The ultimate mechanical properties of polyurethane determine their possible applications under various conditions of mechanical action. The mechanical properties of nine polyurethane and polyurethane urea samples were investigated in a range of stretching rates 0.56÷0.002 s −1 . A part of experiments was performed at several temperature values under conditions of stepwise variable stretching rates. The interrelationship between rate dependence of strength-strain properties of polyurethane compositions and the structure thereof was ascertained. The influence of molecular structure's variations, of physical network density and of segmented polyurethane and polyurethane urea morphology on said interrelationship was examined on samples subjected to large strain values. The structure of some samples was radically distorted by plasticizers oppositely influencing micro-phase segregation of soft and hard segments. Multiple kinds of dependency (direct, inverse, moderate and strong) of elastomers' strength versus stretching rate were demonstrated. Produced data and ascertained regularities are useful to perceive reasons for diversity of mechanical behavior of polyurethane materials and to control properties thereof.

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Segmented polyurethane ureas (SPUUs) were synthesized on the base of oligopropylene oxide (PPO), oligotetramethylene oxide (PTMO), 2,4-toluene diisocyanate, isophorone diisocyanate (IDI), and methylene- o-chloroaniline. Structure of polymer chains with thermodynamically compatible PTMO and PPO soft segments (SS) was identified using data from rheokinetic studies of reactionary mixes with different diisocyanates. The significant swelling value in low-polar solvent toluene and non-elevated softening temperature indicates the formation of loose (defect) structure of the hard phase in compositions, synthesized using IDI. Thermal, thermomechanical, and physicomechanical properties of SPUU with variable compositions of hard segment and SS (blocks) were investigated. An interrelation between structure and properties of block copolymers of new type was estimated. Investigation results showed a significant increase in the strength of polyurethane urea at the equimolar ration between various hard blocks and SS on the base of PPO and PTMO. High strength values were obtained for SPUU in a wide diapason of stretching rates (0.56–0.003 s−1). Structural factors contributing to stability of strength properties of tetrablock-copolymers, namely: stronger inter-chain interaction in the soft phase and a “loose” structure of the hard phase. were revealed. The data relating to elevation of thermostability of these materials were given. New materials can be applied for various conditions of mechanical loading.

A number of novel fluorophores have been synthesized containing an electron‐withdrawing pyrimidine core and electron donating N,N‐dimethylaminophenyl, 4‐(9H‐carbazol‐9‐yl)phenyl, phenyl and pyrrol‐1‐yl fragments at positions 2, 4 and 6 of the pyrimidine ring. Thermal, optical and electrochemical properties of these substances have been studied. The structure‐property dependences of substituted pyrimidines have been established.

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