Fluoropolymer addition to an epoxy: phase inversion and tribological properties

Morphology, elastic modulus, static and dynamic friction of a commercial ep oxy resin + fluorinated poly(aryl ether ketone) (12F-PEK) system have been studied. The system was cured at 24 and 70 degreesC. We have obtained signi ficant friction lowering, namely 30% less than the value for the plain epox y at the 12F-PEK concentration of only 10 wt% after curing at 24 degreesC. By contrast, after curing at 70 degreesC, increases in both static and dyna mic friction are observed. At 24 degreesC, the SEM analysis shows that a ph ase separation starts at 10% 12F-PEK; completely phase-inverted morphology was found above 30% of the fluoropolymer. The system cured at 70 degreesC h as more compact structure and the phase separation process is shifted towar ds higher fluoropolymer concentrations. We explain the phase inversion at l ow fluoropolymer concentrations by the low free surface energy of 12F-PEK; as a consequence, we observe its accumulation on the surfaces of the sample s. The samples with high 12F-PEK concentrations exhibit elevated elastic mo dulae and are highly ductile. (C) 2001 Elsevier Science Ltd. All rights res erved.