Francisco Célio Feitosa de França

Antioxidant activity of cashew nut shell liquid (CNSL) derivatives on the thermal oxidation of synthetic cis-1,4-polyisoprene

CNSL is a mixture of meta-alkylphenols with variable degree of unsaturation attached to the benzene ring. The kinetic study of the thermal degradation at 140 °C of synthetic cis-1,4-polyisoprene film, in the presence of technical CNSL and some derivatives (cardanol, hydrogenated cardanol and alkylated hydrogenated cardanol) was carried out by FTIR. The amount of OH/OOH and C=O formed and also of C=C consumed during the degradation was determined. All materials increase the induction period and decrease the apparent rate constants of thermal-oxidation. Based on kinetic parameters, the order of antioxidant activity was: CNSL >> cardanol @ hydrogenated and alkylated cardanol > hydrogenated cardanol. The effect of CNSL could be attributed to the extra contribution of the other components besides cardanol and to the unsaturation on the long side chain. This greater activity is important because CNSL is much more cost effective than its derivatives.

Comparison between physico-chemical properties of the technical Cashew Nut Shell Liquid (CNSL) and those natural extracted from solvent and pressing

Cashew nut shell liquid (CNSL) is a by-product of the cashew kernel industry, applied mainly to produce polymeric derivatives. The technical CNSL (CNSLT) was obtained industrially, extracted by roasting the cashew nut shells at temperatures between 180 and 200 °C. Two methods were used to produce natural CNSL. For the extraction of CNSLNP, the cashew nut shells were pressed at room temperature. CNSLNS was extracted in hexane at room temperature and recovered at 50 °C. A comparison was made of the composition determined by HPLC and properties generated by viscosity measurements and also by TG, DSC and IPDT (integral procedural decomposition temperature). Natural CNSLs displayed higher content of cardol and anacardic acid and lower percentage of cardanol than CNSLT. The higher content of cardanol in CNSLNS was the major difference between natural CNSLs. CNSLNP had higher levels of impurity, higher viscosity, lower thermoxidative stabilities and lower ebullition temperature. The CNSL obtained by cold solvent extraction and recovery at 50 °C better preserves the original properties of the liquid.

Thermal Oligomerisation of Cardanol

Abstract Cardanol was extracted from technical Cashew Nut Shell Liquid (CNSL), a naturally occurring meta-substituted long chain phenol and oligomerized by heating at 140 °C. Products were characterized by rheology, infrared and 1H NMR spectroscopy and thermogravimetric analysis (TGA). Increase in viscosity and the flow activation energy was found with increasing time of heating. The relative absorbance of double bond of the hydrocarbon chain decreased with time of heating and indicated that the oligomerization is taking place through the unsaturation of the side chain. Decrease in internal double bond as well as in vinyl bond, observed by 1H NMR, pointed out to the participation of these two kinds of unsaturation as well as monoene, diene and triene. The oligomerization is a slow process. With 40 h of heating, the average molecular weight increases only by 46%. Great differences were found in TGA curves of cardanol with different times of oligomerization. Thermal stability increases with time of heating. The degree of oligomerization could be determined from relative mass loss of the first event of TG, or from flow activation energy.

Novos surfactantes alquil poliglicosídicos à base de amilose extraída da batata inglesa (Solanum tuberosum L.)

