Polytriazole Elastomers Based on Akyne-Terminated Polyethylene Glycol

Elastomers have a wide range of applications and a large market capacity, while general-purpose elastomers have the disadvantages of poor heat resistance and complex synthesis processes. Compared with traditional elastomer, polytriazole elastomer (PTAE) has the advantages of good heat resistance and simple synthesis, while the existed PTAE has poor mechanical properties (tensile strength ＜10 MPa). In order to obtain PTAE with excellent mechanical properties, a series of novel PTAEs with soft segments and hard segments alternately distributed along the main chain were synthesized via a metal-free 1,3-dipolar cycloaddition reaction. Based on the structural characteristics, alkynyl-terminated polyethylene glycol (DPPEG) with various amounts of polyether segments, biphenyl dibenzyl azide (BPDBA) with rigid aromatic rings and diethynylbenzene (m-DEB) were employed as soft segments, hard segments, and chain extender, respectively. The PTAEs possess good mechanical properties and thermal stability. With the increase of the DPPEG molar content, the tensile strength decreases from 16.27 MPa to 1.70 MPa, the elongation at break first increases and then decreases, ranging from 249% to 990%. And with the increase of DPPEG molecular weight, the tensile strength first increases and then decreases, ranging from 0.80 MPa to 22.5 MPa, and the elongation at break first decreases and then increases, ranging from 196% to 325%. Although the thermal stability of PTAE decreases with the increase of molar content and molecular weight of DPPEG, the decomposition temperature of 5% mass loss still exceeds 335 ℃, which proves that the structure has good thermal stability. The glass transition temperature of PTAE is less than 10 ℃ , which can maintain elasticity at room temperature.