Intrinsic Viscosity and Molecular Weights

The molecular weight of SAN can be easily determined by either intrinsic viscosity or size-exclusion chromatography (sec). Relationships for both multipoint and single point viscosity methods are available (18,19). Two intrinsic viscosity and molecular weight relationships for azeotropic copolymers have been given (20,21) ... 

Pouradier Venet (1952), showed that an equation of the type [tf = 0.166M o. ss exists between the intrinsic viscosity and molecular weight of gelatin. Whereas k and a were each the same for two alkali-processed gelatins, they were different for an acid-processed gelatin (Zhao 1999). 

It should be emphasized that Eq. (52) is empirical in origin. However, the more complicated theoretical expressions to be discussed in Chapter XIV can be approximated quite closely by this simple equation over ranges of as much as a hundredfold in M. The convenience of application of the empirical relationship assures its continued use for correlating intrinsic viscosities and molecular weights. 

For a statistical coil, the product of polymer intrinsic viscosity and molecular weight is directly proportional to the cube of the root-mean-square radius of gyration RG 77137... 

The need for a viscosimeter capable of online measurement of the intrinsic viscosity of a polymer sample arose when it was shown that polymer molecules elute in order of decreasing hydrodynamic volume.81 The hydrodynamic volume can be related to the product of intrinsic viscosity and molecular weight. 

It was shown that the logarithm of the product of intrinsic viscosity and molecular weight of polymers of different chemical and stereochemical composition, configuration, or molecular weight is linearly related to the elution volume.81 A plot of log (r) M) vs. elution volume provides a single calibration curve, useful for samples of similar composition, and is termed a universal... 

Empirical Correlations between Intrinsic Viscosity and Molecular weight for Linear Polymers... 

Table 13.1 Intrinsic viscosity and molecular weight data for the three characterized polymers (cf. Figure 13.2) [13]. From Some effects of the rheological properties of PET on spinning line profile and structure developed in high-speed spinning , Perez, G., in High-Speed Fiber Spinning, Ziabicki, A. and Kawai, H. (Eds), 1985, pp. 333-362, copyright (1985 John Wiley Sons, Inc.). Reprinted by permission of John Wiley Sons, Inc.

Mark-Houwink equation phys chem The relationship between intrinsic viscosity and molecular weight for homogeneous linear polymers. mark hau.wigk l.kwa-zhan Markovnikoff s rule org chem in an addition reaction, the additive molecule RH adds as H and R, with the R going to the carbon atom with the lesser number of hydrogen atoms bonded to it. mar kov-ns.kofs, riil ... 

The size exclusion chromatography for this study was done in the routine manner execept for the inclusion of an online viscosity detector called a Differential Viscometer <3> (Viscotek Corp., Porter, Texas, USAl. This instrument together with an RI concentration detector permits the calculation of intrinsic viscosities across the chromatogram. An IBM PC data system with software is also provided (5). The software acquires data from both detectors, and performs calculations of intrinsic viscosity and molecular weight distributions using the Universal Calibration Method. 

Figure 16. Relationship between intrinsic viscosity and molecular weight for Butarez CTL. Fractionation of blend H by gel chromatography...

A summary of the results obtained from GPC/DV on the first day and the third day after solution preparation is shown in Table II. For Red Oak and RO PO, the number average molecular weight decreased by approximately 6% from the first day to the third day. However, the intrinsic viscosities increased. According to traditional polymer solution theory (42), the product of intrinsic viscosity and molecular weight yields the hydrodynamic volume specifically, it has been shown that the molecular weight that... 

Grubisic et al. (3) showed that for many polymers a single calibration curve can be drawn through a plot of the product of intrinsic viscosity and molecular weight ( [7/] M) vs. retention volume. This relationship certainly supports the model of molecular separation based on hydro-dynamic volume since [77] M is proportional to the hydrodynamic volume of the molecule in solution. Hence, molecular weights of the two polymers (calibration standard polymer and sample) which have identical retention volume under identical GPC analytical conditions can be expressed in terms of each other by combining the Grubisic relationship ... 

MARK.-HOUW1NK EQUATION. Defines the relationship between the intrinsic viscosity and molecular weight for homogeneous linear polymers. 

The surface tension of aqueous solutions of PVA varies with concentration, temperature, degree of hydrolysis, and acetate distribution on the PVA backbone. Surface lension decreases slightly as the molecular weight is reduced. The relationship between the intrinsic viscosity and molecular weight changes with degree of hydrolysis of the polymer. 

Wagner, R. H. Intrinsic viscosities and molecular weights of polyvinyl acetates. J. Polymer Sci. 2, 21 (1947). 

The intrinsic viscosities and molecular weights of poly(vinyl acetate), poly(vinyl trideuteroacetate), and poly(trideutero-vinyl acetate) at three conversions. 

Experimental evidence on whether L or other molecular parameters (Stokes radius, viscosity radius, radius of gyration, the product of intrinsic viscosity and molecular weight, etc.) govern partitioning in SEC supports has been summarized by Dubin [29]. He concludes that none of these parameters perfectly correlates with SEC partitioning when a wide variety of macromolecules, of both rigid and flexible structure, are used as test probes. This may result from the complex uncharacterized nature of the pore space occupying the porous supports commonly utilized. 

G1 Gaylord, N. G., and S. Rosenbaum Intrinsic viscosity and molecular weight of polyethylene terephthalate. J. Polymer Sci. 39,545 (1959). 

P 1 Parrini, P., F. Sebastiano and G. Messina Intrinsic viscosity and molecular weight of isotactic polypropylene, Makromol. Chem. 38, 27 (1960). 

The product of intrinsic viscosity and molecular weight is equal to... 

Table 16. Intrinsic viscosities and molecular weights for SBS toughened composites...

This brings us to the relationship between the intrinsic viscosity and molecular weight This was first established empirically from plots of log r vs log Mol Wr., which were found to be linear (Figure 12-29), meaning that the relationship between the two quantities has the form (Equation 12-47) ... 

Well, this is all very nice to have this useful empirical relationship between intrinsic viscosity and molecular weight, you might say, but is there any underlying theory that would explain the form of the relationship and the nature of the constants a and K l Also, we have been very careful to specify that these constants depend upon the polymer, the solvent and the temperature why is this ... 

A parameter J is defined as the product of intrinsic viscosity and molecular weight of a monodisperse species i. That is,... 

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