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In this work, the binary blend of poly(ethylene vinyl acetate) (EVA)/poly(e-caprolactone) (PCL) with different compositions were prepared and the shape memory behaviors were evaluated first. Then, carbon nanotubes (CNTs) were introduced into the composition that exhibited relatively better shape memory effect (SME) to prepare the ternary blend composites with electrically actuated SME. The morphologies of the blend and/or blend composites, the crystallization of the component, and the selective location states of CNTs in the blend composites were comparatively investigated. The results demonstrated that the binary EVA/PCL blends exhibit a typical sea–island structure at low PCL content, a quasi-cocontinuous structure at mediate PCL content and then the sea–island structure at high PCL content. Among these binary blends, the EVA/PCL (60/40) sample exhibits relatively better SME with not only high shape fixing ratio but also shape recovery ratio. The presence of the CNTs further induces the changes of morph...

In this work, dynamically vulcanized poly(l-lactide) (PLLA)/poly(ethylene vinyl acetate) (EVA) blends with different compositions were prepared. The morphologies, rheological properties and the crystalline structures of the samples were systematically investigated. The results demonstrated that with the increase of the PLLA component in the dynamically vulcanized samples, the blend morphologies varied from sea-island structure to cocontinuous structure, and then changed to sea-island structure again. A chemically cross-linked structure was introduced into the EVA component. Annealing treatment did not influence the crystallization of the EVA component, but it greatly promoted the cold crystallization of the PLLA component and consequently, a large amount of PLLA crystallites were emerged in the PLLA component. The shape memory behaviors of the dynamically vulcanized samples were detected, and the results showed that the samples exhibited good shape memory behaviors, which were greatly dependent upon the blend compositions and the annealing treatment. Samples with high content of EVA exhibited relatively higher shape fixity ratio (Rf) and shape recovery ratio (Rr). Although annealing treatment induced the decrease of Rf, largely enhanced Rr was obtained for the annealed samples, especially at relatively longer annealing time. The mechanisms for the enhanced shape memory effects of the annealed samples were then analyzed.

A small amount of carbon nanotubes (CNTs) was added into poly(vinylidene fluoride) (PVDF)/boron nitride (BN) composites through melt blending processing. The thermal conductivity, microstructure changes including the crystallization behavior of PVDF matrix and the dispersion states of fillers in the composites, and the electrical conductivity of the composites were comparatively investigated. The results demonstrated that compared with the PVDF/BN composites at the same BN content, the ternary PVDF/BN/CNT composites exhibited largely enhanced thermal conductivity. In the PVDF/BN/CNT composites, the crystallinity of the PVDF matrix was slightly increased while the crystal form remained invariant. BN particles exhibited homogeneous dispersion in the PVDF/BN composites, and they did not affect the rheological properties of the PVDF/BN composites when the BN content was lower than 10 wt %. The presence of CNTs did not affect the interfacial adhesion between BN and PVDF, but they facilitated the formation of d...

Mesoporous MCM-41 supported Schiff base and CuSO4·5H2O shows high catalytic activity in the cyclocondensation of mercaptoacetic acid with imines (or aldehydes and amines) to afford pharmaceutically important thiazolidinone derivatives. The catalytic reactions involving two-components or three-components afforded the desired product in high yields (up to 98% and 99%). Moreover, the catalyst works well with respect to recyclability, giving the product in 85% and 83% yields after recycling six times.

In this work, different contents of graphene oxide (GO) were introduced into poly(butylene succinate) (PBS) to study the effects of GO on crystallization of PBS matrix and the resultant hydrolytic degradation behaviors of the PBS/GO composites. The initial crystalline structures of PBS in the composites were investigated using a polarized optical microscope (POM), differential scanning calorimetry (DSC) and a wide angle X-ray diffraction (WAXD). The results demonstrated that GO showed nucleation effect for the crystallization of PBS matrix. However, high content of GO also restricted the growth of crystallite, resulting in the decrease of PBS crystallinity and the reduction of crystal size. The hydrophilicity of sample was evaluated by measuring the contact angle of water on the sample surface. The results demonstrated that the presence of GO greatly enhanced the hydrophilicity of the sample. The hydrolytic degradation behavior of sample in alkaline solution was investigated at 37 °C. The results showed that the hydrolytic degradation ability of PBS was greatly enhanced by adding GO. The more the GO in the composites, the higher the hydrolytic degradation ability was. The increased hydrophilicity that enhanced the wettability of sample surface by water, the decreased crystallinity of PBS matrix, and the presence of the defects in the composite, e. g. at the interface between the PBS matrix and GO particles, mainly contributed to the largely enhanced hydrolytic degradation ability of PBS. The microstructure changes during the hydrolytic degradation process were also analyzed. This work provided an alternative way to accelerate the hydrolytic degradation of PBS.

Field isolates of Alternaria alternata from peach were previously characterized for their sensitivity to succinate dehydrogenase inhibitor (SDHI) fungicides and the underlying molecular basis of resistance was determined. In the present study, we report that isolates resistant to the SDHI fungicide boscalid, regardless of genotype, were also resistant to pyraclostrobin and thiophanate-methyl. Resistance to pyraclostrobin was due to the G143A mutation in cytochrome b and resistance to thiophanate-methyl was due to 167Y in β-tubulin. Representatives of the two most commonly isolated SDHI resistance genotypes, H277Y in sdh subunit B and H134R in sdh subunit C, as well as genotype D123E in sdh subunit D, were selected for fitness evaluations. Genotypes H277Y and H134R suffered no fitness penalties based on mycelial growth on potato dextrose agar, spore production in vitro, osmotic sensitivity, oxidative sensitivity, germination ability, or the ability to cause disease on peach fruit. Hypersensitivity to oxidative stress and weak sporulation was observed only in genotype D123E. No competitive advantage was detected for sensitive isolates over the course of five consecutive transfers on peach fruit when spores were mixed with genotypes H277Y or H134R. Results suggest that, in the absence of fungicide pressure, A. alternata isolates resistant to methyl benzimidazole carbamate, quinone outside inhibitor, and SDHI fungicides carrying the H277Y mutation in SDHB and the H134R mutation in SDHC may effectively compete with the boscalid-sensitive populations.

