Preparation of multishell ICF target plastic-foam cushion materials by thermally induced phase-inversion processes

Homogenous, low-density plastic foams for ICF targets have been prepared by thermally induced phase inversion processes. Uniform, open cell foams have been obtained by the rapid freezing of water solutions of modified cellulose polymers with densities in the range of 5 mg/cm3 to 0.7 mg/cm3 and respective average cell sizes of 2 to 40 micrometers. In addition, low-density, microcellular foams have been prepared from the hydrocarbon polymer poly(4-methyl-l-pentene) via a similar phase inversion process using homogenous solutions in organic solvents. These foams have densities from 2 to 5 mg/cm3 and average cell sizes of 20 micrometers. The physical-chemical aspects of the thermally induced phase inversion process is presented