--%>
Assignment Help - homework help

What are biodegradable polymers? Present some examples.

 

These are polymers that can be broken into small segments by enzyme-catalysed reactions. The required enzymes are produced by microorganism. It is a known fact that the carbon-carbon bonds of chain growth polymers are inert to enzyme-catalysed reactions, and hence they are non biodegradable. To make such polymers biodegradable we have to insert certain bonds in the chains so that these can be easily broken by the enzymes. Now when such polymers are buried as waste, microorganisms present in the ground can degrade the polymer.

One of the most excellent methods of making a polymer biodegradable is by introducing hydrolysable ester group into the polymer.

For example if acetal is added to an alkene undergoing radical polymerisation, ester group will be inserted into the polymer.

The weak links in the polymer are susceptible to enzyme catalysed hydrolysis.

Aliphatic polyesters are one of the significant categories of biodegradable polymers. Some other examples of biodegradable polymers are described below:

(i) PHBV (Poly-hydroxybutrate-co- 856_Biodegradable1.png-hydroxy valerate):  it is a copolymer of 3-hydroxy butyric acid and 3-hydroxypentanoic acid.
378_Biodegradable.png 


PHBV is used in orthopaedic devices and controlled drug release. The drug put in PHBV capsule is released after this polymer is degraded by enzymatic action. It can also be degraded by bacterial action.

(ii) Poly glycolic acid and poly lactic acid: these are also biodegradable polymers and are used for post operative stitches. These are bioabsorbable structures.

(iii) Nylon-2-Nylon: it is an alternating polyamide copolymer of glycine2233_Biodegradable3.png  and amino caproic acid1005_Biodegradable4.png and is biodegradable.

907_Biodegradable2.png

 

 

 

 

 

   Related Questions in Chemistry

  • Q : Chem Silicon has three naturally

    Silicon has three naturally occurring isotopes. 28Si, mass = 27.976927; 29Si, mass = 28.976495; 30Si, mass = 29.973770 and 3.10% abundance. What is the abundance of 28Si?

    		•
  • Q : How haloalkanes are prepared from

    Alkyl halides can be prepared from alkanes through substitution and from alkenes through addition of halogen acids or through allylic substitution.    From alkanesWhen alkanes are treated with halogens, chlo

    		•
  • Q : Explain reactions of carbonyl oxygen

    In these reaction oxygen atom of carbonyl group is replaced by either one divalent group or two monovalent groups. Reaction by ammonia derivatives: aldehydes and ketones react with a number of ammonia derivatives such as hydroxylaminem hydrazine, semicarbazide etc. in weak acidic medium.

    		•
  • Q : Gibberella fusarium in bioremediation

    in bioremediation gibberella fusarium is used to break down____?

    		•
  • Q : Molecular basis of third law. The

    The molecular, or statistical, basis of the third law can be seen by investigating S = k in W.The molecular deductions of the preceding sections have led to the same conclusions as that stated in the third law of thermodynamics, namely, that a value can be

    		•
  • Q : Molecular weight of solute Select right

    Select right answer of the question. A dry air is passed through the solution, containing the 10 gm of solute and 90 gm of water and then it pass through pure water. There is the depression in weight of solution wt by 2.5 gm and in weight of pure solvent by 0.05 gm. C

    		•
  • Q : Determining Mole fraction of water Can

    Can someone please help me in getting through this problem. The mole fraction of water in 20% aqueous solution of H2O2 is: (a) 77/68 (b) 68/77 (c) 20/80  (d) 80/20

    		•
  • Q : Calculation of concentration of the

    Choose the right answer from following. 200ml of a solution contains 5.85 dissolved sodium chloride. The concentration of the solution will be(Na= 23: cl = 35.5 ) (a) 1 molar (b) 2 molar (c) 0.5 molar (d) 0.25 molar

    		•
  • Q : Problem on reversible and irreversible

    The second law states that  dS ≥ (dQ/T), where dS = dQ/T for a reversible process and dS > dQ/T for an irreversible process.   a. Show that since dW12 = -dW21 (dWreverse = -dWforward) for a r

    		•
  • Q : Ddd 4) The addition of S2- ion to

    4) The addition of S2- ion to Fe(OH)2(s). Explain why the addition of S2- ion to Cr(OH)3(s) does not result in the formation of Cr2S3(s).

    		•