Toughening of a polytriazole resin with diprogargyl poly(propylene glycol)s

The rapid development of aerospace technology has put demands on the high tough thermosetting resins. Polytriazole (PTA) resins are a kind of high performance thermosetting resins as matrices of structural composites for aerospace parts. It is necessary to develop polytriazole resins with high toughness. In this paper, propargyl‐terminated polypropylene glycols (PtPGs) with various molecular weights (PtPG400, PtPG600, PtPG725) were synthesized and characterized. A series of PtPG‐toughened polytriazole (PPTA) resins were prepared by the “Click” reaction of PtPG and N,N,N′,N′‐tetrapropargyl‐4,4′‐diaminodiphenylmethane (TPDDM) with 1,1‐bisazidomethyl‐4,4′‐biphenyl (BAMBP). The curing behavior of the PPTA resins and the thermal, mechanical, as well as water absorption of the cured PPTA resins were investigated. The results show that the PPTA resins have excellent processing properties and can be cured and molded at 80°C. The molecular weight and the amount of PtPG have a significant influence on the mechanical properties of PPTA resins. When PtPG600 with the molar ratio of alkyne groups 1.0% is formulated, the impact strength of the cured PPTA‐600‐1.0 resin reaches 63.6 ± 8.2 kJ·m−2 and KIC 2.57 MPa·m−1/2, which are 57.4% and 41.2% higher than those of PTA resin respectively. The glass transition temperature (Tg) and water absorption of the cured PPTA‐600‐1.0 resin are 223.8°C and 0.22% respectively. Toughened polytriazole resins with heat resistance and low water absorption