Effect of UV and thermal radiation on polyNIMMO

To reduce the sensitivity of explosive compositions, inert polymers and pla sticisers have been incorporated. The polymers bind the explosive crystals together whilst the plasticisers reduce the rigidity of the compositions. I n order to improve the performance of these compositions without compromisi ng on safety, energetic polymers and energetic plasticisers are now being i nvestigated. While energetic plasticisers have been successfully developed energetic polymers are still very much in the research and development phas e. The UK have for the past decade been concentrating on polyNIMMO and to a lesser extent, polyGLYNN. In order to understand the stability of these po lymers to ageing, a study was conducted to investigate the effect of ultra- violet (UV) and thermal radiation on polyNIMMO. PolyNIMMO was found to ther mally degrade in the presence and absence of oxygen at temperatures of 70, 100 and 130 degreesC. DSC and FTIR results indicate that polyNIMMO undergoe s degradation by three different mechanisms, namely homolytic scission of t he O-NO2 bond, scission of the polyether backbone and crosslinking of the p olymer chains. PolyNIMMO was also found to degrade when subjected to W radi ation at ambient temperature. Evidence from analyses indicates that only tw o of the degradation mechanisms are taking place namely homolytic scission of the O-NO2 bond, and scission of the polyether backbone. PolyNIMMO will o nly undergo crosslinking when subjected to W at higher temperatures (i.e. 1 00 degreesC). (C) 2001 Elsevier Science Ltd. All rights reserved.