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

Post a Comment

Popular posts from this blog

How to write a Forensic Case Study: Murder of Junko Furuta

Image
Photo of Junko Furuta  For one to score high marks in a Forensic Case Study, one must  adhere to the following: Background of the case: This section contains details about the crime. It includes; the reasons for committing the offense, the conditions which the crime was committed, the circumstances of the crime scene and clear identification of the suspect(s) and the victim(s). One should ensure that the information in this part gives a precise idea of what the case is all about.   Pick and Write an article on Iwriter Website Evidence: This encompasses the piece of evidence found at the crime scene. The evidence should be described in details, that is, ways in which the evidence was collected, processed and preserved.   Forensic Tests: The tests should be two or more that were used to analyze the evidence. The science or theory of instrumentation used must be described fully.   Results: This consists of a detailed explanation of the forensic ...
Read more

Roles of Sodium Carbonate when Extracting Caffeine from Tea Leaves

Image
A student failed to add sodium carbonate (Na 2 CO 3 ) when extracting caffeine from tea leaves with hot water. Though, high yield of caffeine was produced. The crystals melted at temperatures between 202  and 214 degree  Celsius. Explain. This happened because sodium carbonate did not interfere with the caffeine content of the tea leaves. Sodium carbonate (which is a base) deprotonates the phenolic hydroxyl group (-OH) (acidic) of tannins rendering them anionic. Hence, making them highly soluble in water, but parsimoniously soluble in methylene chloride. So, if sodium carbonate is not added when extracting caffeine with hot water, the extracted caffeine would also contain tannins. Additionally, sodium carbonate is added during the extraction to keep caffeine (an alkaloid which is an organic base)  in a free base form. It prevents caffeine from reacting with available acid available, which may lead to the formation cation. It reacts with a phenolic h...
Read more

Arrhenius equation: Increasing temperature increases the rate reaction

Image
The rate of reaction of a particular reaction often increases as one increase the temperature. However, how can this belief be proved using Arrhenius equation? According to the Arrhenius equation, the rate constant (k) is obtained by the ratio of Ea to RT, in which Ea denotes required energy while RT is the available thermal energy. The Arrhenius Equation is given by: k=Ae - (Ea/RT) When Ea is larger, it results in slower reactions. On the other hand, when RT is large, it leads to faster rate of reaction. Larger Ea gives smaller rate constant k, but larger RT produces larger rate constant (k). Larger rate constant increases the rate of reactions.  By using Arrhenius equation, one can easily see that when the temperature is increased, the rate constant will also increase. Let us consider these two scenarios. In the first scenario, Ea=120,000 Joules/mole, R=8.31 mol -1 K -1 , and K=373K.In the second scenario, Ea=120,000Joules/mole, R=8.31 mol -1 K -1 , and K...
Read more