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1.
ACS Omega ; 9(20): 21864-21878, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38799365

RESUMEN

The synthesis of InVO4-CdS heterojunction photocatalysts has been achieved by a novel two-step approach, including a microwave-assisted technique, followed by a moderate hydrothermal method, marking the first successful instance of such a synthesis. X-ray diffraction, field-emission scanning electron microscopy, elemental color mapping, high-resolution transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, Raman analysis, photoluminescence, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller were employed to investigate the crystal structures, surface morphologies and particle sizes, chemical compositions, and optical characteristics of the as-synthesized materials. The research results indicated that the heterojunction InVO4-CdS, as synthesized, consisted of InVO4 microrods with an average size of around 15 nm and cadmium sulfide (CdS) microflowers with a diameter of 1.5 µm. Furthermore, all of the heterojunctions had favorable photoabsorption properties throughout the visible-light spectrum. The photocatalytic efficiency of the samples obtained was thoroughly assessed by the degradation of acid violet 7 (AV 7) under visible light irradiation with a wavelength greater than 420 nm. The photocatalytic efficiency for the decomposition of AV 7 was greatly enhanced in the InVO4-CdS (IVCS) heterojunctions when compared to prepared bare InVO4 and CdS. Additionally, it was observed that the composite material consisting of IVCS 3 wt % InVO4 combined with CdS exhibited the most significant enhancement in catalytic effectiveness for the photodegradation of AV 7 dye. Specifically, the catalytic performance of this composite material was found to be around 69.4 and 76.2 times greater than that of pure InVO4 and CdS, respectively. Furthermore, the experimental procedure including active species trapping provided evidence that h+ and •O2- radicals were the primary active species involved in the photocatalytic reaction process. Additionally, a potential explanation for the improved photocatalytic activity of the InVO4-CdS heterojunction was presented, taking into account the determination of band positions.

2.
Langmuir ; 40(10): 5360-5368, 2024 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-38427799

RESUMEN

Emulsions, formed by dispersing a liquid into another immiscible one by virtue of emulsifiers, have been widely applied in commercial applications like foods, pharmaceuticals, cosmetics, and personal care, which always confront environmental and/or toxic questions due to emulsifiers' high dosage. Recently, a study on Pickering emulsions points out a solution to stable emulsions based on the costabilizing effect of colloidal particles, which focused on surface-active particles cooperating with oppositely charged ionic surfactants. Costabilized emulsions adopting a charge-similar ionic surfactant and particles were less studied. In this article, a hexane-in-water emulsion was prepared in use of a cationic surfactant cetyltrimethylammonium bromide (CTAB) with positively charged magnesium hydroxide (MH) nanosheets at low concentrations (10-5 M and 10-2 wt %, respectively). The emulsion is stable due to the synergy by CTAB and MH nanosheets, which functions in virtue of the electric repulsion by similarly charged particles, the mechanical shielding by MH nanosheets, and restrained water drainage in lamellae between droplets due to the gelation of MH nanosheets. Moreover, the emulsion is doubly switchable within emulsification/demulsification via convenient pH or ion manipulation, a mechanism based on the breakdown and rebuilding of the costabilizing synergy. Such dual-responsive emulsions show high potential for the delicate control of drug delivery, release, and biphasic biocatalysis applications.

3.
ACS Appl Mater Interfaces ; 15(40): 47531-47540, 2023 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-37787377

RESUMEN

Polypropylene (PP) has been widely used in health care and food packaging fields, however, it lacks antibacterial properties. Herein, we prepared the polymeric antibacterial agents (MPP-NDAM) by an in situ amidation reaction between 2,4-diamino-6-dialkylamino-1,3,5-triazine (NDAM) and maleic anhydride grafted polypropylene (MPP) using the melt grafting method. The effects of reaction time and monomer content on the grafting degree of N-halamine were investigated, and a grafting degree of 4.86 wt % was achieved under the optimal reaction conditions. PP/MPP-NDAM composites were further obtained by a melt blending process between PP and MPP-NDAM. With the adoption of surface segregation technology, the content of N-halamine structure on the surface of PP/MPP-NDAM composites was significantly increased. The antibacterial tests showed that the PP/MPP-NDAM composite could achieve 99.9% bactericidal activity against 1.0 × 107 CFU/mL of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) within 10 and 5 min of contact, respectively. The antibacterial effect became more pronounced with the prolongation of chlorinated time, and it could achieve 99.9% bactericidal activity against E. coli within merely 1 min of contact.


