This book provides a detailed insight on the organically modi?ed Indian Bentonite nanoclay using cationic surfactant hexadecyltrimethyl ammonium bromide by cation exchange capacity method being dispersed in vinylester. Addition of 5 wt. % nanoclay decreased the diffusivity and permeability of vinylester in artificial sea water medium but these diffusion parameters increased in demineralized water medium for 146 days and the combined effect of naturally available Indian bentonite nanoclay and halogen free fire-retardants (HFFR) on the fire retardation behavior of vinylester and their results were discussed.