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The aim of this research is to study the thermal degradation kinetics and some physicochemical properties of starch nanoparticles (SNPs) produced from potato starch (PS) by nanoprecipitation. Native PS is used as a control. The powder samples are analyzed by means of light and transmission electron microscopies, X‐ray diffraction, Fourier transform infrared, and thermogravimetric analysis. PS shows oval and spherical granular shaped with a diameter between 6 and 18 µm, whereas SNPs display spherical and elliptical shapes with particle sizes between 50 and 150 nm. The relative crystallinity is 25.4% to PS, and it decreases to approximately 23.5% for SNPs. Activation energy (E) associated to the water evaporation and thermal degradation is calculated using the Newton model as well Ozawa‐Flynn‐Wall (OFW) and Kissinger‐Akahira‐Sunose (KAS) models, respectively. The E values using the Newton model increase from 43.7 kJ mol−1 (PS) to 84.1 kJ mol−1 (SNPs). The E values using the OFW and KAS models vary between 165 and 227 kJ mol−1 for PS, and between 180 and 400 kJ mol−1 for SNPs. Modifications in E values are associated with the increase in surface area in SNPs. This research reports new information of the thermal properties of SNPs.

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Se prepararon membranas de Polivinil Difluoruro y Acido Hipofosforoso (PVDF/H3PO2) con diferentes concentraciones de ácido. Los resultados de calorimetría diferencial de barrido (DSC), presentan un escalón característico de la transición vítrea alrededor de 250 K. También se observan dos anomalías endotérmicas: una cercana a 357 K debido a la evaporación de agua, y otra cerca a los 422 K atribuida a la fusión de la fase cristalina del PVDF. Los análisis de Espectrometría de masas (MS) acoplado con Termogravimetría (TGA), revelan la posible presencia de moléculas de (C2H2O) y ácido fluorhídrico (HF), esto plantea la posibilidad de que el H3PO2 perdió un átomo de hidrógeno y se enlazó a la cadena polimérica del PVDF desplazando un átomo de flúor. Se evidencia la presencia de moléculas de agua a diferentes temperaturas, que sugiere la formación de agua superficial, interna y estructural en el sistema polímero-acido. Esta característica, hace que el sistema PVDF/H3PO2 sea propuesto como electrolito solido en celdas de combustible.

Some physical properties of spider silks, including mechanical strength and toughness, have been studied in many laboratories worldwide. Given that this silk is organic in nature, composed of protein, and has similar properties to metal wires or polymers, it has the potential for application in medicine, nanoelectronics, and other related areas. In this study, we worked on spider silk from the Nephila clavipes species collected from the wild and kept it in the nursery of the Autonomous University of the West, Cali, Colombia, to determine its physical, thermal, and mechanical properties, seeking possible applications in the medical and industrial sectors and comparing the material properties of the silk from the species from southwestern Colombia with those of the previously studied species from other regions. The mechanical characterization of the material was performed using a universal testing machine; thermal behavior was captured by a thermogravimetric analysis, differential scanning calorimetry, and mass spectrometry; and structural characterization was performed using diffraction X-rays. The results of the thermal characterization demonstrate that the spider silk loses 10 % of water content at 150 °C with significant changes at 400 °C, while the mechanical characterization indicates that the spider silk is much tougher than Kevlar 49 and Nylon 6 since it is capable of absorbing more energy before rupture.