scholarly journals Chitosan Derivatives: Introducing New Functionalities with a Controlled Molecular Architecture for Innovative Materials †

2018 ◽  
Author(s):  
Waldo M. Argüelles-Monal ◽  
Jaime Lizardi-Mendoza ◽  
Daniel Fernández-Quiroz ◽  
Maricarmen T. Recillas-Mota ◽  
Marcelino Montiel-Herrera
Keyword(s):  
Chemical Structure ◽  
Molecular Architecture ◽  
Structure And Properties ◽  
New Materials ◽  
Important Condition ◽  
Experimental Conditions ◽  
Innovative Materials ◽  
Chitin And Chitosan ◽  
Macromolecular Architecture ◽  
Advanced Applications

The functionalization of polymeric substances is of great interest for the development of innovative materials for advanced applications. For many decades, the functionalization of chitosan has been a convenient way to improve its properties with the aim to prepare new materials with specialized characteristics. In the present article, we summarize the latest methods for the modification and derivatization of chitin and chitosan, trying to introduce specific functional groups under experimental conditions, which allow a control over the macromolecular architecture. This is motivated because an understanding of the interdependence between chemical structure and properties is an important condition for proposing innovative materials. New advances in methods and strategies of functionalization such as click chemistry approach, grafting onto copolymerization, coupling with cyclodextrins and reactions in ionic liquids are discussed.

Materials technology: Innovations and progress

Impact ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. 52-53
Author(s):  
Lucy Sharp
Keyword(s):  
Material Properties ◽  
New Materials ◽  
Medical Problems ◽  
Technology Innovations ◽  
Societal Challenges ◽  
New Material ◽  
Innovative Materials ◽  
The Creation ◽  
Novel Applications

Materials technology is a constantly evolving discipline, with new materials leading to novel applications. For example, new material properties arise from combining different materials into composites. Researching materials can help solve societal challenges, with the creation of innovative materials resulting in breakthroughs in overcoming hurdles facing humankind, including energy challenges and medical problems. Innovative materials breathe new life into industries and spur on scientific and technological discovery.

scholarly journals Grafting of (3-Chloropropyl)-Trimethoxy Silane on Halloysite Nanotubes Surface

2021 ◽  
Vol 11 (12) ◽  
pp. 5534
Author(s):  
Asmaa M. Abu El-Soad ◽  
Giuseppe Lazzara ◽  
Alexander V. Pestov ◽  
Daria P. Tambasova ◽  
Denis O. Antonov ◽  
...  
Keyword(s):  
Active Site ◽  
Chemical Engineering ◽  
Coupling Reaction ◽  
Ammonium Hydroxide ◽  
Halloysite Nanotubes ◽  
Chemical Activity ◽  
Molar Ratio ◽  
New Materials ◽  
Experimental Conditions ◽  
Trimethoxy Silane

Modified halloysite nanotubes (HNTs-Cl) were synthesized by a coupling reaction with (3-chloropropyl) trimethoxysilane (CPTMS). The incorporation of chloro-silane onto HNTs surface creates HNTs-Cl, which has great chemical activity and is considered a good candidate as an active site that reacts with other active molecules in order to create new materials with great applications in chemical engineering and nanotechnology. The value of this work lies in the fact that improving the degree of grafting of chloro-silane onto the HNT’s surface has been accomplished by incorporation of HNTs with CPTMS under different experimental conditions. Many parameters, such as the dispersing media, the molar ratio of HNTs/CPTMS/H2O, refluxing time, and the type of catalyst were studied. The greatest degree of grafting was accomplished by using toluene as a medium for the grafting process, with a molar ratio of HNTs/CPTMS/H2O of 1:1:3, and a refluxing time of 4 h. The addition of 7.169 mmol of triethylamine (Et3N) and 25.97 mmol of ammonium hydroxide (NH4OH) led to an increase in the degree of grafting of CPTMS onto the HNT’s surface.

Synthesis and Characterization of Alkeyl Imidazolium Ionic Liquids

2014 ◽  
Vol 1048 ◽  
pp. 452-455
Author(s):  
Qiang Wang ◽  
Shi Dong Wang ◽  
Ming Chen Qi ◽  
Shu Liang Zang
Keyword(s):  
Ionic Liquids ◽  
Chemical Structure ◽  
Direct Synthesis ◽  
Synthesis Method ◽  
Structure And Properties ◽  
Spectra Analysis ◽  
Infrared Spectrometer ◽  
Liquid Salts ◽  
Structure Of Matter

Two new imidazole ionic liquid salts, 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) and 1-allyl-3-methy-imidazolium hydrogen sulfate ([EMIM]HSO4), were synthesized with direct synthesis and two-step synthesis method, using a viscosity meter, PH meter, conductivity meter, densitometer, infrared spectrometer determined its chemical structure and properties. The results show that two ionic liquids in the range is slightly different, the trend is roughly same. As the temperature increases, the viscosity decreases, PH gradually increased, the density decreases slightly, can be regarded as constant, the conductivity gradually increased. Ionic liquids of the two IR spectra analysis show its structure and synthetic route consistent with the structure of matter.

