Terpolymerization reactions

Analysis of data obtained from reactions with mixtures of purified monomers (18) permitted calculations of Kp2/Kt and kinetic chain lengths for these terpolymerization reactions using the following two relationships (6,9) ... 

Analogous to the case of styrene, the terpolymerization reactions of propene with ethene were carried out to identify the factors responsible for enantioface discrimi-... 

Table 4 Summary of ethylene/propylene/p-MS and ethylene/l-octene/p-MS terpolymerization reactions using [( -C5Me4)SiMe2-( 7 -NCMe3)]TiCl2/MAO catalyst...

Due to the low polymerizability of carboxylic acids by metallocene catalysts, only a limited number of successful copolymerization reactions have been published. Beside copo-lymerization reactions of 10-undecenoic acid with ethene ° and propene,co- and terpolymerization reactions of norbomenecatboxylic add 34 (Figure 17) with a-olefins have been reported. " ... 

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). 

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. 

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

Terpolymers made from two different olefins and CO are known. They were first described in Brubaker s initial patent and involved the free radical initiated terpolymerization of CO and C2H with another olefin such as propylene, isobutylene, butadiene, vinyl acetate, diethyl maleate or tetrafluoroethylene More recently, in another patent, Hammer has described the free radical initiated terpolymerization of CO and C2H with vinyl esters, vinyl ethers or methyl methacrylate 26Reaction temperatures of 180-200 °C and a combined pressure of 186 MPa were employed. Typically a CO QH4 olefin molar ratio of 10 65 25 was observed in the terpolymers. In other patents, Hammer 27,28) has described the formation of copolymers with pendant epoxy groups by the free radical initiated polymerization of CO, QH4, vinyl acetate and glycidyl methacrylate. Reaction conditions similar to those stated above were employed, and a typical CO C2H vinyl acetate glycidyl methacrylate molar ratio of 10 65 20 5 was observed in the product polymer. 

The terpolymerization of CO, QH and SOz using free radical initiators has been claimed 32). The reactions were typically run at 80-90 °C under a total pressure of 41-69 MPa. 

A retarding effect of monomers similar to 3 on the overall rate of the polymerization and on the molecular masses of the products was explained by evoking the reaction of the azo compounds with the chain propagating radicals to yield the stabilized hydrazyl radicals. The results of the terpolymerization with 4-6 are given in Table 3.11 52). 

In the terpolymerization of styrene, 2-ethylhexyl acrylate, and glycidyl acrylate a continuous-addition type of technique was used, and attempts were made to achieve maximum conversions. Relationships were sought between molecular weights, molecular weight distributions, reaction temperature, initiator concentration, half-life of the initiator, and rate of monomer-initiator addition. The molecular weights of the products depended strongly upon reaction temperature and on the rate of initiator decomposition. Narrower molecular weight distributions resulted from the use of initiators with shorter half-lives. 

The terpolymerizations described were carried out by a continuous feed method, unless stated otherwise, where both the monomer mixture and the initiator were added together continuously to the reaction kettle (18). The variables studied were (1) effects of initiators with different half-lives, (2) effects of variations in temperature, and (3) effects of variations in concentrations of initiators. Attempts were also made to study the extent of heterogeneity in the products. 

When both monomer and initiator are added simultaneously, the rate of monomer and initiator addition to the reaction doesn t appear to be very critical. This was shown in a study of homopolymerization of styrene (19) and appears to be true in this terpolymerization (Table IX). Variations in Mw/Mn appear small. However, there is a decrease in Mw... 

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 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 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 ... 

In the terpolymerization of styrene, methyl methacrylate and acrylonitrile (s/MMA/AN = 50/25/25 mole ratio) in the presence of EASC, the terpolymer composition is approximately 50/36/1 1, independent of the temperature within the range of 10-90°C, whether the reaction is conducted in the dark or under UV radiation (lO). However, the terpolymerization rate is increased 2-5 times under UV light. 

Homogeneous vanadium-based catalysts formed by the reaction of vanadium compounds and reducing agents such as organoaluminum compounds [10-12] are used industrially for the production of elastomers by ethylene/propene copolymerization (EP rubber) and ethylene/propene/diene terpolymerization (EPDM rubber). The dienes are usually derivatives of cyclopentadiene such as ethylidene norbomene or dicyclopentadiene. Examples of catalysts are Structures 1-4. Third components such as anisole or halocarbons are used to prevent a decrease in catalyst activity with time which is observed in the simple systems. 

Various water-soluble diphosphine ligands have been used for the copolymerization reaction or for fhe terpolymerization with propene (Scheme 8.9). 

Furthermore, the phosphine-dihydrooxazole hgands show an unusual behavior with respect to ethene and styrene. The productivity of those systems is larger for styrene than for ethene under equal reactions conditions nevertheless, in the terpolymerization experiments ethene, and not styrene, is prevailingly inserted. Considering that ethene was inserted more rapidly than styrene into model acetyl complexes [103], the poisoning" effect of ethene can be explained by assuming that ethene is coordinated more easily, without rapid olefin dissociation, and that rate-determining carbon monoxide insertion into the two different alkyl intermediates occurs. 

The quantitative treatment of terpolymerization is more complex than two-component copolymerization though the method is similar. In the copolymerization of three monomers Mi, M2, and M3 there are three different types of growing chain ends aam/Mi, mwM2 , and wwMa. Each of these can react with any of the three monomers of the system, and hence there are nine different chain propagation reactions, as shown below ... 

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