Carbonyl addition elimination mechanism

This is a step growth polymerisation mechanism. This method is important for the preparation of condensation polymers. Here addition and elimination at the carbonyl double bond of carboxylic acids or it's derivative occurs.

Step growth polymerisation mechanism.

The species in the bracket is at metastable equilibrium and it can either return to it's original state by eliminating Y or it can proceed to its final state by eliminating X. Example of this reaction is interfacial condensation.

Interfacial condensation

The reaction of acid halide with a glycol or a diamine can be proceed rapidly to high molecular weight polymers, if carried at the interface between two liquids, each containing one of the reactants.

Typically an aqueous phase containing glycol or diamine and an acid acceptor is layered at room temperature over the organic phase containing acid chloride. The polymer formed at the interface can be pulled off as a continuous film or filament.

The polymers formed by interfacial condensation are polyureas, polyphenyl esters, polyamides, polyurethanes etc. Those polymers which are unstable at higher temperature are formed by interfacial condensation.

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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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