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Herein, a ternary blend from poly(butylene succinate) (PBS), poly(propylene carbonate) (PPC), and poly(vinyl acetate) (PVAc) with improved crystallization rate, stiffness, and toughness was initially prepared via melt compounded. The influence of PVAc content on morphology, miscibility, thermal behavior, and rheological and mechanical properties was investigated. Scanning electron microscopy observation showed phase morphology of PBS/PPC/PVAc ternary blends evolved from sea-island dispersion to co-continuous structure. Dynamic mechanical analysis revealed that PBS and PPC were immiscible. The presence of PPC inhibited the crystallization of PBS, while simultaneous incorporation of PVAc and PPC promoted the crystallization. Furthermore, the introduction of PPC and PVAc enhanced the rheological properties of PBS. Unexpectedly, prominent improvement in tensile modulus, yield strength, and elongation was obtained for the PBS/PPC/PVAc ternary blend with 10 wt% PVAc due to the morphological evolution from sea-island to co-continuous structure, which was respectively increased by 93%, 52%, and 26% compared with neat PBS.

Herein, poly(3-hydroxybutyrate-co-4-hydroxyvalerate) (P34HB), poly (L-lactic acid) (PLA), and poly(vinyl acetate) (PVAc) were initially melt compounded to prepare a ternary blend with balanced properties. Further, the miscibility, phase morphology, thermal and crystallization behaviors, and rheological and mechanical properties of the blends were studied. The dynamic mechanical analysis (DMA) results indicated that P34HB and PLA were partially miscible; however, PVAc showed full miscibility with PLA and P34HB. PVAc would selectively disperse in the PLA phase when considering low content, whereas it would gradually diffuse into the P34HB phase with the increasing PVAc concentration. A phase-separated morphology was observed for all the blends using scanning electron microscopy (SEM), and the diameters of the dispersed phases increased with the increasing PVAc concentration. The crystallization of P34HB was enhanced by the presence of PLA alone and was restrained by the simultaneous incorporation of PVAc and PLA. The rheological properties of P34HB were significantly improved because of the PVAc phase. Unexpectedly, the toughness and stiffness of the P34HB in ternary blends clearly improved because of the incorporation of PLA and PVAc.

The effects of molecular weight (Mw) and content of poly(vinyl acetate) (PVAc) on the crystallization behaviors, competing crystallization of homocrystallites and stereocomplex crystallites (SCs), crystalline structure, and mechanical properties of poly(L-lactic acid) (PLLA)/poly(D-lactic acid) (PDLA) blends were investigated. The crystallization of PLLA/PDLA component is accelerated after the addition of low-Mw PVAc and is suppressed with high-Mw PVAc. The ability of SC formation is enhanced via blending with PVAc, irrespective of its Mw, and becomes prominent with low-Mw PVAc. The exclusive SCs are obtained in the blends with 30 mass % low-Mw PVAc. The improvement in thermomechanical property above 170 °C is ascribed to the enhancement of SC content. This work presents guidance for achieving the melt processability of SC-PLA, thus proving their potential as a high-performance substitute for conventional plastics.

Poly(butylene succinate) (PBS)/poly(vinyl acetate) (PVAc) blends were prepared by melt mixing. The miscibility, morphology, non-isothermal and isothermal crystallization, and rheological and mechanical properties of PBS/PVAc blends were investigated. The blends were a partial miscible two-phase system with PVAc evenly dispersed in the PBS matrix. The incorporation of PVAc accelerated the crystallization rate of PBS due to the heterogeneous nucleation, but decreased the degree of crystallinity. The rheological properties of PBS were greatly improved by the incorporation of PVAc, because of the high viscosity of PVAc in melt state. The most intriguing result was that the stiffness, strength, and toughness could be improved simultaneously by the addition of PVAc. The modulus, breaking strength, and elongation at break of PBS containing 10 wt% PVAc increased by 3.5%, 15.7%, and 43.4%, respectively. The synergetic improvement in the crystallization, rheological, and mechanical properties may be of much importance for widening the application of PBS.

