Different Kinds Of Polymers And Polymers

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A polymer is a large molecule that is made from many small repeating chemicals called monomers. In the Greek language, polymer literally means “many parts.” Polymers are being used more and more in medical devices, such as drug delivery, screws, plates, fixation pins, suture anchors and many other applications. Some of the most useful polymers for medical uses are poly(lactic acid) (PLA) and poly(glycolic acid) (PGA). They are useful in medicine because of the fact that they can degrade within the body to lesser components that will cause very minimal negative effects. Scientists have found many different ways to control the degradation of these two polymers. Combining two or more different kinds of monomers during polymer formation is called copolymerization. Changing the amount of different kinds of monomers during copolymerization of either poly(lactic-co-glycolic) (PLGA) or PLA can change degradation characteristics. [2] For example, combining lactic acid and glycolic acid to make PLGA will degrade quicker. There are also stereo-copolymers, such as L-lactic acid, and D-lactic acid which are the same chemical, but are mirror images of each other (figure 1). These can be combined to also lower the degradation times of PLA or PGLA. Figure 1. Difference between L- and D-lactic acids (Gupta et al, 2007) Synthesis of PLA and PLGA Synthesis of PLA is started through the fermentation of bacteria. There are several types of bacteria that produce L-, D-lactic acid or a
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