In this work, graphene oxide (GO) and polyvinylpyrrolidone (PVP) were introduced into poly(vinylidene fluoride) (PVDF) membranes that were prepared through phase inversion induced by immersion precipitation technique. The effects of GO and PVP on hydrophilicity, pore morphology and porosity of membranes were systematically investigated. The results demonstrated that GO and PVP exhibited synergistic effects in controlling the hydrophilicity, morphology and porosity of composite membrane. Largely enhanced hydrophilicity and porosity were simultaneously achieved for the PVDF/PVP/GO composite membrane. Furthermore, the effects of GO content on the morphology and porosity of composite membranes were also investigated. It was found that increasing GO content not only induced apparent changes of pore morphology but also induced the increase of the porosity of composite membrane. The adsorption ability of membranes were evaluated by immersing membranes in the solution of Methylene blue. It was found that the PVDF/PVP/GO composite membrane exhibited excellent adsorption ability for Methylene blue particles. The more the GO in the composite membrane was, the better the adsorption ability was. This work provides a highly effective method to greatly improve the hydrophilicity and adsorption ability of PVDF-based composite membrane with great potential in the field of wastewater treatment.

Here we demonstrated a remarkable improvement in the dielectric performance of poly (vinylidene fluoride) (PVDF)-based composites via incorporating distinguished hybrid nanofibers, namely, Ag nanoparticles-embedded BaTiO3 (Ag@BaTiO3, Ag@BT) nanofibers, which were fabricated by coaxial electrospinning technology followed by calcination. The Ag nanoparticles on BaTiO3 nanofibers were found to play a comprehensive role on the dielectric performances, including the better dispersion of hybrid nanofibers leading to homogeneity of electric field, the formation of charge transfer complex in the hybrid region which enhanced the interfacial polarization, and the Coulomb blockade effect of Ag nanoparticles to further suppress the interfacial charge accumulation. As a result, the PVDF/Ag@BT composites exhibited high dielectric constant of 38.87@1 kHz and low loss of 0.02@1 kHz.

Polymer-based dielectric nanocomposites with high dielectric constant and low loss have been widely used for energy storage applications in power electronics and power delivery systems. However, there are still changes in preparing polymer-based dielectric nanocomposites with the suppressed loss (tan δ) and maintain breakdown strength (Eb) through simple compound method. In this work, a simple approach to fabricate outstanding comprehensive performance dielectric composites was proposed by cooperating molybdenum disulfide-polypyrrole (MoS2-PPy) hybrids with polyvinylidene Fluoride (PVDF). The MoS2-PPy hybrids were prepared by in situ polymerization of pyrrole with exfoliated MoS2 nanosheets, showing a “sandwich-like” structure of PPy/MoS2/PPy. MoS2-PPy hybrids significantly influenced the dielectric properties of their composites. As result, PVDF/MoS2-PPy composites achieved high dielectric constant (149.5@1 kHz), suppressed dielectric loss (0.19@1 kHz) and high breakdown strength (250.6 MV m−1). The emphasized reasons of high dielectric property are the enhanced interfacial polarization and formation of nano- and micro-capacitor networks. This work could provide an effective method to design and improve the performance of polymer-based dielectric nanocomposites for power system and energy storage applications.

Enhancing the synergistic efficiency of different fillers in the composites is very significant from viewpoints of reducing fabricating cost and acquiring promising comprehensive properties. Inspired by the stem parasitic plant cuscuta austrails (dodder), the highly efficient conductive network in the composites was constructed through the ‘rigid’ submicron vapor grown carbon fibers (s-VGCFs) and ‘reelable’ carbon nanotubes (CNTs), in which the homogeneously dispersed s-VGCFs acted as the framework while CNTs bridged adjacent s-VGCFs and also partly entangled on s-VGCFs. Compared with the binary composites containing only s-VGCFs (or CNTs), the presence of very small quantity of CNTs (or s-VGCFs) led to the significant reduction of percolation thresholds from 3.082 wt% to 0.876 wt% (or from 0.258 wt% to 0.024 wt%), and the extremely high synergistic efficiency of 1.5 × 107 was achieved. Specifically, the impact of different compounding sequences on the hybrid network structure of fillers was also discussed. This work provides a new strategy to construct the hybrid network structure of fillers with extremely high synergistic effect and it might be applied in fabrication of the conductive composites with excellent mechanical properties.

The advanced utilization of phase change materials (PCMs) is limited by the strong rigidity, liquid leakage and lack of photoabsorption ability. In this work, a novel form-stable PCM with solar-to-thermal energy storage ability and thermal/light-actuated shape memory property was prepared. Herein, paraffin wax (PW) served as a latent heat storage material and a switching phase for shape fixation, melamine foam (MF) acted as a supporting material to prevent the leakage and a permanent phase for shape recovery, and reduced graphene oxide (RGO) assembled on MF skeletons worked as a light absorption medium. Due to the light weight and abundant porosity of MF/RGO foam, the MF/RGO/PW PCMs possessed excellent encapsulation ability, high latent heat (144.8 J/g), good solar-to-thermal energy conversion and storage ability. Simultaneously, combining the elasticity of MF/RGO foam, the MF/RGO/PW PCMs exhibited thermal/light-sensitive shape memory property by triggering the phase transition of PW. The MF/RGO/PW PCMs showed excellent cyclic shape memory performance and thermal reliability. A light-sensitive and temperature-controlled board was further exploited, which could be installed on the roof of the house and maintained the temperature constancy. This study provides a strategy to prepare flexible, light-sensitive and form-stable PCMs via using the elastic MF/RGO foam as a supporting scaffold, and these PCMs have great potential in solar energy utilization and energy-saving buildings.

Interfacial interaction exhibits important role in determining the performance of polymer composites, especially at high filler content. In this work, illuminated from the braze welding technology that is applied to joint different metals using the welding stick with relatively high plastic deformation ability or high toughness, a new concept of ‘interfacial welding’ was proposed to engineer the strong interfacial interaction of the thermally conductive composites. A commercial elastomer, i.e. anhydride-modified ethylene-based copolymer (AEC), was incorporated into the polyamide 6 (PA6)/carbon nanofibers (CNFs) composites. Due to the presence of the insulating AEC and the stronger interfacial affinity between CNFs and AEC, the ternary PA6/CNF/AEC composite samples showed largely enhanced electrical resistance and comparable thermal conductivity compared with the binary PA6/CNF composite samples. Specifically, largely enhanced fracture toughness was achieved for the ternary composite samples. The concept of ‘interfacial welding’ may be extended to fabricate the other composites with excellent comprehensive performances.

