PDLLA HMW
Grade
HMW = high molecular weight structural grade
Pick for interference screws, anchors and plates needing maximum strength retention over the first months of resorption.
Values for the HMW condition
Other PDLLA grades and fills
PDLLA is listed in 6 conditions; see the grade overview at PDLLA.
Compare all 6 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
PDLLA-PEG block copolymer | Pick for micelles, thermogels and hydrophilic nanoparticle carriers; behaves as a soft/waxy or gelling material rather than a rigid plastic. | 8 | 10 | 60 | 45 Shore D |
Plasticized / impact-modified PDLLA compound | Pick when ductile membranes, films or flexible resorbable sheets are required; plasticizer (e.g. citrate/PEG/oligolactide) trades stiffness and Tg for elongation. | 24 | 28 | 120 | 62 Shore D |
Low molecular weight drug-delivery grade | Pick for microspheres, implants and in-situ gels needing weeks-to-months release; mechanically weak, used as a matrix not a structural part. | 25 | 25 | 2.5 | 78 Shore D |
Acid-terminated (free carboxylic end-group) grade | Pick when faster hydrolysis and higher hydrophilicity are needed for burst/short-term drug release or rapid-resorbing coatings. | 30 | 30 | 3 | 79 Shore D |
HMWThis page High molecular weight structural grade | Pick for interference screws, anchors and plates needing maximum strength retention over the first months of resorption. | 55 | 58 | 7 | 84 Shore D |
Poly(L-lactide-co-D,L-lactide) 70:30 stereocopolymer | Pick for resorbable fixation where amorphous, crack-free implants are wanted but with higher stiffness and slower degradation than pure PDLLA. | 58 | 60 | 6 | 84 Shore D |
What is PDLLA HMW?
PDLLA HMW is PDLLA in the HMW grade — pick for interference screws, anchors and plates needing maximum strength retention over the first months of resorption. PDLLA HMW has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 58 MPa (8.41 ksi) — stronger than 62% of polymer grades. Elongation at break is 7% and the elastic modulus is 3.3 GPa (0.479 Msi). PDLLA HMW has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 64% of polymer grades. Its glass-transition temperature is 57°C (135 °F).
Advantages
- Low embodied carbon — 2.2 kg CO₂/kg, better than 93% of polymer grades
- Low, predictable mold shrinkage — 0.4%, better than 82% of polymer grades
- Stiff — 3.3 GPa (0.479 Msi), better than 80% of polymer grades
- Polishes to a fine finish — 70/100, better than 77% of polymer grades
Limitations
- Needs corrosion protection — 35/100, worse than 99% of polymer grades
- Limited service temperature — 48°C (118 °F), worse than 96% of polymer grades
- Poor heat conductor — 0.15 W/m·K (0.0867 BTU/hr·ft·°F), worse than 80% of polymer grades
PDLLA HMW properties
Typical room-temperature values for PDLLA HMW; 27 are specific to this condition. Other listed values are PDLLA reference data and may not represent this condition. Bars are the position among polymer grades.
Physical6
PDLLA HMW has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 64% of polymer grades. Its glass-transition temperature is 57°C (135 °F).
Mechanical14
PDLLA HMW has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 58 MPa (8.41 ksi) — stronger than 62% of polymer grades. Elongation at break is 7% and the elastic modulus is 3.3 GPa (0.479 Msi).
Thermal11
PDLLA HMW is rated for continuous service to 48°C (118 °F). It conducts heat at 0.15 W/m·K (0.0867 BTU/hr·ft·°F), worse than 80% of polymer grades. Thermal expansion is 85 µm/m·K (47.2 µin/in·°F).
Electrical5
PDLLA HMW is an electrical insulator with a dielectric strength of 17 kV/mm (431.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 99% of polymer grades. UV resistance is fair.
Sustainability3
Producing a kilogram of PDLLA HMW takes about 55 MJ of energy and emits 2.2 kg of CO₂ — less than 98% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PDLLA HMW's machinability is good (65/100, better than 66% of polymer grades); weldability fair (45/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with PDLLA HMW
Is PDLLA easy to machine?
