Biocotalysis provides polymers with a broad range of solid-state properties

High molecular weight polymers that cannot be obtained by chemical routes are easily synthesized by lipase-catalyzed polymerization. Some lipases such as Candida antarctica Lipase B, when used in ring opening polymerization, allow incorporation of different monomers along the chain leading to copolymers with defined composition and microstructure. Control over microstructure is critical to the ultimate goal of tailoring the physical, mechanical, and biological properties of copolymers. Hydrophilic/hydrophobic balance can be adjusted by a suitable choice of the two monomers and of composition, leading to materials with tunable hydrolytic degradation rate for environmental and biomedical applications. Copolymers of omega-pentadecalactone with epsilon-caprolactone, valerolactone, dioxanone and trimethylenecarbonate are highly crystalline over the whole composition range, an unusual behavior due to co-crystallization of the co-monomer units. Copolyestercarbonates, copolyesteramides and polyol-containing copolyesters synthesized by lipase-catalysed polycondensation show strongly composition dependent physical properties, that can be easily tailored by composition control and cover the whole range from hard solid materials down to gluelike substances.