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In direct polymerization, lactide is formed and decomposed simultaneously, and
hence, it is not used for large-scale production. Though this method produces lowquality PLA which is useless, using a melt condensation step, this methodology can
be used to obtain PLA of high M W .
3.3 Ring-Opening Polymerization (ROP)
To obtain PLA of high M W , ring-opening polymerization (ROP) is generally applied.
ROP usually involves three steps:
1. Polycondensation of LA monomers to produce low M W PLA (direct
polymerization)
Fig. 3 Principle routes to prepare PLA
Biological and Environmental Degradations of Polyamides, Polylactic Acid…
In direct polymerization, lactide is formed and decomposed simultaneously, and
hence, it is not used for large-scale production. Though this method produces lowquality PLA which is useless, using a melt condensation step, this methodology can
be used to obtain PLA of high M W .
3.3 Ring-Opening Polymerization (ROP)
To obtain PLA of high M W , ring-opening polymerization (ROP) is generally applied.
ROP usually involves three steps:
1. Polycondensation of LA monomers to produce low M W PLA (direct
polymerization)
Fig. 3 Principle routes to prepare PLA
Biological and Environmental Degradations of Polyamides, Polylactic Acid…