Terpolymerization

A quantitative treatment of terpolymerization, where three different monomers are interpoly-merized, becomes complex. Nine growth reactions take place  

With the same assumptions as in Section 22.1, copolymerization equations can also be derived for the copolymerization of more than two monomers. Relationships of this kind are very important in industry, since with terpolymerization, as many as 160,000 three-monomer combinations can be achieved with just 100 different monomer types. As the number of monomers per system increases, however, the equations rapidly become difficult to handle. 

Basically, just as in the case of two monomers, a copolymerization equation for three monomers can be derived using the probability of formation of the sequence. Here, however, the older kinetic derivation has been chosen for illustration purposes. It must also be stressed that the introduction of the steady-state condition required in this derivation is not absolutely necessary, since the same results can be obtained with a statistical derivation without this assumption. 

In analogy to equation (22-1), the copolymerization of three monomers involves a total of nine rate constants fcn, kj3, /c22 33 31  

Some special cases found in terpolymerization can be treated especially simply  

To determine the reactivity ratios, therefore, it is necessary to carry out copolymerization experiments with every monomer pair. 

However, it should be noted that even these elementary calculations are not needed, since the absence or presence of the inner azeotrope can be rigorously 

When the types of all boundary SPs and their topological indexes are established by means of Table 5.2, one should use the rule of azeotropy (5.18). In the case of terpolymerization this rule can be written as  

In accordance with the general principles of the above classification the three-component systems can be divided into 7 types which are shown in Fig. 6. Each of the diagrams I, II, IV, VII may have two subtypes. The type of the concrete system which is characterized by a set of arrow directions on the triangle sides depends only upon a matrix of signs of values 1 — ay. 

In order to classify the systems in terms of their genus for each system one should also (i) establish the types of the binary azeotropes by determining the signs of the proper values of X (see Table 5.2) and (ii) estimate the topological parameter 8 from formula (5.19). According to Table 5.2 the separatrix of the binary azeotrope enters it when X 0 and leaves it when X 0, and the number 

The system of genus 1 is regarded to be an exclusive one since it only has the stable inner azeotrope when the coefficient oq is positive (see Table 5.1). Therefore the four kinds of the system of genus 1 correspond to the four combinations of signs of the oq and p values. If, as it is usually admitted under the topological classification of the dynamic systems, one doesn t distinguish for the sake of 

Six reactivity ratios are then required to describe the system. 

Application of a steady state assumption (cqs. 33-35) enables derivation of the composition relationship (eq. 36). 

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). 

Expressions for other cases, for example, where two monomers (B and C) are slow to propagate, were also derived. An equation related to eq. 37 has application in the analysis of binary copolymerizations in the presence of a transfer agent (Section 7.5.6). 

The complexity of the terpolymer composition equation (eq. 36) can be reduced to eq. 41 through the use of a modified steady state 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 appeal to work well. It can be noted that when applying the Q-e scheme a terpolymer equation of this form is implied. 

2-hydroxyethyl methacrylate, glycidyl methacrylate, and -butyl methacrylate Three different solvents, -butanol, toluene, and W,W-dimethylformamide were used. They found that aU three solvents effected the composition of styrene-2-hydroxyethyl methacrylate copolymer. Liang and Hutchinson [147] also observed variations in monomer reactivity ratios with solvent polarity. Butanol was the only one that affected styrene butyl methacrylate copolymer composition. None of the solvents appeared to effect the composition of the styrene-glycidyl methacrylate copolymer. 

By assuming steady state conditions for the three radicals, Mj, M2, and Ms it is possible to write  

An equation for terpolymer composition was developed from the rate expressions by expressing the steady state with the relationships [94]  

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]. 

Most clearly the simplicity of the derivation of an algorithm of a kinetic model of a route can be illustrated by the co-polymerization process of three monomers. In the simplest variant the kinetic scheme of chain propagation consists of only elementary reactions of the (2.115) and (2.116) type  

We can see three own routes U, and tfj in the basis(sets) W(Ri), WfR ) and W(/ j) represented by hinges from elementary reactions 5, S2 and Sj, yielding the final 

are formed via the sequence of elementary reactions 4, 6, 9 and 8, 7, 5, respectively they yield the final chemical transformation 41 + A2 + A3 A kinetic matrix of the third order is as follows  

As we can see, in the kinetic matrix B again there are no intensities of the transitions on the elementary reactions S -S, since they do not change the ratio between 

Then the rate of a route can be written in the shorter form  

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Morishima et al. [42] prepared polyanions (A-x, 3) of various charge densities tagged with the merocyanine dye (Me) by terpolymerization of acrylic acid (AA), acrylamide (AAm), and a small mole fraction of l-(2-methacryloyloxyethyl)-4-(2-(4-hydroxyphenyl)ethenyl)pyridinium bromide (MA-Mc). Since these polyanions carry only 1 mol% of the MA-Mc units, they can practically be treated as copolymers of AA and AAm with a wide range of composition. 

