Random and alternating copolymers of PLA

Random polymers are the statistical arrangement of comonomer in their backbone. Numerous monomers have been used to copolymerize with LA, such as lactones, cyclic carbonates, hydroxyl acid, amino acid, and so on, to improve the flexibility, thermal stability, degradability, biocompatibility, hydrophilicity, functionality, etc. The most widely used technique to synthesize random copolymers of PLA is controlled/ living ring-opening polymerization. 

The highly crystalline and hydrophobic nature of PLLA has interfered with modulation of their degradation rate and mechanical properties. It has also been difficult to impart flmctionality to these polymers by application of the ordinary chemical modification methods. JCimura and coworkers have developed a cyclic diester monomer, 3-( )-[(benzyloxycarbonyl)methyl]-l,4-dioxane-2,5-dione (BMD) and 3-(s)-[(dodecyloxycarbonyl)methyl]-l,4-dioxane-2,5-dione (DMD) which consist of both glycolate and a-malate components. The aliphatic polyesters synthesized by their pol)nnerization and copolymerization are functionalized with pendant ester groups that are derived from the a-malate units [21]. 

Copolymers containing carbonate units are very interesting for many biomedical applications because of their increased flexibility, the reduced acidity of the degradation products, and the distinctive profile of hydrolytic degradation [28]. These materials can be obtained through polycondensation [29, 30], 

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