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Thermoplastic elastomers (TPEs) having unusual physical and chemical properties were prepared by copolymerization of LLA with TMC. Recently, a batch procedure for the preparation of degradable TPEs based on multiblock copolymers of LLA with TMC were reported [71] using a combination of ring‐expansion polymerization and ROP. The initiator used was 2,2‐dibutyl‐2‐stanna‐1,3‐oxepane. The block lengths were varied via the monomer/initiator and TMC/LLA ratio. These copolymers were transformed in situ into multiblock copolymers by ring‐opening condensation with sebacoyl chloride (Figure 4.9). Li et al. [126] developed the synthesis of a PLA/PPC [poly(propylene carbonate)] multiblock copolymer based on a one‐pot copolymerization of epoxides/carbon dioxide and LA using a ternary catalyst system that proceeds via an intermolecular chain transfer mechanism.

FIGURE 4.9 Representative structure of multiblock copolymers based on LLA and TMC [71].