Asunto(s)
Escherichia coli , Polipropilenos , Polipropilenos/química , Staphylococcus aureus , Antibacterianos/farmacología , Antibacterianos/química
4.
Int J Food Microbiol ; 406: 110369, 2023 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-37666026

RESUMEN

Oysters are recognized as important vectors for human norovirus transmission in the environment. Whether norovirus binds to bacteria in oyster digestive tissues (ODTs) remains unknown. To shed light on this concern, ODT-54 and ODT-32, positive for histo-blood group antigen (HBGA) -like substances, were isolated from ODTs and identified as Pseudomonas composti and Enterobacter cloacae, respectively. The binding of noroviruses (GII.4 and GII.6 P domains) to bacterial cells (ODT-32 and ODT-54; in situ assay) as well as extracted extracellular polysaccharides (EPSs; in vitro assay) was analyzed by flow cytometry, confocal laser scanning microscopy, ELISA, and gene knock-out mutants. ODT-32 bound to neither GII.4 nor GII.6 P domains, while ODT-54 specifically binds with GII.6 P domain through Psl, an exopolysaccharide encoded by the polysaccharide synthesis locus (psl), identified based on gene annotation, gene transcription, Psl specific staining, and ELISAs. These findings attest that ODT bacteria specifically bind with certain norovirus genotypes in a strain-dependent manner, contributing to a better understanding of the transmission and enrichment of noroviruses in the environment.

5.
Polymers (Basel) ; 15(9)2023 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-37177219

RESUMEN

It is challenging to improve the water resistance, flame retardancy, mechanical performance, and balance of halogen-free flame-retardant polypropylene (PP) composites. For this purpose, a linear vinyl polysiloxane (PD) was synthesized and then self-crosslinked under benzoyl peroxide to prepare surface-coated ammonium polyphosphate (APP@PD). Apparently, this linear vinyl polysiloxane self-crosslinking coating strategy was completely different from the commonly used sol-gel-coated APP with silane monomers. After coating, the water contact angles (WCA) of APP and APP@PD were 26.8° and 111.7°, respectively, showing high hydrophobicity. More importantly, PP/APP@PD/dipentaerythritol (DPER) showed a higher limiting oxygen index (LOI) and better UL-94 V-0 rate in comparison with PP/APP/DPER composites. After water immersion at 70 °C for 168 h, only PP/APP@PD/DPER kept the UL-94 V-0 rate and lowered the deterioration of the LOI, reflecting the better water-resistance property of APP@PD. Consistently, the cone calorimeter test results displayed a 26.2% and 16.7% reduction in peak heat release rate (PHRR) and total smoke production (TSP), respectively. Meanwhile, the time to peak smoke production rate (TPSPR) increased by 90.2%. The interfacial free energy (IFE) between APP@PD and PP was calculated to evaluate the interfacial interaction between PP and APP@PD. A reduction of 84.2% in the IFE between APP@PD and PP is responsible for the improvement in compatibility and the increase in flame retardancy, water resistance, and mechanical properties of the composites.

6.
Materials (Basel) ; 15(20)2022 Oct 21.
Artículo en Inglés | MEDLINE | ID: mdl-36295436

RESUMEN

It is well known that ultraviolet (UV) and blue light cause a series of health problems and damages to polymer materials. Therefore, there are increasing demands for UV-blue light-shielding. Herein, a new type of iron-doped titania (Fe-TiO2) nanoparticle was synthesized. Fe-TiO2 nanoparticles with small particle size (ca. 10 nm) are composed of anatase and brookite. The iron element is incorporated into the lattice of titania and forms a hematite phase (α-Fe2O3). The iron doping imparted full-band UV and blue light absorption to Fe-TiO2 nanoparticles, and greatly suppressed the photocatalytic activity. The prepared Fe-TiO2/polyurethane (PU) films exhibited prominent UV-blue light-shielding performance and high transparency, which showed great potential in light-shielding fields.