Machinable with sharp carbide/single-flute tools at high speed and low feed with air or cryogenic cooling — no water coolant (hydrolysis) and keep the part well below the 55 °C Tg to avoid smearing.
Can PDLLA be welded?
Joined by solvent bonding (dichloromethane, chloroform, ethyl acetate) or low-temperature hot-plate/ultrasonic welding; avoid prolonged melt exposure which cuts molecular weight and degradation lifetime.
Can PDLLA be formed, bent or molded?
Dry to <250 ppm (40–45 °C vacuum, never above Tg) then injection-mold at 160–200 °C melt / 20–45 °C tool with short residence time; amorphous so parts demold clear with low, isotropic shrinkage.
What surface finishes work on PDLLA?
Vapor-polish or flame-free solvent polishing gives clarity; sterilize by ethylene oxide or e-beam/gamma at controlled dose — steam autoclaving destroys the part, and gamma reduces molecular weight.
PDLLA 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 lactide monomermedical grades typically <0.5 % | 0 – 1 | 0.3 |
| tin(II) 2-ethylhexanoate catalyst residuring-opening polymerization catalyst; limited for implant use | 0 – 0.02 | 0.01 |
| alcohol initiator / end-cap (dodecanol, controls molecular weight and degradation rate | 0 – 2 | 0.5 |
| D,L-lactide (racemic lactide) repeat uni≈50:50 D- and L-lactic acid units; atactic chain, no crystallinity | ≥ 98 (balance) | — |
PDLLA HMW — frequently asked
What is PDLLA HMW used for?
PDLLA HMW is typically used for drug delivery microspheres, resorbable surgical implants, tissue engineering scaffolds and medical coatings. In short: fastest-degrading PLA type; amorphous, clear resorbable grade; drug-release matrix polymer.
What is the yield strength of PDLLA HMW?
PDLLA HMW has a typical yield strength of 55 MPa (7.98 ksi) and a tensile strength of 58 MPa (8.41 ksi) — stronger than 62% of polymer grades. Strength varies by condition: see the 6 listed tempers.
Is PDLLA HMW easy to machine?
Reasonably — machinability is rated good (65/100, better than 66% of polymer grades). Machinable with sharp carbide/single-flute tools at high speed and low feed with air or cryogenic cooling — no water coolant (hydrolysis) and keep the part well below the 55 °C Tg to avoid smearing.
Can PDLLA HMW be welded?
With care — weldability is rated fair (45/100). Joined by solvent bonding (dichloromethane, chloroform, ethyl acetate) or low-temperature hot-plate/ultrasonic welding; avoid prolonged melt exposure which cuts molecular weight and degradation lifetime.
What surface finishes work on PDLLA HMW?
Vapor-polish or flame-free solvent polishing gives clarity; sterilize by ethylene oxide or e-beam/gamma at controlled dose — steam autoclaving destroys the part, and gamma reduces molecular weight.
Can PDLLA HMW be formed, bent or molded?
Dry to <250 ppm (40–45 °C vacuum, never above Tg) then injection-mold at 160–200 °C melt / 20–45 °C tool with short residence time; amorphous so parts demold clear with low, isotropic shrinkage.
What is the maximum service temperature of PDLLA HMW?
PDLLA HMW is rated for continuous use to about 48°C (118 °F), and briefly to 60°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM F1925 — Standard Specification for Semi-Crystalline Poly(lactide) Polymer and Copolymer Resins for Surgical Implants — ASTM International (2022)
- ASTM F1635 — In Vitro Degradation Testing of Hydrolytically Degradable Polymer Resins and Fabricated Forms — ASTM International (2021)
- RESOMER R-series (poly(D,L-lactide)) product information — Evonik Health Care (2023)
- PURASORB PDL / PLDL bioresorbable polymer datasheets — Corbion (Purac Biomaterials) (2023)
- Handbook of Biodegradable Polymers / Poly(lactic acid): Synthesis, Structures, Properties, Processing and Applications — Wiley (2010)
- Bio-based thermoplastics property tables (PLA/PDLLA) — CAMPUS / producer compilations (2023)
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.