Synthesis of Propargyl-Terminated Polybutadiene and Properties of Polytriazole Elastomers

Compared with the traditional polyurethane curing system with polyisocyanate group and hydroxyl group prepolymer, the click chemistry curing system with the polyazide group and the terminal alkyne prepolymer has the advantages of single reaction selectivity and insensitivity to oxygen and water. In this paper, the propargyl-terminated polybutadiene (PTPB) has been synthesized by using hydroxyl terminated polybutadiene (HTPB), potassium t-butoxide and bromopropyne as raw materials, and the yield is 98.6 %. The polytriazole elastomers have been prepared through copper-catalyzed azide-alkyne huisgen [3+2] dipolar cycloaddition reactions between the propargyl-terminated polybutadiene (PTPB) as binder and azide (−N₃) compound as curing agent. Furthermore, the effects of catalyst type, azide functionality and curing parameters (R value) on elastomer properties are investigated by FTIR, DMA, TG, DSC and mechanical tests. It has been obtained that the crosslinking elastomer formed with the PTPB and azide of 3.8 functionality has better mechanical properties and thermal stability. When the molar ratio R of azide group to alkyne group in curing the PTPB is equal to 1, the PTPB elastomer has the biggest tensile strength and smallest tensile strain, and the change of the R value has little effect on the glass transition temperature and thermal stability of the PTPB elastomers.