7.
Arch Microbiol ; 203(7): 4065-4072, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34050782

RESUMEN

A novel F-specific RNA bacteriophage (FRNAPH) YM1, affiliating to genogroup I (GI) of Levivirus, is isolated for the first time from human stool samples using double-layer agar plates with the Escherichia coli ATCC700891 as the host. The complete genomic sequence of YM1 is 3551 nt in length, obtained through next-generation sequencing, and contains four genes encoding for maturation protein, coat protein, lysis protein, and RNA-dependent RNA polymerase (RdRp). The genomic sequence of YM1 shares the highest similarity of 95.3% with that of a GI FRNAPH DL16 isolated from surface water of Great Bay. The YM1 possesses a non-enveloped, icosahedral virion of 23 ± 0.45 nm in diameter. One-step growth curve analysis shows that the burst time of YM1 is 30 min post-infection (p.i.) with the average burst size of 264 PFU/cell. The YM1 lyses only E. coli strains tested, revealing high host specificity. This newly discovered phage may serve as a candidate for viral indicator to monitor human enteric virus, especially norovirus, contamination in the environments.


Asunto(s)
Bacteriófagos , Monitoreo del Ambiente , Heces , Fagos ARN , Bacteriófagos/genética , Monitoreo del Ambiente/métodos , Escherichia coli/virología , Heces/virología , Genoma Viral/genética , Especificidad del Huésped , Humanos , Norovirus/genética , Fagos ARN/genética , Fagos ARN/aislamiento & purificación
8.
Arch Microbiol ; 203(6): 3117-3124, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33797591

RESUMEN

A bacterial strain ODT-83 is isolated from oysters, which is capable of adsorbing norovirus (NoV) via histo-blood group antigen-like (HBGA-like) substances. To better understand its genetic background associated with the production of HBGA-like substances, the genome of the ODT-83 was completely sequenced and analyzed. The ODT-83 only contains one circular chromosome, with a length of 5,384,159 bp. Both the 16S rRNA gene phylogeny and the average nucleotide identity (ANI) analyses confirm that the ODT-83 is a new Pseudomonas oleovorans strain. The whole genome encodes a total of 5037 predicted open reading frames (ORFs), 66 tRNA genes and 12 rRNA genes. Two gene clusters are detected on the genome, which are involved in the synthesis of polysaccharides of alginate and Pel, respectively. These results lay the foundation for further research on the interaction between the P. oleovorans strain ODT-83 and NoV.


Asunto(s)
Genoma Bacteriano , Ostreidae , Pseudomonas oleovorans , Animales , Técnicas de Tipificación Bacteriana , Ácidos Grasos/análisis , Genoma Bacteriano/genética , Ostreidae/microbiología , Filogenia , Pseudomonas/genética , Pseudomonas oleovorans/clasificación , Pseudomonas oleovorans/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Especificidad de la Especie
9.
Langmuir ; 37(14): 4082-4090, 2021 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-33784455

RESUMEN

Surfactants are often used as a cooperation stabilizer with solid particles for increasing the efficiency of Pickering emulsion. Accordingly, the effects of interaction between surfactants and solid particles on stabilizing Pickering emulsions have been attracting great attention. In this study, magnesium hydroxide (MH) nanosheets adsorbed with different amounts of sodium dodecyl sulfate (SDS) surfactants were designed and used to stabilize paraffin-water emulsions. Using SDS-adsorbed MH nanosheets as a stabilizer, the phenomenon of double phase inversion was found for Pickering emulsion. Pickering emulsion was inverted initially from O/W to W/O at about 0.022 mmol/g of the adsorption amount of SDS on the MH nanosheets, and subsequently back to O/W at about 2.312 mmol/g. The first phase inversion was because of the increased hydrophobicity of modified MH nanosheets, where SDS molecules were monolayer-adsorbed on the MH nanosheets surface. The second phase inversion occurred due to the bilayer adsorption of SDS on MH nanosheets, which converted the modified MH nanosheets hydrophilic again. These results are of great importance to understanding the double phase inversion of Pickering emulsions with the addition of surfactants and finding prospective applications in fields such as reversible drilling fluids and oil extraction.

