Polycondensation

This type of polymerisation generally involves repetitive condensation between two bifunctional monomers. Polycondensation results in loss of simple molecules like water, alcohol etc, and lead to formation of high molecular weight polymers. Here the product formed is also bifunctional species and the sequence of condensation goes on. Each step forms a distinct bifunctional species and each species is independent of each other, thus this process is also called step growth polymerisation.

The formation of PET/ Terylene/ Dacron occurs by this type of polymerisation.

Formation of PET

Polymerisation mechanism

Step growth process proceeds via stepwise reaction between the funtional group of reactants. The size of polymer increases at a relatively slow pace in condensation polymerisation.

One proceeds from monomer to dimer, trimer, tetramer, pentamer and so on until eventually a large sized polymer is formed.

Polycondensation.

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Difference between organic and inorganic polymers.

Difference between organic and inorganic polymers. Definition Organic polymers are the polymers that essentially contain carbon atom in the backbone. Inorganic polymers are the polymers that have no carbon atom in the backbone. Structure Most organic polymers have simple structures. Almost all inorganic polymers are highly branched and have complex structures. Electrical Conductivity In most of the aqueous solutions, organic polymers are typically poor conductors of electricity and heat. Inorganic polymers in aqueous solutions are good conductors of electricity, this is because they have high ability to ionise and this makes them better conductors. Flammability Organic polymers are flammable whereas inorganic polymers are nonflammable. Effect on nature Organic polymers are environmental friendly as these are biodegradable. Inorganic polymers are not environmental friendly as these are non biodegradable. Examples Organic polymers include polysaccharide...

Monomers.

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Determination of molecular weight of polymers by viscosity method.

Determination of molecular weight of polymers by viscosity method. It is a simple method for determining the molecular weight of polymers. Addition of polymers in the solvent increases the viscosity of the solvent, due to introduction of inhomogeneities by the polymers. If η₀ is the viscosity of the solvent and η is the viscosity of the solution at the same temperature, then the relative viscosity is given by Relative viscosity. Specific viscosity: It is defined as the relative increase in viscosity and is given as Specific viscosity. Reduced viscosity: It is defined as the relative increase in viscosity per unit concentration (C) of polymer and is given as Reduced viscosity. Intrinsic viscosity: The reduced viscosity is dependent on concentration (C). If a graph is plotted between reduced viscosity vs concentration then the extraplotation value when C=0 is called intrinsic viscosity. Intrinsic viscosity. Graph of reduced vi...

Polymers

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