Ternary monomer system

When using three different types of monomers, not only the GI profiles but also various other profiles are obtained when the monomers satisfy the following conditions  

An Mj -rich terpolymer is formed in the initial stage of copolymerization, an M2-rich terpolymer in the intermediate stage, and an Mg-rich terpolymer in the final stage. Because the terpolymer phase grows inward toward the center axis, the composition changes from Mj-richer terpolymer to Mg-richer 

These profiles can be predicted prior to the actual fabrications. In the multiple monomer system (Mg, M2,. .., M ), the differential equation of the copolymer 

The weight fraction (y. ) of the M. monomer unit in the copolymer is expressed as 

By solving the differential Equation (5.5) and relating it to the conversion (P) from the monomer to the polymer, the change in the copolymer composition during the reaction of a multiple monomer system can be calculated. The weight fraction (x/ ) of the Mj- monomer (k = 1, 2,. .., ) in the remaining monomer mixture with conversion P is expressed as 

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Most coordination catalysts have been reported to be formed in binary or ternary component systems consisting of an alkylmetal compound and a protic compound. Catalysts formed in such systems contain associated multinuclear species with a metal (Mt)-heteroatom (X) active bond ( >Mt X Mt—X > or — Mt—X—Mt—X— Mt = Al, Zn, Cd and X = 0, S, N most frequently) or non-associated mononuclear species with an Mt X active bond (Mt = Al, Zn and X = C1, O, S most frequently). Metal alkyls, such as triethylaluminium, diethylzinc and diethylcadmium, without pretreatment with protic compounds, have also been reported as coordination polymerisation catalysts. In such a case, the metal heteroatom bond active in the propagation step is formed by the reaction of the metal-carbon bond with the coordinating monomer. Some coordination catalysts, such as those with metal alkoxide or phenoxide moieties, can be prepared in other ways, without using metal alkyls. There are also catalysts consisting of a metal alkoxide or related compound and a Lewis acid [1]. 

Another interesting monomer for copolymerisation with carbon dioxide is isomeric 2-butene oxide. In copolymerisation in a ternary comonomer system consisting of 2-butene oxide, 1-butene oxide and carbon dioxide with the diethylzinc-water catalyst, m-2-butene oxide was incorporated in the copolymer, while trans-2-butene oxide hardly underwent an enchainment [230]. Thus, the smaller steric hindrance for the r/.v-isomer than for the irans-isomer throughout the coordination copolymerisation with carbon dioxide is to be taken into account. 

The possibility of changing the polymerisation mechanism depending on the kind of monomer as well as the catalyst, especially in binary or ternary comonomer systems, is obvious. This may also concern change in the nature of the growing species throughout the propagation of one polymer chain in the presence of both multinuclear catalysts [scheme (33)] and mononuclear catalysts [scheme (34)] ... 

In addition to the polymerization of dienes the versatility of NdP-based catalysts is exceptional regarding the number of different non-diene monomers which can be polymerized with these catalysts. Acetylene is polymerized by the binary catalyst system NdP/AlEt3 [253,254]. Lactides are polymerized by the ternary system NdP/AlEt3/H20 [255,256]. NdP/TIBA systems are applied in the copolymerization of carbon dioxide and epichlorhy-drine [257] as well as for the block copolymerization of IP and epichloro-hydrin [258]. The ternary catalyst system NdP/MgBu2/TMEDA allows for the homopolymerization of polar monomers such as acrylonitrile [259] and methylmethacrylate [260]. The quaternary system NdP/MgBu2/AlEt3/HMPTA is used for the polymerization of styrene [261]. 

The literature referring to catalyst preformation of binary catalyst systems is not addressed in this work. In this review the available studies on ternary catalyst systems are summarized. The available literature is discussed in the following two subsections Preformation without Monomer and Preformation in the Presence of Diene Monomers . 

Copolymerizations of BD with 1-alkenes such as 1-octene and 1-dodecene aim at short chain branching of BR. Kaulbach et al. used the ternary catalyst system NdO/TIBA/EASC (htiba/ Nd = 25, nci/nNd = 3) for the respective copolymerizations of BD/l-octene and BD/l-dodecene [508]. These authors showed that only small amounts of 1-alkenes are incorporated and that no neighboring 1-alkene moieties are present in the copolymer. The copolymerization parameters have been determined by the method of Kelen-Tiidos rBD = 25 and ri-octene 0 rBD = 18 and r dodecene = 0.1. With increasing amounts of 1-alkene in the monomer feed catalyst activity decreases drastically. The cis- 1,4-contents of the BD units in the copolymer were around 90% and were barely affected by increases of the 1-alkene content in the monomer feed. 