Urban park accessibility is an important indicator to measure the level of urban modern development, and the harmonious relationships between people and land. It is meaningful for efficiently increasing urban park accessibility, fully providing services functions of urban park and promoting healthy development of cities to understand objective influencing factors of urban park accessibility and its extent of impact. The service area and service efficiency of urban parks in three-ring area of Shenyang City were evaluated basing on ArcGIS 9.3 software platform and network analysis methods. The regularity of the service area and service efficiency of urban parks changing with the urban park area, urban park shape and road network density were analyzed. The results showed that urban park area had significant positive correlation with service area and significant negative correlation with service efficiency. Urban park shape had significant positive correlation with service area and service efficiency. Road network density had significant negative correlation with service area of urban parks, but had no significant correlation with service efficiency. Based on the extent of impact on urban park service area, the importance of three influencing factors was in the order of urban park arearoad network densityurban park shape. Based on the extent of impact on urban park service efficiency, the importance of three influencing factors was in the order of urban park areaurban park shaperoad network density. Urban park area was the most important influencing factor for the service area and service efficiency of urban parks.公园绿地可达性是衡量城市现代化发展水平、和谐人地关系的一个重要指标.了解公园绿地可达性客观影响因素及作用程度,对有效提高公园绿地可达性、充分发挥公园绿地的服务功能、促进城市健康发展具有重要意义.本文基于ArcGIS 9.3软件平台,运用网络分析法评价了沈阳市三环以内公园绿地服务面积及其服务效率,并分析了公园绿地服务面积及其服务效率随公园绿地面积、公园绿地形状、路网密度的变化规律.结果表明: 公园绿地面积与其服务面积呈显著正相关,与其服务效率呈显著负相关;公园绿地形状与其服务面积及服务效率呈显著正相关;路网密度与公园绿地服务面积呈显著负相关,与其服务效率没有显著相关关系;3个影响因子中,对公园绿地服务面积的影响程度依次为:公园绿地面积路网密度公园绿地形状,对公园绿地服务效率的影响程度依次为:公园绿地面积公园绿地形状路网密度;公园绿地面积是其服务面积及服务效率的最重要影响因子.

As one of the materials from natural resources, the functionalization and application of cellulose attract increasing concerns. In this work, we reported a facile method to prepare the bio-inspired functionalization of microcrystalline cellulose (MCC) aerogel through polydopamine (PDA) coating, which was realized via the self-polymerization of dopamine in the MCC/LiBr solution followed by the freeze-drying technology. The morphological characterization showed that the pore morphologies of the compounded aerogel were influenced by the content of PDA. Adsorption measurements toward methylene blue (MB) showed that the compounded aerogel had high adsorption ability. Moreover, the compounded MCC/PDA aerogel exhibited excellent adsorption selectivity and it exhibited high efficiency to remove MB from different solutions, such as the mixed solution with anionic dyestuffs, the mixed solution with cationic dyestuffs and the mixed solution with common salt (NaCl). The high adsorption ability and excellent adsorption selectivity endows the compounded MCC/PDA aerogel with great potential applications in wastewater treatment.

Ordered mesoporous siliceous material has been identified as one of the key elements of the catalysis concept. Here we report an efficient Friedel-Crafts reaction of indoles with isatins catalyzed by PWA/MCM-41, which got the di(indolyl)indolin-2-ones derivatives with high yield. Moreover, the catalysts were characterized by XRD and SEM/EDS, the EDS spectrum indicated that the catalyst used in this reaction also contains tungsten, and the proposed mechanism for the synthesis of 3,3-di(indolyl)indolin-2-ones was also discussed. Finally, the catalyst can be reused repeatedly for several times without obvious loss of activity.

In this work, different contents (10–40 wt%) of poly(butylene succinate) (PBS) were introduced into poly(lactic acid) (PLA) through the common melt compounding processing. The microstructure and morphologies of the blends were investigated through differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and scanning electron microscope (SEM). The results showed that the presence of PBS neither induces the crystallization nor enhances the crystallinity of PLA matrix, and completely amorphous PLA was obtained in all samples. PBS exhibited dispersed particles in the PLA matrix and there were clear gaps between components. The hydrophilicity of samples was evaluated by measuring contact angles. The results demonstrated that adding PBS improved the hydrophilicity of samples. The hydrolytic degradation measurements were carried out at 37 °C in alkaline solution. The results showed that the presence of PBS accelerated the hydrolytic degradation of PLA matrix. Specifically, the higher the content of PBS was, the bigger the weight loss per unit area of sample was. The hydrolytic degradation mechanism was then analyzed.

Cocontinuous PLA/EVA (60/40 wt%) blends were filled with reduced graphene oxides (0.1–3 wt%) through the master batches of PLA/rGOs and EVA/rGOs, respectively. The results show that rGOs are located at the interface when the blend nanocomposites were prepared from PLA masterbatch. On the other hand, rGOs are located in EVA component when the blend nanocomposites were prepared from EVA/rGOs materbatch. The underlying mechanism for selective localization of rGOs in PLA/EVA was systematically investigated. First, theoretical prediction indicates the interface energies between two polymer components and rGOs are similar and rGOs prefer to locate at the interface of blend. Therefore, kinetic effects, including interfacial stability of rGOs and viscoelastic properties of polymer, play an important role on the selective localization of rGOs migration. Finally, The electrical resistivity measurements show that nanocomposites with rGOs locating at the interface is endowed much lower resistivity and percolation threshold compared to the blend nanocomposites with rGOs locating at EVA component. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers

A small amount of graphene oxide (GO) was introduced into poly(vinylidene fluoride) (PVDF)/carbon nanotube (CNT) composites through solution compounding. The thermal conductivity, crystallization behavior of PVDF matrix, and the dispersion states of CNTs and/or CNT/GO in the PVDF composites were comparatively investigated. The results demonstrated that with the presence of only 1 wt% GO, the PVDF/CNT/GO composites exhibited largely enhanced thermal conductivity compared with the PVDF/CNT composites at the same CNT content. Although the crystallinity of matrix in the PVDF/CNT/GO composites is apparently decreased in comparison with that in the PVDF/CNT composites, a large number of polar γ-form crystallites were induced. The presence of GO facilitated the dispersion of CNTs and the formation of denser CNT/GO network structure in the PVDF matrix. The theoretical simulation further demonstrated the experimental observations. The mechanisms for the largely enhanced thermal conductivity of the PVDF/CNT/GO composites were then analyzed.

The effects of annealing on microstructure and mechanical properties of an impact resistant polypropylene copolymer (IPC) were investigated. Different annealing temperatures ranging from 80 °C to 160 °C were selected. The phase reorganization of IPC during annealing process was studied through morphological characterization technologies, including scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystalline structure changes in the IPC sample, including the iPP matrix and PE component, were investigated using wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). Dynamic mechanical analysis (DMA) was used to analyze the relaxation extent of IPC before and after annealing. The results showed that annealing induced phase reorganization in IPC and the degree of phase reorganization depended on annealing temperature. The annealed IPC samples exhibited largely increased crystallinity compared with the unannealed one. Intensified damping peak with increased molecular chain mobility was achieved for the annealed IPC samples. At an appropriate annealing temperature (140 °C), largely enhanced impact strength was achieved for the annealed IPC sample. The toughening mechanisms were analyzed based on the phase reorganization and relaxation behavior.

