Three component interpenetrating polymer networks (IPN's) of polyurethane (PU)-poly(n-butyl methacrylate) (PBMA)-epoxy were prepared by either simultaneous polymerization or sequential polymerization.
To compare with three component IPN's two component IPN's of PU-PBMA, PBMA-epoxy, PU-epoxy were also prepared.
To investigate the effects of interpenetration on the properties of IPN's and related systems, semi-IPN's, in which only one of the constituent polymers is crosslinked, were also prepared.
The dynamic mechanical properties, glass transition behavior, tensile strength, elongation at break, equillibrium swelling ratio and density of the three component IPN's were compared with variations in composition and synthesis method.
The $T_g$ behavior studied by the dynamic mechanical analyze showed inward shift in $T_g$. Broader and higher damping peaks were observed in 3-comp. IPN's.
Tensile strength of three component IPN's was increased in case of a certain composition compared with homopolymers and 2-comp. IPN's.
