Why do PLA plastic polymers have variable physical properties? 1

[Hisham Maalik]

I was on the wiki page for PLA polymers and the physical properties given were all ranges of values rather than specific values:

Example:
Young’s modulus: 2.7 to 16 GPa

So are PLA polymers just a type of polymer of which there are various subtypes?
Why are their properties ranges of values

 

[Latexman]

PLA polymers range from amorphous glassy polymer to semi-crystalline and highly crystalline polymer with a glass transition 60–65 °C, a melting temperature 130-180 °C, and a Young's modulus 2.7–16 GPa.

The polymer itself can be made into a wide range of end products. The degree of polymerization, or molecular weight (MW) of the polymer, can be varied. The MW distribution and particle size distribution can be varied. It can be annealed or not annealed. It can be blended with minor amounts of other components to enhance specific properties, but the major ingredient can still be mostly PLA. It is a versitile polymer, thus the wide range of properties to cover the wide range of end products.

Good Luck,
Latexman