Lactide production technology

Lactide production technologies have been in use since the 1930s, with the related pubhcation by Carothers et al. (1932) about the reversible polymerization of six-membered cyclic esters. After that, lactide technology underwent a period of inactivity because the purity of lactide was insufficient for large-scale production. Lactide technology did well after DuPont developed a purification technique. This ultimately led towards mass-scale production by NatureWorks. This section mainly focuses on the mass-scale lactide production as developed by Cargill—DuPont (currently known as NatureWorks) in the early phases, as well as some related lactide technologies. 

Y Irradiation has proven useful for many lactide/glycolide formulations. This again is an extension of technology from the biodegradable suture field. The appropriate dose of y irradiation must be determined for each new drug delivery product (57). The D value, the amount of irradiation in Mrads needed to achieve a 90% reduction in the microorganism population, can be determined from Eq. (1) ... 

Results are presented of some preliminary tests of the irreversible immobilisation of poly(L,L-lactide) microspheres loaded with Triclosan antibacterial agent onto viscose non-woven structures. The research covered the production of a suspension containing microspheres loaded with Triclosan, tests on the bonding of microspheies with the base textile material and a quantitative assessment of the effect achieved (including microbiological tests). These results indicate the potential for development of new technologies for medical textiles. 11 refs. 

Biodegradable plastics based on lactic acid have been available on a small scale for many years. They have been used In applications such as medical implants, but their high price was a deterrent to widespread use in lower value applications such as packaging. However, new technologies for production of lactide monomers greatly lowered costs, making the polymers much more competitive. Generally, the lactic acid is obtained from corn or other biobased materials by a fermentation process, and then chemical synthesis is used to produce the polymer from the lactic acid or lactide monomers. 

Van Aardt, M., Duncan, S.E., Marcy, J.E., Long, T.E., O Keefe, S.F., Sims, S.R. 2007. Release of antioxidants from poly(lactide-co-glycolide) films into dry milk products and food simulating liquids. International Journal of Food Science and Technology, 42(11) 1327-1337. 

New processes have been developed to produce solvents which are based on non-conventional materials (e.g., lactide and drying oil). The resultant solvent is non-volatile and useful in production of coatings, paints and inks. These new technological processes are driven by the need to reduce VOCs. 

In 2011, the first plant to use a new polymerisation technology for PLA, developed by Sulzer Chemtech and Purac Biochem and built by Synbra Technology in the Netherlands, started industrial production of Synterra PLA grades. The new plant has a capacity of 5,000 tonnes/year it uses L- and D-lactides from Purac, produced from genetically modified organism (GMO)-free plant feedstock, which is 100% biobased. 

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