National Research Development Corporation

The Secretary of State for Defence

Secretary of State for Defence in Her Majesty's Government of the United

David H Richards

Norman C Paul

Ross W Millar

Peter John Pearce

Malcolm J Stewart

Anthony Vernon Cunliffe

A process for the production of a high energy nitrate ester involves reacting, in an inert organic solvent, a heterocyclic compound, selected from oxiranes, oxetanes, N-substituted aziridines and N-substituted azetidines, with either N.sub.2 O.sub.4 or N.sub.2 O.sub.5, and when the compound is reacted with N.sub.2 O.sub.4, oxidizing the O- or N-nitrate substituents or substituent in the product to O- or N-nitrate substituent or substituents. The remaining ring carbon atoms on the heterocyclic compound may be substituted or unsubstituted. Preferred substituent groups for the C and/or N ring atoms on the compound include alkyl, cyanoalkyl, haloalkyl, nitroalkyl, and substituted aryl. Several novel nitrate ester are also provided, including nitrated derivatives of polybutadiene, in which between 1% and 25% of the carbon atoms in the polymer are substituted by vicinal nitrate ester (--ONO.sub.2) groups.

Process for the production of high energy materials

A process for the production of a high energy material involves reacting, in an inert organic solvent, a heterocyclic compound selected from oxirane, aziridine, oxetane or azetidine with a nitrogen oxide selected from dinitrogen tetroxide (N.sub.2 O.sub.4) and dinitrogen pentoxide (N.sub.2 O.sub.5) and, when the nitrogen oxide is N.sub.2 O.sub.4, oxidizing the O- or N- nitroso substituent or substituents in the product obtained to O- or N- nitro substituent or substituents. The heterocyclic compounds may be substituents or unsubstituted. In the former case the preferred substituents groups are halogen, alkyl, alkenyl, nitro and epoxy (as in epoxidized polybutadiene). The solvent is preferably a chlorinated alkane. Novel nitrated derivatives of polybutadiene, in which between 1% and 25% of the carbon atoms in the polymer are substituted by nitrate (ONO.sub.2), are also provided. These novel materials are liquid rubbers when the polybutadiene starting material has a molecular weight between 2000 and 10000.

Process for the production of high energy material

A process for the anionic polymerization of a conjugated 1,3-diene in a polar solvent consists of contacting the 1,3-diene with an organo alkali or alkaline earth metal initiator and a sterically hindered Lewis acid, allowing the 1,3-diene to polymerize in the polar solvent and terminating the polymerization reaction. Preferably the Lewis acid is a substituted triaryl derivative of a Group III element, especially boron. However in certain cases (e.g. where the aryl derivative itself is large) the Lewis acid may be an unsubstituted triaryl derivative of a Group III element. Suitable Lewis acids include trimesityl boron and tri (2,6-dimethylphenyl) boron. In preferred embodiments of the present process the 1,3-diene is butadiene, the polar solvent is tetrahydrofuran and the initiator is a difunctional initiator, especially an electron transfer reagent. The main advantages of the present process are that polymers with enhanced 1,4-content, a narrow molecular weight distribution and, in the case of telechelic polymers, with an enhanced difunctional specificity are obtained.

Anionic polymerization of conjugated dienes in the presence of hindered

Epoxide materials suitable for use in flexible adhesives are prepared by reacting a diene, such as butadiene or isoprene, with an electron donor, typically an alkali metal, in the presence of a polyepoxide normally in a molar ratio diene:polyepoxide of less than 3:1. The polyepoxide is typically a conventional epoxy resin such as DGBA. The product normally separates into two phases, the upper of which comprises epoxy-terminated diene oligomers with degrees of polymerization of about 6 to 14. This separation may be avoided by incorporating a minor proportion of acrylonitrile into the product by addition to either the original diene or the anionic living polymer immediately before hydrolysis. The products may be cured with conventional epoxide curing agents to give an internally flexibilized adhesive having useful combinations of tensile and shear strengths.

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Waltham Abbey, United Kingdom

David H Richards