New multi-block isophorone diisocyanate-based copolymers with urethane urea hard segments

Abstract

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.