Properties of PLA



The physical properties of polylactic acid are similar to polystyrene. It can also be modified to make it similar to PE (Polyethylene) or PP (Polypropylene). It has performance benefits similar to petrochemical-based plastics but is biodegradable by composting.

  1. PLA-based polymers are completely degradable under compost conditions.
  2. Although PLA is not water soluble, microbes in marine environments can also degrade it into water and carbon dioxide.
  3. PLA-based resins can be modified to adapt to many applications, from disposable food-service items, sheet extrusion, or coatings for paper.
  4. PLA can be processed through for example injection moulding, foil blowing and deep drawing.
  5. PLA may be applied as a coating.
  6. PLA is water resistant but cannot withstand high temperatures (>55°C). In comparison to starch biopolymer the degradation process is very slow. However, within a composting facility it can be broken down in 3 to 4 weeks.
  7. Polylactic acid can be molded, vacuum formed, blown or extruded to yield products typically made from petroleum-based conventional plastics.

PLA is a hard material, similar in hardness to acrylic plastic with hardness on the Rockwell H Scale of more than 60. Therefore, when we extrude a pure PLA sheet and a die is used to cut out the product being printed, the cutting edge of the die wears out rapidly. In addition, due to the hardness, the PLA fractures along the edges creating a product that cannot be used. To overcome these limitations PLA has to be compounded with materials to adjust the hardness and eliminate the fractures when the material is die cut. Mazin¹s hardness (which can be altered easily) is approximately 20.6 on the Rockwell H Scale. Printers whom have worked with it have found the stiffness of the card acceptable and die wear almost eliminated.

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