Microstructures of Strontium Aluminates and Polystyrene Phosphorescent Composite Films

2010 ◽  
Vol 428-429 ◽  
pp. 544-547 ◽  
Author(s):  
Ye Tang Guo ◽  
Yuan Ming Huang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Composite Films ◽  
Green Light ◽  
Inorganic Materials ◽  
Moisture Resistance ◽  
Information Display ◽  
Light Emitting ◽  
Scanning Electron

Strontium-aluminates-based phosphorescent composite films were prepared by homogeneously distributing the green light emitting phosphors within polystyrene hosts. The composite films have the unique properties of flexibility of the polymers and the long-lasting phosphorescence of the strontium-aluminates-based phosphors. The microstructures of the flexible composite films were characterized with scanning electron microscopy. The results indicated that the organic and inorganic materials can be combined with each other better, and the composite films can be easily rolled but will not generate cracks. Therefore, this composite technology can effectively enhance the moisture resistance of the phosphors and the films can be used in the filed of information display.

Green Aluminate Phosphors Used for Information Display

2010 ◽  
Vol 428-429 ◽  
pp. 421-425 ◽  
Author(s):  
Ye Tang Guo ◽  
Yuan Ming Huang
Keyword(s):  
Electron Microscopy ◽  
Composite Films ◽  
Green Light ◽  
Combustion Method ◽  
Information Display ◽  
Light Emitting ◽  
Conventional Combustion ◽  
Information Displays ◽  
Inorganic Composite ◽  
Scanning Electron

Well known long-persistent phosphorous strontium aluminates were synthesized by conventional combustion method in a furnace at about 600oC. By incorporating the obtained phosphorous strontium aluminates into organic host polystyrene, we prepared the organic-inorganic composite material (i.e., phosphor-polystyrene) which could be cast into flexible and green-light- emitting films. The morphology of the obtained phosphorous strontium aluminates and the phosphorescence of the organic-inorganic composite films were characterized with the scanning electron microscopy and the fluorescence spectroscopy, respectively. Our results show that the organic-inorganic composite films can be used as green-light- emitting roll-able screens in the industry of information displays.

Kaolinite dispersion in cassava starch-based composite films: a photonic microscopy and X-ray tomography study

2018 ◽  
Vol 38 (7) ◽  
pp. 641-647
Author(s):  
Jean Aimé Mbey ◽  
Fabien Thomas ◽  
Sandrine Hoppe
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dimethyl Sulfoxide ◽  
Polymer Matrix ◽  
Composite Films ◽  
Cassava Starch ◽  
X Ray ◽  
Clay Dispersion ◽  
Combined Use ◽  
Scanning Electron

Abstract In the present study, a combined use of photonic microscopy, scanning electron microscopy and 3D X-ray tomography is carried out in order to analyze the dispersion and the distribution of raw and dimethyl sulfoxide (DMSO)-intercalated kaolinite used as filler in cassava starch-based films. It is shown that the association of these techniques allows a valuable analysis of clay dispersion in polymer-clay composite films. In the case of kaolinite-starch composite films on which this study is focused, it is obvious that previous intercalation of kaolinite with DMSO is an efficient way to improve dispersion and distribution of kaolinite in a starch polymer matrix.

scholarly journals Properties of Luffa Fiber Reinforced PHBV Biodegradable Composites

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1765 ◽  
Author(s):  
Yong Guo ◽  
Li Wang ◽  
Yuxia Chen ◽  
Panpan Luo ◽  
Tong Chen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Flexural Strength ◽  
Room Temperature ◽  
Moisture Resistance ◽  
Hot Press ◽  
Biodegradable Composites ◽  
Hot Press Forming ◽  
Pre Treatment ◽  
Scanning Electron

In this study, composites of poly (hydroxybutyrate-co-valerate) (PHBV) with untreated luffa fibers (ULF) and NaOH-H2O2 treated luffa fibers (TLF) were prepared by hot press forming. The properties of luffa fibers (LFs) and composites were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and other analysis methods. Results showed that pre-treatment effectively removed pectin, hemicellulose, and lignin, thus reducing the moisture absorptivity of LFs. The flexural strength of TLF/PHBV was higher than that of ULF/PHBV. With 60% LF content, the flexural strengths of ULF/PHBV and TLF/PHBV reached 75.23 MPa and 90.73 MPa, respectively, 219.7% and 285.6% more than that of pure PHBV. Water absorptivities of composites increased with increase in LF content. Water absorptivity of TLF/PHBV was lower than that of ULF/PHBV. The flexural strengths of composites decreased after immersion in water at room temperature. Meanwhile, flexural strength of TLF/PHBV was lower than that of ULF/PHBV. Pretreatment of LFs effectively improved the bonding between fibers and PHBV, resulting in enhanced and thus improved the moisture resistance of composites.