It has been pointed out that analysis of terpolymerization data or copolymerization with chain transfer could, in principle, provide a test of the model. 5 However, to date experimental uncertainty has prevented this. 

Terpolymerizations or ternary copolymerizations, as the names suggest, are polymerizations involving three monomers. Most industrial copolymerizations involve three or more monomers. The statistics of terpolymerization were worked out by Alfrey and Goldfinger in 1944.111 If we assume terminal model kinetics, ternary copolymerization involves nine distinct propagation reactions (Scheme 7.9). 

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. 

The overall composition at low conversion of binary copolymers formed in the presence of a chain transfer agent can be predicted analytically using an expression analogous to that used to describe terpolymerization where one monomer does not undergo propagation (Section 7.3.2.4),2j6 Making the appropriate substitutions, eq. 37 becomes eq. 70 ... 

Thermal degradation studies of EB-cured terpolymeric fluorocarbon rubber [430] by nonisothermal thermogravimetry in the absence and presence of cross-link promoter TMPTA reveal that thermal stability is improved on radiation and more so in the presence of TMPTA. Initial decomposition temperature, maximum decomposition temperature and the decomposition... 

Water-soluble dicationic palladium(II) complexes [(R.2P(CH2)3PR.2)Pd-(NCMe)2][BF4]2 proved to be highly active in the carbon monox-ide/ethene copolymerization under biphasic conditions (water-toluene). In the presence of an emulsifier and methanol as activator, the catalytic activity increased by a factor of about three. Also higher olefins could be successfully incorporated into the copolymerization with CO and the terpolymerization with ethene and CO.184... 

A Japanese patent72) claims the synthesis of thermally stable copolymers by free-radical terpolymerization of dialkylstannyl dimethacrylates, glycidyl methacrylate and vinyl monomers (vinyl chloride, styrene, vinyl acetate, etc.). The products contain 0.5 to 30% tin and 0.05 to 7 % epoxide oxygen. 

Some characteristics of free-radical terpolymerization of tri-butylstannyl methacrylate, styrene and maleic anhydride governed by the pentacoordination state of the tin atom are reported in Refs. 95),96). It is shown that a coordination-bound monomer has a considerable effect on chain initiation and propagation. Copolymerization mainly involves the participation of complex-bound monomers. 

More active zinc phenoxide initiators of the type [Zn(0Ar)2(Et20)2]956 were found to catalyze both the copolymerization of CHO with C02 and the terpolymerization of CHO, PO, and C02 attempts to copolymerize PO and C02 yielded predominantly cyclic carbonates. For example, (332) copolymerizes CHO and C02 at 80 °C and 800 psi to give a copolymer containing 91% syndiotactic polycarbonate linkages (and 9% polyether junctions due to the non-insertion of C02) with good activity (>350g polymer/g [Zn] in 69 h).957 However, the polymerization is not well-controlled (Mw/Mn>2.5). Variation of the phenoxide ligands revealed that (333) is 4 times... 

In all cases, the cloud-point temperature was slightly dependent on polymer concentration for a given copolymer it increased with decreasing concentration. This effect is enhanced with increasing number of PEO grafts per chain. Also, the PNIPAM collapse seemed to be less abrupt with decreasing concentration. Upon dilution of the solution the distance between polymer chains increases, which favours intrapolymeric interactions over in-terpolymeric attractions. Dilution also enhances the surface stabilisation of the polymer particles by PEO. 

A microgel of a dz = 76 nm which is suitable for coupling with proteins, can be prepared by emulsion terpolymerization of NjAT -tetramethylene bisacrylamide, n-hexylmethacrylamide and propene acid amide-N-(4-methyl-2-butyl-1,3-diox-olane) [291 ]. The diameter of these microgels may be varied by the concentration of the emulsifier (Fig. 57) and is rather uniform. As the CMC of this system is about 2.5 X10"3 mol SDS/1, it may be assumed that below this value the copolymerization essentially takes place in the monomer droplets, whereas at higher concentrations of SDS preferentially the monomers in micelles are polymerized. 

The water-soluble palladium complex prepared from [Pd(MeCN)4](Bp4)2 and tetrasulfonated DPPP (34, n=3, m=0) catalyzed the copolymerization of CO and ethene in neutral aqueous solutions with much lower activity [21 g copolymer (g Pd) h ] [53] than the organosoluble analogue in methanol. Addition of strong Brpnsted acids with weakly coordinating anions substantially accelerated the reaction, and with a catalyst obtained from the same ligand and from [Pd(OTs)2(MeCN)2] but in the presence of p-toluenesulfonic acid (TsOH) 4 kg copolymer was produced per g Pd in one hour [54-56] (Scheme 7.16). Other tetrasulfonated diphosphines (34, n=2, 4 or 5, m=0) were also tried in place of the DPPP derivative, but only the sulfonated DPPB (n=4) gave a catalyst with considerably higher activity [56], Albeit with lower productivity, these Pd-complexes also catalyze the CO/ethene/propene terpolymerization. 