The microstructure changes of β-nucleated isotactic polypropylene (β-iPP) during the annealing process and the resultant macroscopic physical property responses were comparatively investigated. The results demonstrated that the annealing process not only increased the crystallinity of β-iPP samples but also enhanced the chain-segment mobility in the amorphous region. Interestingly, it was observed that the annealed β-iPP samples obtained at an appropriate annealing temperature exhibited accelerated creep deformation when the tensile creep measurement was carried out at relatively low environmental temperatures and/or small tensile stresses. However, at relatively higher measuring temperatures and/or larger tensile stresses, the role of the crystalline structure in influencing the creep deformation of β-iPP became dominant, and consequently, the creep resistance of β-iPP increased with increasing annealing temperature. Furthermore, it was demonstrated that the creep deformation of β-iPP is also highly depe...

Thermoplastic polyurethane (TPU) composites containing different carbon nanotube (CNT) contents ranging from 0.5 to 5 wt% were prepared and the main attention was focused on investigating the relation between the network structure of CNTs and the macroscopic physical properties of the composites. The network structure of CNTs in the TPU/CNT composites was demonstrated through morphological characterization and rheological measurement. Tensile properties, electrical properties, strain sensitivity and shape memory properties were comparatively investigated. The results showed that CNTs at content above 2 wt% formed the percolated network structure in the TPU composites. High content of CNTs exhibited excellent reinforcement effect. Adding a few CNTs greatly reduced the electrical resistivity of the composites. The TPU/CNT composites exhibited good strain sensitivity, and the variation of electrical resistivity during the stretching-restoring process was dependent upon CNT content. At room temperature, CNTs delayed the shape recovery behavior of the composites, especially when the percolated CNT network structure was formed. However, with the aid of electrical actuation, largely accelerated shape recovery behavior was observed for the TPU/CNT sample containing 5 wt% CNTs.

As a part of serial work about tuning the selective location of carbon nanotubes (CNTs) in immiscible polymer blends, this work reports the effects of component polarity and viscosity ratio between components on the selective location of CNTs and the resultant electrical resistivity of the nanocomposites. To achieve the research aim, maleic anhydride (MA) was grafted onto poly( l -lactide) (PLLA) main chain through a reactive compounding processing. After that, different contents of CNTs were incorporated into blends of high density polyethylene (HDPE) and PLLA (or PLLA-g-MA). The morphologies of the ternary nanocomposites and the selective location of CNTs in the nanocomposites were characterized using scanning electron microscope (SEM) and transmission electron microscope (TEM). The microstructure of nanocomposites and the dispersion of CNTs were further proved by rheological measurement. Finally, the electrical resistivity of nanocomposites containing different CNT contents was measured. The results showed that through increasing the polarity of PLLA and decreasing the melt viscosity, CNTs were kinetically trapped at the blend interface region. Consequently, largely decreased percolation threshold was achieved for the PLLA-g-MA/HDPE/CNT nanocomposites. The morphological changes as well as the rheological properties were also comparatively analyzed.

In this work, a graphene oxide (GO)-filled polypropylene (PP) adsorptive membrane was developed through an environmentally benign plasma-treatment technology. The PP/GO composite membrane was prepared through melt-compounding and subsequent compression molding processing. The composite membrane was further modified through the plasma treatment with allylamine as the monomer. The results showed that the modified composite membrane exhibited a high hydrophilicity, which is attributed to the introduction of a large number of nitrogen-containing and oxygen-containing groups. The plasma assisted surface modification technology was applied to the porous composite membrane that was prepared through uniaxial stretching processing. Although the porosity of the porous membrane gradually decreased with increasing discharge time during the plasma treatment, the modified porous membrane exhibited an excellent adsorption ability. When adsorbing the particles from the solution, the amount of adsorbed Congo-red particles increased with increasing discharge time. The adsorption mechanism of the treated porous membrane was then analyzed. This work provides an efficient method to apparently improve the hydrophilicity and adsorption ability of a PP-based composite membrane which has great potential in the field of wastewater treatment.

In this work, carbon nanotubes (CNTs) were treated using polyvinylpyrrolidone (PVP). Different contents of pristine CNTs and PVP treated CNTs were introduced into poly(vinylidene fluoride) (PVDF) to prepare the PVDF/CNT and PVDF/CNT@PVP nanocomposites, respectively. The thermal conductivity measurement showed that there was the most appropriate PVP content, at which the nanocomposites exhibited the highest thermal conductivity. For all nanocomposites, the thermal conductivity increased gradually with increasing CNT (or CNT@PVP) content. However, more pronounced increase was observed for the PVDF/CNT@PVP nanocomposites. Research on the crystallization behaviors showed that PVP did not change the crystalline structure of PVDF matrix apparently. However, morphology characterization and rheological measurements showed that PVP greatly improved the dispersion of CNTs and induced denser CNT network structure in PVDF matrix through the special interaction between CNTs and PVP and the hydrogen bonding effect between PVDF and PVP. The denser CNT network structure and the intensified interfacial interaction between CNTs and PVDF were suggested the main mechanisms for the largely enhanced thermal conductivity of the PVDF/CNT@PVP nanocomposites.

Poly(L-lactide) (PLLA) based shape memory materials (SMP) recently attracted much attention due to their great potential application in biomedical materials. In this work, we introduced carbon nanotubes (CNTs) into a blend of PLLA/thermoplastic polyurethane (TPU) through a simple melt compounding processing to develop a new kind of PLLA SMP. The effects of CNTs on morphologies of blend composites, the selective location of CNTs, the dynamic mechanical properties of samples and the microstructure of CNTs in the blend composites were characterized using a scanning electron microscope (SEM), a transmission electron microscope (TEM) and rheological measurements, respectively. The results demonstrated that CNTs selectively located in the TPU component and induced apparent change of the blend composite morphology. High content of CNTs also formed the percolated network structure in the material, which resulted in the dramatic decrease of electrical resistivity. The shape memory behaviors of the samples were comparatively investigated in two different conditions, i.e. thermally activated and electrically activated conditions. It was demonstrated that CNTs prevents the thermally activated shape recovery process of the blend composites, especially when CNTs formed the percolated network structure. However, with the aid of electrical actuation, largely accelerated shape recovery process and enhanced degree of shape recovery were achieved for the blend composites containing 5 wt% CNTs, especially at relatively low recovery temperatures. The main mechanism was attributed to the largely enhanced electrical conductivity, which provides more Joule heating in the sample. This work provides an alternative way to develop PLLA-based shape memory materials through a simple melt compounding processing.

