanced stability.

[ABSTRACT FROM AUTHOR]

Reversible addition–fragmentation chain transfer (RAFT) polymerization initiated by a radical-forming redox reaction between a reducing and an oxidizing agent (i.e. 'redox RAFT') represents a simple, versatile, and highly useful platform for controlled polymer synthesis. Herein, the potency of a wide range of redox initiation systems including enzyme-mediated redox reactions, the Fenton reaction, peroxide-based reactions, and metal-catalyzed redox reactions, and their application in initiating RAFT polymerization, are reviewed. These redox-RAFT polymerization methods have been widely studied for synthesizing a broad range of homo- and co-polymers with tailored molecular weights, compositions, and (macro)molecular structures. It has been demonstrated that redox-RAFT polymerization holds particular promise due to its excellent performance under mild conditions, typically operating at room temperature. Redox-RAFT polymerization is therefore an important and core part of the RAFT methodology handbook and may be of particular importance going forward for the fabrication of polymeric biomaterials under biologically relevant conditions or in biological systems, in which naturally occurring redox reactions are prevalent. The capability of several redox initiation systems and their application in initiating reversible addition–fragmentation chain transfer (RAFT) polymerization are reviewed. The redox-RAFT technique is therefore a core part of the RAFT methodology handbook and may be of particular significance going forward for the fabrication of polymer-based biomaterials under bio-related conditions. [ABSTRACT FROM AUTHOR]

Despite the wide industrial application of poly(tetrafluoroethylene- co -perfluoroalkylvinyl ether) (PFA) in semiconductor processing, its crystallization behavior has little been studied. In this work, three PFA resins with similar molecular weight but different comonomer content and distribution were synthetized. Then the non-isothermal crystallization kinetics and crystalline structures were studied by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction systematically. It is found that the incorporation of comonomers destroys the chain regularity and reduces the crystallizability of PFA thermodynamically, while the comonomer insertion improves the chain flexibility to accelerate the crystal growth dynamically. When the comonomer content of PFA is low, both the nucleation and growth rates are quite fast, which is favorable for the formation of spherulite. As the comonomer content increases or distribute uniformly in the chain, the nucleation rate declines notably and the side groups distort the crystal cell to increase the spacing of [100] plane. Moreover, two-dimensional growth mode is dominant to form bundle-like structure when crystallizing at slow cooling, where nucleation is suppressed by growth. But three-dimensional symmetrical spherulite can be activated and perfected at high cooling rate due to the initiation of substantial nucleation sites. This unique crystallization behavior is opposite to that of conventional polymers, providing a guidance for the polymerization and processing of PFA. When the comonomer content of PFA is low, thick lamellar crystals are formed. As the comonomer content increases or distribute uniformly in the chain, the nucleation rate declines notably and the side groups distort the crystal cell to increase the spacing of [100] plane. Moreover, two-dimensional growth mode is dominant to form bundle-like structure when crystallizing at slow cooling. But three-dimensional symmetrical spherulite can be activated and perfected at high cooling rate due to the initiation of substantial nucleation sites. [Display omitted] • The evolution of the crystallization behavior of PFA was studied. • The effect of PPVE content and distribution on the crystalline behavior of PFA was compared. • The effect of cooling rate on the crystalline structure of PFA was studied. [ABSTRACT FROM AUTHOR]

Polyphenylene sulfide (PPS) has a prospective application in high-frequency communication due to its excellent dielectric properties. However, owing to the strong melt memory effect, the crystalline structure of PPS is very sensitive to the processing conditions and difficult to be controlled. To date, the melt memory effect of polymer cannot be detected directly and quantitatively. In this work, four PPS samples were successively prepared via polymerization, extrusion and dissolution treatment. The Fourier infrared transform spectroscopy (FTIR), high-temperature gel permeation chromatography (HT-GPC) and dynamic rheological tests disclose that these four PPS samples have analogous molecular structure and only differ in entanglement density. The molecular weight between entanglements (M e) decreases gradually from 1188 to 354 g/mol. Furthermore, differential scanning calorimetry (DSC) and polarized optical microscopy (POM) measurements were carried out to study the effect of entanglement density on the crystallization kinetics of PPS. It is found that entanglement density is a key indicator to characterize the melt memory effect of PPS semi-quantitatively, and the residual local ordered structures in PPS melt is proportional to M e. In addition, the crystallization kinetics of PPS is determined by the cooperation of melt memory effect (nucleation) and entanglement density (growth). Accordingly, the relationship of "chain entanglements" → "melt memory effect" → "crystallization behavior" of PPS is established, constructing a roadmap for the precise control of crystalline structures of PPS products during practical processing. Diagram of the relationship of "chain entanglements" → "melt memory effect" → "crystallization behavior" of PPS. [Display omitted] • Entanglement density of PPS was controlled by different methods (1188-354 g/mol). • Entanglement density can be used to characterize the memory effect of PPS. • Memory effect and entanglement together affect the crystallization kinetics of PPS. [ABSTRACT FROM AUTHOR]

