Silane-functionalized graphene nanoplatelets for silicone rubber nanocomposites

Silane-functionalized graphene nanoplatelets (GNPs) were prepared using a newly developed approach based upon a simple two-step strategy. The effect of their dispersion and interfacial bonding on the mechanical properties and thermal conductivity of reinforced silicone rubber (SR) was investigated. It was found by Raman mapping that the silane-functionalized GNPs could be dispersed uniformly into the SR matrix, leading to an increase of up to 25% in Young’s modulus at only 2 parts per hundred rubber (phr) loading and a considerable enhancement of up to 150% in the thermal conductivity at 5-phr loading. Both the Young’s modulus and thermal conductivity experimental results were found to be in agreement with the values predicted using theoretical models. Graphical abstract

Evaluation of the Miscibility of Novel Cocoa Butter Equivalents by Raman Mapping and Multivariate Curve Resolution–Alternating Least Squares

Cocoa butter (CB) is an ingredient traditionally used in the manufacturing of chocolates, but its availability is decreasing due to its scarcity and high cost. For this reason, other vegetable oils, known as cocoa butter equivalents (CBE), are used to replace CB partially or wholly. In the present work, two Peruvian vegetable oils, coconut oil (CNO) and sacha inchi oil (SIO), are proposed as novel CBEs. Confocal Raman microscopy (CRM) was used for the chemical differentiation and polymorphism of these oils with CB based on their Raman spectra. To analyze their miscibility, two types of blends were prepared: CB with CNO, and CB with SIO. Both were prepared at 5 different concentrations (5%, 15%, 25%, 35%, and 45%). Raman mapping was used to obtain the chemical maps of the blends and analyze their miscibility through distribution maps, histograms and relative standard deviation (RSD). These values were obtained with multivariate curve resolution–alternating least squares. The results show that both vegetable oils are miscible with CB at high concentrations: 45% for CNO and 35% for SIO. At low concentrations, their miscibility decreases. This shows that it is possible to consider these vegetable oils as novel CBEs in the manufacturing of chocolates.

WO3 as Additive for Efficient Photocatalyst Binary System TiO2/WO3

Two different methods of synthesis of TiO2/WO3 heterostructures were carried out with the aim to increase photocatalytic activity. In this study, anodic TiO2 nanotube films were synthesized by electrochemical anodization of titanium foil. WO3 particles were applied to anodic Ti/TiO2 samples in two different ways – by electrophoretic deposition (EPD) and insertion during the anodization process. Structural and photocatalytic properties were compared between pristine TiO2 and TiO2 with incorporated WO3 particles. Raman mapping was used to character-ise the uniformity of EPD WO3 coating and to determine the structural composition. The study showed that deposition of WO3 onto TiO2 nanotube layer lowered the band gap of the binary system compared to pristine TiO2 and WO3 influence on photo-electrochemical properties of titania. The addition of WO3 increased charge carrier dynamics but did not increase the measured photo-current response. As the WO3 undergoes a phase transition from monoclinic to orthorhombic at approximately 320 ℃ proper sequence WO3 deposition could be beneficial. It was observed that secondary heat treatment of WO3 lowers the photocurrent.