scholarly journals Unique structure and property of cyclodextrin and its utility in polymer synthesis

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Jie Hu ◽  
Rong Huang ◽  
Shunsheng Cao ◽  
Yinqun Hua
Keyword(s):  
Organic Solvent ◽  
Chemical Modification ◽  
Present Article ◽  
Inclusion Complexes ◽  
Polymer Synthesis ◽  
Guest Molecules ◽  
Structure And Property ◽  
Chemically Modified ◽  
Unique Structure ◽  
Polymerization Method

AbstractOwing to their unique structure and property, natural cyclodextrins and their chemically modified derivatives can include many kinds of organic monomers to form guest/host complexes. The formation of these complexes results in significant changes of the solubility and activity of the guest molecules, but without chemical modification. It is found that the complexed hydrophobic monomers can be successfully polymerized directly in water without any organic solvent or surfactant, which induces a green way to polymer synthesis. It is found that this new cyclodextrin-mediated polymerization method differs strongly from classical methods. The present article reviewed the formation and the structure of the cyclodextrin/monomer inclusion complexes, and the influence of cyclodextrins on polymer synthesis. At last, the possible theory of the cyclodextrin-mediated reaction is discussed.

scholarly journals Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

2016 ◽  
Vol 12 ◽  
pp. 549-563 ◽  
Author(s):  
Vito Rizzi ◽  
Sergio Matera ◽  
Paola Semeraro ◽  
Paola Fini ◽  
Pinalysa Cosma
Keyword(s):  
Inclusion Complexes ◽  
Pyrimidine Ring ◽  
Protective Role ◽  
Supramolecular Structures ◽  
Water Soluble ◽  
Aqueous Environment ◽  
Spectroscopic Techniques ◽  
Guest Molecules ◽  
H Nmr ◽  
Cv Measurements

Since several years the inclusion of organic compounds (guests) within the hydrophobic cavity (host) of cyclodextrins (CDs) has been the subject of many investigations. Interestingly, the formation of inclusion complexes could affect the properties of the guest molecules and, for example, the influence of the delivery system can be a method to improve/change the photochemical behavior of the guest. In particular, very recent studies have shown the protective role of CDs preventing the degradation of the encapsulated guest. Starting from this consideration, in this work, only the structure and complexation mode of the inclusion complexes involving 4-thiothymidine (S4TdR, a known photosensitizer) and five CDs, namely 2-hydroxypropyl-α-cyclodextrin (2-HP-α-CD), 2-hydroxypropyl-β-cyclodextrin (2-HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (2-HP-γ-CD), heptakis-(2,6-di-O-methyl)-β-cyclodextrin (DIMEB CD) and heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TRIMEB CD) were investigated by different spectroscopic techniques (UV–vis, FTIR–ATR, 1H NMR) and cyclic voltammetry analysis (CV). This work is necessary for a prospective research on the photoreactivity of S4TdR in aqueous environment and in the presence of CDs to prevent its degradation under irradiation. UV–vis, FTIR–ATR and CV measurements suggested the formation of supramolecular structures involving the employed CDs and mainly the pyrimidine ring of S4TdR. 1H NMR analyses confirmed such indication, unveiling the presence of inclusion complexes. The strongest and deepest interactions were suggested when TRIMEB and DIMEB CDs were studied. The S4TdR affinity towards CDs was also evaluated by using the Benesi–Hildebrand (B–H) equation at 25 °C employing CV and 1H NMR methods. The stoichiometry of the interaction was also inferred and it appears to be 1:1 for all examined CDs.

Improvement of the organic solvent stability of a commercial lipase by chemical modification with dextran

2019 ◽  
Vol 142 ◽  
pp. 1-6 ◽  
Author(s):  
Shota Kajiwara ◽  
Kyohei Komatsu ◽  
Ryosuke Yamada ◽  
Takuya Matsumoto ◽  
Masahiro Yasuda ◽  
...  
Keyword(s):  
Organic Solvent ◽  
Chemical Modification ◽  
Solvent Stability ◽  
Commercial Lipase

scholarly journals A-βcyclodextrin/siloxane hybrid polymer: synthesis, characterization and inclusion complexes

2010 ◽  
Vol 21 (10) ◽  
pp. 1867-1876 ◽  
Author(s):  
Camilla Abbehausen ◽  
André L. B. Formiga ◽  
Edvaldo Sabadini ◽  
Inez V. P. Yoshida
Keyword(s):  
Inclusion Complexes ◽  
Polymer Synthesis ◽  
Hybrid Polymer

Effect of Surface Grafting-Modified on Structure and Property of Cellulose Fibers

