PHB
also Biopol
The simplest and most crystalline member of the PHA family, produced by bacterial fermentation of sugars/lipids; brittle and stiff, used mainly as a base resin blended with plasticizers or copolymerized as PHBV/PHBH.
Reference datasheet — PHB is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
PHB grades and fills
PHB is supplied in 6 conditions, soft to hard.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Poly | Use the adjustable-4HB copolymer where flexibility dominates — up to 200% elongation at 0.5 GPa — for films, straws and resorbable medical parts, accepting rigid-to-elastomeric low stiffness. | 14 | 20 | 200 | 50 Shore D |
Plasticized / impact-modified PHB compound | Pick the citrate/ATBC-plasticized or rubber/PBAT-toughened compound for production films and molded parts: 40% elongation and usable impact traded against 1.2 GPa stiffness and 70 °C service. | 18 | 20 | 40 | 62 Shore D |
Poly | Choose the HHx copolymer for straws, films and cutlery coatings needing 80% elongation and the best seawater degradation; stiffness drops to 0.8 GPa and service temperature to 75 °C. | 22 | 80 | 60 Shore D | |
Natural-fiber / wood-flour filled PHB | Choose the 20–30% wood-flour, bamboo or wheat-straw filled fully bio-based compound for disposable containers and garden parts, accepting 2% elongation, higher brittleness and water uptake. | 28 | 28 | 2 | 78 Shore D |
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), 3–12 mol% HV | Pick the 3–12 mol% HV copolymer for cutlery, packaging and molded parts: HV units lower melting point and crystallinity, widening the processing window and raising elongation to 12% at 30 MPa. | 30 | 12 | ||
Nucleated / talc-filled PHB | Specify the 1–15% talc or boron-nitride nucleated grade for thin-wall molded tableware: shorter cycles, no secondary-crystallization embrittlement, highest stiffness at 4.2 GPa but only 3% elongation. | 32 | 32 | 3 | 80 Shore D |
Supply forms, finishes and certifications
Ways PHB is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FOOD | Food-contact grade | Certification |
MED | Medical / resorbable implant grade | Certification |
NATDefault | Unfilled PHB homopolymer, natural | Standard supply |
What is PHB?
The simplest and most crystalline member of the PHA family, produced by bacterial fermentation of sugars/lipids; brittle and stiff, used mainly as a base resin blended with plasticizers or copolymerized as PHBV/PHBH. PHB has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 64% of polymer grades. Its glass-transition temperature is 4°C (39 °F). PHB has a yield strength of 35 MPa (5.08 ksi) and a tensile strength of 36 MPa (5.22 ksi) — weaker than 66% of polymer grades. Elongation at break is 5% and the elastic modulus is 3.5 GPa (0.508 Msi).
What is PHB used for?
- rigid biodegradable packaging
- PHA blend base resin
- agricultural film additive
- medical microcapsules
Advantages
- Low embodied carbon — 2.2 kg CO₂/kg, better than 93% of polymer grades
- Stiff — 3.5 GPa (0.508 Msi), better than 83% of polymer grades
PHB properties
Typical room-temperature values; bars are the position among polymer grades.
Physical6
PHB has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 64% of polymer grades. Its glass-transition temperature is 4°C (39 °F).
Mechanical11
PHB has a yield strength of 35 MPa (5.08 ksi) and a tensile strength of 36 MPa (5.22 ksi) — weaker than 66% of polymer grades. Elongation at break is 5% and the elastic modulus is 3.5 GPa (0.508 Msi).
Thermal11
PHB is rated for continuous service to 100°C (212 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 56% of polymer grades. Thermal expansion is 90 µm/m·K (50 µin/in·°F).
Electrical4
PHB is an electrical insulator with a dielectric strength of 20 kV/mm (508 V/mil) and a resistivity of 1×10¹³ Ω·m.
Chemical & Environmental2
UV resistance is fair.
Sustainability3
Producing a kilogram of PHB takes about 60 MJ of energy and emits 2.2 kg of CO₂ — less than 96% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PHB's machinability is good (55/100, worse than 64% of polymer grades); weldability fair (50/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. PHB is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PHB
Is PHB easy to machine?
Turns, mills and drills, but the material is brittle and a poor conductor of heat. Use sharp tools, high speed, light feed and ample cooling to avoid stress cracking and edge chipping.
Can PHB be welded?
Hot-plate, ultrasonic and hot-air welding all work, but temperature must be held close to 175 °C. Overheating causes immediate thermal degradation with yellowing and odour.
Can PHB be formed, bent or molded?
Dry before injection moulding or extrusion (80 °C for 2-4 h, moisture below 0.05 %) and hold melt strictly at 165-180 °C with the shortest possible residence time. High crystallinity causes marked post-moulding shrinkage, so use a nucleating agent and 50-60 °C tools; thermoforming and blown film normally need copolymer or plasticised grades.
PHB 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 |
|---|---|---|
| residual biomass / ashfermentation extraction residue; lower for medical grade | 0 – 1.5 | 0.5 |
| 3-hydroxybutyrate (3HB)homopolymer; partly replaced by 3HV/3HHx/4HB in copolymers | ≥ 97 (balance) |
What surface finishes work on PHB?
Printable and labellable, and takes water-based or UV coatings, preferably after corona treatment. Not suitable for high-temperature bake finishes or solvent cleaning, since chlorinated solvents dissolve it.
Equivalent designations
Standards and trade names that resolve to PHB in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Biopol
How much does PHB cost?
PHB is a premium-cost polymer ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PHB — frequently asked
What is PHB used for?
PHB is typically used for rigid biodegradable packaging, PHA blend base resin, agricultural film additive and medical microcapsules. In short: stiffest PHA grade; highest-temperature PHA; brittle base blending resin.
What is the yield strength of PHB?
PHB has a typical yield strength of 35 MPa (5.08 ksi) and a tensile strength of 36 MPa (5.22 ksi) — weaker than 66% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is PHB easy to machine?
Reasonably — machinability is rated good (55/100, worse than 64% of polymer grades). Turns, mills and drills, but the material is brittle and a poor conductor of heat. Use sharp tools, high speed, light feed and ample cooling to avoid stress cracking and edge chipping.
Can PHB be welded?
With care — weldability is rated fair (50/100). Hot-plate, ultrasonic and hot-air welding all work, but temperature must be held close to 175 °C. Overheating causes immediate thermal degradation with yellowing and odour.
What surface finishes work on PHB?
Printable and labellable, and takes water-based or UV coatings, preferably after corona treatment. Not suitable for high-temperature bake finishes or solvent cleaning, since chlorinated solvents dissolve it.
Can PHB be formed, bent or molded?
Dry before injection moulding or extrusion (80 °C for 2-4 h, moisture below 0.05 %) and hold melt strictly at 165-180 °C with the shortest possible residence time. High crystallinity causes marked post-moulding shrinkage, so use a nucleating agent and 50-60 °C tools; thermoforming and blown film normally need copolymer or plasticised grades.
What is the maximum service temperature of PHB?
PHB is rated for continuous use to about 100°C (212 °F), and briefly to 140°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PHB cost?
PHB is a premium-cost polymer ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Handbook of Biodegradable Polymers — polyhydroxyalkanoates chapter — De Gruyter / Rapra (2020)
- ENMAT Y1000 series PHBV resin data — TianAn Biopolymer (2023)
- Green Planet PHBH resin technical data — Kaneka (2023)
- CAMPUS / UL Prospector — CAMPUS (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.