Ring-Opening Metathesis Polymerization and Hydrogenation of Ethyl-substituted Tetracyclododecene

Abstract

Ring-opening metathesis polymerization (ROMP) of an ethyl-substituted tetracyclododecene (8-ethyltetracyclo[<TEX>$4.4.0.1^{2,5}.1^{7,10}$</TEX>] dodec-3-ene, Et-TCD) was carried out in the presence of a ternary catalyst system consisting of <TEX>$WCl_6$</TEX>, triisobutyl aluminium (iso<TEX>$Bu_3Al$</TEX>), and ethanol. The optimal molar ratio of Et-TCD/<TEX>$WCl_3$</TEX>/iso-<TEX>$Bu_3Al$</TEX>/ethanol was found as 500/1/3/2 at which the yield of ring-opened polymer was 100%. 1-Hexene was shown to be an effective molecular weight controlling agent for ROMP reaction of Et-TCD. The hydrogenation of the ring opened polymer (p-Et-TCD) was conducted successfully using Pd(5 wt %)/<TEX>${\gamma}$</TEX>-<TEX>$Al_2O_3$</TEX> at <TEX>$80^{\circ}C$</TEX> for 1 h. Chemical structures of p-Et-TCD and its hydrogenated product(<TEX>$H_2$</TEX>-p-Et-TCD) were characterized using 2D NMR techniques (<TEX>$^1H-^1H$</TEX> COSY and <TEX>$^1H-^{13}C$</TEX> HSQC). The changes of physical properties such as thermal stability, glass transition temperature and light transmittance after the hydrogenation were also investigated using TGA, DSC, and UV.