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Type your question here EX) A polymer sample consists of five different molecula

ID: 798838 • Letter: T

Question

Type your question here

EX) A polymer sample consists of five different molecular-weight (MW) fractions, each of equal weight. The molecular weight of these fractions increase from 30,000 to 150,000 in increments of 30,000. Determine the number-average MW, weight-average MW and Polydisperse Index of the sample.   

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A)      Briefly address the typical methods which are suitable for measuring the number-average MW, weight-average MW and MW distribution.

B)In a condensation polymerization for making polyester, if the fractional conversion in an ester interchange reaction is 0.99999, what would be the degree of polymerization (DP) of the polyester produced?  

Explanation / Answer

ex)

A)

number-average MW=N1M1+N2M2+N3M3+N4M4+N5M5(/N1+N1+N3+N3+N5)


=(30,000+60,000+90,000+120000+1,50,000)/(5)=9*10^4


B)WEIGHT AVG.MWT= [ N1*M1^2+N2M2^2 +N3M3^2+N4M4^2 N5M5^2]/[N1M1+N2M2+N3M3+N4M4+N5M5]


=[ 30000]^2 +[60000]^2+[90000]^2+[120000]^2+[150000]^2/ (30,000+60,000+90,000+120000+1,50,000)


=110000

A) THE METHODS ARE USED TO CALCULATE number-average MW, weight-average MW and MW distribution.

COLLIGATIVE PROPERTYSCH AS OSMATIC PRESSURE

LIGHT SCATTERING

ULTRACENTRIFUGATION

SEDIMENTATION