In this work, different contents of CNTs were introduced into an immiscible poly(L-lactide)/ethylene-co-vinyl acetate (PLLA/EVA) blend that exhibited a sea-island structure to further demonstrate the toughening probability of CNTs on the immiscible polymer blends. The fracture toughness was evaluated through impact measurements. The impact-fractured surface morphologies as well as the morphological changes of the blend induced by adding CNTs were characterized using scanning electron microscope. Furthermore, rheological properties and glass transition behaviors of samples were comparatively investigated to better understand the toughening mechanisms. The results demonstrated that although the presence of CNTs resulted in the formation of EVA particles with irregular shape and simultaneously increased diameters and matrix ligament thickness, which were usually thought to be unfavorable for the improvement of fracture toughness according to the Wu's toughening mechanism, the blend composites still exhibited largely enhanced fracture toughness compared with the binary blend, and the impact strength increased gradually with increasing content of CNTs. The plastic deformation ability of PLLA matrix during the fracture process was greatly enhanced, especially when CNTs formed the physical network structure. Further results demonstrated that the glass transition behavior of EVA particles was greatly influenced by CNTs. Then, the toughening mechanism was proposed on the basis of the morphological changes of EVA particles, the formation of CNT physical network structure and the glass transition behavior of EVA. The other mechanical properties were also measured and analyzed. This work further demonstrated the toughening effect of CNTs on the immiscible polymer blends, and the methodology can be widely adopted in industry application.

A small amount of graphene oxide (GO) was incorporated into polypropylene (PP) to prepare a composite membrane, assisted by the pore-forming agent polyoxyethyleneoctylphenyl-10 (OP-10). The composite membrane was obtained through melt-compounding and a subsequent tensile process. The dispersion of GO in the composite, the dynamic mechanical properties and the melting and crystallization behaviors of the melt-compounded samples were investigated to clearly understand the initial microstructures of the samples. Different tensile strains were applied to obtain the stretched PP composite membrane, and then the morphologies of the composite membrane and the porosity were comparatively investigated. The results showed that the dispersion of GO was apparently improved with the aid of OP-10 and many initial pores were simultaneously introduced into the PP/GO/OP-10 composite, which induced a slight decrease in the storage modulus and glass transition temperature of the PP matrix. OP-10 suppressed the crystallization of the PP matrix, while GO compensated for this effect. Both the stretched PP/OP-10 and the composite membranes exhibited larger mean pore sizes compared with the stretched pure PP membrane. Furthermore, compared with the stretched PP, PP/GO and PP/OP-10 membranes, greatly increased porosity was achieved for the stretched PP/GO/OP-10 composite membrane, especially at relatively high tensile strain. In addition, it was suggested that the initial pores, which were introduced by adding OP-10, acted as a stress concentrator, promoting the formation of more pores during the tensile process by inducing lamellar separation and breakage. This work provided a new method for the preparation of PP-based composite membranes and also endowed them with great potential in many fields.

In this work, chemically modified graphene oxide was successfully prepared by emulsion polymerization of styrene, leading to grafting polystyrene (PS) onto graphene oxide (GO). Different contents of polystyrene grafted graphene oxide (PS–GO) were incorporated into immiscible polyamide 6/acrylonitrile–butadiene–styrene (PA6/ABS) blend and it was expected that PS–GO could tune the morphology and improve mechanical property. The mechanical testing showed a great improvement on ductility of polymer blends, in which the elongation at break increased by nearly 400% and the impact strength increased by nearly 200% with only 0.5 wt% PS–GO. The underlying mechanism for toughening was carefully discussed via investigations on effects of PS–GO on morphology, chain mobility as well as interfacial interaction. The morphology changes of the blend with PS–GO show slight increase of continuity of ABS. The fracture morphologies showed that the addition of PS–GO induced enhanced interfacial adhesion, exhibiting finer fracture morphology. DMA results verified the enhanced interfacial interaction between ABS and PA6 with the addition of PS–GO. Furthermore, the results demonstrated the interface localization of PS–GO in PA6/ABS. Combined with these observations, it was suggested that the PS–GO located at interface of immiscible blends PA6/ABS and enhanced the interfacial adhesion via the dual interactions with two components, in which one was the electronic stacking interaction between grafted PS on PS–GO and ABS while the other one was the interaction between polar groups on PS–GO and PA6, finally resulting in a great improvement on ductility.

In order to induce embryo from callus and set up the integral somatic embryo induction system from monoclonal cell, the differences of cell morphology and structure from different types of alfalfa callus were observed and compared by quick section and microscopic examination. The results show that giant callus cells were larger, elongated and yellow-white; loose callus cells were smaller, spherical, soft and yellow-green; hard-type callus cells were round, hard and dark green. The cell volume of giant callus was 4.5 times more than loose callus cells and 9 times more than hard-type callus cells. The biggest change of vacuole number and form were giant callus cells, which had 48%cells of 5-8 big vacuoles. Loose callus cells had 89%cells of 2-4 small vacuoles and hard-type callus cells had 97% cells with one large central vacuole. Loose callus cells had more chloroplast, which were 4.65 times more than giant callus cells. The chloroplast of hard-type callus cells was gathered into groups, which had 3-5 chloroplasts in it. The most nucleuses of giant callus cells and loose callus cells were located in the central of cell and 96.8% nucleus of hard-type callus cells were located on the edge. In hard-type callus cells there were different number of rings, thread and textured ducts. In short, there were lower cell differentiation and clearer vacuolization in giant callus, and high degree of differentiation and tissue aging in hard-type callus. The loose callus was undifferentiated, was lower on vacuolization and apparent on characteristics of embryonic callus, so that it was more suitable for induction of somatic embryos.

In order to know the key factors of callus development on single cell clone, characteristics of physiology and biochemistry and morphological structure on two types of Alfalfa callus was studied. The results showed that the cell membrane permeability and malondialdehyde content was same on two types of callus; but, their soluble sugar content and peroxidase activity in cells was larger different, the soluble sugar content: soft callus > huge callus, and soft callus was 2.09 times of huge callus; peroxidase activity: huge callus > soft callus, and huge callus was 1.35 times of soft callus. Huge callus cells were larger, loosely arranged, cell vacuolization and cytoplasm was thinner than soft callus. However, soft callus cells were smaller, loosely arranged, cell vacuoles was smaller and cytoplasm was thicker than hug callus. Huge cells had the same membrane metabolic with soft cells, but soft cells had higher sugar accumulation than huge cells, and soft cells metabolism are vigorous, while huge cells are more aging.