scholarly journals Antioxidant Activity of Quercetin: A Mechanistic Review

2016 ◽  
Vol 4 (12) ◽  
pp. 1134 ◽  
Author(s):  
Senay Ozgen ◽  
Ozgur Kivilcim Kilinc ◽  
Zeliha Selamoğlu
Keyword(s):  
Antioxidant Activity ◽  
Free Radical ◽  
Cardiovascular Diseases ◽  
Chemical Structure ◽  
Radical Scavenging ◽  
Antioxidant Property ◽  
Free Radical Scavenging ◽  
Polyphenolic Compounds ◽  
Structure And Properties ◽  
Treatment Of Diabetes

Flavones and flavonoids are known to have potent antioxidant activity due to intracellular free radical scavenging capacities. Flavonoids are found ubiquitously in plants as a member of polyphenolic compounds which share diverse chemical structure and properties. Quercetin is among the most efficient antioxidants of the flavonoids. The antioxidant property of quercetin has been highlighted in this review. These compounds have pivotal role in treatment of diabetes, cancers and some cardiovascular diseases.

scholarly journals Effect of Heterogeneous Deacetylation on the Properties of Northern Shrimp Chitin and Chitosan

2020 ◽  
Author(s):  
Nataliia Dolgopiatova ◽  
Yuliya Kuchina ◽  
Tatiana Dyakina ◽  
Tatiana Volkova
Keyword(s):  
Molecular Weight ◽  
Shear Stress ◽  
Alkaline Treatment ◽  
Degree Of Crystallinity ◽  
Repeated Treatment ◽  
Experimental Conditions ◽  
Northern Shrimp ◽  
Chitin And Chitosan ◽  
Chitosan Deacetylation ◽  
The Degree Of Crystallinity

The effect of alkaline treatment of shrimp chitin on the molecular weight, the degree of deacetylation and degree of crystallinity of the resulting chitosan is studied. The viscosity of chitosan solutions from repeatedly deacetylated chitin is studied. It is shown that repeated treatment of chitin/chitosan with alkali causes the destruction of polysaccharide macromolecules. After four-time deacetylation and one-time deacetylation of chitin/chitosan for four hours, the molecular weight of the polysaccharide decreases by ten times. The maximum degree of chitosan deacetylation under experimental conditions was 92.0 -92.5%. The diffractograms of chitin and chitosan from the Northern shrimp are of the form typical for samples containing an amorphous phase in addition to a crystalline phase. The degree of crystallinity of chitin from Northern shrimp was 40.8%, of chitosan samples after one-, two-, and three-time deacetylation was 62-65%. For a sample of chitosan obtained after four-time deacetylation, recrystallization, and drying in a freeze dryer, the degree of crystallinity is close to the degree of crystallinity of shrimp chitin. The investigated acetic acid chitosan solutions with a concentration of 5% (wt.) and the chitosan molecular weight of 250, 160 and 130 kDa in their rheological properties are liquid-like non-Newtonian systems, their viscosity decreasing with increasing shear stress. After four-time deacetylation of chitin, the viscosity of chitosan solutions practically does not change with increasing shear stress, which apparently can be due to a significant decrease in the molecular weight of chitosan under these conditions.

Chemical Structure and Properties of Heat Treated Coal in the Early State of Carbonization (XIII)

1968 ◽  
Vol 47 (12) ◽  
pp. 864-871 ◽  
Author(s):  
Hidehiko Sugimura ◽  
Yoshihiro Osawa ◽  
Akira Ikutaand ◽  
Hidemasa Honda
Keyword(s):  
Chemical Structure ◽  
Structure And Properties ◽  
Early State ◽  
Heat Treated

Characterisation of innovative materials for Direct Laser Sintering

2004 ◽  
Vol 860 ◽  
Author(s):  
E. Bassoli ◽  
A. Gatto ◽  
L. Iuliano ◽  
E. Atzeni
Keyword(s):  
Laser Sintering ◽  
Rapid Manufacturing ◽  
Cad Model ◽  
New Materials ◽  
Aluminium Composite ◽  
Direct Laser ◽  
Powder Deposition ◽  
End Products ◽  
Innovative Materials ◽  
Mechanical Performances

ABSTRACTThe performances achieved by Rapid Prototyping techniques are progressively leading towards Rapid Manufacturing, that is the capability to produce end products, directly from the CAD model. Even so, the diffusion of these techniques is hardly supported by scientific knowledge about the micro-mechanisms ruling the macroscopic performances of the part. In the present research, mechanical performances of new materials produced by Direct Laser Sintering technique have been studied: a Polyamide and an innovative Polyamide-Aluminium composite (Alumide). Specimens were produced with different orientations in regard to powder deposition plane and laser path, to investigate how the manufacturing anisotropy affects the part performances.

Sign in / Sign up

Export Citation Format

Share Document