10.
Glob Chall ; 4(11): 2000002, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33163224

RESUMEN

Transition metal orthovanadates are emerging 2D materials for promising electrochemical energy storage applications. Facile hydrothermal method for nanocrystalline indium vanadate (InVO4) semiconducting materials' fabrication is economical because of its direct chemical synthesis. X-ray diffraction studies, field emission scanning electron microscope (SEM) images, transmission electron microscopy (TEM), and photoelectron X-ray spectrum are used to describe the semiconductor materials as synthesized. InVO4 microspheres have attracted a lot of attention in the energy and environmental sector. These microsphere-derived semiconductor materials are recognized to offer the advantages of their large surface area, tunable pore sizes, enhanced light absorption, efficient carrier (electron-hole) separation, superior electronic and optical behavior, and high durability. From the results of SEM and TEM, InVO4 shows a microsphere construction with a mixture of nanosized particles. Diffuse reflectance UV-visible measurements are used to determine the bandgap, and it is found to be 2.1 eV for InVO4. The electrochemical analysis reveals a superior performance of the pseudocapacitor with hydrothermally derived microspheres of InVO4. Alongside an improved pseudocapacity, developed after 4000 cycles, it has excellent cycling stability with a retention of ≈94% of its original specific capacitance efficiency.

11.
Radiol Imaging Cancer ; 2(5): e190079, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-33778732

RESUMEN

Purpose: To summarize the data of previously reported medical imaging features on human malignancies to provide a scientific basis for more credible imaging feature selection for future studies. Materials and Methods: A search was performed in PubMed from database inception through March 23, 2018, for studies clearly stating the decoding of medical imaging features for malignancy-related objectives and/or hypotheses. The Newcastle-Ottawa scale was used for quality assessment of the included studies. Unsupervised hierarchical clustering was performed on the manually extracted features from each included study to identify the application rules of medical imaging features across human malignancies. CT images of 1000 retrospective patients with non-small cell lung cancer were used to reveal a pattern for the value distribution of complex texture features. Results: A total of 5026 imaging features of malignancies affecting 20 parts of the human body from 930 original articles were collated and assessed in this study. A meta-feature construct was proposed to facilitate the investigation of details of any high-dimensional complex imaging features of malignancy. A correlation atlas was constructed to clarify the general rules of applying medical imaging features to the analysis of human malignancy. Assessment of this data revealed a pattern of value distributions of the most commonly reported texture features across human malignancies. Furthermore, the significant expression of the gene mutational signature 1B across human cancer was highly consistent with the presence of the run length imaging feature across different human malignancy types. Conclusion: The results of this study may facilitate more credible imaging feature selection in all oncology tasks across a wide spectrum of human malignancies and help to reduce bias and redundancies in future medical imaging studies.Keywords: Computer Aided Diagnosis (CAD), Computer Applications-General (Informatics), Evidence Based Medicine, Informatics, Research Design, Statistics, Technology AssessmentSupplemental material is available for this article.Published under a CC BY 4.0 license.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Diagnóstico por Computador , Neoplasias Pulmonares , Carcinoma de Pulmón de Células no Pequeñas/diagnóstico por imagen , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Estudios Retrospectivos , Tomografía Computarizada por Rayos X
12.
Polymers (Basel) ; 11(1)2019 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-30960059

RESUMEN

In this work, a multi-functional nanoparticle (TiO2-KH570-DOPO) has been successfully synthesized through the attachment of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-methacryloxy propyl trimethoxyl silane on the surface of titanium dioxide (TiO2). Supercritical carbon dioxide was used as the solvent in order to increase the grafting level. The chemical structure of TiO2-KH570-DOPO was fully characterized using Fourier transform infrared spectra, thermogravimetric analysis and transmission electron microscopy. The modified TiO2 was incorporated into flexible polyurethane foam (FPUF). The fire performance of FPUF blends was evaluated using microscale combustion calorimetry. Peak heat release rate and total heat release values were reduced from 657.0 W/g and 28.9 kJ/g for neat FPUF sample to 519.2 W/g and 26.8 kJ/g of FPUF specimen containing 10 wt % of TiO2-KH570-DOPO. Analysis of thermal stability and the observation of char formation suggests that TiO2-KH570-DOPO is active in the condensed phase.

