Study on Preparation and Properties of Polyether Polytriazole Elastomer

To explore the application of click chemistry in the field of elastomer materials, propargyl-terminated ethylene oxide-tetrahydrofuran copolymer （PTP（E-co-T）） was prepared from hydroxyl-terminated ethylene oxide-tetrahydrofuran copolymer （P（E-co-T）） by end-etherisation modification. FTIR and ^13C-NMR results indicate that P（E-co-T）-terminated hydroxyl was etherified thoroughly, yielding the target product PTP（E-co-T）, and the content of terminated alkynyl of PTP（E-co-T） was evaluated to be 0.428 mmol.g^-l. Using a polyazide compound as a cross-linker, polytriazole elastomers with various functional molar ratio （R） values were prepared from PTP（E-co-T） by virtue of the CuAAC reaction. Mechanical property tests indicate that with the increase in R, the modulus E and stress Orb of the polytriazole elastomers first increase and subsequently decrease, whereas the strain first decreases and later increases. The mechanical properties of the polytriazole elastomers show a parabolic dependence on the R value. Near the stoichiometric ratio, E and Orb show maxima and the strain εb shows a minimum. Swelling tests demonstrate that the apparent molecular weight of polytriazole elastomer strands also first decreases and subsequently increases. At the stoichiometric ratio, the network structure possesses strands with a minimum apparent molecular weight and a maximum apparent density. Dynamic mechanical analysis reveals that the polytriazole elastomers presented damping peaks at approximately -64℃, corresponding to the glass transition of copolyether strands, and the elastomer exhibited the lowest dissipation factor tanδ at the stoichiometric ratio. Thermal analysis suggests that the weight-loss process of the polytriazole elastomer is characteristic of one-step decomposition, and the elastomer begins to decompose from polyether strands, not triazole groups.