Novel branched azobenzene-modified POSS nanostructures have been prepared.

The article is concerned with hybrid amorphous polymers synthesized basing on epoxy oligomer of diglycide aliphatic ester of polyethylene glycol that was cured by polyethylene polyamine and lithium perchlorate salt. Structural peculiarities of organic-inorganic polymer composites were studied by differential scanning calorimetry, wide-angle X-ray spectra, infrared spectroscopic, scanning electron microscopy, elemental analysis, and transmission and reflective optical microscopy. On the one hand, the results showed that the introduction of LiClO4 salt into epoxy polymer leads to formation of the coordinative metal-polymer complexes of donor-acceptor type between central Li+ ion and ligand. On the other hand, the appearance of amorphous microinclusions, probably of inorganic nature, was also found.

In the present work, ion-conductive hybrid organic-inorganic polymers based on epoxy oligomer of diglycide aliphatic ester of polyethylene glycol (DEG) and lithium perchlorate (LiClO4) were synthesized. The effect of LiClO4 content on the electrophysical properties of epoxy polymers has been studied by differential scanning calorimetry (DSC) and broadband dielectric spectroscopy (BDS). The effect of LiClO4 content on the structure has been studied by wide-angle X-ray scattering (WAXS). It was found that LiClO4 impacts on the structure of the synthesized hybrid epoxy polymers, probably, by formation of coordinative complexes {ether oxygen-lithium cations-ether oxygen} as evidenced from a significant increase in their glass transition temperatures with increasing LiClO4 concentration and WAXS studies. The presence of ether oxygen in DEG macromolecules provides a transfer mechanism of the lithium cations with the ether oxygen similar to polyethylene oxide (PEO). Thus, the obtained hybrid polymers have high values of ionic conductivity σ' (approximately 10−3 S/cm) and permittivity ϵ' (6 × 105) at elevated temperatures (200°С). On the other hand, DEG has higher heat resistance compared to PEO that makes these systems perspective as solid polymer electrolytes able to operate at high temperature.PACS81.07.Pr; 62.23.St; 66.30.hk

Polymer mixtures are an important object of scientific and industrial interest and doping with salts is a common way to implement composite conductivity. The structure and properties of composites based on oligomers of different molecular weight, namely amorphous diglycidyl ether of poly(ethylene glycol) (DEG-1, Mw  372 g/mol) and highly crystalline poly(ethylene glycol) (PEG, Mw  10,000 g/mol), and Li + ions have been investigated. Polymeric organic-inorganic systems have been investigated by differential scanning calorimetry (DSC), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), and broadband dielectric spectroscopy. Using DSC and WAXS methods, it has been shown that composites with PEG have an amorphous-crystalline structure. The average crystallite size is 4.0 nm according to the study of WAXS. The DSC method revealed a decrease in the degree of PEG crystallinity in the composite due to the plasticizing ability of DEG-1 and the interaction of PEG with lithium perchlorate salt. Using the SAXS method, it has been established that there are regions of heterogeneity with a size of 95-130 nm in the volume of the studied composites. Studies of the electrical characteristics of polymer systems have shown that the doping of the composite with a lithium salt leads to an increase in the conductivity of the samples by two orders of magnitude. The temperature dependences of the conductivity at direct current for the studied composites do not obey the Arrhenius dependence and are analyzed using the Vogel-Tamman-Fulcher equation. The studied composites can be attributed to fragile.

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Kinetic methods for analyzing the curing process of thermosetting polymer systems are an important area for controlling the formation conditions for viscosity, which depends on the temperature and chemical composition of the composite. The curing reactions determine the morphology and structure of the system, affecting the properties of the final material. This work analyzes the curing process of po­lymer composites based on epoxy oligomer - polyethylene glycol diglycidyl ether (DEG), polyethylene polyamine hardener (PEPA) and lithium perchlorate salt LiClO4. The initial components, the mixture of DEG/PEPA composition and the DEG/PEPA/LiClO4 system supplemented with salt were investigated. Using the methods of Fourier-transform infrared spectroscopy and rheological analysis in dynamic mode the curing conditions of the systems were established. It was shown that the nature of the distribution of vibration bands in the IR spectra of the DEG/PEPA and DEG/PEPA/LiClO4 systems is a superposition of the IR spectra of the initial components. Lithium perchlorate in the salt-doped initial system is in an undissociated state and dissociates in the polymer matrix over time during the curing of the system. In particular, the time dependences of the concentration of epoxide groups in the DEG/PEPA system calculated using the integral intensity ratios were analyzed by IR spectroscopy data. To study the curing process with increased segmental mobility of the reacting macromolecules, rheokinetic measurements were performed at 50°C. Analysis of the nature of changes in the elastic and viscosity moduli over time allowed us to estimate the gel time of the initial and doped systems. Differences in the IR spectra for both systems before the formation of the three-dimensional structure and at the gel point, as well as the IR spectra of these systems after the curing reaction, were analyzed. Attention was also paid to the nature of the influence of dopant on the curing process and its state in the mixture/composite of DEG/PEPA/LiClO4 composition. Lithium perchlorate LiClO4 is an effective catalyst for the aminolysis of the oxirane ring, which explains the acceleration of the curing reaction of the system in the presence of salt.