Studies on the Effect of a Covalently Bonded PGN Based Reactive Plasticizer on the Thermal Decomposition Behavior of Glycidyl Azide Polymer

Abstract

Plasticizers are one of the additives that are added to polymers to increase the plasticity or decrease the viscosity of the material. Here, we have synthesized and characterized a new PGN-based reactive energetic plasticizer that has an oligomeric structure. The reactive energetic plasticizer can be grafted onto glycidyl azide polymer via a Cu-free Huisgen azide-alkyne 1,3-dipolar cycloaddition. The effect of the covalently bonded PGN-based plasticizer on the thermal properties of GAP-g-PGN copolymer has been investigated through thermogravimetric analysis and differential scanning calorimetry. The results indicate that the glass transition temperature of the prepolymer is decreased from-47.8 to-50.7 °C. Also, the kinetics of the thermal behaviour of GAP-g-PGN copolymer was determined by the application of the Kissinger and FWO kinetic models. The activation energies calculated by the Kissinger method were 165 and 188 kJ/mol for peak 1 and peak 2, respectively. Furthermore, the critical temperature (Tb) of thermal explosion for this energetic copolymer was estimated to be 182 °C.

An overview on the recent developments in reactive plasticizers in polymers

“…Increasing the level of grafting leads to an increase in the nitrato content of copolymer and subsequently enhance dipole‐dipole interactions between the nitrato groups and reduce the mobility of polymeric chain. So, an appropriate grafting level of PGN‐based reactive oligomeric plasticizers remains up to 10% of total azido groups of GAP …”

Inserting urethane into 1,2,3‐triazole click‐cured solid propellant binder to form microphase separation and enhance mechanical and combustible performances

“…17,18 The GAP binder system can further form a triazole-based network via alkyne-azide Huisgen cycloaddition, 19,20 which is insensitive to humidity, simpler, and faster than the traditional isocyanates curing system. [21][22][23] However, the practical application of a triazole-cured binder system is inhibited by unsatisfied mechanical properties. 24,25 Unlike the isocyanates curing system, the rigid triazole rings failed to induce the aggregation of hard segments to form a micro-phase separation structure, 26 due to insufficient intermolecular force.…”

“…The GAP system takes advantage of high energy density, high energy output, and moderate mechanical sensitivity 17,18 . The GAP binder system can further form a triazole‐based network via alkyne‐azide Huisgen cycloaddition, 19,20 which is insensitive to humidity, simpler, and faster than the traditional isocyanates curing system 21–23 . However, the practical application of a triazole‐cured binder system is inhibited by unsatisfied mechanical properties 24,25 .…”