13.
Chemosphere ; 197: 526-534, 2018 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-29407814

RESUMEN

As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO2 (PDs-TiO2) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO4)2. Under visible light irradiation, the PDs-TiO2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO2 is 3.6 and 9.5 times higher than that of pure TiO2 and commercial P25, respectively. In addition, the PDs-TiO2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO2, therefore contribute to the excellent photocatalytic activity.


Asunto(s)
Procesos Fotoquímicos , Polímeros/química , Titanio/química , Compuestos Azo , Carbono , Catálisis , Luz , Modelos Químicos , Rayos Ultravioleta , Agua/química
14.
Nanotechnology ; 29(12): 125602, 2018 Mar 23.
Artículo en Inglés | MEDLINE | ID: mdl-29311422

RESUMEN

Rutile TiO2 are widely used for applications of coatings, cosmetics, photoelectric devices and so on. However, effective control of well-defined morphology, size and composition of rutile TiO2 nanoparticles from agglomeration has always been a challenge. A new synthesis strategy was proposed to prepare rutile TiO2 with controllable morphology varied from flower-like structures to single-separated nanorods. The ß-FeOOH nanoparticles were generated by the hydrolysis of FeCl3 solution and could prevent the aggregation of TiO2 nanocrystals at early stages of the reaction; thus, could control the morphology of rutile nanoparticles. The morphology of rutile TiO2 nanoparticles could be controllably regulated from flower-like structures to individually separated nanorods. Meanwhile, the preformed ß-FeOOH also played a role of dopant. Fe ions were substitutionally doped into the bulk lattice of TiO2 nanocrystals and reduced the bandgap, which extended the solar radiation absorption range of rutile TiO2. The prepared TiO2 may be suitable for novel UV-blue light shielding agents and many other applications in photoelectric devices, photocatalysis, and so on due to its small size, unprecedented discrete rod-like structure and unique UV-vis light permeability.

15.
Mitochondrial DNA A DNA Mapp Seq Anal ; 28(3): 332-334, 2017 05.
Artículo en Inglés | MEDLINE | ID: mdl-26713715

RESUMEN

The complete mitochondrial genome sequence of the serpent mudskipper Parapocryptes serperaster was first determined in this study. The circle genome was 17 243 bp long and consisted of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 1 control region. The nucleotide composition of the heavy strand of P. serperaster is 28.65% for A, 30.07% for C, 25.31% for T, and 15.97% for G, with a slight A + T bias of 53.96%. Only the NADH dehydrogenase subunit 6 (ND6) and eight tRNA genes were encoded on the light strand, all other mitochondrial genes were encoded on the heavy strand. A 178-bp tandem repeat, which started from the 827-bp site of the control region, was identified. Like most other gobies, P. serperaster also has the typical vertebrate mitochondrial gene arrangement. The phylogenetic analysis showed that the kinship between Parapocryptes and Boleophthalmus is closer than those between Parapocryptes and other selected genera.


Asunto(s)
Genoma Mitocondrial/genética , Perciformes/genética , Animales , ADN Mitocondrial/genética , Genes Mitocondriales/genética , Perciformes/clasificación , Filogenia , ARN de Transferencia/genética , Análisis de Secuencia de ADN
16.
IEEE Trans Neural Netw Learn Syst ; 27(10): 2084-94, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-26540719

RESUMEN

This paper aims to propose an efficient network and applies it as an adaptive filter for the signal processing problems. An adaptive filter is proposed using a novel interval type-2 fuzzy cerebellar model articulation controller (T2FCMAC). The T2FCMAC realizes an interval type-2 fuzzy logic system based on the structure of the CMAC. Due to the better ability of handling uncertainties, type-2 fuzzy sets can solve some complicated problems with outstanding effectiveness than type-1 fuzzy sets. In addition, the Lyapunov function is utilized to derive the conditions of the adaptive learning rates, so that the convergence of the filtering error can be guaranteed. In order to demonstrate the performance of the proposed adaptive T2FCMAC filter, it is tested in signal processing applications, including a nonlinear channel equalization system, a time-varying channel equalization system, and an adaptive noise cancellation system. The advantages of the proposed filter over the other adaptive filters are verified through simulations.

