Thermomechanical and Morphological Characteristics of Cross‐Linked GAP and GAP–HTPB Networks with Different Diisocyanates

Abstract

This paper describes the mechanical and thermal characterisation of cross‐linked glycidyl azide polymer (GAP) and GAP–hydroxyl terminated polybutadiene (HTPB) networks. Cross‐linked GAP and GAP–HTPB networks were prepared by reacting GAP diol and GAP–HTPB diol mixture with different diisocyanates. The physical and mechanical characteristics were found to be influenced by the type of isocyanate curing agents, [NCO]/[OH] equivalent ratios and concentration of GAP. For all the three types of curing agents, GAP–HTPB blends of 50 : 50 to 30 : 70 ratios show higher mechanical strength over the virgin networks of GAP or HTPB. Thermal decomposition of cross‐linked GAP–HTPB networks was evaluated by thermogravimetric analysis (TGA). The kinetic parameters for the decomposition of GAP–HTPB blends were found to be dependant on the concentration of GAP and HTPB in the blend. The cross‐linked GAP–HTPB blends were subjected to dynamic mechanical analysis (DMA). The glass transition characteristics of the blends were evaluated by DMA and it was found that blends prepared with GAP content up to 30% showed single transition in the loss tangent trace indicating no phase separation in the cured network.

Structure and mechanical properties of novel composites based on glycidyl azide polymer and propargyl‐terminated polybutadiene as potential binder of solid propellant

“…4 At the same time, HTPB exhibits other excellent properties for the application of rocket propellant, such as low glass transition temperature, high flexibility, hydrolytic stability, and resistance to solvents. 17 The crosslinked GAP-HTPB composites containing higher than 30 wt % of GAP showed higher mechanical strength over the virgin GAP or HTPB crosslinked with diisocyanates, and only single glass transition was observed. To make full use of the advantages of GAP and HTPB, the composites of GAP and HTPB had been attempted to develop.…”

Energetic interpenetrating polymer network based on orthogonal azido–alkyne click and polyurethane for potential solid propellant

“…The first stage decomposition of triazole takes place in the temperature range of 190 ̶ 270 o C with a weight loss of 38 % due to liberation of nitrogen, 17,21 while the second stagedecomposition involves the degradation of polyether main chain of Acyl-GAP in the temperature range of 270 ̶ 464 o C. The residue left behind after the decomposition is around 29 %. 31 HTPB cross-linked network decomposition undergoes in two stages with indistinct separation. The first stage decomposition is in the range of 210 ̶ 415 o C with a mass loss of 21 % due to depolymerization, cyclization and partial decomposition of cyclized products.…”

Synthesis, spectroscopic characterization, thermal stability and compatibility properties of energetic PVB-g-GAP copolymers

“…Glycidyl azide polymer (GAP) is an azide energetic material. It is a wellrecognized energetic polymer suitable for energetic materials, such as propellants and composite explosives, because of its high energy, higher density, higher nitrogen content and lower mechanical sensitivity [17][18][19][20][21][22][23][24]. Moreover, the terminal hydroxyl group of GAP can also be easily modified through various reactions [23,24].…”