PP vs PVDF: Choosing the Right Non-Metallic Pump Material for Your Chemical
Both polypropylene and PVDF handle aggressive chemistry — but they differ sharply on temperature, solvent resistance and cost. A practical selection guide.
When a pump wetted end must survive acids, alkalis or solvents day after day, non-metallic construction removes corrosion from the failure list entirely. The two workhorse polymers in our range are Polypropylene (PP) and Polyvinylidene Fluoride (PVDF). They look similar on a datasheet. In service they are not interchangeable.
The short answer
Choose PP when the liquid is an acid or alkali below 70 °C and budget matters. Choose PVDF when temperature climbs toward 90–110 °C, when the liquid is a strong oxidising agent or a solvent, or when the cost of a failure far exceeds the price difference.
Where PP wins
Polypropylene covers the majority of electroplating, effluent treatment and general acid-transfer duties we see from Indian process plants. Dilute hydrochloric, sulphuric up to moderate concentrations, caustic soda, and most plating baths at ambient temperature are comfortably within PP's envelope. It machines well, welds well, and keeps the purchase price of a PP & PVDF Centrifugal Pump attractive for utilities that run many units.
Its limits are firm: sustained service above roughly 70 °C softens the material and accelerates creep at the casing joints, and certain chlorinated or aromatic solvents attack it.
Where PVDF earns its premium
PVDF holds mechanical strength to about 110 °C in our magnetic-drive construction and resists a far wider chemical spectrum — concentrated sulphuric acid, bromine, strong oxidisers, and most solvents that would destroy PP. It is also the safer choice for high-purity duties in pharmaceutical and specialty chemical plants because of its low extractables.
The trade-off is cost: PVDF resin is several times the price of PP, and that shows in the pump price. For a duty that PP handles comfortably, PVDF buys nothing.
Temperature is usually the decider
In our experience the selection conversation is settled by two questions. First: what is the maximum liquid temperature, including upset conditions and cleaning cycles? A CIP flush at 85 °C will quietly damage a PP casing specified for a 40 °C process. Second: what is the exact chemical, concentration and any trace contaminants? 'Sulphuric acid' at 10% and at 98% are two different pumps.
What we ask before quoting
Liquid name and concentration, normal and maximum temperature, specific gravity, and any solids. With those four answers the PP-versus-PVDF decision is usually obvious, and we confirm the material against our chemical resistance charts before manufacture. Material Test Certificates are supplied with every order on request.
If you are unsure, send us the duty point — a wrong material choice costs far more than the pump.
Have a duty point to discuss?
Send it over — an applications engineer responds within 24 working hours.