Polymers from Novel Monomers

Polymers from Novel Monomers.—Novel compounds that have been polymerized by cationic mechanisms usually incorporate the reactive functional groups of more conventional monomers, and several recently developed monomers can be classified as analogs of vinyl ethers, vinyl carbazole, p-methoxystyrene, or previously studied oxygen heterocycles. 

A substituted vinyl ether, 1,2-dimethoxyethylene, has been polymerized to high molecular weight in the presence of alkyl aluminium chloride at —50 C in 

Lukaszczyk, E. H. Schacht, and E. Coethals, Makromol. Chem., Rapid Commun., 1980, 1, 79. 

Vinyl indoles, which bear structural similarities to vinyl carbazole, tend to form cyclic dimers through ring substitution at the 3-position. When this position is blocked by an alkyl group, linear polymers are formed. Difunctional monomers incorporating a p-methoxystyryl group and allyl or propargyl ether functions have been synthesized for use as photo cross-linkable compounds.These monomers were found to oxidize when exposed to the atmosphere. 

5-anhydro-l,2-0-isopropylidene-a-D-xylofuranose (3) through attack on the three-membered ring, and l,5-anhydro-2,3-0-benzylidene- -D-ribofuranose (4) through attack on the disubstituted dioxolane ring.  

Polymers from Novel Monomers.—Novel monomers which have been polymerized recently by cationic mechanisms may be categorized as follows oxygen heterocycles, optically active monomers, and bifunctional monomers. 

Although 5,6-anhydro-l,2-0-isopropylidene-a-D-glucofuranose contains THF and dioxolan moieties as well as an oxirane ring (1) the cationic polymerization of this monomer proceeded exclusively throu the three-membered ring at temperatures below 10 °C. Molecular weights of 1290—9500 were obtained with metal halide initiators. 

When similar initiators were employed in the polymerization of 6,8-dioxa-bicyclo[3.2.1]octan-7-one (2) macrocyclic oligomers containing alternating tetrahydropyran and ester units resulted at low temperatures. At higher temperatures the lactone homopolymer was formed. The mechanism of polymerization of 2,3-dihydropyran derivatives (3) depended on the nature of the substituents, with low molecular weight polymers being formed in all cases studied.  

At a recent symposium in his honour, Bailey reviewed the theory and chemistry of ring-opening polymerizations with expansion in volume. Monomers in 

Optically-active vinyl carbazole derivatives can be polymerized cationically to yield polymers whose optical rotation depends upon the initiator system employed. In contrast cationic polymerization of a series of 2-phenylvinylalkyl thioethers produced polymers of optical rotations identical to those of the corresponding mode compounds.  

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Since their discovery over a decade ago, late transition metal a-diimine polymerization catalysts have offered new opportunities in the development of novel materials. The Ni(II) catalysts are highly active and attractive for industrial polyolefin production, while the Pd(II) catalysts exhibit unparalleled functional group tolerance and a propensity to form unusually branched polymers from simple monomers. Much of the success of these catalysts derives from the properties of the a-diimine ligands, whose steric bulk is necessary to accelerate the insertion process and inhibit chain transfer. 

The first 26 chapters represent a cross-section of the numerous processes available for the polymerization of common monomers. Through the understanding of process kinetics and through novel technology, we are able to build better polymers from these monomers. The remaining 22 chapters should leave the reader with the impression that we can build new or modified polymers at will and design them for specific... 

TTie extension of tandem catalysis to polymer chemistry is, however, not trivial. In order to reach high molecular weight polymers, each reaction has to proceed with almost perfect selectivity and conversion. Obviously, combining different catalytic reactions limits the choice of suitable reactions since they must also be compatible with each other. We recently introduced Iterative Tandem Catalysis (ITC), a novel polymerisation method in which chain growth during polymerisation is effectuated by two or more intrinsically different catalytic processes that are both compatible and complementary. If the catalysts and monomers are carefully selected, ITC is able to produce chiral polymers from racemic monomers, as was shown by us for the ITC of 6-MeCL and the DKR polymerisation of sec-diols and diesters. ... 

Toshima, N., Novel synthesis of electroconducting polymers from simple monomers with transition metal complex catalysts, Makromol. Chem. Macromol. Symp., 59, 123-134 (1992). 

The expected contribution of catalysis in this area will derive both from the availability, at low processing costs, of new monomers obtained from biomasses and from the development of an optimized combination of biotechnology processes with classical and new biocatalytic processes. Research priorities for catalysis in the area of polymers from renewable materials for packaging, furniture, domestic water purification and recycling include the need to develop novel catalysts, e.g., for functionalization of polymeric and dendrimeric materials, with side-chain photoactive molecular switches (to be used as smart materials), or the development of multifunctional materials, combining, for example, nanofiltration with catalytic reactivity. 

After the demonstrations of preparation of stereoregular polymers having novel properties by means of special ionic methods, die possibilities of free radical methods were examined extensively. It must be concluded that in free radical systems the structures of homopolymers and copolymers can be little influenced by specific catalysts and other reaction conditions, but are determined largely by monomer structure. This is consistent with the relative uniformity of comonomer reactivity ratios in radical copolymerizations. However, it has been found possible to obtain somewhat more syndiotactic structure, dldl. than normally obtained by radical reactions, at low temperatures and by selecting solvents. Examples are polyvinyl chlorides of higher than usual crystallinity from polymerizations at low temperature e.g.. —50°C under ultraviolet light... 

The computer calculation of some conformational parameters, such as bond angles, rotation barriers, and minimal energies of conformational isomers, can nowadays give valuable information to explain the behaviour of novel materials, and to predict the properties of polymers synthesized from new monomers. An illustrative example of these theoretical methods, is given in the appendix. 

A Flame Resistant ABS-Type Polymer from Terpolymerization with a Novel Bromine-Containing Monomer... 

Polycondensates 27 and 28 (Fig. 9-22), incorporating either the 1,3- or 1,1 -disubstituted ferrocene unit, were prepared by solution polymerisation. Polymers 27 [25] were obtained by reaction of the novel monomer 29 [25] (Fig. 9-23) with the desired bis(acid chloride) 31 (Fig. 9-23) in refluxing CH2CI2 in the presence of triethylamine. Polymers 28 [25] were prepared following the same procedure from bis-phenol 30 [16] (Fig. 9-23). 

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