Macroporous open cell polyester amphigel using citric acid and PEO: Solvent absorption, thermal behavior, and slow release of pesticide

Abstract

This article describes citric acid cross-linked amphiphilic poly(ethylene oxide) (PEO) macroporous open cell polyester amphigel, optimally synthesized using response surface methodology by applying central composite design to screen significant reaction parameters for maximizing percent water sorption. The chemical structure of the amphigel was confirmed by proton nuclear magnetic resonance (1 H NMR), FT-IR and the thermal behavior was studied using thermo-gravimetric and DSC. Due to amphiphilic nature, the amphigels also showed high chloroform (1151.33%-1193.33%) and water (755.33%-865%) absorption capacity. Thermal analysis revealed that amphigels are less thermal stability as compared to PEO, however, the degradation process was found to be multi step. The amphigel was effectively used as a carrier for easy loading of a hydrophobic pesticide and showed a slow release of the same.

Remotely triggered curcumin release from stimuli‐responsive magneto‐polymericlayer‐by‐layerengineered nanoplatforms

“…To elucidate the kinetics and the mechanism by which curcumin is released through polymeric‐magnetic nanostructures, using pH and temperature stimuli, the Korsmeyer‐Peppas and Gallagher‐Corrigan mathematical models were applied. The data obtained with the application of the Korsmeyer‐Peppas mathematical model (Table S1 ‐ Supporting information) indicate that the curcumin release mechanism takes place by Fickian diffusion through the pores of the polymeric layers, since the diffusion coefficient n obtained was ≤0.43 for all samples in the two temperature and pH ranges 36 . According to the data obtained with the application of the Gallagher‐Corrigan mathematical model (Table S2 ‐ Supporting information), it can be inferred that the mechanism of release of curcumin, from the magnetic nanoplatforms, occurred in a two‐stage process, generating two release constants, k 1 and k 2 .…”

“…The data obtained with the application of the Korsmeyer-Peppas mathematical model (Table S1 -Supporting information) indicate that the curcumin release mechanism takes place by Fickian diffusion through the pores of the polymeric layers, since the diffusion coefficient n obtained was ≤0.43 for all samples in the two temperature and pH ranges. 36 According to the data obtained with the application of the Gallagher-Corrigan mathematical model (Table S2 -Supporting information), it can be inferred that the mechanism of release of curcumin, from the magnetic nanoplatforms, occurred in a two-stage process, generating two release constants, k 1 and k 2 . The first stage (k 1 ) reflects the dissolution of curcumin into the medium, controlled by diffusion, which was clearly seen in the first few hours of release.…”

“…Results obtained were presented as percentage of curcumin released over time. In order to determine the kinetics and mechanism of curcumin release, the data obtained in the release studies were fitted to the mathematical models of Korsmeyer-Peppas, 36 and Gallagher-Corrigan. 37 The applied mathematical models quantify the evolution of the amount of drug released as a function of time.…”

Facile construction of cationic lignin modified bentonite–alginate nanocomposite gel for sustained release of alachlor

“…Therefore, encapsulating alachlor in a composite gel, as opposed to applying it directly to the real environment, ensures both herbicidal efficacy and prolonged drug action. To explore the release mechanism of alachlor from nanocomposite, the release data was fitted using the Rigter–Peppas empirical equation 65,66 where M t / M 0 is the drug release rate at moment t , k is a constant and n is the diffusion exponent.…”

“…To explore the release mechanism of alachlor from nanocomposite, the release data was fitted using the Rigter-Peppas empirical equation. 65,66…”