Manganese and Nickel Acetylacetonates as Curatives for Chloroprene Rubber Based on Heck’s Reaction

The commonly used curing system for chloroprene rubber (CR) is a combination of two metal oxides, such as magnesium oxide (MgO) and zinc oxide (ZnO). Application of MgO and ZnO enables to obtain a good balance between processability of rubber compounds and mechanical properties of the vulcanizates. Despite high activity in crosslinking reactions, ZnO is classified as ecotoxic to aquatic organisms, thus environmental legislation requires its quantity in technology to be limited. In our studies more environmentally friendly curing systems were applied, which enabled eliminating ZnO from CR compounds. These curing systems consisted of manganese acetylacetonate (Mn(acac)) or nickel acetylacetonate (Ni(acac)) and triethanolamine (TEOA) used as a base necessary to perform Heck’s reaction. Both metal acetylacetonates exhibited high activity in crosslinking reactions, which was confirmed by a great torque increment during rheometric measurements and high degree of elastomer crosslinking. The type of metal acetylacetonate and the amount of TEOA seemed to have less influence on the efficiency of the curing system than the filler used. Rubber compounds filled with carbon black (CB) were characterized by definitely shorter optimal vulcanization times and higher degree of crosslinking compared to CR composites filled with nanosized SiO2. Moreover, application of the proposed curing systems allowed to obtain CR vulcanizates with mechanical properties comparable with the benchmarks cured with metal oxides.

FeNi3 Nanoparticle for the Localization of Temporal Lobe Epilepsy by MRI

From the perspective of targeting factors, iron acetylacetonate and nickel acetylacetonate were used as major materials, and oleylamine was used as a solvent. Through thermal decomposition, the uniformly distributed nanoparticle FeNi3 was obtained. Then, the α-methyltryptophan (AMT) was used to modify FeNi3, thereby the material (FeNi3-AMT) would be biocompatible. The prepared material was used as a targeting factor to explore whether it could target the epileptogenic focus in temporal lobe epilepsy model rats. In the experiment, the animal models of temporal lobe epilepsy were constructed by using the lithium chloride-pirocarpine method. According to the injection of the nuclear magnetic factor, the models were divided into the FeNi3 group, the FeNi3-AMT group, and the saline group. The model rats received intravenous injections 48 hours after the onset of epilepsy. The activity of the epileptic seizure sites before and after injection, the penetration of nanoparticles, and the toxic and side effects of the material were compared. The results showed that the rat models of temporal lobe epilepsy were successfully constructed (the success rate was more than 85%). Meanwhile, the epilepsy lesions of the rat models added with nanoparticles were darker (P < 0.05). The staining of rat brain sections confirmed the distribution of iron particles. In the FeNi3-AMT group, there were more iron particles distributed (P < 0.05). In addition, various abnormal neurons appeared in the hippocampus of the three groups, and there was no significant difference between the different groups (P < 0.05). There was no significant difference in the number of positive neurons in the CA3 region of the brain between different groups (P < 0.05). However, the imaging effect based on FeNi3-AMT was more prominent (P < 0.05), which confirmed that the FeNi3-AMT group had better targeting location effects. The study confirmed that the iron nano alloy particle material had excellent application values in the localization of temporal lobe epilepsy.

Deposition of Ni nanoparticles onto porous supports using supercritical CO 2 : effect of the precursor and reduction methodology

The deposition of Ni nanoparticles into porous supports is very important in catalysis. In this paper, we explore the use of supercritical CO 2 (scCO 2 ) as a green solvent to deposit Ni nanoparticles on mesoporous SiO 2 SBA-15 and a carbon xerogel. The good transport properties of scCO 2 allowed the efficient penetration of metal precursors dissolved in scCO 2 within the pores of the support without damaging its structure. Nickel hexafluoroacetylacetonate hydrate, nickel acetylacetonate, bis(cyclopentadienyl)nickel, Ni(NO 3 ) 2 ⋅6H 2 O and NiCl 2 ⋅6H 2 O were tried as precursors. Different methodologies were used: impregnation in scCO 2 and reduction in H 2 /N 2 at 400°C and low pressure, reactive deposition using H 2 at 200–250°C in scCO 2 and reactive deposition using ethanol at 150–200°C in scCO 2 . The effect of precursor and methodology on the nickel particle size and the material homogeneity (on the different substrates) was analysed. This technology offers many opportunities in the preparation of metal-nanostructured materials.