The aim of this study is to use natural orotic acid (OA) as a sustainable, environmentally friendly additive to improve the crystallization, rheological, thermal, mechanical, and biodegradation properties of bacterially synthesized poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB). OA was found to be an efficient nucleating agent for P34HB, and dramatically enhanced both non-isothermal and isothermal crystallization rates. The incorporation of OA increased nucleation density and decreased spherulite size, but had little effect on the crystalline structure. The rheological properties of the P34HB were greatly improved by the solid filler OA, particularly when a percolation network structure was formed in the blends. The thermal stability of P34HB was strongly enhanced, as exemplified by the ~23 °C increase in the onset thermal decomposition temperature (To) for the blend loaded with 5 wt% OA compared to that of pure P34HB. Moreover, the yield strength and elongation at break of P34HB containing 0.5 wt% OA increased by 25% and 119%, respectively. The most intriguing result was the clear enhancement in the enzymatic hydrolysis rates of the P34HB/OA blends compared to that of neat P34HB. The synergetic improvement in these properties may be of significant importance for the wider practical application of biosourced P34HB.

In this work, fully biodegradable poly (lactic acid) (PLA)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)) blends of various compositions were uniaxially stretched at different stretch ratios above the glass transition temperature (Tg) of PLA. These stretched blends exhibited a closed microvoid structure, as evaluated by scanning electron microscopy. Differential scanning calorimetry and wide-angle X-ray diffraction analyses verified that stretching-induced crystallization in the α-form could be achieved in the PLA matrix. This hierarchical structure could improve the multifunctional performance of PLA blends. The density of drawn blends with a P(3HB-co-4HB) content of 30 wt% and stretch ratio of 6 was reduced by 20% as compared to neat PLA. The excellent combination of strength, modulus, and ductility of drawn blends with a P(3HB-co-4HB) content of 10 wt% and stretch ratio of 6 was demonstrated; compared to neat PLA, these parameters increased by 300%, 320%, and 317%, respectively in breaking strength, modulus, and elongation at break (172.2 MPa, 4200 MPa, and 18.4%), respectively. Meanwhile, control over the degradation rate and thermomechanical-property improvement was achieved by adjusting the stretch ratio and/or blend composition. In practical terms, this processing technique provides a new way to manufacture lightweight and high-performance microvoid-containing biopolymers.

To improve the intrinsic brittleness and crystallization capacity of poly(lactic acid) (PLA), fully sustainable PLA composites were prepared. The biodegradable PLA composites consisted of 10 wt% epoxidized soybean oil (ESO) and different amounts of functional eggshell (FES) with surface modified with calcium phenylphosphonate (PPCa) were prepared by melt blending. Mechanical and crystallization behavior were studied in terms of the weight percentage of FES. ESO-plasticized PLA showed an excellent tensile toughness with the elongation at break increased over than 160% compared to 6% of pure PLA. The elongation at break for PLA composites was still higher than 70% even filled with 30 wt% FES. Besides, the tensile and storage moduli of PLA/ESO/FES composites did not suffer significant deterioration as compared with pure PLA. For cold crystallization behavior, FES with surface modified by PPCa as a good nucleating agent improved the nucleating ability of PLA. The rates of nonisothermal and isothermal cold crystallization of PLA were improved due to the synergistic effect of plasticization and nucleation. The nonisothermal cold crystallization peak temperature (Tcc) of PLA composites decreases considerably from 118.7 °C (for pure PLA) to 90 °C. The crystallization half-time of PLA composites is lower than 10 min compared with 162 min of pure PLA after isothermal crystallized at 75 °C. As a consequence, it is encouraging that ESO and FES exhibit great viability for modifying the mechanical and crystallization properties of PLA matrix, which make PLA a promising sustainable alternative to petroleum-based polymers in conventional fields.

This work examined the effect of content and particle size of nucleating agent on nonisothermal melt crystallization behavior of poly(l-lactide) (PLLA). Two different particle sizes of talc were used as the nucleating agents of PLLA. Scanning electron microscopy observation revealed that both big and small particles of talc were homogeneously dispersed in the PLLA matrix. Talc significantly accelerated the nonisothermal melt crystallization rate of PLLA. The effect of smaller particle talc on crystallization was obviously better than that of the bigger one. The activation energy based on Friedman equation was evaluated. Lower activation energy was obtained for nucleated PLLA. Finally, addition of talc did not modify the crystal structure.

The eggshell power decorated with calcium phenyphosphonate (NES), an effective nucleating agent for poly(lactic acid) (PLA), was introduced into PLA simultaneously with a plasticizer, poly(ethylene glycol) (PEG), via melt blending. The morphology and melt crystallization behaviors of PLA composites were studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). PEG improved compatibility and interfacial adhesion between NES and PLA, which made NES dispersed more evenly in PLA matrix. The isothermal melt crystallization rate of PLA/PEG/NES was fastest in all the composites, indicative of a synergistic effect between PEG and NES. For the nonisothermal melt crystallization, the Avrami and Mo’s model could describe the experiment data successfully. Whereas the Ozawa equation failed to provide an adequate description for the composites. Moreover, the crystallization activation energy was further evaluated based on Friedman equation.

