Economical, Direct Route to Making PLA Soon to be Employed
17. August 2015
PLA has made significant inroads in commercial applications, particularly in biodegradable drinking cups, disposable cutlery, vegetable wrapping and holds significant promise for medical applications due to its biocompatibility, and is also making its mark in 3D printing. But its cost is still high due to its costly multi-step production process, which to some degree is stunting the material’s growth.
Recent news from Belgium’s KU Leuven Centre for Surface Chemistry and Catalysis is that researchers have not only come up with a more economical, direct route to making PLA, but they have also sold their technology patent to a yet unnamed chemical company which has plans for industrial-scale use of the new production process.
In a KU Leuven university press release, postdoctoral researcher Michiel Dusseler explained that the technique basically entails applying a petrochemical concept to biomass. “We speed up and guide the chemical process in the reactor with zeolite as a catalyst. Zeolites are porous minerals…by selecting a specific type on the basis of its pore shape, we were able to convert lactic acid directly into the building blocks for PLA without making the larger by-products that do not fit into the zeolite pores. Our new method has several advantages compared to the traditional technique. We produce more PLA with less waste and without using metals. In addition, the production process is cheaper, because we skip a step.”
The existing PLA production process is expensive because of its intermediary steps, according to Professor Bert Sels. It starts with lactic acid being fed into a reactor and converted into a type of pre-plastic under high temperature and in a vacuum. The pre-plastic—a low quality plastic—is then broken down into building blocks for PLA. Says Sels, “In other words, you are first producing an inferior plastic before you end-up with a high-quality plastic. And even though PLA is considered a green plastic, the various intermediary steps in the production process still require metals and produce waste.”
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