In this work, we report that super-toughened and high-strength polylactide/poly(butylene adipate-co-terephthalate) (PLA/PBAT) blends can be successfully prepared by interfacial compatibilization and dynamic vulcanization during reactive melt-blending with small amounts (0.5–3 wt %) of epoxy-functional styrene-acrylic oligomers (ESA). The results show that the compatibilization is realized with the grafting of some PLA and PBAT chains onto ESA backbones to in-situ generate PLA- graft -PBAT copolymers at the blend interface. Meanwhile, the ESA-mediated vulcanization gives rise to the highly cross-linked PBAT particles with a unique network-like distribution in the PLA matrix. Both the strengthened interfaces and networked PBAT particles are favorable to the triggering of massive matrix plastic deformation required for effective energy dissipation and thus the toughening effect is substantially enhanced. Impressively, the notched Izod impact toughness and elongation at break of the PLA/PBAT (70/30) blends can reach as high as 62.4 kJ/m2 and 232%, while the tensile strength increases from 44.2 MPa to 51.5 MPa, indicating a balanced toughness and strength. Most notably, it is demonstrated that tuning the molecular structure of ESA (i.e., epoxy group density and backbone length) is essential to improving the interfacial adhesion and phase morphology, enabling high toughening efficiency. Our facile yet robust strategy presents an unprecedented opportunity for the development of high-performance fully biodegradable PLA blends. [Display omitted] • Full biodegradable PLA/PBAT blends with balanced toughness and strength are prepared. • Dynamic vulcanization leads to the highly cross-linked PBAT domains in PLA matrix. • Copolymers are in-situ generated at the interface for effective compatibilization. • The formation of PBAT particle network is responsible for the desired properties. • The key role of ESA structure in tailoring the morphology and properties is verified. [ABSTRACT FROM AUTHOR]

Abstract: Li-excess Li[Li0.18Ni0.15Co0.15Mn0.52]O2 layered cathode material is prepared by the sol-gel method. The material is aged in a LiPF6 based electrolyte and then is subjected to a series of structural and electrochemical analyses. X-ray diffraction shows that aging in electrolyte does not change the C2/m ordering of the material crystal lattice. But the surface of the material is etched by the electrolyte which is confirmed by transmission electron microscope and Raman scattering. This causes dissolution of some transition metal elements (especially Ni and Co) and formation of a spinel-like surface layer. Also, some by-products resulted from the electrolyte decomposition are detected on the surface of the material. Electrochemical impedance spectroscopy shows that aging in electrolyte severely hinders the electrochemical kinetics of the material. Cyclic voltammetry indicates that the aged sample has large electrode polarization which prevents the oxygen loss process and the activation of Mn4+ ions. As a result, the discharge capacity of the aged sample continuously increases from 134 mAh g−1 to 215 mAh g−1 in the initial several cycles. [Copyright &y& Elsevier]

Abstract: The mechanical responses including monotonic and cyclic tensile responses have been investigated on a microphase-separated poly (styrene-isoprene-styrene) triblock copolymer (SIS). The specimens were injection-molded by using different melt temperatures to acquire different microphase structures. As a result of temperature-dependent segregation driving force, the specimens with reduced microphase separation can be obtained by increasing processing melt temperature from 180 °C to 240 °C. On the basis of stress-strain behavior, Young''s modulus was found to increase with increasing PS domain continuity in the order of disorder state to disordered spheres to body-cubic-centered (BCC) spheres to oriented cylinders morphology. Meanwhile, cyclic hysteresis decreases with reduced microphase separation and with decreasing the applied predetermined maximum tensile strain. In addition, the Mooney–Rivlin phenomenological approach was used to evaluate and explore the relationship between the polymer topological networks and the rubber elasticity of thermoplastic elastomers. [Copyright &y& Elsevier]

Abstract: Crystalline structures especially the interfacial crystalline layers of semi-crystalline polymer/filler composites are markedly affected by the extensional force and keep an important role in macroscopic properties. In this study, we prepared the polypropylene and SiO2–MgO–CaO whisker (SMCW) composite fibers by melt-spun technology. The structure–property relationship of the PP/SMCW composite fibers was investigated by scanning electron microscopy, polarizing light microscopy, differential scanning calorimeter, the polarized Fourier transform infrared spectroscopy and tensile test. Two different interfacial crystalline structures were observed by adopting two drawn ratios – shish-calabash structure obtained at the low drawn ratio and transcrystalline (TC) structure obtained at the high drawn ratio. Remarkable reinforcement of the fibers was realized for the composite fibers prepared at high drawn ratio, compared with that obtained at the low drawn ratio. It was deduced that the formation of transcrystalline structure could result in a better interfacial interaction than shish-calabash structure, and could be one of the most important reasons for the large improvement of tensile properties of composite fibers fabricated at high drawn ratio. [Copyright &y& Elsevier]