In this study, biodegradable poly(e-caprolactone) (PCL)/polyvinyl alcohol (PVA) fiber composites were prepared using melt processing techniques with different PVA fiber contents. The effect of PVA fiber on the non-isothermal and isothermal melt crystallization kinetics of PCL/PVA fiber composites was studied by using differential scanning calorimetry. Non-isothermal crystallization peak temperatures were enhanced significantly, as exemplified by about 20 K increase for the composite loaded with 5 wt% PVA fiber at a cooling rate of 20 K/min compared to that of neat PCL. The crystallization half-time decreased from 1.67 min for neat PCL to 0.80 min for composite with 5 wt% PVA fiber at a cooling rate of 5 K/min. PVA fiber was also found to dramatically accelerate the isothermal crystallization rate of PCL/PVA fiber composites. The crystallization half-time of composite containing 5 wt% PVA fiber was reduced by more than 10 times compared with neat PCL. Moreover, dynamic mechanical analysis results showed that PVA fiber had a strengthening effect on the PCL.

Functionalized eggshell powder (NES) with nucleating surface of calcium phenylphosphonic acid (PPCa) for poly(l-lactide) (PLLA) was compounded with PLLA via melt blending to improve the cold crystallization process of PLLA. The cold crystallization behavior of the PLLA/NES composites was studied by differential scanning calorimetry. The isothermal cold crystallization rates have been enhanced obviously in the PLLA/NES composites than in the neat PLLA, indicative of the excellent nucleating effects of NES on PLLA. For the nonisothermal cold crystallization, the overall crystallization rate of PLLA increased with both increasing NES loadings and heating rate. It was found that the Avrami equation and the combined Ozawa–Avrami model could describe the experiment data successfully.

Biodegradable poly(e-caprolactone) (PCL)/nanocellulose (NC) nanocomposites were prepared using solvent-free melt processing techniques with various NC contents. Both the nonisothermal and isothermal melt crystallization processes of PCL/NC nanocomposites were significantly accelerated by adding NC. The nonisothermal melt crystallization peak temperature obviously increased from 18.8 °C for neat PCL to 30.9 °C for the PCL/NC nanocomposite with 10 wt% NC content at a cooling rate of 10 °C min−1; moreover, the half-time isothermal crystallization at 40 °C significantly decreased from 12.2 min for neat PCL to 2.0 min. Apparently, NC enhanced PCL's crystallization rate. The crystalline morphology study confirmed the increased nucleation density of PCL spherulites, indicating the role of NC as an efficient nucleating agent. Moreover, the loading of NC did not change the crystal structure of PCL, and with increase in NC content, the Young's modulus and yield strength increased; however, the elongation-at-break and the breaking strength decreased. Compared with pure PCL, the thermomechanical properties of PCL/NC nanocomposites were significantly improved. These biodegradable PCL/NC nanocomposites showed excellent crystallization capabilities and tailored mechanical properties, thus proving their potential as a substitute for traditional commercial plastics.

Herein, biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) was mixed with amorphous poly(vinyl acetate) (PVAc) to prepare a binary blend system by melt compounding. The miscibility, thermal behavior, isothermal crystallization behaviors, and mechanical and rheological properties of P34HB/PVAc blends were investigated. Only one glass transition temperature of the blends indicated that P34HB and PVAc were miscible. The introduction of PVAc suppressed the cold crystallization of the blends and reduced the degree of crystallinity. The study of isothermal crystallization behaviors revealed that the addition of amorphous PVAc reduced the crystallization rate of blends, but did not change the crystallization mechanism. In addition, the blends showed a remarkable improvement in the rheological properties compared with those of neat P34HB. The most intriguing result was a greatly increased elongation at break, coupled with an only slightly reduced modulus and strength for blends.

the relationship between catalyst structure and catalytic activity is an important and challenging topic for researchers in the field of catalysis. in this work, the effect of oxygen vacancies on the activity of znpd/zno-al catalysts was studied in an important reaction-glycerol hydrogenolysis. interestingly, the catalytic activity improved significantly with the addition of a small amount of al, and high selectivity to 1,2-propanediol (>90%) was achieved in glycerol hydrogenolysis over znpd/zno-al catalysts. importantly, the formation of oxygen vacancies benefits from the substitution of al atoms, and the al content in the zno lattice is related to the oxygen vacancies density and catalytic activity. moreover, the important role played by oxygen vacancies in glycerol hydrogenolysis has been discussed in detail.

