Thermodynamic work of adhesion and peel adhesion energy of dimethoxysilyl-terminated polypropylene oxide/epoxy resin system jointed with polymeric substrates

The characterization of the interfacial surface of a dimethoxysilyl-termina ted polypropylene oxide (DMSi-PPO)/diglycidylether of bisphenol A (DGEBA) s ystem, which has the phase structure of DGEBA particles in a DMSi-PPO matri x, was investigated by using model joints with polymeric substrates. The su rface free energy (gamma) of the DMSi-PPO/DGEBA system had varied with the gamma of each substrate. When the system contacted to low surface free ener gy materials such as Teflon, polypropylene, and polyethylene, the gamma of the system showed about 14.3-31.6 mJ/m(2); on the other hand, when the syst em contacted to high surface free energy substrates such as polyethylene-te lephthalate and polyimide, the gamma of the system showed 50.4 and 64.6 mJ/ m(2), respectively, because the concentration of the DGEBA as a polar compo nent in the system changed around these interfaces. In the low surface ener gy substrates used, the actual peel adhesion energy value was in good agree ment with the thermodynamic work of adhesion (Wa) determined independently. However, in the high surface energy materials used, the peel adhesion ener gies were 10(3)-10(4) times larger than Wa because the energy was dissipate d viscoelastically at the jointed points. (C) 2001 John Wiley & Sons, inc.