Abstract: The polar crystalline phase is the most important crystal mode for poly(vinylidene fluoride) (PVDF); its high content is urgently desired in the large-scale processing fabrication likes injection-molding. In this study, we proposed a convenient pathway to achieve large amount of polar phase in injection-molding part through cooperation of exerting oscillatory shear field and adding nanoclay. The effects of these two factors on the polymorphic composition were well demonstrated by infrared spectroscopy and X-ray diffraction. The increment of polar phase content was limited when shear field was solely imposed or only less amount of nanoclay, 1 wt%, was added. Whereas, by simultaneously exerting shear field and adding 1 wt% nanoclay, an extremely high polar phase fraction was achieved. So a positive cooperative effect of shear and nanoclay on the formation of polar phase can be proved absolutely. The simultaneously exerting shear and adding nanoclay leaded to not only high content of polar phase but also highly oriented structure. With this unique structure, an order-of-magnitude increase in the ductility (elongation) as well as good piezoelectric property has been achieved for the molded parts of PVDF/nanoclay nanocomposites. [Copyright &y& Elsevier]

Abstract: In this study, isotactic polypropylene (iPP) samples were prepared by conventional injection molding (CIM) and pressure vibration injection molding (PVIM), in which a periodical shear field was imposed on the iPP melt during the cooling solidification. The distribution of supermolecular structures of samples was investigated by Polarized Light Microscopy (PLM) and Scanning Electron Microscopy (SEM). Results show that the through-the thickness-morphology of sample prepared by CIM features a typical skin-core structure, as a result of general shear-induced crystallization. This structure can be divided into three layers, including a skin layer in which the shish–kebab structure was found, a transition region with deformed spherulite structure and a core layer with spherulitic structure. However, the morphology of the sample prepared by PVIM, as a result of periodical shear-induced crystallization, features a richer and fascinating supermolecular structure and can not be roughly divided into three layers. A region full of shish–kebab-like cylindrulite structures was found between the transition region and the core layer, which is rare to be seen in conventional injection molding. Based on their various core structures, two kinds of shish–kebab-like cylindrulites were defined: one is multi-fibril-core cylindrulite of which core is an assembly of multiple fibrils, and the other is single-fibril-core cylindrulite of which the core just contains a single fibril. Based on the investigated results, a schematic illustration is proposed to depict the through-the thickness-distribution of supermolecular structure of iPP sample prepared by PVIM. The mechanism of the formation of the two kinds of shish–kebab-like cylindrulite structures is also depicted by a schematic illustration, and it was discussed in terms of periodical shear-induced crystallization. [Copyright &y& Elsevier]

Abstract: Long fiber reinforcement is well known to offer thermoplastic materials with high performances. But little work has been done to systematically investigate the effect of shear on the structures and properties of long glass fiber reinforced thermoplastics. The purpose of this work is to investigate the effect of shear on fiber orientation, fiber breakage and matrix molecular orientation in long glass fiber reinforced polypropylene composites, and to construct the structure–property relations. A so-called dynamic packing injection molding (DPIM) technique, which imposed oscillatory shear (10s−1) on the gradually cooled melt during the packing solidification stage, was used to prepare the dynamic samples, and optical microscope (OM), scanning electron microscope (SEM), micro-Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were used to characterize the samples. The results show that despite the well-published enhanced fiber and matrix orientation, shear will cause a remarkable fiber breakage. Combined effect of fiber breakage and orientation on the mechanical properties of the composites was qualitatively investigated and tensile properties of the dynamic samples, the conventional injection molded samples and the short glass fiber reinforced samples were compared. It is demonstrated that shear will induce more severe fiber breakage in long glass fiber reinforced polypropylene than in short glass fiber reinforced polypropylene, and that compromising the decreased strength caused by the severe fiber breakage is very difficult. [Copyright &y& Elsevier]

Abstract: The structural development during cold crystallization of poly (l-lactide) has been explored by time-dependent Fourier transform infrared spectroscopy and depolarized light scattering, respectively. It is indicated that the conformation-sensitive 956 cm−1 band changes first during induction period, followed by formation of 103 helix sequence (921 cm−1 band) in the disordered crystals; after that, the inner structure of new-formed disordered crystals is further perfected, giving rise to frequency shift of 871 cm−1 band to higher wavenumber. Moreover, the formation and subsequent perfection of disordered crystals are also evidenced by the sharp transition of integrated scattering intensity revealed by depolarized light scattering measurements. It is strongly suggested that the cold crystallization of poly (l-lactide) follows a sequential ordering or multi-step process at atomic scale. Furthermore, such a sequential ordering is independent of crystallization temperature and the thermal history (melt cooling rate) of samples prior to cold crystallization. Increasing crystallization temperature or decreasing melt cooling rate just shortens the onset time related to above-referred each step. [Copyright &y& Elsevier]

