Copolymers from thiophene/furan

Thiophene-Furun. A copolymer based on 2-(2 -thienyl)fiiran has been prepared [652] (Fig. 49c). Most furan-containing pofymers, however, have been synthesized from a-linked three-ring systems. The different trimeric tems of Figure 49c have been polymerized [776,778,782]. 

Similar to furan and benzofuran monomers,thiophene and 1-benzothiophene " are also known to copolymerize in a 1 1 fashion with MA. Thiophene will not undergo free-radical homopolymerization or copolymerization with monomers such as styrene, methyl methacrylate, or acrylonitrile. However, when an equimolar mixture of thiophene and MA are combined with chloroform containing AIBN and heated at 60°C, a white copolymer starts to precipitate after only a few minutes reaction time. Varying the molar feed ratios showed that both yields and reduced viscosities were maximum for equimolar feeds. Copolymerizations in solution from 1 bar to 3 kbars show that rates and yields are increased with pressure.Through composition studies and comparing the NMR spectrum of the copolymer with the NMR spectra of 2,3- and 2,5-dihydrothiophene, structure 88 was assigned to the copolymer. 

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