Effect Of Temperature And Field On The Quality Of Hollow PS Microspheres

Inertial confinement fusion?ICF?is one of the main ways to control the reaction of nuclear fusion.Hollow polymer micro-spheres?HPM?is a necessary material basis of ICF research.Due to its excellent chemical stability and good mechanical properties,polystyrene?PS?has become one of the main materials for studing the preparation of HPM used in the ICF research.To achieve the centering of spherical implosion,there are stringent requirements on the specification of HPM.In this paper,hollow PS microspheres were prepared by the microencapsulation technology.The effects of temperature and flow field on the shape of hollow PS microspheres were investigated.The effect of temperature on the spherisity and wall-thickness uniformity of PS shells were investigated by adjust the curing temperature?the curing temperature was set as 25??45??and 65? respectively to solidify PS compound droplets respectively?.The results shows that decreasing the temperature can increase the interfacial tension between O phase and W₂ phase,and reducing the solidification rate of compound droplets,thereby the driving force of being spherical is enhanced and the time for reversible formation is extended.Therefore,the sphericity and wall-thickness uniformity of PS shells is improved.Based on the research of the effect of the solidifying temperature on the quality of PS shells,a further study on controlling the solidifying temperature by step was made.The experimental results?curing at 25?and heating up at different point of time?shows that when the heating point of time was prolonged,the yield of PS shells with good sphericity and wall-thickness uniformity increases firstly and reduces later.When the cooling time delayed,?curing at 55? and cooling at different point of time?,the yield of PS shells with good sphericity and wall-thickness uniformity decline.Primary cause of these result are that when it was 25?,a higher density difference between W1 phase and O phase shrink when the temperature was raised up.At the earlier stage,the fluxility of droplets still good enough to recover the formation when the temperature was raised.At the later period of curing,the O phase lose its fluidity,resulting in that the shape is hard to recover again.In terms of the effect of flowing field on the quality of PS shells,we studied the effects of the rotating speed and quality of PS shells.The result show,as to the thick-wall PS shells,higher rotating speed was more benefit to the wall-thickness uniformity,it might for the reason that higher spin speed improved shear force,its benefit to the centering of the compound droplets.The experimental result of different flask with various diameter experiment showed that when the number of the droplets are the same,the sphericity and wall-thickness uniformity of shells that increase firstly and decline later as the length increasing,and had no difference when the number of PS shells in proportion to volume of W₂.