OBJECTIVE: To observe the effects of initial doses and treatment timing of levothyroxine (L-T4) on the clinical effcacy in children with congenital hypothyroidism (CH). METHODS: This study included 98 children who had an abnormal level of thyroid stimulating hormone (TSH) in neonatal screening in four regions of Yunnan Province and who fnally had a confrmed diagnosis of CH. They received treatment with L-T4 and were divided into standard dose group (10-15 μg/kg per day) and low dose group ( < 10 μg/kg per day) by the therapeutic dose of L-T4. Meanwhile, these patients were also classifed into two treatment groups based on the starting time of L-T4 treatment, namely under 2 months old group and more than 2 months old group. The thyroid function and physical and neural development were examined before and after treatment. RESULTS: Compared with the low dose group, the standard dose group had a signifcantly lower TSH level and a signifcantly higher free thyroxine (FT4) level at 2 weeks after treatment (P < 0.05). There were no signifcant differences in TSH and FT4 levels at other time points after treatment between the standard and low dose groups (P > 0.05). The physical and neural development were not signifcantly different between the two dose groups before and at all time points after treatment (P > 0.05). At all time points after treatment, the levels of TSH and FT4 and physical development were not signifcantly different between the different starting time groups (P > 0.05). However, the Gesell score was signifcantly higher in the under 2 months old group than in the more than 2 months old group at all time points after treatment (P < 0.05). CONCLUSIONS: The standard dose group has a better treatment outcome than the low dose group, whereas the symptoms of hyperthyroidism deserve close attention. The treatment timing is vital to the neurodevelopment of children with CH. Once diagnosed, the patients should receive treatments immediately.

OBJECTIVE: To explore the differences of NKX2.5 and TBX5 gene mutations between in vitro fertilization (IVF) children with congenital heart disease (CHD) and naturally conceived children with CHD. METHODS: Blood samples from 68 IVF children with CHD and 98 naturally conceived children with CHD were collected. The mutations in coding regions 1 and 2 of the NKX2.5 gene, and coding regions 4, 5, and 8 of the TBX5 gene were examined by polymerase chain reaction (PCR) and DNA sequencing. RESULTS: An A-to-G mutation at nucleotide 63 (c.63A > G) in coding region 1 of the NKX2.5 gene was found in both IVF and naturally conceived children with CHD. There were no significant differences in genotype and allele frequencies at c.63A > G locus of the NKX2.5 gene between the two groups. No mutations were detected in coding region 2 of the NKX2.5 gene and coding regions 4, 5 and 8 of the TBX5 gene. CONCLUSIONS: There is no difference in NKX2.5 and TBX5 gene mutations between IVF and naturally conceived children with CHD. Therefore, it is presumed that assisted reproductive technology may not lead to mutations in the NKX2.5 and TBX5 genes.

OBJECTIVE: To investigate the infections occurring in the induction period of childhood acute lymphoblastic leukemia (ALL), the pathogens of the infections, and drug resistance of isolated strains. METHODS: A retrospective analysis was performed for the clinical data of 130 children with newly-diagnosed childhood ALL. Infections occurring during the induction chemotherapy, pathogenic strains, and drug-resistance spectrum were analyzed. RESULTS: The incidence rate of clinical infection and/or microbial infection reached 76.2%. The lungs were the most common infection site (46.2%). The children with severe infection accounted for 52.3%, among whom 60 had pulmonary infection and/or 21 had sepsis. A total of 50 pathogenic strains were detected, which consisted of 29 bacterial strains and 21 fungal strains. Of all the children, 28.5% experienced infections caused by at least one microbe. Among the 29 bacterial strains, there were 19 (65.5%) Gram-negative bacteria and 10 (34.5%) Gram-positive bacteria. The most common Gram-negative bacteria were Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa, which were 100% sensitive to imipenem. The most common Gram-positive bacterium was Streptococcus viridans, which was 100% sensitive to vancomycin. The infections caused by fungi accounted for 16.2%, with Candida albicans as the most common fungus. Compared with those with non-severe infections, the children with severe infections had a significantly shorter time to the occurrence of agranulocytosis, a significantly longer duration of agranulocytosis, significantly higher incidence of fever and C-reactive protein (CRP) level, and a significantly longer length of hospital stay (P < 0.05). CONCLUSIONS: Pulmonary infections are common in the induction period of childhood ALL. Gramnegative bacteria are the most common pathogenic bacteria. Severe infections can be controlled by carbapenems combined with vancomycin and antifungal agents.

In order to discuss improving effect of ecological forest on heavy saline-alkali soil and to provide reference for biological improvement of saline-alkali soil, the soil chemical properties (pH, salt content, organic matter, available potassium and cation exchange capacity) of 20cm-depth in four different stages of growth on pure forest of Fraxinus velutina planted on heavy saline-alkali soil were studied. The results showed that pH value of forest soil in other stages of growth except defoliating stage was lower than that of CK, pH value in flowering stage decreased by 0.77 unit, and the decrease was the largest. The organic matter obviously increased in four different stages of growth, but the best effect of soil organic matter improvement was defoliating stage. During defoliating stage in mid-October, salt content of forest soil was 1/2 of CK, and cation exchange capacity was three point two nine times of CK. The available potassium of forest soil obviously increased in flowering stage and peak leafing stage. All in all, there was greater effect for the soil chemical properties of 20cm-depth in different growth stages of pure forest of Fraxinus velutina, so when salt-tolerance plant was used to improve saline-alkali soil, we should use scientific measure to cultivation and management in consideration of requirement of different growth stages of forest for soil water and soil nutrient in order to consolidate the improving achievements and to accelerate the improving process.

The poly(butylene succinate) (PBS)/graphene oxide (GO) composites containing different GO contents were prepared. The dispersion of GO was investigated using optical microscope (OM), scanning electron microscope (SEM), and transmission electron microscope (TEM). The results showed that GO exhibited good dispersion in the polar PBS matrix. The rheological measurements showed that the presence of GO induced largely increased melt viscosity for the composites. Specifically, high content of GO formed the percolated network structure. The non-isothermal crystallization kinetics was investigated using differential scanning calorimetry. The results showed that the non-isothermal crystallization behavior of PBS was influenced by GO content and cooling rate. At relatively small content, GO dramatically accelerated the crystallization of PBS. More integrated PBS crystalline structure was achieved by introducing GO. The nucleation effect of GO in the composites was proved further by the variation of isothermal crystallization morphologies.

