Claudia Sayer - Academia.edu (original) (raw)

Papers by Claudia Sayer

Anais do XX Congresso Brasileiro de Engenharia Química, 2015

Polymers, 2019

Crosslinking of an unsaturated aliphatic polyester poly(globalide) (PGl) by bistriazolinediones (... more Crosslinking of an unsaturated aliphatic polyester poly(globalide) (PGl) by bistriazolinediones (bisTADs) is reported. First, a monofunctional model compound, phenyl–TAD (PTAD), was tested for PGl functionalisation. 1H-NMR showed that PTAD–ene reaction was highly efficient with conversions up to 97%. Subsequently, hexamethylene bisTAD (HM–bisTAD) and methylene diphenyl bisTAD (MDP–bisTAD) were used to crosslink electrospun PGl fibres via one- and two-step approaches. In the one-step approach, PGl fibres were collected in a bisTAD solution for in situ crosslinking, which resulted in incomplete crosslinking. In the two-step approach, a light crosslinking of fibres was first achieved in a PGl non-solvent. Subsequent incubation in a fibre swelling bisTAD solution resulted in fully amorphous crosslinked fibres. SEM analysis revealed that the fibres’ morphology was uncompromised by the crosslinking. A significant increase of tensile strength from 0.3 ± 0.08 MPa to 2.7 ± 0.8 MPa and 3.9 ± ...

Anais do XX Congresso Brasileiro de Engenharia Química, 2015

Journal of materials chemistry. B, 2024

Food Research International, Nov 1, 2023

Macromolecular Symposia, Nov 1, 2006

Page 1. Batch and Semicontinuous StyreneButadiene Emulsion Copolymerization Reactions Aluisio Pi... more Page 1. Batch and Semicontinuous StyreneButadiene Emulsion Copolymerization Reactions Aluisio Pinelli Filho,1 Odair Araujo,2 Reinaldo Giudici,1 Claudia Sayer*3 ... 1985, Suppl. 10/11, 105128. [5] E. Saldivar, O. Araujo, R. Giudici, C. López-Barrón , J. Appl. Polym. Sci. ...

Green Chemistry Letters and Reviews, Jan 2, 2022

ABSTRACT The silver nanoparticles (AgNPs) green synthesis has been investigated by selecting natu... more ABSTRACT The silver nanoparticles (AgNPs) green synthesis has been investigated by selecting naturally occurred reduction and stabilizing/capping agents. In this work, Ilex paraguariensis aqueous extract in the one-step biosynthesis of AgNPs is reported. The synthesis was carried out at room temperature under different pH (5.0, 6.8 and 8.5) and extract concentrations (2.5, 5.0 and 7.5% v v−1) resulting in average diameters ranging from 34 to 144 nm and polydispersity index (PDI) up to 0.51. The morphological characterization was performed by Transmission Electron Microscopy, associated with the UV–Vis Spectroscopy, showing that at higher pH the shape of AgNPs was more spherical rather than ellipsoidal. X-ray diffraction (XRD) pattern of AgNPs exhibited 2θ values corresponding to silver nanocrystals. Colloidal AgNPs solution synthesized with pH 8.5 and extract concentration of 2.5% v v−1 remained stable for 10 months of storage at ambient temperature. Fourier Transform Infrared Spectroscopy suggested that the polyphenols were responsible for the AgNPs formation. AgNPs presented bacteriostatic and bactericidal activity. AgNPs presented in vitro rat brain acetylcholinesterase (AChE) activity, with higher inhibition potential at 200 µL. So, it is concluded that AgNPs were synthesized with success, the pH and extract concentration influences in AgNPs size and morphology, consequently in its antimicrobial and AChE activity. GRAPHICAL ABSTRACT

Industrial & Engineering Chemistry Research, Jul 15, 2019

1,2-Limonene oxide was synthesized for the first time via epoxidation reactions of (R)-(+)-limone... more 1,2-Limonene oxide was synthesized for the first time via epoxidation reactions of (R)-(+)-limonene mediated by a new immobilized preparation with low-cost material from Candida antarctica lipase f...

European Polymer Journal, Apr 1, 2023

Anais do Congresso Brasileiro de Engenharia Química, Sep 26, 2014

Pharmaceutical Development and Technology, Apr 23, 2019

The current paucity of effective and affordable drugs for the treatment of leishmaniasis renders ... more The current paucity of effective and affordable drugs for the treatment of leishmaniasis renders the search for new therapeutic alternatives a priority. Gallic acid related compounds display anti-parasitic activities and their incorporation into drug carrier systems, such as polymeric nanoparticles may be a viable alternative for leishmaniasis treatment. Therefore, this study focused on the synthesis and characterization of octyl gallate (G8) loaded poly(methyl methacrylate) (PMMA) nanoparticles via miniemulsion polymerization in order to increase the leishmanicidal activity of this compound. G8 laoded PMMA nanoparticles presented a spherical morphology with a mean size of 108 nm, a negatively charged surface (-33 ± 5mV) and high encapsulation efficiency (83% ± 5). FTIR and XRD analysis confirmed that G8 was encapsulated in PMMA nanoparticles and presented a biphasic release profile. The G8 loaded PMMA nanoparticles did not present cytotoxic effect on human red blood cells. G8 loaded PMMA nanoparticles displayed a leishmanicidal activity almost three times higher than free G8 while the cytotoxic activity against human THP-1 cells remained unchanged.