Terpolymerization monomer ratio

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... 

In copolymerizations of three monomers there are nine growing steps to be taken into account. From these, six reactivity ratios can be derived. They are difficult to obtain from terpolymerizations and are therefore taken from binary copolymerizations. 

The diradical nature of the intermediate in the copolymerization of monomers through a charge transfer intermediate has been suggested by Zutty et al. (88) as a result of studies on the copolymerization and terpolymerization of monomer systems containing bicycloheptene and sulfur dioxide. The third monomer apparently enters the copolymer chain as a block segment, while the donor-acceptor monomer pair enter the chain in a 1 1 molar ratio, irrespective of the ratio present in the monomer mixture. 

The parameters a = l/rij5 the number of which equals m(m — IX are reciprocal reactivity ratios (2.8) of binary copolymers. Markov chain theory allows one, without any trouble, to calculate at any m, all the necessary statistical characteristics of the copolymers, which are formed at given composition x of the monomer feed mixture. For instance, the instantaneous composition of the multicomponent copolymer is still determined by means of formulae (3.7) and (3.8), the sums which now contain m items. In the general case the problems of the calculation of the instantaneous values of sequence distribution and composition distribution of the Markov multicomponent copolymers were also solved [53, 6]. The availability of the simple algebraic expressions puts in question the expediency of the application of the Monte-Carlo method, which was used in the case of terpolymerization [85,99-103], for the calculations of the above statistical characteristics. Actually, the probability of any sequence MjMjWk. .. Mrl 4s of consecutive monomer units, selected randomly from a polymer chain is calculated by means of the elementary formula ... 

When the reactivity ratios ry can be expressed in terms of the parameters of the well-known Q-e scheme of Alfrey-Price [20,157], the condition (4.20) always holds [147, 150] and in the case of terpolymerization the general Eqs. (3.8) and (4.10) transform into the simplified equation [158]. It is rather curious that similar equations have been derived at the end of the 1940s [159] within the framework of the Alfrey-Price scheme, being investigated even for the general case of copolymerization of arbitrary number m of monomer types. 

First let us demonstrate the possibilities of predicting transparency and heat resistance of (styrene + methylacrylate + heptyl acrylate) terpolymerization of the products prepared at complete conversion of monomers. The elements ry of the matrix of reactivity ratios ... 

CH3)3CO— is an initiator residue]. With copolymerization of free monomers, they should have observed an increasing A/B ratio according to the method used with complex propagation, A/B should remain constant. The authors observed both cases. They concluded that maleic anhydride with a monomeric donor, like styrene, yields a DA complex by a reversible reaction, with an equilibrium constant of 10-1 to 10-2 dm3 mol-1. The initiating radical is formed from the complex, and the copolymerization is in fact a terpolymerization involving the two free monomers and their complex. These authors have applied the same technique in a study of the type of radicals formed in copolymerization of maleic anhydride with vinyl sulphides. Even in this case they provided evidence of the existence of a complex. 

The composition of llie copolymer formed from n monomers in addition polymerization can be expressed in terms of the monomer feed composition and n n — 1) binary reactivity ratios. Thus, for terpolymerization [16],... 

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... 

Whereas in the case of terpolymerization there is only one relationship of type (17), in the case of n monomers there are them. In fact, if a monomer, e.g. M, is fixed, the othas can follow it in n— 1) ways, to which (w — 1) products of the reactivity ratios correspond. 

The effect of the penultimate unit in binary copolymerization has been studi i extensivety 33,34,33). The analogous probkm in the ca of teipolymerization is rather complex 26) owing to the existence of twenty seven possible propagation reactions, compared with eight in the case of binary copolymerization. If for a certain terminal monomer imit in the growing chain a penultimate effect exists, the reactivity ratios in the Alfrey-Goldfinger terpolymerization eqs. (7) may be replaced as follows ... 

Ethylene has been co-polymerized with virtually any conceivable a-olefin, from propylene to vinyl-terminated PE and PP macromonomers. Ethylene/propylene (E/P) copolymerization to produce saturated rubbers and ethylene/propylene/diene (EPD) terpolymerization to produce unsaturated, vulcanizable rubbers will be discussed in Section 4.09.4.1.3. 1-Butene, 1-hexene, and 1-octene are the most commonly used co-monomers for the production of LLDPE. Ethylene/octene co-polymers, developed by Dow and marketed under the Engage tradename, have been shown to have improved thermal properties compared to ethylene/butene and ethylene/hexene co-polymers.503 In ethylene/a-olefin (E/O) co-polymeriza-tions, the critical parameters are co-monomer reactivity and co-monomer distribution . The former is most conveniently described by the relative reactivity parameter, R, defined as the ratio between polymer composition and reactor medium composition. 

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]. 

The terpolymer composition can be predicted on the basis of binary copolymerization experiments. If, however, one (or more) monomer is slow to propagate one of the reactivity ratios will approach zero and eq. 36 will become indeterminate. This situation arises in terpolymerizations involving, for example, MAI I or AMS. Alfrcy and Goldfingcr" derived eq. 37 for the ease w hcrc one monomer (C) is slow to propagate i.e. and hence rc, and ren — 0). 

Effects of Composition. Reactivity ratio studies of the NaAMPS-AMPDAC pair showed high alternation as expected for ion-paired systems (i, 33). The acrylamide functionality of both monomers would also be expected to terpolymerize well with acrylamide. Therefore, the series of ter-polymers shown in Table II was prepared. Molecular weights, second virial coefficients, and intrinsic viscosities at 25 °C in 1.0 M NaCl solutions are given in Table III. The numbers following the AD AS AM acronym represent... 

To estimate the relative reactivity of ethylene, 1-octene and p-MS, the identical concentration for the three monomers was used as shown in run p478. The molar ratio of [ethylene]/[l-octene]/[p-MS] in the terpolymer is 73.3/18.5/8.12 = 9/ 2.3/1, which clearly indicates that the reactivity of the monomer in the terpolymerization follows the order of ethylene > 1-octene > p-MS. Therefore, one could empirically control the composition of the terpolymer by varying the composition of the monomer in the feed. 

Here, a third monomer can be included to interpolymerize with the complex that acts as a unit. The product is a terpolymer. A diradical intermediate was also postulated in sulfur dioxide copolymerizations and terpolymerizations with bicycloheptene and other third monomers. These third monomers enter the copolymer chain as block segments, while the donor-acceptor pairs enter the chains in a one-to-one molar ratio. This one-to-one molar ratio of the pairs is maintained, regardless of the overall nature of the monomer mixtures. 

These complexes then react as one unit in free radical polymerizations. Then, of course, it is no longer a question of the reaction of a free radical with another monomer, but of the unipolymerization of the charge transfer complex. If the monomers are present at the right mixture ratio (mostly 1 1) and if the complex is much more reactive than the monomers, then a strictly alternating copolymer is formed. Otherwise, a terpolymerization of the monomers with the charge transfer complex will be observed. 

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... 

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. 

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