PP · grade · default condition
PP Homopolymer
Properties of the Homopolymer condition, compared with the other PP grades.
Default choice for stiff, heat-resistant, low-cost parts used above 0 °C: housings, containers, chemical tanks, living hinges.
What is PP Homopolymer?
PP Homopolymer is PP in the Homopolymer grade — default choice for stiff, heat-resistant, low-cost parts used above 0 °C: housings, containers, chemical tanks, living hinges. PP Homopolymer has a yield strength of 33 MPa (4.79 ksi) and a tensile strength of 35 MPa (5.08 ksi) — weaker than 72% of polymer grades. Elongation at break is 150% and the elastic modulus is 1.5 GPa (0.218 Msi). PP Homopolymer has a density of 0.91 g/cm³ (0.0327 lb/in³), lighter than 80% of polymer grades. Its glass-transition temperature is -10°C (14 °F).
Advantages
- Readily welded — 92/100, better than 97% of polymer grades
- Low embodied carbon — 2 kg CO₂/kg, better than 96% of polymer grades
- Low moisture uptake — 0.02%, better than 92% of polymer grades
- Good corrosion resistance — 92/100, better than 91% of polymer grades
- Tough — resists crack growth — 3.5 MPa·√m (3.19 ksi·√in), better than 80% of polymer grades
Limitations
- Degrades in UV without stabilisers — 20/100, worse than 88% of polymer grades
PP Homopolymer properties
Typical room-temperature values for PP Homopolymer — 11 properties are specific to this condition; the rest are grade-level values shared by every PP grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.
Physical6
PP Homopolymer has a density of 0.91 g/cm³ (0.0327 lb/in³), lighter than 80% of polymer grades. Its glass-transition temperature is -10°C (14 °F).
Mechanical16
PP Homopolymer has a yield strength of 33 MPa (4.79 ksi) and a tensile strength of 35 MPa (5.08 ksi) — weaker than 72% of polymer grades. Elongation at break is 150% and the elastic modulus is 1.5 GPa (0.218 Msi).
Thermal11
PP Homopolymer is rated for continuous service to 100°C (212 °F). It conducts heat at 0.22 W/m·K (0.127 BTU/hr·ft·°F), better than 60% of polymer grades. Thermal expansion is 110 µm/m·K (61.1 µin/in·°F).
Electrical7
PP Homopolymer is an electrical insulator with a dielectric strength of 25 kV/mm (635 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (92/100), better than 91% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PP Homopolymer takes about 78 MJ of energy and emits 2 kg of CO₂ — less than 88% of polymer grades. Typical recycled content is 5%.
Manufacturability8
PP Homopolymer's machinability is good (60/100, better than 51% of polymer grades); weldability excellent (92/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PP grades and fills
PP is also supplied in 13 other conditions. The full side-by-side table is on the PP overview.
- HomopolymerDefaultDefault choice for stiff, heat-resistant, low-cost parts used above 0 °C: housings, containers, chemical tanks, living hinges.33 MPa yield
- GF40Maximum stiffness/strength PP compound where metal replacement and dimensional stability outrank toughness and surface finish.100 MPa tensile
- GF30Workhorse structural PP: highest strength/stiffness per cost for under-hood, pump and HVAC parts to ~130 °C.85 MPa tensile
- GF20Balanced stiffness/toughness/cost for pump housings, fan shrouds and appliance structures.65 MPa tensile
- GF10Small stiffness/HDT boost with minimal warpage and cost penalty; light structural brackets.45 MPa tensile
- StandardGeneric commodity PP when the datasheet does not distinguish homo- from copolymer; safe average design values.30 MPa yield
- Talc FilledCheap stiffness, lower shrinkage/warpage and better dimensional stability and scratch feel; used for automotive trim, appliance and packaging parts.29 MPa yield
- CopolymerPick when toughness below 0 °C matters — automotive interior parts, crates, battery cases, cold-store containers.26 MPa yield · 68 Shore D
- PCRLowest-cost / lowest-carbon option for non-critical parts; expect batch-to-batch variation in colour, MFR and impact.26 MPa tensile
- Random CopolymerFor hot/cold water pipe and fittings and for clearer thin-wall packaging; softer, lower Tm, better clarity and weld strength.25 MPa yield
- FR V0Halogen-free or brominated FR compound for electrical housings, battery boxes and appliance parts needing V-0.25 MPa tensile
- As PrintedUse for chemically resistant, living-hinge or fatigue-flexing printed parts; expect anisotropy, low layer adhesion and severe warping without PP build surface.22 MPa tensile
- EPPMulti-impact energy absorbing foam for automotive bumper cores, head-impact pads and reusable packaging.0.8 MPa tensile
Working with PP Homopolymer
Is PP easy to machine?
