The study of mechanical and creep properties of glycidyl azide polyol energetic thermoplastic elastomer binder with bonding group with RDX and its interface reinforcement mechanism

Bonding agents as additional modifiers are used to improve the reinforcement effect between binder and high solid filler in propellant formula. However, polar bonding agents are easily soluble with polar plasticizer and weak bonding effect. Thus, grafting the bonding group into binder to form neutral polymeric is a novel approach to avoid the preceding shortcomings mentioned and is also meaningful to improve interface properties of propellant. In this work, glycidyl azide polyol energetic thermoplastic elastomer binder with -CN bonding group (named G-1binder) was synthesized and the influences of -CN bonding groups on the mechanical and creep resistance properties of G-1/RDX composites were studied. Then, the mechanism of interfacial interactions between binder with -CN group and cyclotrimethylenetrinitramine (RDX) were also illustrated through Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy and contact angle analyzer. Results demonstrated G-1/RDX propellants have stronger interfacial reinforcement effect and good mechanical and creep resistant properties. As well, the induced effect model was proposed, and the binding energy of interface was calculated by Materials Studio software. Computational results show that G-1/RDX propellant has a high binding energy and strong interactive force due to the existence of induced effect between -CN group and -NO₂ group, which resulted in an increase in constrained regions around the RDX surface and led to the significant promotions of mechanical and creep resistance properties of G-1/RDX propellant.