Condensation polymers are formed when monomers join together, and in the process also form a separate small molecule such as a water molecule. The ends of the monomer molecules must have functional groups that can join with other functional groups on neighbouring molecules.
Condensation polymerisation is the process in which two monomers combine with the elimination of a smaller molecule. One way that two different monomers can combine and in doing so lose a molecule of water and represents condensation polymerisation. This process continues and each remaining end joins with another monomer—each time lengthening the chain. One way to think of this is a “head-to-tail” joining.
Synthetic condensation polymers include nylons and polyesters. Natural condensation polymers include cellulose, cotton, wool, and silk.
Cellulose is a complex carbohydrate or polysaccharide. It is the most abundant biopolymer in nature. Carbohydrates consist of molecules containing C, H and O atoms. Carbohydrates contain many alcohol functional groups.
• Cellulose consists of long chains of β-glucose monomers.
• Glucose is an example of a simple carbohydrate or monosaccharide.
Structure of glucose :
Glucose (C6H12O6) is a ring molecule. The carbon atoms in the ring are numbered as shown. The –OH functional groups may be orientated above or below the plane of the ring. These different orientations at C, produce the alpha and beta forms of the glucose monomers.
• Glucose is an organic compound
• Ring can open up in solution to form a straight-chain structure. Open and chain forms are in equilibrium that cause glucose to exist as anomers, β-glucose and α-glucose.
Biopolymer is a naturally occurring polymer such as cellulose, starch, gluten, DNA and protein.
Formation of cellulose:
Cellulose is a condensation polymer which is formed when glucose monomers condense together through beta-1,4-glycosidic bonds. This involves a reaction between the –OH groups at the C1 and C4 carbons of adjacent glucose molecules.
The process begins by the condensation reaction between two glucose monomers to form a beta-maltose dimer. A water molecule is eliminated during this reaction. More glucose monomers condense and the chain grows until about 10 000 glucose monomers are linked in long, unbranched, ribbon-like strands.
Strong hydrogen bonding exists between –OH groups of neighbouring, close-packed strands. This produces a water-insoluble polymer with great strength and rigidity. Plants use cellulose as a structural carbohydrate for their cell walls.
Post time: Jun-21-2017