| abstract |
Syntactic foam compositions are manufactured by heat-curing, in the presence of a free radical generator, a mixture comprising a resin and hollow spheres; the resin consists of (a) 10 to 100% of polybutadiene with 20-95% 1,2 units, 5-60% thereof being in a carbocyclic cyclized form, its number average molecular weight being at most 100,000; (b) 0 to 90% of polybutadiene with 40-98% 1, 2 units and 2-60% 1, 4 units, its number average molecular weight being at most 100,000; and (c) 0 to 90% of a polymerizable liquid vinyl monomer. |