Oxygen Polylactide

One approach to compartmentalize hemoglobin is to encapsulate hemoglobin in biodegradable polymer-PEG-polylactide (30). These nanocapsules have a diameter of 80-150 nm and contain superoxide dismutase, catalase, carbonic anhydrase, and other enzymes of Embden-Meyerhof pathway that are needed for long-term function of an oxygen carrier (31,32). The polylactide capsules are metabolized in vivo to water and carbon... 

The polymerization of lactones with tin alkoxides is thought to follow the co-ordination-insertion mechanism[77a]. The ring-opening of the monomer proceeds through acyl-oxygen cleavage with retention of the configuration. Tin(IV) complexes have been used to produce predominantly syndiotactic poly((3-hy-droxybutyrate) [78,79],macrocyclic poly((3-hydroxybutyrate) [80],poly(e-CL), and polylactide [77,76,81]. 

Auras and co-workers [61] studied the variations in the oxygen diffusion solubility, permeability coefficients and water sorption of polylactide films at different temperatures (5, 23, and 40 °C) and water activities (A = 0-0. 9). The results were compared with the oxygen diffusion, solubility and permeability coefficients obtained for PET films under the same experimental conditions. 

The permeability - water vapor, oxygen, and carbon dioxide - of polylactide nanocomposites reinforced with MMT, was affected using two types of MMT (Cloisite 30B and Nanofil 2), with the addition of two organic modifiers (poly(methyl methacrylate) and ethylene/vinyl alcohol copolymer) and two compatibilizers (PCL and poly(ethylene glycol)). Zenkiewicz and Richert [287] found that Cloisite 30B decreased the film permeability much more than Nanofil 2 and that all the modifiers and compatibilizers reduced the carbon dioxide transmission rate, while only the modifiers reduced the transmission rates of water vapor and oxygen. 

Yourdkhani M, Mousavand T, Chapleau N, Hubert P. Thermal, oxygen barrier and mechanical properties of polylactide-organoclay nanocomposites. Compos Sci Technol 2013 82 47-53. 

These polymers, some of which are listed next are used to modify the atmosphere within packaged foods, beverages, pharmaceuticals and cosmetics and to control the ingress of, for example, oxygen, ethylene-vinyl alcohol, perfectly alternating polyketones, thermoformable ethylene-vinyl, alcohol blends, polylactide, and polyethylene terephthalate. 

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