PP – polypropylene homopolymer
Weldable, chemical-resistant polyolefin up to about 100 °C
Polypropylene homopolymer is the stiffest polyolefin with the highest service temperature (about 100 °C). It is light, weldable and highly resistant to acids, bases and aqueous solutions, which is why it dominates tanks, gas scrubbers and electroplating equipment. It is brittle below 0 °C.
Designations and equivalents
| System | Designation |
|---|---|
| Abbreviation (ISO 1043) | PP-H |
| Trade names | Polystone P homopolymer (Roechling); TECAFINE PP (Ensinger) |
Standards by product form
| Form | Standard |
|---|---|
| Sheets and rods | Stock-shape manufacturer's specification |
| Food contact | FDA 21 CFR 177.1520; EU 10/2011 (depending on grade) |
| Machined part to drawing | ISO 2768 tolerance or as per drawing |
Composition and filler
Pure polymer
| Component | Content |
|---|---|
| PP homopolymer | 100% |
Mechanical properties
Typical values from the stock-shape manufacturer's catalog, 23 °C; ISO/ASTM methods as per the source
| Property | Value |
|---|---|
| Tensile strength | >30 MPa |
| Modulus of elasticity (tensile) | >1,500 MPa |
| Elongation at break | >50% |
| Hardness | Shore D >70 |
| Notched impact | >4 kJ/m² |
Typical physical and thermal properties
| Property | Value |
|---|---|
| Density | >0.90 g/cm³ |
| Maximum continuous service temperature | 100 °C |
| Maximum short-term temperature | 150 °C |
| Minimum service temperature | 0 °C |
| Melting point or glass transition | 162-167 °C |
| Linear thermal expansion | 120-190 µm/m·K |
| Thermal conductivity | 0.2 W/m·K |
| Water absorption (24 h) | <0.1% |
| Dielectric strength | >40 kV/mm |
| Flammability (UL 94) | HB |
Calculate the weight of PP – polypropylene homopolymer bar, plate or pipe →
Chemical resistance
| Medium | Resistance |
|---|---|
| Acids | Excellent (except strong oxidizers) |
| Bases (alkalis) | Excellent |
| Solvents | Good |
| Hydrocarbons and oils | Limited (aromatics and chlorinated solvents cause swelling) |
| Steam and hot water | Good up to ~100 °C |
Stock forms and sizes
- Sheet (plate)
- Rod (round bar)
- Weldable sheet
- Tube and bushing
- Raw material: rod (round bar), sheet (plate) and tube, cut to size
- Machined part to drawing or sample, in the same order as the metal parts
- Lot certificate of conformity; FDA/EU 10/2011 declaration when the grade allows
Service temperature, machining and assembly
| Item | Usual practice |
|---|---|
| Service temperature | Continuous service up to 100 °C, short peaks up to 150 °C; minimum 0 °C (unloaded; under load, limited by HDT and creep). |
| Annealing (stress relief) | Not usual. |
| Bonding and welding | Welds very well by hot plate, extrusion and hot air welding. |
| Machining | Machines easily. |
Typical applications
- Tanks and chemical treatment equipment
- Gas scrubbers and ducts
- Electroplating parts
- Pump and filter parts
Alternatives: PVDF for more aggressive chemicals and higher temperature; HDPE for low temperature.
Frequently asked questions
Which standards cover PP?
Sheets and rods: Stock-shape manufacturer's specification. Food contact: FDA 21 CFR 177.1520; EU 10/2011 (depending on grade). Machined part to drawing: ISO 2768 tolerance or as per drawing.
Up to what temperature can PP be used?
Continuous service up to 100 °C, short peaks up to 150 °C; minimum 0 °C (unloaded; under load, limited by HDT and creep).
Which materials can replace PP?
PVDF for more aggressive chemicals and higher temperature; HDPE for low temperature.
Can PP handle hot water?
Up to about 100 °C without load. For steam and higher temperatures with chemicals, use PVDF or PTFE.
