PLA – polylactic acid is a type of bioplastic that has similar qualities to polypropylene,  polyethylene, or polystyrene that is also used for packaging. It is derived from renewable resources like cornstarch or sugar cane unlike most plastics that are derived from the distillation and polymerization of petrochemicals that are nonrenewable.

On the hierarchy of the largest production volume of any bioplastic, PLA ranks second. This also implies that it is widely acceptable and equally utilized.

PLA is chemically made by two distinct processes: condensation and polymerization. The polymerization technique in this case is called the ring-opening polymerization. In this process, metal catalysts are utilized in combination with lactide to create the bigger PLA molecules. Eventually, there is a release of by-products as a consequence of the condensation reaction.

There are a wide range of applications of PLA. Of the many that could be mentioned, it could be used in producing films and renewable medical devices. They can be used as a shrink wrap material; since the material constricts under heat. Also its ability to melt makes it useful in 3D printing.

Properties of PLA

The following are properties of PLA:

Technical Name. -    Polylactic Acid (PLA).

Chemical Formula -    (C3H4O2)n

Melt Temperature -    PLLA: 157 - 170 °C (315 - 338 °F)

Typical Injection Molding Temperature -    PLLA:  178 - 240 °C (353 - 464 °F)

Heat Deflection Temperature (HDT)    - 49 - 52 °C (121 - 126 °F) at 0.46 MPa (66 PSI)

Tensile Strength -     PLLA:  61 - 66 MPa (8840 - 9500 PSI)

Flexural Strength -    PLLA:  48 - 110 MPa (6,950 - 16,000 PSI)

Specific Gravity -    PLLA: 1.24

Shrink Rate -    PLLA: 0.37 - 0.41% (0.0037 - 0.0041 in/in)

Characteristics of Polylactic Acid

PLA are commonly classified as thermoplastic polyester, which is because of the way the plastic responds to heat. One major advantage of that phenomenon, that is,  as a thermoplastic is that they can be heated to their melting point, cooled and reheated again without being significantly degraded. Since thermoplastics like PLA don’t burn, they liquefy, which them to be easily  remoulded and recycled. On the contrary, thermoset materials can only be heated once – during the injection process. If after that it is tried to be  heated, it would be burnt. This explains why thermoset materials are not considered favorable for recycling. PLA are categorized under SPI resin identification code of 7.

Types of Polylactic Acid

There are several different types of Polylactic Acid which include: Racemic PLLA (Poly-L-lactic Acid), Regular PLLA (Poly-L-lactic Acid), PDLA (Poly-D-lactic Acid), and PDLLA (Poly-DL-lactic Acid). They each have slightly different characteristics but are similar in that they are produced from a renewable resource (lactic acid: C3H6O3) as opposed to traditional plastics which are derived from non renewable petroleum.

PLA film has become a generally acceptable form of packaging. It is cost-efficient and a non petroleum plastic product. It is also highly favored because of its versatile use and also because it naturally degrades when disposed to the environment. It is also among the services we provide in  Roberts Technology Group Shelf life extending equipment.