GH Polypro membrane hydrophilic polypropylene exporter . Membrane disc filters, GH Polypro (GHP) | VWR. Pall GHP Polypropylene membrane will be discontinued effective October 31st, 2019. This discontinuation affects devices including Centrifugal Devices, PTFE Membrane Filters. Aug 4, 2008 Zefluor™ membrane now available in 0.5 µm pore size