Mark-Houwink-Sakurada relationship

Mark-Houwink-Sakurada relationship, 1 309, 310t 20 439-440 Markov chain, 26 1006, 1018, 1024, 1025 HSTA algorithm and, 26 1030-1031 Markov chain Monte Carlo (MCMC) sampling method, 26 1017-1018 Markovnikov addition, in silicone network preparation, 22 563... 

While it can be expected that a number of physical properties of hyperbranched and dendritic macromolecules will be similar, it should not be assumed that all properties found for dendrimers will apply to hyperbranched macromolecules. This difference has clearly been observed in a number of different areas. As would be expected for a material intermediate between dendrimers and linear polymers, the reactivity of the chain ends is lower for hyperbranched macromolecules than for dendrimers [125]. Dendritic macromolecules would therefore possess a clear advantage in processes, which require maximum chain end reactivity such as novel catalysts. A dramatic difference is also observed when the intrinsic viscosity behavior of hyperbranched macromolecules is compared with regular dendrimers. While dendrimers are found to be the only materials that do not obey the Mark-Houwink-Sakurada relationship, hyperbranched macromolecules are found to follow this relationship, albeit with extremely low a values when compared to linear and branched polymers [126]. 

Table 11. Exponents and constants of the Kuhn-Mark-Houwink-Sakurada relationship [r ]=KMa for PDADMAC in 1 mol L 1 NaCl ([r ] in cm3 g, M in g-rnol )...

Intrinsic viscosity [t]] of a polymer solution is related to its viscosity average molecular weight by the Mark-Houwink-Sakurada relationship ... 

The macromolecular concept was proposed in 1917 by Staudinger, who received the Nobel Prize for chemistry in 1953. His theory was supported by the work of other researchers. Mark described the relationship between the viscosity of a polymer solution and its molecular weight (i.e. the Mark-Houwink-Sakurada relationship), demonstrating that cellulose was made of giant molecules. Carothers demonstrated the existence of synthetic macromolecules, and his researches led to the invention of the famous Nylon 6-6. 

In the literature, this dependence is referred to as the [/j]-M-relationship or the Kuhn-Mark-Houwink-Sakurada-relationship (KMHS-relationship). and a are constant for a given solvent and temperature. 

The intrinsic viscosity [r] of a polymer in solution is a measiu-e of its molecular volume divided by its molecular weight. The [ j] value can be empirically correlated to the viscosity-average molecular weight (Af,) via the Mark-Houwink-Sakurada relationship (67) [r]] = K,M,ja,j. Poly(acrylamide) and ionic copolymers of acrylamide follow this empirical relationship, which is often used to estimate the polymer molecular weight. Table 4 lists suggested literature values of K, and Qn for poly(acrylamide) and several copolymers in a variety of solvents. 

Beginning with the Mark-Houwink-Sakurada relationship, equation (3.97), it is easy to show that the average molecular size is given by... 

In such solvents, it is possible to establish Mark-Houwink-Sakurada relationships ... 

Intrinsic viscosity is actually the hydrodynamic volume of the macromolecule in the solvent (water in this case) solution. It is obvious from the Table 3.1 that the intrinsic viscosities of all the synthesized grades by conventional, microwave-initiated, and microwave-assisted techniques were greater than that of agar. This can be explained by the increase in hydrodynamic volume due to the grafting of the PAM chains on the main polymer backbone (agar). Further, this is in good agreement with Mark-Houwink-Sakurada relationship... 

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