Synthesis of Bioplastic(Polylactic acid) from Corn



Polylactic acid (PLA) products are polymers (plastics) manufactured from lactic acid. Lactic acid is an organic molecule which occurs naturally in living organisms. Lactic acid is synthesized from glucose through anaerobic fermentation (fermentation without oxygen). It is commercially manufactured from starchy plant materials such as corn or potatoes. Lactic acid is capable of polymerizing to form PLA (polylactic acid) products. PLA is one of the most bioplastics receiving more attention in different parts of the world. The process commences with first reacting starch derived from corn and water enzymatically. The process breaks the glycosidic linkages of starch to yield glucose (a monomer). Glucose is then converted to lactic acid via anaerobic fermentation. A three carbon atoms compound (pyruvate) is produced in the process as in the glycolysis process step number ten (10).
 Lactic acid released in the process is enantiomerically enhanced with 99.5% in L form (Fig b). Polymerisation of lactic acid into prepolymer (oligomer) is the next step.  The polymerization takes place in a mild solventless condensation. A pre-polymer with low molecular weight is produced in the condensation polymerization. This pre-polymer is then catalytically broken down into two cyclic linked monomers (dimer) or what is known as lactide (dimer of lactic acid), which can form three stereochemical isomers. The step that follows is the separation of these three stereochemical isomers into two distinctive groups, that is, L-lactide and D-/meso lactide (Fig c). These lactide subunits (L-lactide and D-/Meso lactide) are catalytically linked together in a solventless ROP (Ring-Opening Polymerization) to yield high molecular weight polymer (PLA). Ring-opening polymerization is an additional reaction. These processes taking place and the different compounds that are produced during the process are outlined below (Fig a, b, c and d).
Fig  a: 
Fig b: 
Fig c:

 Fig d: 



                                                                                                                                                                

Comments

  1. Cristin22 July 2018 at 07:20

    This is my first time visit here. From the tons of comments on your articles,I guess I am not only one having all the enjoyment right here! Polylactic acid

    ReplyDelete
  2. alfachemistry8 August 2018 at 11:37

    In stock products can be shipped out within 3-5 business days upon receipt of customers' purchase order. Polylactic acid

    ReplyDelete

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