Thermal insulation layer in solid rocket motors is a vital component during the rocket flight. Many factors can affect the performance of this insulation layer. Bonding property between rocket propellant and the thermal insulation layer are examined in this study. Hydroxyl terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI) as a curative was chosen as the most common type of rocket propellant. The effect of two types of polymeric insulation layer such as nitrile butadiene rubber (NBR) and ethylene-propylene-diene monomer (EPDM), on the bonding performance at the interface between (HTPB/IPDI) propellant and the respective insulation layer has been investigated. Results revealed that both types of insulation layer considerably decreased the interfacial bonding performance of the (HTPB/IPDI) propellant. NBR was proven to be more severe on weakening the adhesion strength than that of the EPDM. We further investigated the effects of the thickness and water content of NBR on the bonding performance, and proved that bonding strength was inversely proportional to the thickness and the water content.

Background: Re-stenosis following infra-popliteal angioplasty could results in many serious consequences like recurrence of ischemic symptoms or break through of wound healing. With the evolving techniques of Paclitaxil release and the rapid advancement in the manufacturing of endovascular equipment, drug eluting balloons emerge as a useful option to overcome intimal hyperplasia and subsequent restenosis. Aim of Study: To highlight the clinical impact of additional DEB application in patients with CLI attributed to infrapopliteal disease regarding the re-stenosis rate, amputation free survival and limb salvage. Material and Methods: This study is prospective observational study over a period of one year including 33 patients who underwent infra-popliteal angioplasty using DEB. Results: 33 patients (36 limbs) were included in the study, 24 cases (27 limbs) were presented by a re-stenosis or occlusion after previous trial of angioplasty using plain balloon, while 9 patients come with the first presentation (Denovo lesions). Stenotic lesions were found in 21 limbs (58.3%) while occlusive lesions were observed in 9 limbs (25%) and combined stenotic and occlusive lesions were found in 6 limbs (16.7%). The mean length of the treated lesions within the tibial arteries using DEB was 7.6±3.4m. Primary patency rate at 3, 6 and 12 months was 91.3%, 82.6% and 70.9%. While limb salvage rate at 3, 6 and 12 months was 91.6%, 81.8% and 72.8% respectively. Conclusion: With the rapid advancement in the endovascular tools & equipment, the early results is encouraging and promising with additional application of DEB for patients with infra-popliteal arterial disease in comparison to the traditional use of plain uncoated balloons. However, the midterm and late results of the IN.PACT DEEP study suggest that an extreme caution is to be considered in this field.