Intra-intermolecular polymerization

The importance of intramolecular cyclization was emphasized when Butler and coworkers found that the radical polymerization of N, N, N, /V-diallyldimethylammonium chloride (DADMAC) gave soluble, uncrosslinked polymers with little or no unsaturation (Eq. 6-101) [Butler and Angelo, 1957 Butler and Ingley, 1951 Wandrey et al., 1999]. There is a very low tendency for radical IV to propagate intermolecularly and undergo crosslinking. The predominant reaction is intramolecular cyclization, and the product is a linear product with cyclic structures in the backbone. The reaction is referred to as alternating intra/intermolecular polymerization or cyclopolymerization. 

IQ. Unusual Head-to-Tail Polymerizations 1. Cationic Intra-Intermolecular Polymerizations... 

Ball and Hardwood (105a) reported an unusual cationic intra-intermolecular polymerization in the case of 1,4-dimethylene cyclohexane. The best catalyst was BF- gas in methvlene chloride solution at -78 to -40° C. 

Examples of intra intermolecular polymerizations are cyclic polymerizations of nonconjugated dienes. This can resemble cyclopolymerization by free-radical mechanism ... 

The reaction is essentially an intra-intermolecular polymerization and can proceed via the following mechanism ... 

Intra-Intermolecular Polymerizations Leading to Homocyclic Carbon Rings... 

Intra-intermolecular polymerization or cyclopolymerization is a ringforming polymerization method that has been widely used and studied. The principle on which it operates is shown in the following equations. 

Historically, the development of the intra-intermolecular polymerization can be traced back to early studies on free-radical polymerizations and copolymerizations of diolefinic monomers. According to Staudinger 150), the polymerization of nonconjugated dienes should yield cross-linked polymers. However, studies of the free radical-initiated copolymerizations of methyl methacrylate with ethylene dimethacrylate, and of vinyl acetate with divinyl adipate 165) have shown the existence of a delay in reaching the gel point. In other words, for some unexplained reason the gel point was reached at... 

Butler s successful demonstration of the existence of the intra-intermolecular polymerization mechanism triggered widespread research in this area. As a result, excellent procedures for this type of ring-forming polymerization evolved. Cyclopolymerizations can take place by free-radical, cationic, anionic, Ziegler, and other types of initiations. These various types of intra-intermolecular polymerizations are discussed below. Only all-carbon ring-containing polymers are covered. The formation of heterocyclic polymers by this reaction will be discussed in a forthcoming volume (Part B). 

Method 1. Free-Radical Initiation Intra-intermolecular polymerizations can be initiated by free radicals in several ways. Typical free-radical initiators like peroxides, peracids, azobis-(isobutyronitrile), oxygen, ferrous ion/hydrogen peroxide, and persulfate can... 

The foregoing examples amply illustrate the scope of free radical-initiated intra-intermolecular polymerizations. Several theoretical treatments of this type of polymerization have appeared 12, 29, 60, 61, 159, 160). The kinetics have been described recently 11). A statistical study of the probability of cyclopolymerization showed that a more energetically favorable pathway must... 

The intra-intermolecular polymerization of c/5-l,3-divinylcyclopentane and cyclohexane has been effected by a Ziegler catalyst prepared from titanium tetrachloride and triisobutylaluminum (38). A 38 % conversion to the bicyclo-octane polymer was obtained in 72 hours (11-42). Under similar conditions,... 

The polymerization of alloocimene [121] is reported in the patent literature I39-I41). Silica gel, synthetic silicates, and various Lewis acids were used as the catalysts. However, no details concerning the structure of the polymeric products were given. More recently, the cationic polymerization of alloocimene was investigated by Jones (71). An intra-intermolecular polymerization mechanism was postulated (11-57). The iodine number of the polymer indicated the loss of two double bonds per monomer unit during polymerization. Interestingly, the use of Ziegler-type catalysts did not yield cyclic polymeric structures (95, 96). 

Inorganic polymers, with pendant organic groups, 251 Intra-intermolecular polymerizations, xxiii, 13, see also Cyclopolymerizations Intramolecular crosslinking, 31, see also Cyclopolymerization Iron carbonyl, polymers with... 

The remarkable intra-intermolecular polymerization in which a monomer with a functionality of four gives linear, soluble, high molecular weight polymer is shown schematically in Eq. (Int.-6). In both reactions, Eqs. (lnt.-5) and (Int.-6), the polyfunctionality of the monomers that might lead to cross-linked products is not operative because other factors prevailing in the monomers determine a different reaction course. That this situation can occur with many different types of polyfunctional reactants is amply illustrated by the examples in this book. 

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