scholarly journals Effect of Nanoadditives on Bitumen Aging Resistance: A Critical Review

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Sara Filippi ◽  
Miriam Cappello ◽  
Manuel Merce ◽  
Giovanni Polacco
Keyword(s):  
Layered Silicate ◽  
Layered Silicates ◽  
Polymeric Nanocomposites ◽  
Oxidative Aging ◽  
Polar Components ◽  
Patent Literature ◽  
Expected Benefits ◽  
Double Hydroxides ◽  
Physical And Chemical

Starting from the eighties, the use of nanoadditives registered an increasing attention in the scientific and patent literature, especially for the case of polymeric nanocomposites. In the last decade, this involved bituminous materials, modified either with nanosized fillers or with polymeric nanocomposites. One of the expected benefits is an increased resistance of the binder to aging. After a short introduction underlining the uncertainties and risks of artefacts in aging tests, a review is given, focusing on the antiaging properties of layered silicates, which are by far the most important nanoadditives for bitumens. Together with layered silicates, other materials such as nanohydrated lime, nanosilica, and layered double hydroxides are mentioned. Preparation and characterization of the binary bitumen/layered silicate and ternary bitumen/layered silicate/polymer systems are described in order to individuate the aspects that influence the antiaging effect. Even if the available literature is quite abundant and unanimously confirms that nanoadditives may improve bitumen durability, there is a lack of studies clarifying the involved mechanisms. As it is for conventional fillers, it seems to be a combination of physical and chemical interactions. Nanoadditives with different chemistries, porosities, and interlayer spacings differently absorb the polar components from the bitumen, thus affecting their predisposition to oxidative aging.

EXFOLIATION AND CHARACTERIZATION OF LAYERED SILICATE MINERALS: A REVIEW

2014 ◽  
Vol 21 (02) ◽  
pp. 1430001 ◽  
Author(s):  
FEIFEI JIA ◽  
SHAOXIAN SONG
Keyword(s):  
Layered Silicate ◽  
Influential Factors ◽  
Dramatic Improvement ◽  
Chemical Methods ◽  
Silicate Minerals ◽  
Physical Chemical ◽  
Physical And Chemical

Exfoliated silicate minerals have attracted great attentions because of the dramatic improvement in properties. This paper highlights the preparation of exfoliated silicate minerals, including physical, chemical, mixed physical and chemical methods. The mechanisms by which silicates are exfoliated and the important influential factors are also summarized. Finally, the instrumental techniques to characterize the exfoliated structure and exfoliation degree are presented.

scholarly journals Antibiotic Encapsulated Nanomaterials with Application in Medical Area

2018 ◽  
Vol 55 (4) ◽  
pp. 552-554
Author(s):  
Alina Costina Luca ◽  
Letitia Doina Duceac ◽  
Geta Mitrea ◽  
Madalina Irina Ciuhodaru ◽  
Daniela Luminita Ichim ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
Chemical Properties ◽  
Morphological Characterization ◽  
Drug Controlled Release ◽  
Anionic Clays ◽  
Amoxicillin Clavulanic Acid ◽  
Double Hydroxides ◽  
Physical And Chemical ◽  
And Chemical Properties

Novel materials belonging to the class of anionic clays are synthesized by investigating their properties at nano scale. Thus, hydrotalcites or layered double hydroxides (LDHs) were used as drug delivery carriers in order to prevent or to treat infections produced by some pathogen agents. Their physical and chemical properties allow them to include different molecules in the interlayer space and then to ensure their transport to the target. The current work reveals the obtaining of nanohybrid compounds type amoxicillin/clavulanic acid-layered double hydroxides (Amox/CA-LDHs) followed by structural and morphological characterization of these nanostructures for future applications as drug controlled release systems. IR spectroscopy and Scanning Electron Microscopy pointed out LDHs ability to incorporate the medicines without modification of therapeutic activity.

Characterization of defects in tabular silver halide grains

1990 ◽  
Vol 48 (4) ◽  
pp. 1046-1047
Author(s):  
C. Goessens ◽  
D. Schryvers ◽  
J. Van Landuyt ◽  
A. Verbeeck ◽  
R. De Keyzer
Keyword(s):  
Radiation Damage ◽  
Silver Halide ◽  
Chemical Characteristics ◽  
X Ray ◽  
Free Region ◽  
Central Defect ◽  
Crystallographic Defects ◽  
Physical And Chemical ◽  
Two Sides

Silver halide grains (AgX, X=Cl,Br,I) are commonly recognized as important entities in photographic applications. Depending on the preparation specifications one can grow cubic, octahedral, tabular a.o. morphologies, each with its own physical and chemical characteristics. In the present study crystallographic defects introduced by the mixing of 5-20% iodide in a growing AgBr tabular grain are investigated. X-ray diffractometry reveals the existence of a homogeneous Ag(Br1-xIx) region, expected to be formed around the AgBr kernel. In fig. 1 a two-beam BF image, taken at T≈100 K to diminish radiation damage, of a triangular tabular grain is presented, clearly showing defect contrast fringes along four of the six directions; the remaining two sides show similar contrast under relevant diffraction conditions. The width of the central defect free region corresponds with the pure AgBr kernel grown before the mixing with I. The thickness of a given grain lies between 0.15 and 0.3 μm: as indicated in fig. 2 triangular (resp. hexagonal) grains exhibit an uneven (resp. even) number of twin interfaces (i.e., between + and - twin variants) parallel with the (111) surfaces. The thickness of the grains and the existence of the twin variants was confirmed from CTEM images of perpendicular cuts.

Physical - Chemical Issues of Cephalosporin Intercalated Nanoparticles for Life - Threatening Infections Treatment

2001 ◽  
Vol 71 (3) ◽  
pp. 342-349
Author(s):  
Lucian Eva ◽  
Letitia Doina Duceac ◽  
Liviu Stafie ◽  
Constantin Marcu ◽  
Geta Mitrea ◽  
...  
Keyword(s):  
Chemical Characterization ◽  
Advanced Characterization ◽  
Generation Cephalosporin ◽  
Fourth Generation ◽  
Exchange Method ◽  
Physico Chemical ◽  
Life Threatening ◽  
Double Hydroxide ◽  
Double Hydroxides

The fourth generation cephalosporin antibacterial agent, cefepime, was loaded into layered double hydroxides for enhancing antibiotic efficiency, reducing side effects, as well as achieving the sustained release property. The intercalation of antibiotic into the inter-gallery of ZnAl-layered double hydroxide (LDH) was carried out using ion exchange method, by this constituting a nano-sized organic-inorganic hybrid material for a controlled release novel formulation. Although cefepime is a broad spectrum antibiotic, it has various adverse effects and a significant degradation rate. Thus, the preparation and physico-chemical characterization of nanomaterials able to intercalate this drug is an important study for medical and pharmaceutical field. The antibiotic inclusion into LDHs nanostructure was confirmed by advanced characterization techniques and the release profile of cefepime was analysed with the respect to pH of the simulated media.

scholarly journals Physical and Chemical Characterization of an Oyster Hemagglutinin

1969 ◽  
Vol 244 (15) ◽  
pp. 4128-4135
Author(s):  
R T Acton ◽  
J C Bennett ◽  
E E Evans ◽  
R E Schrohenloher
Keyword(s):  
Chemical Characterization ◽  
Physical And Chemical Characterization ◽  
Physical And Chemical
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