Question
Wed March 30, 2011 By: Aarohi Kc
 

short note on PDI. define plastiser.

Expert Reply
Wed April 06, 2011
Dear Student

 Polydispersity index (PDI)
 
PDI  is a measure of the distribution of molecular mass in a given polymer sample. The PDI calculated is the weight average molecular weight divided by the number average molecular weight. It indicates the distribution of individual molecular masses in a batch of polymers.
The PDI has a value equal to or greater than 1, but as the polymer chains approach uniform chain length, the PDI approaches unity (1). For some natural polymers PDI is almost taken as unity. The PDI from polymerization is often denoted as:
 
Mn is more sensitive to molecules of low molecular mass, while Mw is more sensitive to molecules of high molecular mass.
 
 
Plastiser
An additive that is used to add softness and flexibility to a plastic in order to facilitate the manufacturing process.
 
We hope that clarifies your query.
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Team
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