Number-average molar mass below the gel point

3 Number-average molar mass below the gel point 

Before any bonds are formed (at extent of reaction / = 0) there are only monomers present and the total number of molecules per site is itot(O) = 1 (every site is occupied by an unreacted monomer). Each bond reduces the number of molecules by one because there are no intra-molecular bonds. The maximum number of bonds per site on a Bethe lattice with functionality /is //2, The total number of formed bonds per site at extent of reaction p is pfj2  

The number-average degree of polymerization (the average number of sites per molecule) is the reciprocal of the average number of molecules per site. 

At the gel point p — l f— 1), the number-average degree of polymerization exhibits no unusual behaviour for/ 2 (it is just a finite number)  

For/= 3, N niPc) = 4 meaning that a randomly selected molecule at the gel point has an average degree of polymerization of four. The fact that does 

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