Physical–mechanical evaluation of a microhybrid and a nanofilled composite light activated by quartz-halogen tungsten and light-emitting diode

2018 ◽  
Vol 53 (7) ◽  
pp. 981-990
Author(s):  
Fernanda P Ritto ◽  
Eduardo Moreira da Silva ◽  
Hélio Rodrigues Sampaio-Filho ◽  
Raimundo A Lacerda ◽  
Márcio AP Borges ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Nuclear Magnetic Resonance ◽  
Light Emitting Diode ◽  
Degree Of Conversion ◽  
Dental Composite ◽  
Polymerization Shrinkage ◽  
Light Emitting ◽  
Scanning Electron

The aim of this study was to characterize organic and disperse phase of a microhybrid (Mh – Filtek Z250) and a nanofilled (Nf – Filtek Z350) dental composite and analyze the influence of two LCUs (QHT-quartz-halogen tungsten and LED – light-emitting diode) on its physical–mechanical properties (degree of conversion, polymerization shrinkage, Vickers hardness and diametral tensile strength). Surface morphology was studied by scanning electron microscopy. The disperse phase content was measured using thermogravimetric analysis (TGA) and the organic fractions were qualitatively analyzed by nuclear magnetic resonance spectroscopy. Physical–mechanical properties were analyzed varying dental composite and LCU: Mh-QHT, Nf-QHT, Mh-LED and Nf-LED. The degree of conversion was evaluated using Raman spectrophotometry and polymerization shrinkage was measured by water picnometry. Mechanical behavior was analyzed by Vickers microhardness and diametral tensile testing. Scanning electron microscopy analysis showed similar microstructure of the materials mainly composed with different-sized particles dispersed within methacrylate matrix. Thermogravimetric analysis shows 80.13% of inorganic fraction for microhybrid composite and 75.29% for nanofilled. Nuclear magnetic resonance analysis showed similar organic structure for composites and did not show the presence of the monomer TEGDMA. Different light sources did not influence the tested properties, but considering different composites, nanofilled showed the highest degree of conversion (Gr 2:77%, Gr 4: 79.4%). The study shows that when the optimum radiant exposure (24 J/cm2) was used for polymerization of composites, regardless of the polymerization source, the properties of these resin materials showed satisfactory and similar results in relation to the conversion of polymers, polymerization shrinkage and mechanical behavior.

scholarly journals Preparation and Characterization of K-Carrageenan/Nanosilica Biocomposite Film

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lokesh R. Rane ◽  
Niranjan R. Savadekar ◽  
Pravin G. Kadam ◽  
Shashank T. Mhaske
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Tensile Strength ◽  
Water Vapour ◽  
Transmission Rate ◽  
Composite Films ◽  
Tensile Modulus ◽  
Water Vapour Transmission Rate ◽  
Scanning Electron

The purpose of this study is to improve the performance properties of K-carrageenan (K-CRG) by utilizing nanosilica (NSI) as the reinforcing agent. The composite films were prepared by solution casting method. NSI was added up to 1.5% in the K-CRG matrix. The prepared films were characterized for mechanical (tensile strength, tensile modulus, and elongation at break), thermal (differential scanning calorimetry, thermogravimetric analysis), barrier (water vapour transmission rate), morphological (scanning electron microscopy), contact angle, and crystallinity properties. Tensile strength, tensile modulus, and crystallinity were found to have increased by 13.8, 15, and 48% whereas water vapour transmission rate was found to have decreased by 48% for 0.5% NSI loaded K-CRG composite films. NSI was found to have formed aggregates for concentrations above 0.5% as confirmed by scanning electron microscopy. Melting temperature, enthalpy of melting, and degradation temperature of K-CRG increased with increase in concentration of NSI in K-CRG. Contact angle also increased with increase in concentration of NSI in K-CRG, indicating the decrease in hydrophilicity of the films improving its water resistance properties. This knowledge of the composite film could make beneficial contributions to the food and pharmaceutical packaging applications.

scholarly journals Porosity in Polysilsesquioxane Xerogels

1999 ◽  
Vol 576 ◽  
Author(s):  
Brigitta M. Baugher ◽  
Duane A. Schneider ◽  
Douglas A. Loy ◽  
Kamyar Rahimian
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pore Structure ◽  
Convenient Method ◽  
Sol Gel ◽  
Monomer Concentration ◽  
Inorganic Materials ◽  
Sol Gel Process ◽  
Very High ◽  
Scanning Electron

ABSTRACTPolymerization of organotrialkoxysilanes is a convenient method for introducing organic functionality into hybrid organic-inorganic materials. However, not much is known about the effects of the organic substituent on the porosity of the resulting xerogels. In this study, we prepared a series of polysilsesquioxane xerogels from organotrialkoxysilanes, RSi(OR′)3, with different organic groups (R = H, Me, Et, dodecyl, hexadecyl, octadecyl, vinyl, chloromethyl, cyanoethyl). Polymerizations of the monomers were carried out under a variety of conditions, varying monomer concentration, type of catalyst, and alkoxide substituent. The effect of the organic substituent on the sol-gel process was often dramatic. In many cases, gels were formed only at very high monomer concentration and/or with only one type of catalyst. All of the gels were processed as xerogels and characterized by scanning electron microscopy and nitrogen sorption porosimetry to evaluate their pore structure.