Abstract: The polymer matrix structure and the interface are strongly influenced by filler in semi-crystalline polymer composites because the fillers have the potential to nucleate the polymer crystallization. The structure of the nucleated crystalline polymer on filler is of particular interest and is a key to the interfacial enhancement. In this work, whiskers, with a large length/diameter ratio and with a diameter (0.2–2μm) much larger than that of carbon nanotubes but much smaller than that of common fibers, were used to nucleate crystal morphology in polypropylene (PP)/whisker composites. The crystal morphology, interfacial adhesion and tensile properties of the composites were carefully investigated. A kind of peculiar shish–calabash crystallization morphology, with whisker serves as shish and PP spherulites serves as calabash, was observed for the first time in the thin film via PLM and in the injection molded bars by SEM. The formation mechanism of this shish–calabash structure was attributed to be that only a few nuclei could be induced on the whisker surface, which develop into large PP spherulites without hindrance, and finally stringed by the whisker, forming the shish–calabash structure. As a result, a significant improvement of interfacial interaction and tensile properties has been achieved. [Copyright &y& Elsevier]

Abstract: In this article, we report the synthesis and properties of novel segmented polyurethanes containing alkyl phosphatidylcholine side groups. Alkyl phosphatidylcholine groups were attached to the hard blocks of the polyurethanes. A novel diol, 9-(2-hydroxy-1-hydroxymethyl-1-methyl-ethylcarbamoyl)-nonyl-phosphatidylcholine (HDEAPC), was synthesized and characterized by FTIR, 1H-NMR and mass spectroscopy. Two types of polyurethanes, poly(ether urethane)s and poly(carbonate urethane)s, containing alkyl phosphatidylcholine side groups were synthesized using methylenebis(phenylene isocyanate) (MDI), polytetramethyleneoxide (PTMO), poly(1,6-hexyl-1,5-pentylcarbonate) diol (PHPCD), 1,4-butanediol (BDO) and HDEAPC. The obtained phosphatidylcholine polyurethanes had relatively high molecular weights and good mechanical strength, as characterized by GPC and Instron. XPS and contact angle studies revealed that there was enrichment of alkyl phosphatidylcholine side groups near the surface of the polyurethanes. Biocompatibility was evaluated by protein adsorption using conventional polyurethanes as references. The surface of phosphatidylcholine poly(carbonate urethane)s effectively suppressed protein adsorption. [Copyright &y& Elsevier]

• Batch-to-batch variations existed in nutritional values of corn coproducts. • All spectral parameters varied among different batches except for corn gluten meal. • Changes in chemical and biodegradation traits were strongly related to protein spectral parameters. This study investigated batch-to-batch variations in carbohydrates 1) chemical profile; 2) Cornell Net Carbohydrate and Protein System (CNCPS) carbohydrates subfractions; 3) in situ ruminal degradation kinetics of neutral detergent fiber (NDF); and 4) molecular structure spectral characteristics of carbohydrates (structural carbohydrates, SCHO; cellulosic compounds, CELC; total carbohydrates, TCHO and non-structural carbohydrates, NSCHO) in corn byproducts. The second aim was to correlate the variations in carbohydrates molecular structures with carbohydrates nutritional traits. The corn byproducts selected in this study were corn gluten feed, corn germ, corn germ cake and corn gluten meal. The preprocessed corn kernels were used as control. The results revealed large differences in carbohydrate chemical composition (P < 0.001), CNCPS subfractions (P < 0.001) and rumen degradation kinetics of NDF (P ≤ 0.01) between preprocessed corn kernels and the byproducts. The contents of NDF and non-fiber carbohydrates varied (P ≤ 0.01) among the three batches of corn kernels and the byproducts. Except SCHO area, all the carbohydrates molecular spectral bands areas and ratios differed (P < 0.001) between the preprocessed corn kernels and the byproducts. Significant batch-to-batch variations were observed for different spectral parameters of the byproducts. Regression equations based on carbohydrate spectral data gives relatively good prediction power for carbohydrates chemical profile (P < 0.001; R2 = 0.55-0.80), CNCPS subfractions (P < 0.001; R2 = 0.62-0.86) and ruminal degradation characteristics of NDF (P < 0.001; R2 = 0.78-0.89). In conclusion, batch-to-batch variation was observed in nutritional values of carbohydrates in corn byproducts, and carbohydrates molecular structures spectral data might potentially be used to predict nutritive values of corn and corn byproducts for dairy cows. [ABSTRACT FROM AUTHOR]