Energetic Binder for use in Rocket Propellants
Introduction
High-energy rocket propellants are required to possess improved performance, satisfy insensitive munitions comply with environmental aspects and reduced costs. As such, resent advances in propellant research, are aimed at developing high energy binders which give better performance than the commonly used binder Hydroxy Terminated Poly-butadine (HTPB) and which are compatible with eco-friendly oxidizers Ammonium Nitrate (AN), Hydrazinium Nitroformate (HNF) or Ammonium Dinitramide (ADN). Polymeric azides that include Glycidyl Azide Polymer (GAP) and its copolymers contain azide groups along the polymer chain as pendent groups, which make them highly energetic. These polymers can therefore be used as energetic binders having minimum smoke, reduced pollution and sensitivity. In addition to being fuel rich, these propellants liberate large amounts of Hydrogen, Nitrogen, CO and gaseous hydrocarbons on burning and provide high burning rate.
The process comprises of curing azido polymers such as Poly allyl azide or Glycidyl azide polymers or BMMO (PAA) is prepared by polymerization of low molecular mass allyl chloride (to obtain polymer having molecular weight between 1000 to 300) followed by azidation. The azidization is carriedout using sodium azide and aprotic polar solvent exemplified but not restricuted to dimethyl sulphoxide, (DMSO), dimethyl formamide, (DMF) dimethyl acetamide (DMAC) as solvent at the specified process paramerers.
Poly Allyl azide oligomer (having molecular weight in the range of 1500 to 3000 g/mol). thus obtained is cured using novel dipolarophiles such as poly imides to produce high energetic binder. The polyimides used may be the one containing P, S, and/of aliphatic methlylene units having carbon ranging from 2 to 8. The preferred Imide could be bismaleimide of hexamethylenediamineyl (HMDA) or bis (4,4' -male-imido-phenyl) sulphone or bis maleimide of diaminodiphyenyl sulphone (DADPS), bus (4,4'-maleimidophenyl) ether, (3,3' - maleimidophenyl) methyl phosphine oxide. This has advantages over EGDMA in flexibility of cured product and high char yield. Curing is carriedout at a specific temperature for a specific duration of time using the desired amount of imide in order to prevent the binder from getting brittle.
Special Features
Possess high burn rate; Acts as a high energy binder; Has excellent elastomeric characteristics; The product is devoid of bubbles; Generates high energy output; Has high char yield; High efficiency; Can be produced by economical and eco-friendly process without stringent conditions
Prospective Users
For the production of High Energy rocket propellents
Keywords
Azido polymers, Dipolarophiles, bismaleimides, bisitaconimides, bisnadimides, di/triacrylates, bisacrylamides
Type of Technology
Process Status of IPR Protection: Indian Patent Application No 725/DEL/2003 dated 27.5.2003 with title "Energy Binder (Azido polymer) . (Jointly held with Armament Research Board, DRDO).
Developed by
Prof. (Mrs.) K I Verma
Department
Center for Polymer Science and Engineering
For further information please contact
Managing Director
Foundation for Innovation and Technology Transfer (FITT)
Indian Institute of Technology, Delhi
Hauz Khas, New Delhi-110016, INDIA
Tel : 91-011-26597167, 26857762, 26581013, 26597153
Fax : 91-011-26851169
E-mail : drkdpn@gmail.com