Machines easily but is soft and gummy — use sharp, high-rake tools, high speed with low feed pressure, air blast cooling, and generous support to control springback; annealed stock reduces post-machining distortion.
Can PP be welded?
Excellent hot-gas, extrusion, butt-fusion, socket-fusion, ultrasonic, vibration and spin welding with PP filler; no solvent cementing exists — adhesive bonding needs flame/corona/plasma pretreatment or polyolefin primer.
Can PP be formed, bent or molded?
Injection molds at 200–260 °C melt / 20–60 °C tool; shrinkage is high (1.2–2.2%) and crystallization-driven, so allow for post-mold shrink and warp, use uniform walls, and thermoform sheet in the narrow 150–165 °C window.
What surface finishes work on PP?
Cannot be electroplated or anodized; paint and print only after flame/corona/plasma treatment with adhesion promoter, otherwise use in-mold texture, mass coloring or laser marking.
PP chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| ethylene comonomer2–7% in random copolymer (PP-R), 5–15% EPR phase in impact copolymer | 0 – 12 | 0 |
| antioxidant / process stabilizerhindered phenol + phosphite | 0.05 – 0.5 | 0.2 |
| nucleating agent / acid scavengerCa-stearate, sorbitol clarifier | 0 – 0.3 | 0.1 |
| glass fiberGF10–GF40 variants, MAH-PP coupled | 0 – 40 | 0 |
| talc / CaCO3 fillermineral-filled variants | 0 – 40 | 0 |
| propylene repeat unit (C3H6)isotactic polypropylene backbone; copolymer grades contain ethylene comonomer | ≥ 92 (balance) | — |
PP Homopolymer — frequently asked
What is PP Homopolymer used for?
PP Homopolymer is typically used for chemical storage tanks and liners, food packaging containers and closures, living-hinge lids and boxes, pipe and fittings for corrosive fluids, automotive interior trim and battery cases and laboratory labware and trays. In short: rigid; standard plastic.
What is the yield strength of PP Homopolymer?
PP Homopolymer has a typical yield strength of 33 MPa (4.79 ksi) and a tensile strength of 35 MPa (5.08 ksi) — weaker than 72% of polymer grades. Strength varies by condition: see the 14 listed tempers.
Is PP Homopolymer easy to machine?
Reasonably — machinability is rated good (60/100, better than 51% of polymer grades). Machines easily but is soft and gummy — use sharp, high-rake tools, high speed with low feed pressure, air blast cooling, and generous support to control springback; annealed stock reduces post-machining distortion.
Can PP Homopolymer be welded?
Yes — weldability is rated excellent (92/100). Excellent hot-gas, extrusion, butt-fusion, socket-fusion, ultrasonic, vibration and spin welding with PP filler; no solvent cementing exists — adhesive bonding needs flame/corona/plasma pretreatment or polyolefin primer.
What surface finishes work on PP Homopolymer?
Cannot be electroplated or anodized; paint and print only after flame/corona/plasma treatment with adhesion promoter, otherwise use in-mold texture, mass coloring or laser marking.
Can PP Homopolymer be formed, bent or molded?
Injection molds at 200–260 °C melt / 20–60 °C tool; shrinkage is high (1.2–2.2%) and crystallization-driven, so allow for post-mold shrink and warp, use uniform walls, and thermoform sheet in the narrow 150–165 °C window.
What is the maximum service temperature of PP Homopolymer?
PP Homopolymer is rated for continuous use to about 100°C (212 °F), and briefly to 130°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PP Homopolymer?
Yes — PP Homopolymer is available for CNC machining, sheet metal, injection molding and 3D printing with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM D4101 – Standard Classification for Polypropylene Injection and Extrusion Materials — ASTM International (2023)
- ISO 19069-1/-2 – Plastics: Polypropylene (PP) moulding and extrusion materials — ISO (2019)
- GB/T 2546.1 / GB/T 12670 (PP) — SAC (2018)
- Moplen / Pro-fax / Hostacom PP grade datasheets — LyondellBasell (2023)
- Borealis / Borouge PP homopolymer and copolymer datasheets — Borealis (2023)
- CAMPUS plastics database – PP entries (ISO 10350 property set) — CWFG / CAMPUS consortium (2024)
- Engineered Materials Handbook Vol.2: Engineering Plastics — ASM International (1988)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.