A novel polyester poly(diethylene glycol succinate) (PDEGS) was synthesized and evaluated as a plasticizer for polylactide (PLA) in this study. Meanwhile, an effective sustainable filler, functionalized eggshell powder (FES) with a surface layer of calcium phenyphosphonate was also prepared. Then, PLA biocomposites were prepared from FES and PDEGS using a facile melt blending process. The addition of 15 wt% PDEGS as plasticizer showed good miscibility with PLA macromolecules and increased the chain mobility of PLA. The crystallization kinetics of PLA composites revealed that the highly effective nucleating FES significantly improved the crystallization ability of PLA at both of non-isothermal and isothermal conditions. In addition, the effective plasticizer and well-dispersed FES increased the elongation at break from 6% of pure PLA to over 200% for all of the plasticized PLA composites. These biodegradable PLA biocomposites, coupled with excellent crystallization ability and tunable mechanical properties, demonstrate their potential as alternatives to traditional commodity plastics.

In this study, highly dispersive spherical Li-rich solid solution (Li1.2Mn0.54Ni0.13Co0.13O2) particles are successfully synthesized by a co-precipitation method. Then these particles are treated with aluminum nitrates ethanol solution at 80 degrees C. The treatment can extract lithium (Li2O) from the Li2MnO3 component in the composite of Li1.2Mn0.54Ni0.13Co0.13O2. Simultaneously, a thin layer of Al2O3 can be precipitated on the surface of the electrode particles via direct thermal decomposition of aluminum nitrates. After treatment, the first-cycle coulombic efficiency of the electrode increases from 72.1% to 93.6%, meanwhile it shows a superior cycling stability at 100 mAg(-1) with a discharge capacity of around 220 mAh g(-1) and retention of 92.5% after 100 cycles, which is much higher than that of the pristine electrode (83.2%). Even at a high current density of 2 A g(-1) (10 C), the discharge capacity could still achieve and well maintain as high as 140 mAh g(-1). (C) 2013 Elsevier Ltd. All rights reserved.

In this work, we have developed a new method to grow NiO nanomaterials on the surface of graphene nanosheets (GNSs). The morphologies of NiO nanomaterials grown on GNSs could be tailored by trace amounts of water introduced into the mixed solvents of CO2-expanded ethanol (CE). Small and uniform Ni-salt nanoparticles (Ni-salt-NPs) were grown on the surface of graphene oxide (GO) through the decomposition of nickel nitrate directly in CE. However, when trace amounts of water were introduced into the mixed solvents, Ni-salt nanoflakes arrays (Ni-salt-NFAs) were grown on the surface of GO with almost perpendicular direction. After thermal treatment in N2 atmosphere, these Ni-salt @GO composites were converted to NiO@GNSs composites. The forming mechanisms of the NiO-NPs@GNSs and NiO-NFAs@GNSs were discussed by series comparative experiments. The presence of the trace amounts of water affected the chemical composition and structure of the precursors formed in CE and the growth behaviors on the surface of GNSs. When used as anode materials for lithium-ion batteries, the NiO-NPs@GNSs composite exhibited better cycle and rate performance compared with the NiO-NFAs@GNSs.

Li(Mn 1/3 Ni 1/3 Co 1/3 )O 2 cathode materials were fabricated by a hydroxide precursor method. Al 2 O 3 was coated on the surface of the Li(Mn 1/3 Ni 1/3 Co 1/3 )O 2 through a simple and effective one-step electrostatic self-assembly method. In the coating process, a NHCO 3 -H 2 CO 3 buffer was formed spontaneously when CO 2 was introduced into the NaAlO 2 solution. Compared with bare Li(Mn 1/3 M 1/3 Co 1/3 )O 2 , the surface-modified samples exhibited better cycling performance, rate capability and rate capability retention. The Al 2 O 3 -coated Li(Mn 1/3 Ni 1/3 Co 1/3 )O 2 electrodes delivered a discharge capacity of about 115 mAh·g −1 at 2 A·g −1 , but only 84 mAh·g −1 for the bare one. The capacity retention of the Al 2 O 3 -coated Li(Mn 1/3 Ni 1/3 Co 1/3 )O 2 was 90.7% after 50 cycles, about 30% higher than that of the pristine one.

