Green polylactic acid, biodegradation

Polylactates are an interesting class of biodegradable polymers which may be made from either renewable or petroleum feedstocks. The synthesis of lactic acid raises real issues concerning the relative greenness of the renewable and non-renewable (HCN) route as discussed in Chapter 2. A summary comparison of the greenness of both routes is shown is Table 6.4. Without a full LCA the choice of route on environmental grounds is not easy and at least partly depends on plant location and raw material availability. 

Renewable feedstocks can also be used as the raw materials for the synthesis of green, biodegradable polymers. A pertinent example is polylactate, derived from lactic acid which is produced by fermentation (see earlier). Another recent example is the production of polycarbonates by reaction of C02 with (R)-limonene oxide in the presence of a zinc catalyst (Fig. 8.47) [221]. 

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