  Associative polymers with sticker-and-spacer architectures undergo phase
transitions that combine phase separation and bond percolation. Here, we
generalize mean-field models for bond percolation and extract effective sticker
interaction strengths from experimental data for specific proteins. We use
graph-based Monte Carlo simulations to evaluate effects ignored by mean-field
models. These include bond cooperativity defined as changes to strengths of new
bonds (physical crosslinks) given the presence of a prior bond. We find that
bond cooperativity fundamentally alters phase behavior, especially in
sub-stoichiometric regimes for valencies of complementary stickers.