Contrary to viscosity measurements GPC provides number average molar mass data (Mn). For a few studies on the polymerization of BD with Nd-carboxylate-based catalyst systems GPC was systematically applied for the monitoring of Mn as a function of monomer conversion. In these studies three catalyst systems were used (1) NdV/DIBAH/EASC [178], (2) NdV/TIBA/EASC [179] and (3) NdO/TIBA/DEAC [188]. In the first two studies linear Mn-conversion plots were obtained at various molar ratios Al/ Ndv- In these studies, however, molar mass data at low monomer conversions (<20%) are lacking and positive intercepts on the Mn-axis were found. For the ternary catalyst system NdO/TIBA/DEAC used in the third of these studies the concentrations of Nd and TIBA were varied. A linear increase of Mw and Mn on monomer conversion was found. Deviations from linearity were also observed for low monomer conversions. 

The dependence of molar mass on the ratio of monomer to catalyst ( m/mnpioneering study on the use of ternary catalyst systems Throckmorton investigated the influence of M/ ce on dilute solution viscosities (DSV) [34], Quite surprisingly, for two catalyst systems (1) Ce octanoate/TIBA/EtAlCl2 and (2) Ce octanoate/DIBAH/HBr DSV decreased with increasing ratios of nu/nce- This observation is not at all understood and is in contradiction with the requirements for a living system. 

Binary or ternary catalyst systems from nickel compounds with Group I—III metal—alkyls have many features in common with those from cobalt and it may be inferred that a similar type of catalytic entity is involved. The composition for optimum activity may be different, however, and in the soluble catalyst Ni(naphthenate)2/BF3. EtjO/AlEtj (Ni/B/Al = 1/7.3/6.5) [68] the ratio of transition metal to aluminium is much higher than in cobalt systems. Rates were proportional to [M] and [Ni], molecular weight was limited by transfer with monomer and catalyst efficiency was relatively low (Table 5, p. 178). With the system AlEtj/ Ni(Oct)2/BF3—Et2 0 (17/1/15) the molecular weight rose with increase in [M] /[Ni] ratio and 3—9 chains were produced per nickel atom. It was observed that as molecular weight increased so the cis content of the polymer increased — from ca. 50% up to ca. 90% [292]. 

Ternary blend using binary interaction model Gan et al. [18] found for certain copolymer compositions and volume fractions the ternary blend system of styrene acrylonitrile copolymer (SAN), polycarbonate (PC) homopolymer and polycaprolactone (PCL) was completely miscible. Develop the expression for binary interaction energy B for the ternary blend using binary interaction model. Is the intramolecular repulsion in the copolymer sufficient to drive miscibility with two other homopolymers without any common monomers ... 

To correct some of the problems associated with the use of BIS-GMA and similar monomers, Bowen devised a unique monomer system based on the use of well characterized crystalline dimethacrylates which on proper admixture form ternary liquid eutectics of workable viscosity (15-17). The structure of this monomer system, based on the bis(meth-acryloxyethyl) ester of the isomeric benzenedicarboxylic acids, is... 

Figure 3B. Ternary liquid eutectic monomer system synthesis of aryl diester dimethacrylates.

The methacryloxyethyl derivatives of the various isomeric hydroxybenzaldehydes also are relatively low melting crystalline monomers that can be formulated to give both ternary and binary liquid mixtures (21). The synthesis of these monomers is shown in Fig. 4. These monomers may have application, if not as the main component of a dental resin binder, at least as a unique type of diluent. Clear, tough pol nners that are only partially soluble resulted from their bulk, free radical polymerization. Apparently, the aldehyde functionality enables these monomers to act as chain transfer agents which can delay the onset of gelation, and, perhaps, reduce residual vinyl unsaturation of dental monomer systems which utilize them as diluent comonomers. 

In block copolymers [8, 30], long segments of different homopolymers are covalently bonded to each otlier. A large part of syntliesized compounds are di-block copolymers, which consist only of two blocks, one of monomers A and one of monomers B. Tri- and multi-block assemblies of two types of homopolymer segments can be prepared. Systems witli tliree types of blocks are also of interest, since in ternary systems the mechanical properties and tire material functionality may be tuned separately. 

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. 

In this work, a comprehensive kinetic model, suitable for simulation of inilticomponent aiulsion polymerization reactors, is presented A well-mixed, isothermal, batch reactor is considered with illustrative purposes. Typical model outputs are PSD, monomer conversion, multivariate distritution of the i lymer particles in terms of numtoer and type of contained active Chains, and pwlymer ccmposition. Model predictions are compared with experimental data for the ternary system acrylonitrile-styrene-methyl methacrylate. 

Model predictions are caipared with experimental data In the case of the ternary system acrylonitrlle-styrene-methyl methacrylate. Ihe experimental runs have been performed with the same recipe, but monomer feed composition. A glass, thermostat ted, well mixed reactor, equipped with an anchor stirrer and four baffles, has been used. The reactor operates under nitrogen atmosphere and a standard degassing procedure is performed Just before each reaction. The same operating conditions have been maintained in all runs tenperature = 50°C, pressure = 1 atm, stirring speed = 500 rpm, initiator (KgSgOg) 0. 395 gr, enulsifier (SLS) r 2.0 gr, deionized water = 600 gr, total amount of monomers = 100 gr. 

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