Molecular weight and molecular weight distribution control of ring-opening metathesis polymerization of norbornene

Ring-opening metathesis polymerization of norbornene catalyzed by Grubbs catalyst [(PCY3)(2) (Cl)(2) Ru = CHPh] was carried out. The results of H-1 NMR demonstrated that the polymerization of the norbornene monomer proceeded by the ROMP mechanism. The molecular weight and molecular weight distribution of this reaction can be controlled by changing the stirring time of catalyst, choosing different solvents and the adding of PPh3 during the polymerization. The results show that stirring the catalyst for 15 min, using more polar solvent and adding 2 equiv of PPh3 can optimize the conditions of this reaction. The polydispersity indices ( PDls) of the poly ( norbornene) were nearly monodisperse ( PDls about 1. 18).