A modified polyurethane elastomer using polyfunctional HTPB synthesized by in-situ nitroxide mediated polymerization of 1,3-butadiene

Abstract

Abstract In-situ nitroxide mediated polymerization (NMP) of 1,3-butadiene was carried out in the presence of tetraethylenepentamine (TEPA) as a tri-functional nitroxide precursor, which furnished a high degree of hydroxy functionality. The multi-modal molar mass distribution of the product was elucidated by reductive hydrolyzation of the oligomeric product. The new polyfunctional hydroxyl-terminated polybutadiene (PFHTPB) was characterized and used in preparation of an HTPB-based polyurethane (PU). The effects of this new HTPB on mechanical and dynamic-mechanical properties of its corresponding polyurethane elastomer were studied. The mechanical and dynamic-mechanical characterization of the elastomer was evaluated by tensile and dynamic mechanical thermal analysis (DMTA) tests. A significant enhancement in mechanical properties of the elastomeric product with a small increase in the glass transition temperature was achieved using PFHTPB. In addition, there was a significant decrease in loss of the tangent value over the use of PFHTPB, compared to industrial HTPB, due to an efficient increase in crosslink density of the PFHTPB-based PU elastomer. The thermal stability of PFHTPB-based PU was comparable with its corresponding HTPB-based PU elastomer.