In order to provide a theoretical basis for the development of the sweet cherry under the greenhouse environment in Tianjin area, the black cherry and the Sichuan cherry planted in greenhouses in north China were used to study the physiological and biochemical index under the different salt stress treatments (0, 0.2%, 0.4% and 0.6% ).The result showed that MDA content of Cerasus szechuanica was higher under salt stress; SOD activity of Cerasus szechuanica was almost the same to Cerasus maximowiczii (except under 0.6%Nacl); POD activity of Cerasus maximowiczii was higher under 0.4-0.6%Nacl concentration but lower under 0-0.2%; PRO content of Cerasus maximowiczii was higher under each salt stress but chlorophyll b content of Cerasus maximowiczii was lower under each salt stress.

Different contents of carbon nanotubes (CNTs) were introduced into a miscible poly(vinylidene fluoride) (PVDF)/poly(methyl methacrylate) (PMMA) blend. The interfacial affinity between CNTs and components of the blend was evaluated by calculating the interfacial tension. The dispersion and microstructure of CNTs in the nanocomposites were investigated through scanning electron microscope and rheological measurement. The effect of CNTs on the crystallization of PVDF was comparatively investigated through nonisothermal and isothermal crystallization processes. The results showed that CNTs exhibited stronger interfacial affinity to PMMA. Homogeneous dispersion of CNTs in the nanocomposites was achieved. Largely enhanced crystallization temperature and increased crystallinity of PVDF were obtained by adding CNTs during the nonisothermal crystallization process. The results obtained from the isothermal crystallization process proved that CNTs induced the concentration fluctuation in the sample, which resulted in the formation of spherulites with different types, i.e., the banded spherulites and compact spherulites. Furthermore, both the crystallization temperature and the content of CNTs exhibited great influence on the crystalline morphology of PVDF.

Cell autophagy is a homeostatic mechanism that exists in most eukaryotic cells, and it is known as a kind of highly conservative process. Autophagy can degrade intracellular proteins and organelles in lysosomes, and the main targets are needless biological macromolecules, damaged cytoskeleton, aging organelles, and so on. Therefore, autophagy is not only a way of cell death, but also a self-protection mechanism, just like apoptosis and senescence, and it participates in a lot of physiological processes, including the development and the growth of an organism. The characterization of hepatic autophagy being reported over years has revealed that lysosome-mediated degradation is important not only for the maintenance of liver homeostasis. In fact, the functions of autophagy involve far beyond the elimination of damaged cellular components and protein quality control, it also plays an important role in antigen presentation and participation in the response of stressors, especially in immune inflammatory response and organ transplantation. In this review, we focus on the role of autophagy in the liver immune tolerance and the regulatory mechanism in order to further understand the important effect and potential therapeutic value of autophagy in immunity in liver transplantation. DOI: 10.11855/j.issn.0577-7402.2014.06.16

The aim of the present study was to investigate the therapeutic effects of water-soluble extracts of Banxiaxiexin decoction, a classical traditional Chinese medicine formulation, on BALB/c mice with experimentally induced ulcerative colitis (UC). Water-soluble extracts of Banxiaxiexin decoction were intragastrically administered to BALB/c mice with oxazolone (OXA)-induced colitis. Sulfasalazine (SASP) was administered intragastrically to OXA-treated mice to establish the SASP group (positive control). Following drug administration, the disease activity index (DAI) and the histopathological inflammation score were recorded. In addition, the expression levels of interleukin (IL)-5 and IL-13 mRNA in the colonic tissue were determined by fluorescent quantitative polymerase chain reaction. The DAI and histopathological inflammation score of the model group were significantly greater compared with those of the control group, and the mRNA expression levels of IL-5 and IL-13 in the colonic tissue were also significantly higher in the model group compared with those in the control group. The intragastric administration of water-soluble extracts of Banxiaxiexin decoction significantly lowered the DAI and histopathological inflammation score. The mRNA expression levels of IL-5 and IL-13 in the colonic tissue were also significantly lowered. The therapeutic effect of Banxiaxiexin decoction was found to be comparable to that of SASP. In conclusion, the results from the present study demonstrate that water-soluble extracts of the traditional Chinese medicine formulation Banxiaxiexin decoction have a therapeutic effect on BALB/c mice with OXA-induced colitis.

A few amount of graphene oxide (GO) and β-nucleating agent (β-NA) were introduced into polypropylene simultaneously through melt-compounding processing. The microstructures of the compression-molded samples were characterized and the results showed that in the composite, the nucleation efficiency of the β-NA was higher than that of the GO, which resulted in the formation of a large number of β-PP. The compression-molded samples were stretched under different conditions and the pore morphology and the porosity were investigated. The results showed that the presence of GO induced the formation of pores with smaller size in all conditions. Increasing the stretching temperature or tensile speed induced the decrease of the porosity, although the stretched samples exhibited higher mean pore size. Furthermore, the results showed that the pore size and porosity of the composite increased with increasing the tensile strain, but too high tensile strain also resulted in the decrease of the porosity. Further results proved that annealing pretreatment facilitated the formation of regular pores, and the stretched sample exhibited higher porosity. This work provided a new method to prepare the hybrid porous PP sample with great potential in application.

According to the problem that the traditional remote sensing image classification methods focus only on analyzing the spectral features and have low utilization of the spatial information, a new spatial-spectral classification method is proposed in this paper, its core idea is to combine the spectral features base on the Principal Component Analysis (PCA) algorithm with the spatial features extracted by the Gabor filter. Experiments show that, compared with the traditional classification methods, the proposed method can improve the classification accuracy and the Kappa coefficient, which means to bring better classification and visual effects.

Maleic anhydride grafted styrene-ethylene/butadiene-styrene block copolymer (SEBS-g-MA) was introduced into poly(trimethylene terephthalate) (PTT) to prepare the PTT/SEBS-g-MA blends. The results showed that SEBS-g-MA exhibited dispersed particles and the particle sizes changed with the variation of its content. Furthermore, the crystallization behavior of PTT matrix was restricted by adding SEBS-g-MA. Mechanical properties measurements proved that PTT could be toughened by SEBS-g-MA and the toughening effect was greatly dependent upon the SEBS-g-MA content and the measurement conditions. The toughening mechanism was mainly attributed to the largely enhanced resistance of the crack propagation during the fracture process.