Water-soluble l,3-bis(di(hydroxyalkyl)phosphino)propane derivatives were thoroughly studied as components of Pd-catalysts for CO/ethene (or other a-olefins) copolymerization and for the terpolymerization of CO and ethene with various a-olefins in aqueous solution (Scheme 7.17) [59], The ligands with long hydroxyalkyl chains consistently gave catalysts with higher activity than sulfonated DPPP and this was even more expressed in copolymerization of CO with a-olefins other than ethene (e.g. propene or 1-hexene). Addition of anionic surfactants, such as dodecyl sulfate (potassium salt) resulted in about doubling the productivity of the CO/ethene copolymerization in a water/methanol (30/2) solvent (1.7 kg vs. 0.9 kg copolymer (g Pd)" h" under conditions of [59]) probably due to the concentration of the cationic Pd-catalyst at the interphase region or around the micelles which solubilize the reactants and products. Unfortunately under such conditions stable emulsions are formed which prevent the re-use... 

Lee and coworkers have reported on the use of the highly active and selective cobalt(III) catalyst depicted in Fig. 12 for the terpolymerization of propylene oxide and various epoxides with CO2, including cyclohexene oxide, 1-hexene oxide, and 1-butene oxide [61]. Catalytic activities ranged from 4,400-14,000 h at a CO2... 

Scheme 9 Ring-opening pathways for the terpolymerization of propylene oxide and cyclohexene oxide with CO2...

Other recent reports of interesting terpolymerization processes involving cyclohexene oxide and diglycolic anhydride or vinylcyclohexene oxide have appeared in the literature [66-68]. These processes are indicated in (7) and (8), and were carried out in the presence of p-diiminate zinc catalysts. The vinyl functionalized polymer was intramolecularly crosslinked by a metathesis reaction to afford nanoparticles. 

The overall thermal stability of PPC can further be enhanced through modification of the main chain, i.e., by the incorporation of ether units, or through the terpolymerization with epoxides other than PO or ethylene oxide (EO), and with lactide, lactones and other heterocycles [36-39]. The higher the content of ether linkages in PPC, the higher the thermal stability is [40]. This seems to be a result of... 

Hwang Y, Jung J, Ree M (2003) Terpolymerization of CO2 with propylene oxide and epsilon-caprolactone using zinc glutarate catalyst. Macromolecules 36 8210-8212... 

Liu Y, Huang K, Peng D, Wu H (2006) Synthesis, characterization and hydrolysis of an aliphatic polycarbonate by terpolymerization of carbon dioxide, propylene oxide and maleic anhydride. Polymer 47(26) 8453-8461... 

Shi L, Lu X-B, Zhang R, Peng X-J, Zhang C-Q, Li J-E, Peng X-M (2006) Asymmetric alternating copolymerization and terpolymerization of epoxides with carbon dioxide at mild conditions. Macromolecules 39 5679-5685... 

Darensbourg DJ, Holtcamp MW (1995) Catalytic activity of zinc(II) phenoxides which possess readily accessible coordination sites. Copolymerization and terpolymerization of epoxides and carbon dioxide. Macromolecules 28 7577-7579... 

The two monomers enter into the copolymer in overall amounts determined by their relative concentrations and reactivities. The simultaneous chain polymerization of different monomers can also be carried out with mixtures of three or more monomers. Such polymerizations are generally referred to as multicomponent copolymerizations the term terpolymerization is specifically used for systems of three monomers. 

Terpolymerization, the simultaneous polymerization of three monomers, has become increasingly important from the commercial viewpoint. The improvements that are obtained by copolymerizing styrene with acrylonitrile or butadiene have been mentioned previously. The radical terpolymerization of styrene with acrylonitrile and butadiene increases even further the degree of variation in properties that can be built into the final product. Many other commercial uses of terpolymerization exist. In most of these the terpolymer has two of the monomers present in major amounts to obtain the gross properties desired, with the third monomer in a minor amount for modification of a special property. Thus the ethylene-propylene elastomers are terpolymerized with minor amounts of a diene in order to allow the product to be subsquently crosslinked. 

The quantitative treatment of terpolymerization is quite complex, since nine propagation reactions... 

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... 

TABLE 6-1 Predicted and Experimental Compositions in Radical Terpolymerization"... 

Styrene-1,3-butadiene copolymers with higher styrene contents (50-70%) are used in latex paints. Styrene and 1,3-butadiene terpolymerized with small amounts of an unsaturated carboxylic acid are used to produce latexes that can be crosslinked through the carboxyl groups. These carboxylated SBR products are used as backing material for carpets. Styrene copolymerized with divinyl benzene yields crosslinked products, which find use in size-exclusion chromatography and as ion-exchange resins (Sec. 9-6). 

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. 

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