Hydrostatic pressure-dependent corrosion behaviour of polytetrafluoroethylene composites in the deep sea

The effect of hydrostatic pressures up to 40 MPa on the corrosion behaviour of neat polytetrafluoroethylene (PTFE) and two fibre-reinforced PTFE composites exposed to seawater was studied. The results reveal that the hydrostatic pressure promotes seawater permeation into the PTFE materials, deteriorates the crystallinity of the PTFE matrix and causes an incompletely reversible loss of mechanical strength. The corrosion mechanisms of PTFE and its composites are discussed based on the crystalline structure transformation and the effect of the fibre/matrix interface.