Orthoamide und Iminiumsalze, XCI. N,N′,N″-Peralkylierte Guanidiniumsalze – Ionische Flüssigkeiten als Hilfsmittel in der Elektronenmikroskopie

2016 ◽  
Vol 71 (6) ◽  
pp. 719-735
Author(s):  
Georg Knobloch ◽  
Stefan Saur ◽  
Anja Rebecca Gentner ◽  
Stefan Tussetschläger ◽  
Thorsten Stein ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Sample Preparation ◽  
Cell Cultures ◽  
Inorganic Materials ◽  
Cellulose Fibres ◽  
Coated Materials ◽  
Ionische Flüssigkeiten ◽  
First Time ◽  
Scanning Electron

AbstractPolymeric organic materials, e.g. cellulose fibres or nylon 6 (perlon), as well as inorganic materials, e.g. ceramics, can be coated with liquid or solid guanidinium salts. The coated materials can be inspected by scanning electron microscopy (SEM). The contrast and brightness of the pictures depend on the heaviest atom present in the anions. The best brightness and contrast were obtained with N,N′,N″-peralkylated guanidinium tetraiodidobismutates(III), which were prepared for the first time together with other guanidinium chloridometallates (Sb, Pb, Bi). Biological samples (cell cultures) can also be investigated by SEM with the aid of the guanidinium tetrachloridobismutate 4b after simple sample preparation.

scholarly journals EFFECT OF POLYCAPROLACTONE ON CHARACTERISTICS AND MORPHOLOGY OF ALGINATE/CHITOSAN/LOVASTATINE COMPOSITE FILMS

2018 ◽  
Vol 56 (4A) ◽  
pp. 13 ◽  
Author(s):  
Nguyễn Thúy Chinh ◽  
Hoang Thai ◽  
Loc Thi Thach ◽  
Giang Duc Le ◽  
Thuy Phuong Ngo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Solution Method ◽  
Composite Films ◽  
Total Weight ◽  
Differential Scanning Calorimetric ◽  
Ft Ir ◽  
Scanning Electron

In this work, alginate (AG)/chitosan (CS)/lovastatine (LS) AG/CS/PCL/LS composite films using polycaprolactone (PCL)  are prepared by solution method with the ratio of AG/CS and LS content fixed at 4/1 and 10 wt.% (in comparison with the total weight of CS and AG), respectively.  The PCL content is used at 3, 5 and 10 wt.% (in compared with total weight of AG, CS and LS). The role of PCL as a compatibilizer in AG)/CS)/LS composites is considered by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetric (DSC) methods. Based on the change in FTIR spectra, morphology and thermal parameters of AG/CS/PCL/LS composites, it can be seen that PCL has effectiveness of compatibility for AG, CS, and LS as well as plasticity for the composites. Besides, the influence of PCL content on the swelling degree of the composites is also investigated. 

Scanning Electron Microscopy Cathodoluminescence Studies of Piezoelectric Fields in an InGaN Multiple Quantum Well Light Emitting Diode

2004 ◽  
Vol 831 ◽  
Author(s):  
Kristin L. Bunker ◽  
Roberto Garcia ◽  
Phillip E. Russell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Quantum Well ◽  
Light Emitting Diode ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Piezoelectric Field ◽  
Piezoelectric Fields ◽  
Scanning Electron

ABSTRACTScanning Electron Microscopy (SEM)-based Cathodoluminescence (CL) experiments were used to study the influence of piezoelectric fields on the optical and electrical properties of a commercial InGaN-based Multiple Quantum Well (MQW) Light Emitting Diode (LED). The existence and direction of a piezoelectric field in the InGaN-based LED was determined with voltage dependent SEM-CL experiments. The CL emission peak showed a blueshift followed by a redshift with increasing reverse bias due to the full compensation of the piezoelectric field. It was determined that the piezoelectric field points in the [000–1] direction and the magnitude was estimated to be approximately 1.0±0.2 MV/cm. SEM-CL carrier generation density variation and electroluminescence experiments were used to confirm the existence of a piezoelectric field in the InGaN-based MQW LED.

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