| Based on the application of multilayer plastic microsphere in inertial confinement fusion (ICF) experiment, this paper presents the study on effect of thickness of hydrocarbon ablator layer on gas-barrier property of PVA film in sandwich structure. And the relationship between gas-barrier properties of cross—linked film and GA content in PVA also was studied, after adding GA into PVA. Moreover, simulated study was carried out to investigate the diffusion behavior of gas in multilayer shells according to the experiment.In the study of effect of thickness of hydrocarbon ablator layer on gas barrier permeability of PVA membranes, at 40℃, 70%RH, 80%RH , 90%RH, the measurement of permeability of PVA film was examined, and the permeability coefficient of polystyrene films , hydrocarbon films and PVA films at 40℃ , 90 % RH also was worked out, which is in agreement with the literature, at the same time, the relative humidity of middle layer (PVA) in three-layer plastic microsphere's structure, under 40℃ 90% relative humidity environmental condition was figured out, using an approximate model of multilayer packaging structure. Moreover, the relationship between thickness of hydrocarbon film and relative humidity of middle layer (PVA) in three-layer composite films under given condition was deduced, that is, the thicker hydrocarbon film is, the lower relative humidity of PVA is, and the better gas-barrier property is.In the study of gas-barrier property of PVA film cross linked by glutaraldehyde(GA), glutaraldehyde of 50%, different content was added into the identical blended solution of 10 milliliter, 3% PVA and 20 microlitre hydrochloric acid. Gas-barrier property of polyvinyl glutaral (PVG) membranes was measured after cross linking reaction and permeability coefficient of PVG membranes was worked out. It was Found that the change law of PVG's permeability coefficient is decrease—nncrease—?steadiness—>increase with the increase of GA content in PVG membranes. Moreover, when GA content is 800 microlitre, the permeability coefficient of PVG film is minimum, and gas-barrier properties is the best.In the study of the simulated calculation for diffusion process of gas in multilayer plastic shells, Concentration distribution expre;sion of gas diffusion process at limited distance in multilayer polymer shells, that is, the relationship of gas concentration diffusion -. time and diffusion distance have been derived. In every layer, the relationship of gas concentration and diffusion depth is parabolic for the certain quality gas, which illuminates in the direction of gas diffusion, polymer systems are swelled, and gas will diffusion along the direction of polymer swelling. In the different diffusion time, the concentration of ration gas was increased with time delay at the same place. Which explain polymer free volume was increased owing to polymer systems was swelled, and gas's diffusion path was increased and the diffusion coefficient was improved with concentrations increase in spherical shells.
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