In this work, different contents of the organoclay (0.05–0.25 wt%) were introduced into the polycarbonate/poly(vinylidene fluoride)/carbon nanotube (PC/PVDF/CNT) blend composites by diluting the master batches of the PC/organoclay and the PVDF/CNT through melt-compounding in an internal mixer. In the blend composites, the weight fraction ratio between PC and PVDF was maintained at 40/60, and the content of the CNTs was varied from 0.1 to 0.5 wt%. The morphologies of the blend composites and the dispersion states of the nanofillers were characterized using scanning electron microscope and transmission electron microscope. Differential scanning calorimetry was used to investigate the crystallization behaviors of different blend composites so that the selective localization of the CNTs could be proved further. The results showed that with the presence of the CNTs and/or the organoclay, the blend composites showed the apparent morphological change from a typical sea-island structure to the quasi-cocontinuous structure. Specifically, at the organoclay content of 0.1 wt%, most of the CNTs selectively located at the blend interface. The electrical resistivity was measured and the results showed that organoclay showed apparent influence on the electrical resistivity of the blend composites. Namely, the volume resistivity decreased with increasing organoclay content until a minimum value was achieved, then it increased gradually with further increasing organoclay content. Specifically, all the blend composites exhibited the minimum electrical resistivity at the 0.1 wt% organoclay. Furthermore, a very small percolation threshold of the CNTs (0.06 wt%) was achieved in this work, which was attributed to the selective localization of the CNTs at the blend interface.

Microvoid toughening material is an active research area where the application in polymer matrix still needs to be popularized. In this work, microvoids were introduced into an isotactic polypropylene (iPP) matrix by introducing octylphenol polyoxyethylene ether (OP-10) and the iPP/OP-10 samples were annealed at 140 °C for 3 h. The results showed that the annealed iPP/OP-10 samples exhibited largely enhanced impact strength compared with the annealed pure iPP and the unannealed iPP/OP-10 samples. A synergistic toughening efficiency was proposed to describe the roles of annealing and OP-10 in toughening iPP. Further results showed that the relaxation behavior as well as the crystallization and melting behaviors of the iPP matrix were not influenced by OP-10. However, apparent changes of the microvoid morphology were observed. The annealed iPP/OP-10 samples exhibited largely increased microvoid numbers or decreased inter-microvoid distance. The toughening mechanisms based on the morphology of the microvoid were analyzed.

In this work, maleic anhydride grafted styrene–ethylene–butadiene–styrene copolymer (SEBS-g-MA) and carbon nanotubes (CNTs) were introduced into the immiscible polypropylene/polystyrene (PP/PS) blend. Among the three polymer components, SEBS-g-MA has the strongest affinity to CNTs; thus, it exhibits dual effects to adjust the phase morphology of the blends and the dispersion state of CNTs in the blends. The experimental observations obtained from morphology characterizations using scanning electron microscope and transmission electron microscope confirm the selective localization of CNTs at the interface of the immiscible PP/PS blend. As a consequence, largely decreased percolation threshold is achieved when most of CNTs are selectively localized at the interface region between PP and PS. Copyright © 2014 John Wiley & Sons, Ltd.

In order to explore the relation between tree crown shape and growth development and age of tree, flowering plants, fruiting plants, bearing plants, bearing branch and floweret, length of bearing branch were studied in greenhouse environments after tree corm shape were divided into three groups by live crown ratio of crown width to height and angle from the central leader to first scaffold branch. The result showed that the plants of upright crown shape were 83% at age one year among all plants, 45% at age two years and tree crown shapes, open tree increased to 25% at age of three years. The flowering trees increased from 5% at age of one year to 55% in age of three years and fruit set increased from 0 to 44% following increase of age tree. Open trees had more flowers with 10.6 in 2-year-old tree, 38.6 in 3-year-old tree. Open trees had more percentage of bearing plants with around 47%. The average length of bearing branches was 11.5 cm at open trees, which was more than other crown shapes at age of three years. Open trees had most fruit number per bearing tree (6.5, 8.5 apart). Therefore, creating open tree crown shape may increase flowering, fruiting and yield in greenhouse production of feijoa.

In order to understand the effects of lead on the growth of Lactuca sativa L. and Brassica Campestris L. ssp, the change of growth index of seedling was studied under lead stress (different concentrations of lead nitrate solution), and by soilless cultivation of seedlings in pots and in greenhouse. The results showed that two kinds of plant growth were affected by lead stress of different level, the growth speed of seedlings reduced but a great number of growth index were increased, in addition to fresh weight and dry weight of stem and leaf. The leaf number, leaf area, plant height and the fresh weight, dry weight of stem and leaf in Lactuca sativa L. were declined obviously, and the fresh weight, dry weight of roots were increased under higher levels of lead treatment at the same time. The each growth index of Brassica Campestris L.ssp was decreased in higher concentration of lead treatment. The growth of Lactuca sativa L. was slightly better and Brassica Campestris L. was slightly lower than control under 0.005 mg/L lead treatment. So, Lactuca sativa L. wasmore sensitive in low concentrations of lead than Brassica Campestris L. Both of them reduced their growth significantly, especially Brassica Campestris L.in 0.015 mg/L lead treatment. Each grow index of Lactuca sativa L.and Brassica Campestris L. changed most in all kinds of lead concentration, and the growth was inhibited most in 0.045 mg/L lead. The growth of Brassica Campestris L.was decreased more under higher concentrations of lead compared with Lactuca sativa L..

In this work, a mutually miscible third polymer, i.e. poly(methyl methacrylate) (PMMA), was introduced into an immiscible poly(L-lactide) (PLLA)/poly(vinylidene fluoride) (PVDF) (60/40, wt/wt) blend. The interactions between PMMA and both components of the immiscible blend were first theoretically predicted by calculating the interfacial tensions and then experimentally proven by characterizing the glass transition and crystallization behaviors of the components. The results showed that although PMMA was miscible with PLLA and PVDF, it exhibited stronger interaction with PVDF and had a tendency to merge together with the PVDF component during the melt-compounding processing. There was a competition effect between PLLA and PVDF when they absorbed PMMA. Consequently, the interaction between PVDF and PLLA was enhanced by the bridge effect of PMMA. Furthermore, the migration and diffusion of PMMA carried a part of the PLLA component into the PVDF component (or carried some PVDF component into the PLLA component), forming a so-called occlusion structure. The mechanical properties were measured and the results showed that, at appropriate PMMA content (20–30 wt%), the ternary blends exhibited excellent fracture toughness. The enhanced interaction between components and the formation of the occlusion structure were suggested to be the main toughening mechanisms. This work demonstrated that the microstructure and mechanical properties of the immiscible polymer blends could be tuned by adding a mutually miscible third polymer via a competition mechanism and therefore it provided an alternative strategy for preparing microstructure-/property-controllable materials.