Specific volume of the monomers

Here, /(is a constant that can be calculated from the specific volumes of the monomer and polymer at the appropriate temperature. One can, however, also determine the relationship between U and AU by direct experiment. 

In nonisomorphous systems, the specific volumes of the monomers are different. In this case, the geometry of the resulting polymer becomes important. 

The results relative to the polymerization of DPHD are collected in Table I. The monomer concentrations at the different temperatures have been calculated by measuring in a dilatometer the specific volume of the pure monomer. 

The density in the amorphous state is different from that of the hypothetical liquid. The specific volume of polymer-monomer mixtures at first decreases linearly with increasing polymer concentration (Figure 5-30). 

Free volume n. In a liquid or amorphous sohd, the specific volume minus the volume occupied by the molecules themselves. Free volume increases with rising temperature, causing viscosity to diminish. The PL is calculated from the specific volume of the amorphous polymer (v am) and the specific volume of the liquid polymer (v, ) in a polymer-monomer mixture during polymerization (Elias, 1977). 

The liquid crystalline state can be systematically introduced by rigid anisometric building blocks or by amphiphilic moieties. According to their chemical constitution and basically following the same systematic as known from low-molar-mass liquid crystals, all types of LC phase structure are accessible. Additional aspects to be considered arise from modification of the state of order due to the decreased specific volume of the macromolecules (compared to that of the monomers) and the reduced translational and rotational mobility of the mesogenic units due to their linkage within the macromolecule. 

According to this model, intrinsic viscosity depends not only on the molecular weight but also on the specific volume of the macromolecule and the shielding ratio, de Gennes considered this a model of porous sponge with uniform density. The monomers inside the sponge are screened from the flow. Only those on the surface are subject to friction. 

The self-assembled monolayers (SAM) are prepared by chemically linking ordered rigid molecules to complementary sites on a solid surface. Examples are described in this volume in Chapter 10 (cf. also Section in.D). The topochemical polymerization of diacetylenes should also be regarded as a supramolecularly assisted process requiring very specific arrangements of the monomers within the crystalline state [35]. 

Fig. 30 Generic temperature-density diagram for a polymer melt proposed by Olmsted et al. [4]. The horizontal axis indicates the normalized density pw, which is defined as the average mass density of the melt multiplied by the specific volume w of the monomer... 

This procedure is based on the measurement of the contraction of volume that results from the different densities of the monomer and polymer. The conversion of the volume contraction to the yield of polymer can be made by means of a gravimetrically determined calibration curve or by calculation from the specific volumes (see Example 3-6). 

The molecular weight of cytochrome c peroxidase has been determined to be 34,100 on the basis of a sedimentation constant of 3.55 S, a diffusion constant of 9.44 F, and a partial specific volume of 0.733 ml/g (4 )-The enzyme exists as a monodisperse monomer containing one ferric protoporphyrin IX, which is noncovalently bound (/, , 14). No other transition metal is detected in crystalline preparations of the enzyme (22). The apoenzyme moiety is an acidic protein with an isoelectric point at pH... 

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