An investigation into polyethylene blends for the design of high performance shock tubes

Shock tube initiators are small-diameter hollow plastic tubing used in blasting systems to remotely convey an initiating signal in the form of shock wave to a detonating cap. Since the 1960's, these devices have been widely adopted by the mining industry and are today considered to be crucial parts of explosive initiating systems. Over the past years, researchers have reported the development of various shock tube designs consisting of single, double, and triple polymeric layers. Despite the disclosure of different shock tube designs, the impact of polymeric materials on the properties and performance of shock tubes remains unclear. In this paper, the influence of some polyethylene blends on the properties and performance of two-layered shock tubes is studied, evaluated and reported. The study was conducted by varying the outer layer composition of a two-layered shock tube while keeping the inner layer unchanged. Samples of two-layered shock tubes were made of ethylene based ionomer in the inner layer and blends of 70% HDPE/30% HDPE-g-MAH, 70% HDPE/30% EMA, 70% HDPE/30% ionomer, and 70% LLDPE/30% ionomer in the outer layer. The evaluation methods were similar to that used in industry for commercial shock tubes. The findings revealed that polymeric materials present in the outer layer of a two-layered shock tube could define the tube's properties and performance.