Ring-opening metathesis polymerization and hydrogenation of ethyl-substituted tetracyclododecene

Ring-opening metathesis polymerization (ROMP) of an ethyl-substituted tetracyclododecene (8-ethyltetracyclo[ 4.4.0.1^2,5.1^7,10] dodec-3-ene, Et-TCD) was carried out in the presence of a ternary catalyst system consisting of WCl₆, triisobutyl aluminium (iso-Bu ₃Al), and ethanol. The optimal molar ratio of Et-TCD/WCl₃/ iso-Bu₃Al/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 %)/γ-Al2O3 at 80 °C for 1 h. Chemical structures of p-Et-TCD and its hydrogenated product(H2-p-Et-TCD) were characterized using 2D NMR techniques (¹H-¹H COSY and ¹H-¹³C 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.