Testing and Characterisation of Polymers

Testing and characterisation of polymeric materials is essential for determining their suitability for a particular application. The manufacturers and processors need it for quality cotitrol such as maintaining product uniformity and for assessing the performance of new materials in relation to the existing ones. Proce.ssors and users wanting to better understand the behaviour of the polymeric materials under various conditions are naturally interested in knowing their chemical nature. 

Polymeric materials are very complex in nature. Their high molecular weights, molecular inhomogeneity and their chemical inertness often present difficulties in their identification which therefore requires special techniques and the use of advanced methods of analysis. The problem of characterisation is further complicated by the market availability ofan extremely wide range of materials and the presence of compounding materials such as plasticizers, stabilizers and fillers (which change the physical properties of the product) and thus a complete identification of polymeric materials may not always be po.ssible. 

however, possible to make a positive identification as to the class of polymer (such as polyolefine, polyamide, polyester, etc.) to which a given sample belongs, by carrying out some simple tests and correlating their results. 

Application of tliese tests to the identification of a few most common polymerifc materials is described in the following pages. 

Physical examination of the polymeric materials includes the observation of their colour, rigidity, solubility, density, etc and the behaviour on dry heating and combustion. These tests help in preliminary sorting out and in some cases permit direct conclusions. 

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