Study On Hydrogen Barrier Property Of Poly(vinyl Alcohol) Film

For the PVA was widely used to prevent the DT fuel from leakage in inertial confinement fusion (ICF), the solvent effect on the preparation of PVA film by low speed spin coater was studied for the first time using X-ray powder diffraction (XRD) and atomic force microscope (AFM). Moreover, the effect of molecular weight, alcoholysis degree, condition of anneal and radiation on the Poly(vinyl alcohol) hydrogen barrier property was also described in this paper. The crystallinity in four kinds of poly(vinyl alcohol) film, that is, PVA16-98, PVA22-88, PVA93.4-lOO and PVA95-95, was studied by using H20, DMSO and their admixture as the PVA抯 solvent. Degree of crystallinity in those films takes on a special change as the increasing of the ratio of DMSO to 1120. And the degree of cystallinity in those PVA film reach the maximum value when the ratio of DMSO to 1120 is 7:3 and 3:7. For the first time, AFM was used in the study of PVA film surface under different solvent condition. The AFM study shows that the surface of the poly(vinyl alcohol) films appear with regular change as the increasing of the ratio of DMSO to 1120. Adding the DMSO in the admixtures went against making high quality film. A constant volume/variable pressure gas permeation system was described in this paper. This system is a sensitive and versatile instrument, which could be used in the measurement of the hydrogen permeability in the lower molecular weight PVA films. Increasing the molecular weight and alcoholysis degree of poly(vinyl alcohol) film is propitious to lowering the permeability coefficient of hydrogen in those films, as well as increasing the annealing temperature. As a result, the hydrogen barrier property of PVA film was enhanced. The preferable annealing temperature should be selected under l8O0C to avoid thermal decomposition of the PVA chains. Treated for a long time under the glass transition temperature, the PVA film can also improve its hydrogen barrier property via increasing the connecting point in the amorphous region. For the same molecular weight, those films, which have lower alcoholysis degree, shows a considerable decreasing in the hydrogen permeability coefficient. It is useful to treat the PVA microsphere both under the glass transition temperature and at a higher temperature in enhancing the hydrogen barrier property of the plastic microsphere. The hydrogen permeability coefficient of PVA film exposured under electron beam was measured for the first time. It's found that the barrier property of PVA film has a great badly change. Increasing the dosage and the dosage quotiety can all increasing the hydrogen permeability coefficient in the PVA. But the PVA films that have lower alcoholysis degree would show a less damage. Therefore, selecting lower alcoholysis degree would be useful to resisting radiation decompose in the microsphere preparation. This paper PresentS our study on the preParation of poly(vinyl alcohol) film andthe influence of the film anneal, exposure under electron beam, the effeet of molecularweight and alcoholysis degree on the hydrogen bAner Propey of PVA filIn. And asensihve and versadie gas Penneating system was established in tals inveshgation.ttis wOrk will Provide a teChnical foundation on how tO ProlOng the DT fuel retentiontim in IniCrOsPhere fabrication.