V. A. Zhorin

Heat processes in mixtures of polymers with cyanuric acid after plastic deformation under high pressure according to calorimetric data

Mixtures of cyanuric acid with different polymers are subjected to plastic deformation under pressure of 1 GPa, and the DSC method is used to establish that endothermal processes with enthalpies that can reach 50 J g-1 occur in deformed mixtures under heating in the range of 50–250°C. The occurrence of endothermal processes is related to the destruction of intermolecular bonds formed at the acid–polymer interface and due to formation of double electric layers and appearance of interphase electrostatic attraction.

Thermal effects in mixtures of aluminum with polyvinyl chloride after plastic deformation under high pressure

PVC and mixtures of PVC with aluminum of different compositions were subjected to plastic deformation under a pressure of 0.5–3.0 GPa using setups of Bridgman anvil type. DSC data showed that ΔCp in the polymer was doubled and Tc increased by 20°C. Chemical reactions occurred on the interfaces of freshly opened metal surface/polymer phase under pressure treatment in the mixtures. They were accompanied by formation of volatile and soluble products. When metal-polymer mixtures were heated under pressure after deformation, chemical reactions occurred in them starting at 40°C and reaching the maximum intensity in the temperature range of polymer transition from the vitreous to highly elastic state. Thermogravimetric studies of mixture samples of different compositions were carried out.

Activation of Thermal Processes in Mixtures of Some Vanadium Compounds with LiOH as a Result of Plastic Deformation under High Pressure

V2O5, V2O3, HVO3, and mixtures of these compounds with 15% LiOH were subjected to plastic deformation at a pressure of 2 GPa and room temperature on high-pressure testing machines of the type of Bridgman anvils. The investigation of the samples was performed using differential scanning calorimetry, thermogravimetry, and X-ray diffraction analysis. The presence of LiOH in the mixtures decreased the thermal stability of vanadium compounds. During plastic deformation the LiV3O8 phase was formed in mixtures, the amount of which increased with heating the samples to 200°C. It is assumed that the ions that form by treatment under pressure can affect the structure formation processes in mix samples.

A study of the mixtures of polystyrene and polyvinyl fluoride with aluminum after plastic deformation under high pressure using DSC and thermogravimetry

Mixtures of powdered polystyrene and polyvinyl fluoride with aluminum exposed to plastic deformation under pressure of 1 and 4 GPa, have been studied by DSC and thermogravimetry. It has been established that, in the deformed mixtures at temperatures up to 200°C, exothermal processes take place. Interaction between polymer decomposition products and aluminum has been studied, as have its oxidation and nitrogenation.

Thermally induced processes in mixtures of aluminum with organic acids after plastic deformations under high pressure

DSC is used to measure the thermal effects of processes in mixtures of solid organic dibasic acids with powdered aluminum, subjected to plastic deformation under pressures in the range of 0.5–4.0 GPa using an anvil-type high-pressure setup. Analysis of thermograms obtained for the samples after plastic deformation suggests a correlation between the exothermal peaks observed around the temperatures of degradation of the acids and the thermally induced chemical reactions between products of acid degradation and freshly formed surfaces of aluminum particles. The release of heat in the mixtures begins at 30–40°C. The thermal effects in the mixtures of different acids change according to the order of acid reactivity in solutions. The extreme baric dependences of enthalpies of thermal effects are associated with the rearrangement of the electron subsystem of aluminum upon plastic deformation at high pressures.

A calorimetric study of the process of formation of a supramolecular high-density polyethylene structure in mixtures with different oxides after plastic deformation under high pressure

Mixtures of ultrahigh-molecular-weight polyethylene with 95 wt % oxides of different elements were subjected to plastic deformation under the pressure of 1 GPa at a high pressure device of the Bridgman anvil type and thermal effects were studied using the DSC technique. Thermograms contained exothermic peaks with a maximum at 50–90°C related to cold crystallization of the polymer. The process of polymer fusion was described by two peaks with the maximums at T1 = 125–128°C and T2 = 136–139°C. The low-temperature peak was related to fusion of a structure with high amounts of defects formed on the oxide surface.

X-ray Diffraction and Calorimetric Study of Al-Cu Mixtures Subjected to Plastic Deformation under High Pressure

Aluminum-copper mixtures of various compositions are subjected to plastic deformation at room temperature and pressures from 1 to 5 GPa in a high-pressure apparatus of Bridgman anvil type. According to X-ray analysis, an ultradispersed structure with a coherent scattering region size of 10 to 20 nm is formed in the samples, with hardness of the material being as high as 530 kgf/mm2. Differential scanning calorimetry measurements show that heating from 25 to 285°C induces exothermic process in the samples subjected to deformation with a specific enthalpy of 120 J/g.