Lactic acid and PLA: Characteristics
Brittle and heat-shy: PLA's limits and fixes
Brittle and heat-shy: PLA's limits and fixes What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.PLA's commercial limits are heat and toughness: it softens at about 55-60 C unless crystallised, and it is brittle. The ratio of L- to D-lactide sets crystallinity. It composts only at industrial temperatures, so end-of-life claims depend on local infrastructure.
Properties that matter commercially
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Glass transition | about 55-60 C (indicative) | Limits hot-fill and hot-drink uses unless crystallised or blended | indicative |
| Density | about 1.24 g/cm3 (indicative) | Heavier than PE and PP, so more resin per part | indicative |
| D-content | about 0.5-12% D-lactide (indicative) | Low D gives crystalline, heat-resistant grades; high D gives amorphous film grades | indicative |
| Compostability | EN 13432 / ASTM D6400 certified for industrial composting | Needed for compostable claims; home composting is slow | EN 13432; ASTM D6400 |
Commercial grades
- Thermoforming and sheet
- Film and coating
- Injection moulding
- Fibre and nonwoven
- High-heat crystallised grades
- 3D printing filament
- Lactic acid food grade (E270), technical grade, polymer grade