Characterization of Native and Modified Starches by Potentiometric Titration

Soto, Diana; Urdaneta, J.; Pernía, Kelly

doi:10.1155/2014/162480

Cited by 13 publications

(4 citation statements)

References 35 publications

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“…While in the case of OCS there is a decrease in area of absorption bands at 3500–3200 cm –1 (−OH and NH) and from 2000 to 2300 cm –1 (H 2 O) compared to that of CS. This indicates a decrease in free −OH and −NH 2 groups due to their oxidation . The frequencies at 2875 cm –1 were assigned to the characteristic peak of −CH groups.…”

Section: Resultsmentioning

confidence: 96%

“…This indicates a decrease in free −OH and −NH 2 groups due to their oxidation. 35 The frequencies at 2875 cm −1 were assigned to the characteristic peak of −CH groups. In the case of PVA there is also a broad peak at 3300− 3200 cm −1 due to OH groups, but in the case of OPVA there is decrease in the peak at 3300−3200 cm −1 due to the decrease in the free OH groups, due to oxidation.…”

Section: Resultsmentioning

confidence: 99%

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Thiocarbohydrazide Cross-Linked Oxidized Chitosan and Poly(vinyl alcohol): A Green Framework as Efficient Cu(II), Pb(II), and Hg(II) Adsorbent

et al. 2017

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The macroporous thiocarbohydrazide crosslinked chitosan-poly(vinyl alcohol) framework (TCPF), prepared via the condensation reaction of thiocarbohydrazide and the oxidized products of chitosan (OCS) and poly(vinyl alcohol) (OPVA) is reported with selective and efficient adsorption of Cu(II), Pb(II), and Hg(II). The adsorption of Cu(II), Pb(II), and Hg(II) onto TCPF was studied through batch adsorption experiments, and the adsorption data were analyzed by using various models. The Langmuir model fits best with the experimental values which yields adsorption capacities of 47.16 mg g −1 , 47.39 mg g −1 , and 52.63 mg g −1 for Cu(II), Pb(II), and Hg(II), respectively. The calculated thermodynamic parameters ΔG o , ΔS o , and ΔH o suggest that the adsorption of Cu(II), Pb(II), and Hg(II) is thermodynamically favorable and thus a spontaneous process which follows pseudo-second-order kinetics. The plot of qt versus t 1/2 suggests that intraparticle diffusion is not only the ratecontrolling step but also the positive value of the intercept in Pb(II) and Hg(II) plots. This indicates that several steps are operational in the adsorption mechanism. Furthermore, the excellent recycle performances also were achieved with desorption and regeneration efficiencies close to 97−99%, permitting the recovery of both metal ions and TCPF. Finally, the complete soil degradability which can be attained in approximately 90 days makes the whole process environmentally friendly and economically feasible.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Thiocarbohydrazide Cross-Linked Oxidized Chitosan and Poly(vinyl alcohol): A Green Framework as Efficient Cu(II), Pb(II), and Hg(II) Adsorbent

et al. 2017

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“…The content of negatively charged functionalities on the polymer products was determined via potentiometric titration, according to the procedure described by Soto et al, with slight modifications [ 66 ]. A 0.10 M NaOH solution was used as a titrant, pre-standardized with a 25 mM oxalic acid solution.…”

Section: Methodsmentioning

confidence: 99%

Identification of a βCD-Based Hyper-Branched Negatively Charged Polymer as HSV-2 and RSV Inhibitor

Francese

Cecone

Costantino

et al. 2022

IJMS

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Cyclodextrins and cyclodextrin derivatives were demonstrated to improve the antiviral potency of numerous drugs, but also to be endowed with intrinsic antiviral action. They are suitable building blocks for the synthesis of functionalized polymer structures with potential antiviral activity. Accordingly, four water-soluble hyper-branched beta cyclodextrin (βCD)-based anionic polymers were screened against herpes simplex virus (HSV-2), respiratory syncytial virus (RSV), rotavirus (HRoV), and influenza virus (FluVA). They were characterized by FTIR-ATR, TGA, elemental analyses, zeta-potential measurements, and potentiometric titrations, while the antiviral activity was investigated with specific in vitro assays. The polymer with the highest negative charge, pyromellitic dianhydride-linked polymer (P_PMDA), showed significant antiviral action against RSV and HSV-2, by inactivating RSV free particles and by altering HSV-2 binding to the cell. The polymer fraction with the highest molecular weight showed the strongest antiviral activity and both P_PMDA and its active fractions were not toxic for cells. Our results suggest that the polymer virucidal activity against RSV can be exploited to produce new antiviral materials to counteract the virus dissemination through the air or direct contact. Additionally, the strong HSV-2 binding inhibition along with the water solubility of P_PMDA and the acyclovir complexation potential of βCD are attractive features for developing new therapeutic topical options against genital HSV-2 infection.

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“…In the esterification reaction of starch with saturated fatty acids, various acids and bases, such as pyridine, Na 2 HPO 4 , K 2 CO 3 , CH 3 COONa, potassium silicate, HCl, and NaOH, are used as reaction catalysts [28]. These catalysts weaken the bond strength between the starch chains that are spirally connected by hydrogen bonding and improve the reaction efficiency in the process of inducing a nucleophilic substitution reaction (Fischer's esterification) with the starch hydroxyl group by carbocation formation (Scheme 11).…”

Section: Esterification Of Starchmentioning

confidence: 99%

Reaction Mechanisms Applied to Starch Modification for Biodegradable Plastics: Etherification and Esterification

Kim

Jung

2022

International Journal of Polymer Science

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Although many studies are being actively conducted to develop biodegradable plastic materials, most of these reports focused more on efficiency or performance improvement than on the reaction mechanism. This paper discussed the reaction mechanism applied to starch modification by etherification and esterification, which are the most studied in the field of biodegradable plastics. In the starch-reforming reaction by etherification, the effects of the reaction temperature, pH, solvent, and by-products on the chemical structure and physical properties of biodegradable plastics were discussed. In esterification, the structure of the substituents and the reaction solvents were examined. As a material that can replace plastics, the aim is to help derive new ideas on the design of reaction condition that can expand the use of starch.

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Characterization of Native and Modified Starches by Potentiometric Titration

Cited by 13 publications

References 35 publications

Thiocarbohydrazide Cross-Linked Oxidized Chitosan and Poly(vinyl alcohol): A Green Framework as Efficient Cu(II), Pb(II), and Hg(II) Adsorbent

Thiocarbohydrazide Cross-Linked Oxidized Chitosan and Poly(vinyl alcohol): A Green Framework as Efficient Cu(II), Pb(II), and Hg(II) Adsorbent

Identification of a βCD-Based Hyper-Branched Negatively Charged Polymer as HSV-2 and RSV Inhibitor

Reaction Mechanisms Applied to Starch Modification for Biodegradable Plastics: Etherification and Esterification

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