In step-growth polymerization, Carother's equation gives the number-average degree of polymerization, X_n, for a given fractional monomer conversion, p. Step-growth polymerization is a polymerization process that involves a chemical reaction between multifunctional monomer molecules. ...

Notes:

• X_n is also the average chain length (in monomer units)
• p = (N₀-N)/N₀, where:

N₀ is the number of molecules present initially

N is the number of unreacted molecules at time t

p is also a measure of the extent of reaction, or yield

A high monomer conversion is required to achieve a high number-average degree of polymerization. For example, a monomer conversion, p, of 98% is required for X_n = 50, and p = 99% is required for X_n = 100. Yield in chemistry, also known as chemical yield and reaction yield, is the amount of product obtained in a chemical reaction. ... In chemistry, the phrase conversion has several meanings a chemical reaction, the conversion of molecule A to molecule B relative yield, when the conversion of A to B is 70% (jargon), 70% of A is transformed into B. conversion rate is synonymous with reaction rate This is a disambiguation page... The degree of polymerization, or DP, is the number of repeat units in an average polymer chain at time t in a polymerization reaction. ...

Related equations

Related to the Carother's equation are the following equations:

where:

• X_w is the weight average degree of polymerization,
• M_n is the number average molecular weight,
• M_w is the weight average molecular weight,
• M_o is the molecular weight of the repeating monomer unit,
• PDI is the polydispersity index

The last equation shows that the maximum value of the PDI is 2, which occurs at a monomer conversion of 100%. The number average molecular weight is a way of determining the molecular weight of a polymer. ... The weight average molecular weight is a way of describing the molecular weight of a polymer. ... In chemistry, a monomer (from Greek mono one and meros part) is a small molecule that may become chemically bonded to other monomers to form a polymer. ... In organic chemistry, the polydispersity index (PDI), is a measure of the distribution of molecular weights in a given polymer sample. ...

In practise the average length of the polymer chain is limited by such things as the purity of the reactants, the absence of any side reactions (i.e. high yield), and the viscosity of the medium. The related Category:Units of viscosity has been nominated for deletion, merging, or renaming. ...