ATOMIC-FORCE MICROSCOPY IMAGING OF VISCOELASTIC PROPERTIES IN TOUGHENED POLYPROPYLENE RESINS

The bulk morphology of two toughened polypropylene/(ethylene propylene )copolymer resins (PP/EP) presenting different impact resistances has been studied by means of different atomic force microscopy techniques: contact atomic force microscopy, lateral force microscopy (LFM), and force modulation microscopy (FMM). The three techniques reveal two dif ferent morphologies as observed in transmission electronic microscopy. In LFM, a higher friction force is observed on the rubbery phase whic h has the lower Young's modulus confirming the relationship between fr iction force and elastic properties. In force modulation, the elastic moduli is found to be much lower on the EP nodules in both resins. FMM also reveals that the difference of viscous response between the PP m atrix and the EP nodules is much lower in the resin which is less impa ct resistant. (C) 1995 American Institute of Physics.