17.
Colloids Surf A Physicochem Eng Asp ; 457: 256-262, 2014 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-25419050

RESUMEN

A new bioresorbable polylactide/calcium phosphate composite with improved mechanical strengths and a more basic filler, tetracalcium phosphate (TTCP), was prepared by melt compounding. N-(2-aminoethyl)-3-aminoproplytrimethoxysilane (AEAPS) and pyromellitic dianhydride (PMDA) were used to improve the interfacial adhesion between TTCP and polylactide (PLA). While AEAPS improved the dispersion of TTCP in the matrix, PMDA might react with the terminal hydroxyl group of PLA and the amino group on the surface of AEAPS modified TTCP, which could further enhance the interfacial strength. The tensile strength was improved to 68.4 MPa for the PLA/TTCP-AEAPS composite from 51.5 MPa for the PLA/TTCP composite (20 wt% of TTCP). Dynamic mechanical analysis suggested that there was a 51 % improvement in storage modulus compared to that of PLA alone, when PMDA (0.2 wt% of PMDA) was incorporated into the PLA/TTCP-AEAPS composite (5 wt% of TTCP). Using this new bioresorbable PLA composite incorporated with a more basic filler for biomedical application, the inflammation and allergic effect resulted from the degraded acidic product are expected to be reduced.

18.
ACS Appl Mater Interfaces ; 6(15): 12252-60, 2014 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-24969179

RESUMEN

Acrylonitrile-butadiene-styrene resin (ABS)/graphene nanocomposites were prepared through a facile coagulation method. Because the chemical reduction of graphene oxide was in situ conducted in the presence of ABS at the dispersion stage, the aggregation of the graphene nanosheets was avoided. It was shown by transmission electron microscopy that the graphene nanosheets were selectively located and homogeneously dispersed in the styrene-acrylonitrile (SAN) phase. The electrical conductivity and linear viscoelastic behavior of the nanocomposites were systematically studied. With increasing filler content, graphene networks were established in the SAN phase. Consequently, the nanocomposites underwent a transition from electrical insulator to conductor at a percolation threshold of 0.13 vol %, which is smaller than that of other ABS composites. Such a low percolation threshold results from extreme geometry, selective localization, and homogeneous dispersion of the graphene nanosheets in SAN phase. Similarly, the rheological response of the nanocomposites also showed a transition to solid-like behavior. Due to the thermal reduction of graphene nanosheets and structure improvement of graphene networks, enhanced electrical conductivity of the nanocomposites was obtained after annealing.

19.
ACS Appl Mater Interfaces ; 6(4): 2370-6, 2014 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-24422430

RESUMEN

Abundant and renewable solar light is an ideal resource for the industrial application of TiO2 photocatalysis in environmental purification. Over the past decades, the pursuit for visible-light photocatalysts with low cost, simple process, and high efficiency remains a challenging task. Here, we report a novel organic-inorganic nanohybrid photocatalyst (conjugation-grafted-TiO2) by chemically grafting conjugated structures onto the surfaces of TiO2 nanoparticles through controlled thermal degradation of the coacervated polymer layer. The interfacial C-O-Ti bonds between TiO2 and conjugated structures can act as the pathway to quickly transfer the excited electrons from conjugated structures to TiO2, therefore contribute to high visible-light photocatalytic efficiency. Our findings provide an economic route to prepare the conjugation-grafted-TiO2 nanohybrid, and develop a routine to improve the photocatalytic efficiency of organic-inorganic hybrid materials through the interfacial interaction.

20.
Int J Polym Sci ; 20142014.
Artículo en Inglés | MEDLINE | ID: mdl-25717339

RESUMEN

Addition of filler to polylactic acid (PLA) may affect its crystallization behavior and mechanical properties. The effects of talc and hydroxyapatite (HA) on the thermal and mechanical properties of two types of PLA (one amorphous and one semicrystalline) have been investigated. The composites were prepared by melt blending followed by injection molding. The molecular weight, morphology, mechanical properties, and thermal properties have been characterized by gel permeation chromatography (GPC), scanning electron microscope (SEM), instron tensile tester, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was found that the melting blending led to homogeneous distribution of the inorganic filler within the PLA matrix but decreased the molecular weight of PLA. Regarding the filler, addition of talc increased the crystallinity of PLA, but HA decreased the crystallinity of PLA. The tensile strength of the composites depended on the crystallinity of PLA and the interfacial properties between PLA and the filler, but both talc and HA filler increased the toughness of PLA.

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