Terpolymerizations, Monomers Studied

In relation to the practical interest of synthesizing copolymers of homogeneous composition, a number of studies has been devoted to the problem of azeotropy, i.e., the possibility of preparing a copolymer whose composition is exactly the same as that of the initial monomer feed mixture. In such a case the monomer feed and copolymer composition would remain constant as the reaction proceeds. For most binary compositions, where MA is not involved, this problem is often simply solved. However, the problem of being able to prepare MA copolymers of compositions equal to feed mixtures is well known i.e., MA homopolymerizes with difficulty and copolymerizes with many electron-donating monomers to give only equimolar copolymers. Furthermore, this problem is compounded in MA copolymerizations with two or more monomers (see Chapter 10).Nevertheless, MA has been copolymerized with a wide variety of two or more monomers to obtain polymeric materials that are potentially useful in many areas. We briefly review these copolymerizations and provide a MA terpolymerization patent listing (Table A.l). 

---

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... 

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. 

Several works [311-313, 200] are devoted to a circumstantial research of systems where terpolymerization of styrene and acrylonitrile with a third monomer (brominated acrylate or methacrylate) was studied. It was shown that the terminal model can be employed to describe such systems. One can see this from Table 6.10 and Figs. 20 and 21, where the conversion drifts of the average copolymer composition are presented. 

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 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 ... 

Infrared and n.i.r. spectroscopy are also well suited for kinetic (and thermodynamic) investigations of other monomer-polymer systems. Examples of kinetic studies on acrylate and methacrylate polymerizations in the fluid state up to high pressures are detailed elsewhere. Moreover, copolymeriza-tions and even terpolymerizations have been monitored via high-pressure vibrational spectroscopy. 

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... 

The types of surface moieties stabilizing the latex also are important. The binders used in waterborne coatings are not the hard-sphere, model polymer colloids used in adsorption studies. They are soft (low glass transition temperature), deformable moieties that are stabilized by grafted polymer fragments [e.g., (hydroxyethyl)cellulose (16) or poly(vinyl alcohol)] or by terpolymerized acid monomers extended from the surface of the colloid (IT). Such stabilizers produce a far less hydrophobic surface than is generally depicted in colloid texts. This situation is particularly true if the composition of the latex is predominately methacrylate or vinyl acetate, as they are in most U.S. commercial products. 

A recent study reported the terpolymerization of hexen-l-ol, 10-undecen-l-ol and 10-undecen-oic acid with ethylene and propylene. The catalysts employed were bis-indenyl zirconocenes. Again, the monomers were complexed with trimethylaluminum (TMA). Several mixing strategies were employed, and the comparisons indicate that complexing with TMA is far more effective than complexing using MAO. The target terpolymers could be prepared but at the price of substantial decreases in catalyst activity. 

A series of patents were issued to DuPont in the mid-1970s that covered the terpolymerization of ethylene, propylene, and functional monomers. The catalyst employed was a soluble VCl4/AlEt2Cl in combination with hexachloropropene as a catalyst activator. The functional comonomers studied included 2-hydroxy-5-norbornene, 2-hydroxymethyl-5-norbornene, allylsulfonyl chloride, 2-allylphenol, and... 

Charge transfer complexes of the monomers were studied in the terpolymer-ization of neutral monomers (N) with electron-donor (D) and electron-acceptor (A) monomers [18a]. For example, norbomene as (D) monomer, SO2 as (A) monomer, and acrylonitrile as (N) molecules were studied. Thus acrylonitrile may not be effective in copolymerization but can be terpolymerized with SO2 [18a]. 

Butler and Campus [40] undertook a study to provide further evidence of the formation of the charge-transfer complex between the comonomers and of its participation in the cyclocopolymerization. The 1,4-diene used was divinyl ether (DVE) and the monoolefins were maleic anhydride (MA) and fumaronitrile (FN). The results of the determination of the composition of the charge-transfer complex formed between DVE-MA are shown in Figure 5. Acrylonitrile (AN) was used as the third monomer in the terpolymerization experiments. For comparison, the results of a complex study of styrene-maleic anhydride and ethyl vinyl ether (EVE)-maleic anhydride were also reported. The results of determination of the equilibrium constants for the DVE-MA and styrene-MA complexes by the NMR method are shown in Figure 6. The results... 

---