Name: Maria
Status: educator
Grade:
Country: El Salvador
Date: February 2009
Question:
How do you relate the macroscopic properties of a
substance (plastic) to its microscopic structure?
Replies:
This is a LARGE question. The simple answer is CHEMISTRY, but I do not mean that
to be condescending. It covers a wide range of studies.
EXAMPLE
(1): What substances
dissolve in which solvents? Sounds easy until you find all the "exceptions".
(2): Molecules of certain structures can turn water into a gel or into a long
stringy flow.
Before the last century, say 1850 to 1900 chemists had to determine the structure
of a molecule from the way it reacted with other molecules. There were no sophisticated
tools like spectroscopy available to them. I find that one of the intellectual "giants"
of modern science.
Your specific question about polymers is a special case of building the body of
science. Within a body of polymers there are ways to refine the structure and
properties, changing the chemical components, varying the conditions of their
reaction, altering how they are assembled.
And this is only one of any number of ways of altering the microscopic, molecular
composition and structure and macroscopic properties.
The length of my reply only reflects the richness of possibilities, and the lack of
a simple answers to your inquiry.
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