Symmetric Versus Asymmetric 'Homologous' Vinylic Cross-Linkers in Two-Components Networks: Formation of Pseudo-Conetworks or Pseudo-IPNs

摘要

Radical copolymerizations of heterologous comonomers are compositionally heterogeneous, unless the reaction is performed in continuous conditions. A bicomponent network prepared from a heterogeneous reaction like the mentioned before is therefore a complex structure where chains with different compositions are linked through the cross-linker molecules. It is theoretically shown here that the use of cross-linkers with different structural homologies toward the two comonomers may lead to very different topologies. Thus, a mixture of symmetric cross-linkers, each one homologous to each comonomer, tends to form interpenetrated networks (IPNs). However, the use of a single bihomologous asymmetric cross-linker, where each of the functionalities is homologous toward each of the comonomers, tends to form conetworks. It is shown here that the higher the differential reactivity between the groups, the higher is the tendency toward these extreme structures.