Carbon black-filled and unfilled carboxyl-terminated polybutadiene (CTPB) networks were prepared by using two types of reactive systems at different reactive group ratios to be applied to the solid propellant motor case as a liner. For the preparation of CTPB networks, tris(2-methyl-1 aziridinyl)phosphine oxide (MAPO) and a mixture of liquid bisphenol A-epichlorohydrin (Epikote-828) and MAPO were used as two different reactive systems. The chemistry and thermal stability of the CTPB networks were followed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG) techniques, whereas mechanical and adhesive properties were tested by tensile measurements. The mixed reactive system caused a modification in the ultimate tensile stress and elongation-at-break properties, adhesive properties, and thermal stability of the CTPB networks. It was understood that this modification was due to the inter-and intramolecular bridge formation via the end-linking reaction of Epikote-828 with amine groups of the former network chains. The combination of MAPO with Epikote-828 also imparted better peel and lap-shear strength properties to the CTPB elastomers.