Cyclised polyisoprene

Cyclisation 3040, 1175, 820 CH stretching in trisubstituted double bond due to cyclisation in BR, due to terminal double bond in cyclised polyisoprene [51, 52] [57, 58]... 

Figure 11.10 Cyclised polyisoprene with tetracyclic segment...

Negative near-UV resists are derived mainly from photoinduced crosslinking of partially cyclized c/s-l,4-polyisoprene with bisazido sensitisers [15]. Cyclised cis 1,4-polyisoprene is obtained by heating 1,4-polyisoprene in the presence of a Lewis acid (Zn02, AICI3, SnCl4) (Figure 6.9). 

The photochemical transformations of a bisazide sensitiser leading to the crosslinking of a cyclised cis-1,4-polyisoprene are shown in Figure 6.10. An insoluble three-dimensional crosslinked network is obtained. 

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