In this work, we report a facile method for the synthesis of a Co3O4–functionalized carbon nanotube (Co3O4–f-CNT) composite via the growth of Co3O4 nanoparticles on the surface of functionalized carbon nanotubes (f-CNTs) by thermal decomposition of cobalt nitrate hexahydrate in ethanol. The composite consists of 13% carbon nanotubes and 87% Co3O4 nanoparticles by weight, and all the Co3O4 particles grew compactly along the carbon nanotube axis with a highly uniform dispersion. When used as an anode material for rechargeable lithium ion batteries, the composite manifested high capacities and excellent cycling performance at high and low current rates. The discharge capacity was 719 mA h g−1 at the 2nd cycle and 776 mA h g−1 at the 100th cycle. Even at a current density of 1 A g−1, the specific capacity still remained at about 600 mA h g−1. This superior electrochemical performance was attributed to the unique nanostructure of the composite. Because almost all of the Co3O4 nanoparticles were immobilized on the surface of f-CNTs, physical aggregation of nanoparticles was avoided during the charge–discharge processes. Furthermore, the good mechanical flexibility of f-CNTs can readily alleviate the massive volume expansion/shrinkage associated with a conversion reaction electrode. Finally, f-CNTs are highly conductive matrices for electrons due to their high conductivity, which can shorten the diffusion path for electrons.

The photocatalytic activity of CdS/P25 hybrid catalysts was studied under visible-light irradiation. The CdS quantum dots sensitized P25 (CdS QDs-P25) showed extremely enhanced activity in the reduction of o-chloronitrobenzene (o-CNB) by comparing to CdS-P25 prepared by the direct deposition-precipitation method in the presence of HCOOH. The synergistic effects between CdS QDs and P25 were beneficial for the separation of photogenerated carriers in space and thus the combination of photoelectrons and holes was prevented, and the CdS QDs could provide more photocharges than CdS due to the particle size effect. Furthermore, the process of photocatalytic reduction in the present system was investigated, under visible-light irradiation, the photogenerated electrons transferred from the valence band (VB) to the conduction band (CB) of CdS QDs, and injected into the CB of inactivated P25. Meanwhile, the holes generated in the VB of CdS QDs could oxidize HCOO(-) to give ˙CO2(-) and H(+). Then, o-CNB was reduced to o-chloroaniline (o-CAN) by the couple of e(-) and ˙CO2(-) with H(+). It is a significant method and a green process for hydrogenation of nitro compounds, which may have great potential applications in the reduction of various organic chemicals.

SnS2/graphene nanosheets (SnS2/GNS) composites were synthesized by a one-step hydrothermal method. The composites exhibit remarkably improved Li-storage ability with a good cycling life and high capability superior to that of the pure SnS2 counterpart due to a synergic effect between the graphene and SnS2 nanosheets.

In this work, we presented a new way for the functionalization of carbon nanotubes (CNTs) with the use of biomass as starting materials and introduced a novel concept of knitting process in the chemistry of CNTs for the first time. A mixture of aromatic compounds obtained from the hydrothermal treatment of biomass, rather than the traditional polymer monomers, was used as the nanoscale building blocks to knit an oxygenated network-coat on the CNTs layer-by-layer. It is an effective, mild, green and easily-controlled method for the functionalization of CNTs. The obtained f-CNTs were proved to be a promising catalyst support for metal catalysts, such as Ru/f-CNTs, showed high activity and selectivity for the hydrogenation of citral to unsaturated alcohol. More importantly, we opened a pioneering way for the conversion of low-cost, abundant and renewable biomass into a hydrophilic/chemical reactive network-coat on the inert surface of a wide range of sp2carbon materials, such as prevalent fullerene, carbon nanotubes, carbon nanohorns and hot grapheneetc.

An efficient method for dispersing active metal colloidal nanoparticles onto supports uniformly is revealed in this paper. The critical feature of this method is to separate the stabilizer simply with the phase-switch function of scCO2; with it the highly dispersed Pd colloidal catalysts were prepared, and the forming procedure is analyzed and discussed in detail. The present work not only overcame the common difficulties of removing the stabilizers in the preparation of supported colloidal particles, but also provided a facile and green process for preparing supported metal colloidal nanoparticles with using the environmentally benign solvent of scCO2.