Sunday, February 6, 2011


Polymer blend refer to intimate mixture of two monomers of two or more polymers. The individual polymers may be melt mixed, solution blended and co-precipitated, or lattices may be blended and coagulated before final processing.
Blending of polymers is carried out
1. To reduce the cost of expensive engineering thermoplastic.
2. To increase the process ability of a high temperature heat sensitive thermoplastic
3. To improve the impact strength of a brittle polymer
4. To expand temperature range of applications of a polymer
Commercial blends may be single phase or two phases. If the blend is exhibiting single Tg(glass transition temperature) it is called as miscible blend
Example:- Blend of polystyrene and poly(1,4 phenylene oxide )

Immisible blends shows double Tg
Example:- blends of polystyrene and PMMA(polymethyl methacrylate)

Under microscopic inspection a miscible polymer blend consist of a single phase. In order to miscible some attraction between the two polymers must be present to overcome intramolecular cohesive force of the Individual polymers. Totally miscible polymers are rare in practical life.
In the case of immiscible polymers there exist two phase. There is another type of blend in between above two, in which polymers are neither totally miscible nor totally miscible but holds some where in between these two. These types blends are classified as partially miscible polymer blends.

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