Description:
<jats:title>Abstract</jats:title><jats:p>The free‐radical copolymerization of styrene with small quantities of a commercial DVB (conc.: 0,35 to 0,53 mol‐% DVB) was carried out at 70°C in bulk or in concentrated toluene solution. The extent of the crosslinking reactions beyond the gel point and the structural characteristics of the resulting networks were examined using equilibrium swelling in toluene and gel fraction measurements. The copolymerization reactions yield loosely crosslinked networks together with varying amounts of soluble polymer. The experimental results concerning the formation of the networks and their properties can be explained using the kinetic mechanism of the copolymerization reaction and neglecting cyclization. At a low degree of initial dilution, two opposing effects of the diluent, namely dilution and plasticizing effects, were found to determine the properties of the networks. Calculations using the theory of rubber elasticity indicate that considerable amounts of free chain ends are present in the networks. The crosslinking efficiency was found to decrease, but the size of the primary chains and that of the network chains increase with increasing degree of initial dilution.</jats:p>