Prepararion And Characterization Of Low-density Divinylbenzene Foam Shells

Nowadays in the world, the problem of energy sources becomes increasingly serious along with the rapid and great development of productivity, cleanliness and high efficiency becomes the ultimate request to the energy sources. As a new sort of energy sources, inertial confinement fusion(ICF) is gotten more and more attention. In the study of ICF, in order to increase the energy gain, the density of the target should be debased and the fuel concentration should be heightened. Foam materials with a multi-hole structure and high ratio-area, can not only absorb volume of liquid D-T, but also help the solid D-T to form thin crystal granule through micron-level beehive in the foam structure, which can improve the smoothness of surface and ultimately form an ice layer with smooth surface. As a target which can gain high energy plus, polymer foam shells are obtaining more and more attention, and started to be used as a low temperature refrigerant target in ICF experiment.Target designers believe foam materials that only contain element C and H are the best. So divinylbenzene( DVB, C10H10)foam, as a sort of high-gain target is getting more and more attention. This paper is primarily to study on the fabrication of DVB foam shells that can be used in ICF experiment.Firstly, based on micro-emulsion technology and micro-fluid technology, 4 devices to be used for preparation of double layer micro-emulsion were set up. The 4 devices included tri-orifice droplet generator, T shape microchannel double layer droplet generator, double-T shape microchannel double layer droplet generator and new type tri-orifice droplet generator. By these equipments, with solutions of an oil (DVB monomer, dibutyl phthalate solvent, and azodiisobutyronitrile initiator) as middle phase, DVB double layer micro-emulsion droplet with diameter 0.6~4.0 mm and thickness 80~3500μm were successfully produced. Advantages and disadvantages of 4 devices were analyzed, and factors that affect the dimension of micro-emulsion droplets were discussed. Secondly, level rotating water bathe was used to gel the DVB micro-emulsion droplet, the survival rate was improved as the heating process was optimized. CO2 super critical drying was adopted to dry the gelled shells, shrinkage was reduced and pinhole collapse was avoided. DVB shells'dimension and feature was characterized with optical microscope, electronic scanning microscope and x ray transmission microscope, the result showed that percent of nonconcentricity is less than 5 %, and sphericity is better than 99 %. These shells could meet the requirement of the ICF target. Finally, DVB shells were coated with poly-p-vinylphenol(PVP). A pilot study about coating on DVB shell was done to prepare for the glow discharge polymer(GDP) coating in the future.