Abstract
Propargyl terminal Polybutadiene (PTPB) was successfully prepared through hydroxyl terminal polybutadiene (HTPB) end-capping modification. The FTIR and 13C NMR results indicated that the HTPB terminal hydroxyl was thoroughly replaced and yielded the target product, PTPB, with a theoretical propargyl content of 0.66 mmol g−1. In comparison with HTPB, PTPB has a lower viscosity. Using 1,6-diazide hexane as a curing agent, polytriazole crosslinked polybutadiene (PTriPB) elastomers with various functional molar ratios (R) were prepared by CuAAC reaction, and the glass transition temperatures of the resultant PTriPB elastomers were approximately −75 °C, measured by differential scanning calorimetry (DSC), nearly independent of elastomer R values. Mechanical tests indicated, that with the increase in R, the mechanical properties of PTriPB elastomers exhibit a parabolic dependence on R. In addition, the thermal stability of PTriPB elastomers were also studied. The findings revealed some fundamental features of polytriazole crosslinking elastomer prepared by CuAAC reaction.
Highlights
Polybutadiene is a very important liquid rubber because of its hydrolytic resistance and higher flexibility at low temperatures, raised from its segment hydrophobic character and low glass transition temperature; it has been used in a wide array of applications, such as for sealants, binders, adhesives, waterproof and anticorrosion coatings, foams, electrical insulation, elastomers, etc. [1]
The findings revealed some fundamental features of polytriazole crosslinking elastomer prepared by Keywords: propargyl terminal polybutadiene; polytriazole polybutadiene elastomers; mechanical properties; thermal stability
Reshmi used a little amount of cuprous iodide (CuI) solution of acetonitrile as a catalyst and prepared a CuAAC end-crosslinked propargyl terminated polytetramethylene oxide elastomer, using glycidyl azide polymer as a cross-linker [14]
Summary
Polybutadiene is a very important liquid rubber because of its hydrolytic resistance and higher flexibility at low temperatures, raised from its segment hydrophobic character and low glass transition temperature; it has been used in a wide array of applications, such as for sealants, binders, adhesives, waterproof and anticorrosion coatings, foams, electrical insulation, elastomers, etc. [1]. Schubert directly used CuOAc as the catalyst, and bulk polymerized multifunctional alkynes and azides through CuAAC reaction, and obtained a series of step-growth polymers [13]. These polymers contain a great quantity of triazole ring structure with a high glass transition temperature and cannot be used as elastomers. Reshmi used a little amount of cuprous iodide (CuI) solution of acetonitrile as a catalyst and prepared a CuAAC end-crosslinked propargyl terminated polytetramethylene oxide elastomer, using glycidyl azide polymer as a cross-linker [14]. Using a cuprous hexafluoroacetylacetonate cyclooctadiene as the catalyst and 1,6-diazide hexane as the curing agent, polytriazole crosslinked polybutadiene elastomers (PTri PB) were prepared through bulk CuAAC reaction, under conventional conditions. The structures and properties of PTri PB elastomers were studied in detail
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