Alkyl polyglycosides (APGs) are new biodegradable surfactants, non-toxic, synthesized from abundant renewable sources, potentially more appropriate than anionic surfactants. A range of glycosides denoted APG-Cy was synthesized by the Koenig-Knorr reaction using C10, C16 and C18 alcohols and derived from the degradation of amylose from English potato. The molecular structures of the glycosides were characterized by Nuclear Magnetic Resonance (1H and 13C NMR) together with Infrared Spectroscopy (FTIR) and Gel Permeation Chromatography (GPC). The study by NMR allowed the junctions between hydrophilic head groups and hydrophobic tail-groups to be characterized in detail. Conformation of the glycosidic units is 4C1 type with a b anomeric configuration. The formation of glycosides with five glucose rings linked to the alkyl chain was confirmed by 1H NMR and GPC. Liquid crystals identified by the presence of double melting points were observed by Differential Scanning Calorimetry (DSC) showing thermotropic properties. The surface tension (γ) and critical micelle concentration (cmc) were determined by du Nouy method, noting that increasing the length of alkyl chain led to the expected reduction in the cmc. The energies of adsorption and micellization processes calculated from isotherms γ versus ln c (g.dm-3) indicate cooperativeness of hydrophilic and hydrophobic groups.

Binary Micellar Solutions of Poly(Ethylene Oxide)-Poly(Styrene Oxide) Copolymers with Pluronic® P123: Drug Solubilisation and Cytotoxicity Studies

The non-commercial copolymers E45S8, E45S17 and their mixtures with Pluronic® P123 (E21P67E21) were studied as carriers of the model drug griseofulvin. Critical micelle concentration (cmc) (dye solubilisation method), drug solubilisation capacity (Scp and Sh) determined by ultraviolet-visible (UV-Vis) spectroscopy and 1H nuclear magnetic resonance (1H NMR) and cytotoxicity (LDH activity in human neutrophils) were studied. E45S17 1.0 wt.% dispersions presented colloidal aggregates limiting its Scp in comparison to E45S8, but in 0.1 wt.% solutions this phenomenon seemed to be absent and E45S17 presented a higher Scp. The mixtures that showed the best Scp results contained 50% of P123 and presented low cmc. An evaluation of literature data suggested a minimum Em content of 62% in EmSn copolymers below which the increase of Sn length does not lead to an increase of Sh. The results suggested no toxicity of the copolymers on human neutrophils, supporting the use of P123 and poly(styrene oxide) containing copolymers as drug carriers.

Binary systems of Brij® surfactants with Pluronic® F127 as griseofulvin carrier

Ethanielda de L. Coelhoa, Carolina L. de Mouraa, Deyse de S. Maiaa, Tamara G. de Araújob, Francisco C. F. de Françac, Nadja M. P. S. Ricardoa, Maria Elenir N. P. Ribeiroa,* and Nágila M. P. S. Ricardoa Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, 60451-970 Fortaleza – CE, Brasil Departamento de Farmácia, Universidade Federal do Ceará, 60430-170 Fortaleza – CE, Brasil Faculdade de Educação, Ciências e Letras do Sertão Central, Universidade Estadual do Ceará, 63.900-000, Quixadá – CE, Brasil

SYNTHESIS AND CHARACTERIZATION OF ALKYLPHENYL POLYGLYCOSIDIC SURFACTANTS FROM AMYLOSE AND ALKYL PHENOLS EXTRACTED FROM NATURAL CNSL

The surfactants were synthesized by condensing the obtained oligosaccharides of amylose and alkyl phenols extracted from the natural cashew nut shell liquid (nCNSL). The Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR) data showed aromatic ring bands, glycosidic rings, olefins and paraffins. The Nuclear Overhauser Effect Spectroscopy (NOESY) experiments showed that the conformation of the glycosidic units is of the type 4C1 with an α anomeric configuration. The values of Gibbs free energy of micellization (ΔGomic) indicate that the spontaneity of formed micelles are cardanyl oligoglycosides > cardyl oligoglycosides > anacardyl oligoglycosides. The surface tension (γ) measurements showed that critical micelle concentration (cmc) values were low for surfactants. The study γ versus lnc (g dm-3) indicated that the aggregation behavior of the surfactants is dependent on their structural characteristics, as well as their thermal behavior. The area per molecule (A) values indicates that cardyl oligoglycosides are likely to form aggregates smaller than cardanyl oligoglycosides and anacardyl oligoglycosides. The critical packing parameter (cpp) indicates that the aggregates are of the vesicles and bilayers.