摘要:
IN COMBINATION WITH A SALT OF POLYVINYL SULFONIC ACID.
A process for the suspension polymerization of a prepolymer derived from a mixture of from 70 percent to 98 percent of a vinyl aromatic substance, 2 percent to 30 percent of one or more elastomers, which has been mass-polymerized to a conversion of 10 to 60 percent, in an aqueous phase in the presence of a dispersing agent, which comprises using, as a dispersing agent, a copolymer of an open-chain N-vinylamide of the formula