Direct access to poly(glycidyl azide) and its copolymers through anionic (co-)polymerization of glycidyl azide

Senthil K Boopathi,Yves Gnanou,Xiaoshuang Feng,Nikos Hadjichristidis

doi:10.1038/s41467-018-08251-1

Senthil K Boopathi, Yves Gnanou + Show 2 more

Open Access

https://doi.org/10.1038/s41467-018-08251-1

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Abstract

Glycidyl azide polymer or poly(glycidyl azide) which is considered as an excellent energetic binder or plasticizer in advanced solid propellants is generally obtained by post-modification or azidation of poly(epichlorohydrin). Here we report that glycidyl azide can be directly homopolymerized through anionic ring-opening polymerization to access poly(glycidyl azide) using onium salts as initiator and triethyl borane as activator. Molar masses of poly(glycidyl azide) up to 11.0 Kg/mol are achieved in a controlled manner with a narrow polydispersity index (PDI ≤ 1.2). Similarly, alternating poly(glycidyl azide carbonate) are also prepared through alternating copolymerization of glycidyl azide with carbon dioxide. Lastly, the copolymerization of glycidyl azide with other epoxide monomers is carried out; the azido functions carried by glycidyl azide which are successfully incorporated into the backbones of polyethers and polycarbonates based on cyclohexene oxide and propylene oxide subsequently served to introduce other functions by click chemistry.

Highlights

Glycidyl azide polymer or poly(glycidyl azide) which is considered as an excellent energetic binder or plasticizer in advanced solid propellants is generally obtained by post-modification or azidation of poly(epichlorohydrin)
In contrast to the prior literature, we report in this paper how poly(glycidyl azide) (PGA) can be directly obtained from the anionic ring-opening polymerization (AROP) of glycidyl azide (GA) in the presence of a mild Lewis acid, triethyl borane (TEB)
In the presence of this particular Lewis acid, the AROP of GA occurs in a controlled manner in a range of molar masses between 1000 and 11,000 g/mol. α,ω-dihydroxy telechelics of very low polydispersity carrying all of their azido functions and responding to the requirement of propellant binder can be prepared

Summary

Introduction

Glycidyl azide polymer or poly(glycidyl azide) which is considered as an excellent energetic binder or plasticizer in advanced solid propellants is generally obtained by post-modification or azidation of poly(epichlorohydrin). We report that glycidyl azide can be directly homopolymerized through anionic ring-opening polymerization to access poly(glycidyl azide) using onium salts as initiator and triethyl borane as activator. Glycidyl azide polymer or poly(glycidyl azide) (PGA) is considered as excellent energetic binder or plasticizer in advanced solid propellants because of its high heat of combustion, thermal stability, and good compatibility with oxidizers[1,2,3,4]. In contrast to the prior literature, we report in this paper how PGA can be directly obtained from the anionic ring-opening polymerization (AROP) of GA in the presence of a mild Lewis acid, triethyl borane (TEB). PGA is shown to serve as the precursor for the synthesis of other functional polyethers through the derivatization of its azido groups through “click” reactions or reduction into primary amines[7]

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