Copolymerization of acetylenes

Copolymerizations of benzvalene with norhornene have been used to prepare block copolymers that are more stable and more soluble than the polybenzvalene (32). Upon conversion to (CH), some phase separation of nonconverted polynorhornene occurs. Other copolymerizations of acetylene with a variety of monomers and carrier polymers have been employed in the preparation of soluble polyacetylenes. Direct copolymeriza tion of acetylene with other monomers (33—39), and various techniques for grafting polyacetylene side chains onto solubilized carrier polymers (40—43), have been studied. In most cases, the resulting copolymers exhibit poorer electrical properties as solubiUty increases. 

Figure 7.14 Change in concentration of free radicals trapped in plasma polymers by copolymerization of acetylene with N2 or H2O.

Table 10.6 Metathesis copolymerization of acetylenes with each other...

There are also other approaches to polymer stabilization (Aldiss 1989). For example, it was found that the formation of composites of two conducting polymers, one of which is air stable, improves the stability of polymer materials. Experiments carried out with pyrrole/polyacetylene and polyaniline/ polyacetylene composites have shown that the composites appeared to be more stable than doped polyacetylene and possessed mechanical properties similar to polyacetylene. Stabilization can also be achieved chemically by copolymerization. In particular, it was found that copolymerization of acetylene with other monomers such as styrene, isoprene, ethylene, or butadiene was accompanied by the increase of improvement of polymer stability (Aldiss 1989). Crispin et al. (2003) established that... 

Amass and Stowell et al. replaced the Zeigler-Natta catalyst with a methathesis catalyst for the copolymerization of acetylene with various flexible components including cyclic alkene. The metathesis catalyst has a slower polymerization rate for acetylene and therefore better control of the acetylene segment length. In a series of three papers [67-69], the efficiency of the... 

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