Lincoln Almeida Cavalcante

Polymeric materials are of great value as they are widely used in everyday society, making it important to synthesize and characterize these materials to enhance them. Galactomannan (Gal), for example, is a neutral natural polymer isolated from the legume endosperm and has substantial use in biomedical, food, cosmetic, and pharmaceutical industries. This research objective was to evaluate the influence of the addition of glycerin on Gal's thermal properties. The material was prepared using heating solutions of pure Gal containing the following glycerin contents: 0.5 and 1.0 mL. Characterizations were performed using Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Thermal analysis shows that Gal does not have glycerin in its composition and vitrifies rapidly with the rise of temperature, a process not observed in Gal containing glycerin. Therefore, Gal without the addition of plasticizer presents better characteristics to be applied as glue.

Galactomannans are neutral natural polymers isolated from legume endosperm and with wide use in the biomedical field. As a consequence, there is a need to investigate materials for their properties in order to better understand and apply them. In this study, we analyzed the influence of pH medium on the crosslinking process of galactomannan and glutaraldehyde, changing the pH medium from 3 to 7, using a strong base. The Fourier Transform Infrared Spectrum (FTIR) and the swelling profiles of the glutaraldehyde crosslinked galactomannan were evaluated. We have found that the glutaraldehyde-galactomannan crosslinking process is highly sensitive to the variation of pH medium. According to our results, best swelling capacity was achieved for samples prepared at pH=5, suggesting that this pH medium conditions is suitable for possible production of hydrogels prepared from glutaraldehyde-galactomannan.

The study's aim was to synthesize a crystalline film formed by L‐threonine crystals complexed with Cu²⁺ ions (LTCu) dispersed in a galactomannan (Gal) solution as well as to characterize its structural, vibrational, and thermal properties. Gal(LTCu) films were prepared by the addition of copper II L‐threoninate crystals in concentrations of 0.25, 0.50, and 0.75 in 2% Gal solution. To characterize the Gal(LTCu) properties, we used X‐ray diffraction (XRD), UV–Vis and Raman spectroscopy, thermogravimetry, and thermal analyses (TG‐DTA). XRD showed that the Gal(LTCu) films are crystalline and have acquired coloration similar to the one of LTCu crystal. The UV–Vis spectra revealed that the films tend to assume a square planar conformation due to Jahn Teller effect. Bands related to the interaction between the metal ion with the organic compounds were observed through the Raman spectra. TG‐DTA showed that the films exhibit low thermal stability due to the dehydration process. POLYM. ENG. SCI., 60:71–77, 2020. © 2019 Society of Plastics Engineers