Terpolymerization composition equation

It is claimed that this terpolymerization composition equation is often in good agreement with experimental results. Other, more complicated equations also exist, but apparently they yield results that are similar to those obtained from the above shown expression [94, 149]. 

In the terpolymerization composition equation derived for terpolymers and given by Equations (10.23-10.25), what is the significance of equal reactivity ratios such as r 2 = 13 ... 

Consider the preparation of styrene-acrylonitrile and methyl methacrylate terpolymer in a CSTR. There can be 3x3 = 9 possible dyads formed. These are AA, AS, SA, SS, SM, MS, AM, MA, and MM. The reactivity ratios can be read from Chapter lO, Table 10.1 The terpolymer composition can be calculated using the terpolymerization composition equations for a CSTR given in Equations (10.23-10.25). The dyad probabilities were calculated using an MS Excel spreadsheet and listed in Table 11.3. Let AN be denoted as monomer 1, styrene as monomer 2, and methyl methacrylate as monomer 3. Assuming that the bond formation order does not influence the rate, that is. 

The complexity of the terpolymer composition equation (eq. 36) can be reduced to eq. 41 through the use of a modified steady slate assumption (eqs. 38-40), However, while these equations apply to component binary copolymerizations it is not clear that they should apply to terpolymerization even though they appear to work well. It can be noted that when applying the Q-e scheme a terpolymer equation of this form is implied. 

The terpolymerization and multicomponent composition equations are generally valid only when all the monomer reactivity ratios have finite values. When one or more of the... 

Azeotropic compositions are rare for terpolymerization and Ham 14 has shown that it follows from the simplified eqs. 38-40 that ternary azeotropes should not exist. Nonetheless, a few systems for which a ternary azeotrope exists have now been described (this is perhaps a proof of the limitations of the simplified equations) and equations for predicting whether an azeotropic composition will exist for copolymerizations of three or more monomers have been formulated.20113 This work also shows that a ternary azeotrope can, in principle, exist even in circumstances where there is no azeotropic composition for any of the three possible binary copolymerizations of tire monomers involved. 

Even in the first publications concerning the copolymerization theory [11, 12] their authors noticed a certain similarity between the processes of copolymerization and distillation of binary liquid mixtures since both of them are described by the same Lord Rayleigh s equations. The origin of the term azeotropic copolymerization comes just from this similarity, when the copolymer composition coincides with monomer feed composition and does not drift with conversion. Many years later the formal similarity in the mathematical description of copolymerization and distillation processes was used again in [13], the authors of which, for the first time, classified the processes of terpolymerization from the viewpoint of their dynamics. The principles on which such a classification for any monomer number m is based are presented in Sect. 5, where there is also demonstrated how these principles can be used for the copolymerization when m = 3 and m = 4. 

The coefficients 8.10 and 0.010 in the second equation are usually ascribed to the reactivity ratios rj and rj (Table 19). This catalyst produces poly-propene consisting mainly of syndiotactic stereoblocks, together with short disordered blocks resulting from head-to-head (hh) and tail-to-tail (tt) pro-pene enchainment and occasional isolated isotactic units, and if these features apply to copolymers prepared with vanadium catalysts, the reaction is in effect a terpolymerization. Locatelli et al. [322] derive the equation for monomer/polymer composition ratios... 

The simplified terpolymerization equations (16) give values of the terpolymer composition that are the more in agreement with the experimental data the closer is to We can say that the... 

The conventional [Eq. (7.77)] and simplified [eq. (7.81)] terpolymeriza-tion equations can be used to predict the composition of a terpolymer from the reactivity ratios in the two-component systems M1/M2, M1/M3, and Ms/Ms- The compositions calculated by either of the terpolymerization equations show good agreement with the experimentally observed compositions. Neither equation is found superior to the other in predicting terpolymer compositions. Both equations have been successfully extended to multicomponent copolymerizations of four or more monomers [30,31]. 

In the explicit penultimate model, it is assumed that both the terminal and penultimate units of a polymer radical may affect the rate of the propagation reaction. As in the terminal model, side reactions are considered to be insignificant. The explicit penultimate model was first suggested in 1946 by Merz and co-workers (10), who derived equations for predicting the composition and sequence distribution under this model. A full description of the model—including an expression for ( p)— has since been provided by Fukuda and co-workers (11), and it is their notation that is used below. In addition, penultimate model equations for the case of terpolymerization have been published by Coote and Davis (12). 

It can be seen that the monomer-polymer composition for terpolymerization in a CSTR will depend on the valnes of reactivity ratios. Consider the expression derived for monomer-polymer composition during copolymerization in a CSTR. Equation (10.12) rewritten in terms of monomer 1 composition only is... 

If the terpolymerizations in Table 10.24 occur through the polymerization of the two complexomers (DiAi and D2A1) instead of following the classical copolymerization equations, the resulting polymers should contain 50% of the acceptor, which is common to both charge-transfer complexes. In many of the terpolymerization recorded in Table 10.24 polymers with a molar composition of 50% MA were observed, regardless of the feed... 

We have seen how the compositions in a copolymerizing system can be described in terms of two parameters, o and r2- What does it take to describe the terpolymerization of monomers Mi, M2, and M5 If you are feeling particularly masochistic, you might try to work out the terpolymerization equivalents of Equation 11.11. 

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