Polymers, formed by metathesis polymerization

Stereochemistry of Polymers Formed by Metathesis Polymerization of Bicyclic and Polycyclic Olefins... 

Bellmann et al. [23] reported on a series of hole-transporting triphenylamines based on polynorbonenes. The polymer, formed by ring-opening metathesis polymerization, contains double bonds, which are crosslinked by UV irradiation via a mechanism not fully investigated. However, in their best case crosslinking reduced the efficiency based on the emitter A1Q3 by factor of two approximately (Fig. 9.10). 

The cheapness of dicyclopentadiene (DCPD), obtained as a byproduct from the cracking of oil, makes it an attractive candidate for the production of materials by metathesis polymerization. Its ROMP has been extensively studied and two companies, BFGoodrich and Hercules, have commercialized the corresponding polymer under the tradenames Telene and Metton respectively [34, 35]. Recently, a part of BFGoodrich and APT (Advanced Polymer Technologies) formed a joint venture to produce some related products, especially poly-DCPD. This company has... 

The polymerization of cyclic, strained olefins by transition metal alkylidenes of general formula L M = CRR (L = ligand, R, R = H, alkyl, aryl) yields polymers formed via ring-opening that contain unsaturated double bonds within each repetitive unit. Since the mechanism is based on repetitive metathesis steps, this polymerization reaction is known as ring-opening metathesis polymerization (ROMP) (Scheme 1). 

When 97 is sufficiently dilute its polymerization is no longer thermodynamically allowed, but, in the presence of 8, a mixture of cyclic dimers, cc (84%), ct (14%) and tt (2%), is readily formed, in equilibrium with the monomer. The cc dimer has been isolated and its crystal structure determined247. These cyclic dimers can also be made by metathesis degradation of the polymers or by ADMET of diallyldiphenylsilane (Section VILA.6). 

Dienes are cyclized by intramolecular metathesis. In particular, cyclic alkenes 43 and ethylene are formed by the ring-closing metathesis of the a,co-diene 46. This is the reverse reaction of ethenolysis. Alkene metathesis is reversible, and usually an equilibrium mixture of alkenes is formed. However, the metathesis of a,co-dienes 46 generates ethylene as one product, which can be removed easily from reaction mixtures to afford cyclic compounds 43 nearly quantitatively. This is a most useful reaction, because from not only five to eight membered rings, but also macrocycles can be prepared by RCM under high-dilution conditions. However, it should be noted that RCM is an intramolecular reaction and competitive with acyclic diene metathesis polymerization (ADMET), which is intermolecular to form the polymer 47. In addition, the polymer 47 may be formed by ROMP of the cyclic compounds 43. 

---