2012 ◽  
Vol 627 ◽  
pp. 43-48
Author(s):  
Shu Hua Wang ◽  
Jin Ming Dai ◽  
Hu Sheng Jia ◽  
Bing She Xu
Keyword(s):  
Cellulose Fibers ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Wet Strength ◽  
Structure And Property ◽  
Chemically Modified ◽  
Crosslinking Process ◽  
Acrylamide Polymerization ◽  
Modified Cellulose ◽  
Effect Of Surface

Cellulose fibers were chemically modified on surface by acrylamide polymerization and glutaraldehyde crosslinking. The chemical and morphological structures of modified cellulose fibers were investigated with X-ray diffraction, FTIR spectra, and scanning electron microscopy (SEM). The crystalline conformations of the cellulose fibers were slightly changed in polymerization and crosslinking process. The wet strength of modified cellulose fibers was improved. Appreciable difference between the surfaces of native and modified cellulose fibers was observed from SEM images.

scholarly journals Phosphated Avocado Seed: A Renewable Biomaterial for Preparing a Flame Retardant Biofiller

2021 ◽  
Author(s):  
DAVID Zuluaga-Parra ◽  
L.F Ramos-deValle ◽  
Saul Sanchez ◽  
J.R. Torres-Lubián ◽  
J.A. Rodríguez-Gonzalez ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Chemical Modification ◽  
Flame Retardant ◽  
Photoelectron Spectroscopy ◽  
Morphological Changes ◽  
Ethylene Vinyl Acetate ◽  
Chemically Modified ◽  
Air Atmosphere ◽  
Thermal Stability Of ◽  
Avocado Seed

Abstract The cellulose and starch present in the avocado seed can be chemically modified to obtain biofillers with fire retarding characteristics. The resulting composites could be used as substitute of the corresponding halogenated composites. For this, the avocado seed was first washed, dehydrated and pulverized, and thereafter, chemically modified with phosphoric acid in the presence of urea. This was studied using infrared spectroscopy, nuclear magnetic resonance and X-Ray photoelectron spectroscopy, in order to determine the resulting chemical structure and confirm the presence of the proposed functional groups. In addition, scanning electron microscopy and elemental analysis were used, respectively, to establish the resulting morphological changes, as well as the elements present on the surface of the modified material. Thermogravimetric analysis was also carried out in order to establish the thermal stability of the material and predict the effect on the flame retardancy due to the mentioned chemical modification. Further tests established that the obtained modified structure and morphology of the avocado seed was highly dependent on the method used to dehydrate the pulverized avocado seed. It was also determined that chemical modification greatly increased the thermal stability of the avocado seed in air atmosphere. The flame-retardant effect of the modified avocado seed was assessed in polyethylene/ethylene-vinyl-acetate (PE/EVA) composites via cone calorimeter tests. These results showed that the modified avocado seed decreased the peak of the heat release rate (pHRR) by 50% and the total heat released (THR) by 15%. This phosphated avocado seed could be a good option as a renewable biofiller for polymer composites with enhanced flame-retardant properties.

scholarly journals The nature of the binding site for aromatic compounds in glycogen phosphorylase b

1975 ◽  
Vol 147 (2) ◽  
pp. 369-371 ◽  
Author(s):  
G Soman ◽  
G Philip
Keyword(s):  
Chemical Modification ◽  
Binding Site ◽  
Aromatic Compounds ◽  
Glycogen Phosphorylase ◽  
Relative Effectiveness ◽  
Rabbit Muscle ◽  
Substituent Constant ◽  
Chemically Modified ◽  
Glycogen Phosphorylase B ◽  
Hydrophobic Nature

The inhibition of rabbit muscle glycogen phosphorylase b (1,4-alpha-D-glucan--orthophosphate alpha-glucosyltransferase, EC 2.4.1.1) by aromatic compounds was examined with 15 compounds. The relative effectiveness of the inhibitors correlated well with increasing substituent constant, pi, indicating the hydrophobic nature of the binding site. The inhibition was not affected by the ionic-strength variation of the assay mixtures. The results predict that the course of chemical modification of this enzyme and the properties of the derivatives depend on the nature of the reagent and on the incorporated groups. Many of the dissimilar and sometimes contradictory results reported for chemical-modification studies and for chemically modified phosphorylase b are explained by the findings presented in the paper.

UV-vis Spectral Analysis of Inclusion Complexes between β -Cyclodextrin and Aromatic/Aliphatic Guest Molecules

2008 ◽  
Vol 5 (2) ◽  
pp. 173-176 ◽  
Author(s):  
Huiming Jiang ◽  
Yingmei Xu ◽  
Liyan Na ◽  
Rongchao Jin ◽  
Shufen Zhang
Keyword(s):  
Spectral Analysis ◽  
Inclusion Complexes ◽  
Guest Molecules ◽  
Aliphatic Guest
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