. . "Examples of suitable resistant matrix materials include polymers such as polytetrafluoroethylene (PTFE), polyphenylene sulfide, polysulfones, polyetheretherketone (PEEK), fluorinated ethylene-propylene (FEP), polyvinylidenedifluoride, ter-polymers of PTFE, hexafluoropropylene, and vinylidene fluoride (THV), liquid crystalline polyesters, and glass and other ceramics stable in acidic environments." . . . .