The Number Fraction Sequence of Units

Our first definition is the number fraction sequence of (say) A units of length n, which is the number of such sequences divided by the number of all possible sequences of A units (i.e., from n= 1 to )—Equation 6-32  

any given sequence of A units must end (and begin) with a B unit (Equation 6-33)  

Number fraction sequence of units Number average length of runs Departure from randomness Run fraction or number 

FIGURE 6-18 Useful parameters used to describe copolymer microstructure. 

You might want to compare Equation 6-37 to that of the definition of the number aver- age molecular weight. NA n) is the number fraction of sequences of n A s, which we just. considered. Now, we know that (Equations 6-38)  

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Hence, we arrive at the final equation for the number fraction sequence of units (Equation 6-35) ... 

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