| The technique of the liner crosslinking by the combination of UV and hot curing shows the shorter curing time and lower cost in the liner process.By means of many instruments,it is investigated that the action of many affactors, such as,the viscosity and the gel reaction velocity of the liner slurry,the content of SM6402 and the UV light initiator,the content of binding agent and silica,on the mechanical properties and density of the liner.Many performances of the liner,like the shear strength between liner and metal,the tear strength of the insulation/liner /propellant sample,the linear ablation rate,the temperature of thermal decomposition and glass transition of the liner,are characterized.The phase micrograms of the liner are analyzed.The combined liner is consisted of two curing systems.One is for the photo-crosslinking,which composed of SM6402 and BP/BE photo-reaction initiator. The other is for the hot curing,which composed of HTPB and IPDI.The main formulation of the composite liner is that 50.0%～60.0%HTPB,10.8%～16.9%IPDI, 30.0%～40.0%SM6402,2.0%～4.0%BP/BE,1.7%～2.5%MAPO,and 5.5%～6.5%SiO2. The performance of the liner meets the requirement.The viscosity of the liner slurry incearses slowly under 50℃,its pot life is more than 3 hours.The content of the mixed phto-reaction initiator is about 2.0%～4.0%. The conditions of the curing photo-reaction are the distance from 365nm UV light-house is about 40mm～60mm and the reaction time is about 5～10s.The stress and elongation of the liner reach the maximum when the mass ratio of HTPB/SM6402 IPN is 60/10.The content of the phto-reaction initiator has no remarkable action on the mechanical property and density of the liner.The elongation of the liner decreases with the increase of MAPO content,so the optimum content of MAPO is about 1.7%. The coating process becomes difficult when the content of silica increased.Therefore, the optimum content of silica is about 5.5%～6.5%.With the SEM photos,we can found that there is phase separation and heterogenous island structure on the surface of the liner,which demonstrates the action of IPN network.The glass transition and thermal decomositiontenperature is -64.9℃and 366.9℃。... |
