Polylactic acid

Polylactic acid
The skeletal formula of PLA
Identifiers
ChemSpider
  • None
Properties
Density 1210–1430 kg/m3[1]
Melting point 150 to 160 °C (302 to 320 °F; 423 to 433 K)[1]
0 mg/ml [2]
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
1
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Polylactic acid, also known as poly(lactic acid) or polylactide (PLA), is a plastic material. As a thermoplastic polyester (or polyhydroxyalkanoate) it has the backbone formula (C
3H
4O
2)
n or [–C(CH
3)HC(=O)O–]
n. PLA is formally obtained by condensation of lactic acid C(CH
3)(OH)HCOOH with loss of water (hence its name). It can also be prepared by ring-opening polymerization of lactide [–C(CH
3)HC(=O)O–]
2, the cyclic dimer of the basic repeating unit. Often PLA is blended with other polymers. PLA can be biodegradable or long-lasting, depending on the manufacturing process, additives and copolymers.

PLA has become a popular material due to it being economically produced from renewable resources and the possibility to use it for compostable products.[3] In 2022, PLA had the highest consumption volume of any bioplastic of the world, with a share of ca. 26 % of total bioplastic demand.[4] Although its production is growing, PLA is still not as important as traditional commodity polymers like PET or PVC. Its widespread application has been hindered by numerous physical and processing shortcomings.[5] PLA is the most widely used plastic filament material in FDM 3D printing, due to its low melting point, high strength, low thermal expansion, and good layer adhesion, although it possesses poor heat resistance unless annealed.[6][7]

Although the name "polylactic acid" is widely used, it does not comply with IUPAC standard nomenclature, which is "poly(lactic acid)".[8] The name "polylactic acid" is potentially ambiguous or confusing, because PLA is not a polyacid (polyelectrolyte), but rather a polyester.[9]

  1. ^ a b "Material Properties of Polylactic Acid (PLA), Agro Based Polymers". Matbase - Material Properties Database. Archived from the original on 10 February 2012. Retrieved 6 February 2012.
  2. ^ "Polylactic Acid. Material Safety Data Sheet" (PDF). ampolymer.com. Archived from the original (PDF) on 6 January 2009.
  3. ^ Teixeira LV, Bomtempo JV, Oroski Fd, Coutinho PL (2023). "The Diffusion of Bioplastics: What Can We Learn from Poly(Lactic Acid)?". Sustainability. 15 (6): 4699. doi:10.3390/su15064699.
  4. ^ Ceresana. "Bioplastics - Study: Market, Analysis, Trends - Ceresana". www.ceresana.com. Retrieved 25 October 2024.
  5. ^ Nagarajan V, Mohanty AK, Misra M (2016). "Perspective on Polylactic Acid (PLA) based Sustainable Materials for Durable Applications: Focus on Toughness and Heat Resistance". ACS Sustainable Chemistry & Engineering. 4 (6): 2899–2916. doi:10.1021/acssuschemeng.6b00321.
  6. ^ "Worldwide most used 3D printing materials, as of July 2018". Retrieved 19 January 2024.
  7. ^ Simmons H, Tiwary P, Colwell JE, Kontopoulou M (August 2019). "Improvements in the crystallinity and mechanical properties of PLA by nucleation and annealing". Polymer Degradation and Stability. 166: 248–257. doi:10.1016/j.polymdegradstab.2019.06.001. S2CID 195550926.
  8. ^ Vert M, Chen J, Hellwich KH, Hodge P, Nakano T, Scholz C, et al. "Nomenclature and Terminology for Linear Lactic Acid-Based Polymers (IUPAC Recommendations 2019)". IUPAC Standards Online. doi:10.1515/iupac.92.0001.
  9. ^ Martin O, Avérous L (2001). "Poly(lactic acid): plasticization and properties of biodegradable multiphase systems". Polymer. 42 (14): 6209–6219. doi:10.1016/S0032-3861(01)00086-6.