Synthesis of polar polynorbornenes with high dielectric relaxation strength as candidate materials for dielectric applications

Polar polynorbornenes prepared by ring-opening metathesis polymerization show thermally switchable dielectric permittivity. The polymers exhibit a large dielectric relaxation strength and high glass transition temperature.

Enhancing the mechanical strength and toughness of epoxy resins with linear POSS nano modifiers

Glass transition temperature (Tg) is always deteriorated while improving the strength of epoxy resins which inherently suffered from brittleness. Herein, a novel linear polyhedral oligomeric silsesquioxane (POSS)-epoxy nano modifiers is...

О вакансионной природе высокотемпературного фона внутреннего трения в твердых телах

High-temperature internal friction in an amorphous CuTi alloy is investigated. Exponential regions with different activation energies are observed on the dependence of internal friction on temperature on both sides of the glass transition temperature. An exponential increase in the background of internal friction with temperature in both sites is associated with the migration of vacancy-like defects in the amorphous structure under the influence of mechanical stresses, while frozen defects of constant concentration migrate to the glass transition temperature. After the transition to a state of thermodynamic equilibrium , the concentration the number of migrating defects increases exponentially. Based on the experimental results of measuring the high-temperature background, estimates of the activation energy of migration and the formation of vacancies of similar defects in the amorphous structure of the alloy under study are made.