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The degree of polymerization, or DP, is the number of monomeric units in a macromolecule or polymer or oligomer molecule. [1] [2] [3]For a homopolymer, there is only one type of monomeric unit and the number-average degree of polymerization is given by ¯ ¯ = ¯, where ¯ is the number-average molecular weight and is the molecular weight of the monomer unit.
The total includes all degrees of polymerization: monomers, oligomers and polymers. This equation shows that a high monomer conversion is required to achieve a high degree of polymerization. For example, a monomer conversion, p , of 98% is required for X ¯ n {\displaystyle {\bar {X}}_{n}} = 50, and p = 99% is required for X ¯ n ...
There are many properties of polymeric materials that influence their mechanical properties. As the degree of polymerization goes up, so does the polymer’s strength, as a longer chains have high Van der Waals interactions and chain entanglement. Long polymers can entangle, which leads to a subsequent increase in bulk modulus. [11]
A polymer can be described in many ways: its degree of polymerisation, molar mass distribution, tacticity, copolymer distribution, the degree of branching, by its end-groups, crosslinks, crystallinity and thermal properties such as its glass transition temperature and melting temperature.
In linear polymers, the individual polymer chains rarely have exactly the same degree of polymerization and molar mass, and there is always a distribution around an average value. The molar mass distribution of a polymer may be modified by polymer fractionation. IUPAC definition for average degree of polymerization in polymer chemistry.
In chain-growth polymerization the propagation step is the addition of a monomer to the growing chain. The word kinetic is added to chain length in order to distinguish the number of reaction steps in the kinetic chain from the number of monomers in the final macromolecule, a quantity named the degree of polymerization. In fact the kinetic ...
It can also be calculated according to degree of polymerization, where Đ X = X w /X n, where X w is the weight-average degree of polymerization and X n is the number-average degree of polymerization. In certain limiting cases where Đ M = Đ X, it is simply referred to as Đ.
where is the radius of gyration of the polymer, is the number of bond segments (equal to the degree of polymerization) of the chain and is the Flory exponent. For good solvent, ν ≈ 3 / 5 {\displaystyle \nu \approx 3/5} ; for poor solvent, ν = 1 / 3 {\displaystyle \nu =1/3} .