Kuhn Mark Houwink relation

PET Petri, H.-M., StanunerR, A., and Wolf, B.A., Continuous polymer ftactionation of poly(methyl vinyl ether) and a new Kuhn-Mark-Houwink relation, Macromol. Chem. Phys., 196, 1453, 1995. 

Relating the intrinsic viscosity to N by means of the Kuhn-Mark-Houwink relation ... 

As postulated by (31), the molecular weight dependence of A2 should not be represented in double logarithmic plots, but as a function of M where a is the exponent of the Kuhn Mark Houwink relation. In contrast to the customary evaluation (in double logarithmic plots), this procedure does not in the general case lead to zero A values in most cases they are very small but, outside experimental errors, different from zero. 

Since PHE, produced in different mixtures water-isopropanol, has different values D (i.e., different stmcture), then from the Equations (13) and (23) it follows, that for them values a and K will be different, that is the relation between [q] and A/Mfor the same polymer will be defined by different Kuhn-Mark-Houwink equations. Therefore, strictly speaking, polymer viscosity should be determined in the same solvent, in which it was synthesized. This rule is confirmed by a well known fact [25], that synthesized by different polycondensation modes polyarylates, having the same chemical... 

The exponent a can be determined experimentally from the relation between the intrinsic viscosity, [q], and the molecular weight, M (Mark-Houwink-Kuhn relation) ... 

A viscometric detector together with a concentration detector can provide information on molar masses of macromolecules emerging from the FFF system [76,134,142-144] using the Mark-Houwink-Kuhn-Sakurada coefficients. If these coefficients are not available, an intrinsic viscosity distribution can still be determined without calibration. Detailed features of this distribution are unique to a given polymer sample, and are not affected by changes in experimental conditions [145]. In fact, since the intrinsic viscosity distribution is more directly related to end-use properties, its measurement is preferred in certain applications. 

Several authors have published the method for determining molar masses of DADMAC polymers, primarily in connection with practical applications [1]. In Table 11 intrinsic viscosity-molar mass relations of PDADMAC are summarized in the form of the Mark-Kuhn-Houwink-Sakurada (MKHS) relationship. The relatively high exponent of the relationships is attributed to the greater chain stiffness in comparison with vinyl backbones. One has to look quite skeptically at the values from reference [59] given its deviation from the remainder of the published data. 

Determination of D is the first step in studying macromolecular coils by fractal analysis. D is usually estimated by finding the exponents in the Mark-Kuhn-Houwink type equation, which relate the characteristic viscosity [r ], the translational diffusion coefficient Dq, or the rate sedimentation coefficient Sq) with the molecular weight (M) of polymers [3] ... 

FIGURE 1 The relation between experimental and calculated according to the Eq. (12) Mark-Kuhn-Houwink equation constants for solutions of polyarylates series [5] in 1,1,4,4-tetrachlorethane (1), tetrahydrofuran (2) and 1,4-dioxane (3). 

It is interesting to note, that the same relation between MM and can be obtained, by using a well-known empirical Mark-Kuhn-Houwink equation [25] ... 

As it is known, the same polymer, produced by equilibrium and nonequilibrium, differs by its characteristics, in particular, has different exponents a in Mark-Kuhn-Houwink equation [53], The values a and are linked between themselves by the Eq. (4). For polyarylate on the basis of phenolphthaleine the values D = 1.96 (equilibrium polycondensation) and Dj.=1.80 (nonequilibrium polycondensation) were obtained, that corresponds to p=0.0185 and 0.039. Thus, polycondensation mode change from equilibrium up to nonequilibrium (interfacial) one results to p increase approximately twice. Approximately the same relation is valid at polycondensation mode change for other polyary lates of different chemical structure. 

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