SUMMARY: The polymerization of butadiene (Bd) with the soluble and insoluble parts of the NiCl 2 -methylaluminoxane (MAO) catalyst was investigated. Both parts initiate the polymerization of Bd to give a high molecular weight polymer consisting of mainly cis-1,4-structure. The activity of the soluble part for the polymerization is higher than that of the insoluble part. We presume that NiCl 2 reacts with MAO to give a soluble alkyl-nickel complex that shows high activity for the polymerization of Bd.

The polymerization of methyl methacrylate (MMA) catalyzed with cyclopentadienylnickel‐methylaluminoxane (Cp2Ni‐MAO) was investigated. Polymerization readily proceeds with this catalyst, and the resulting polymer is rich in syndiotactic content. The effects of the MAO/Ni system on the polymerization activity of MMA were observed, and it was found that only small amounts of MAO are required to reach high polymerization activity.

Experimental MaterialsCommercial available Bd was purified by distillation over calcium hydride before use. NiCl 2 was used as an anhydrate prepared by a dehydration of NiCl 2 · 6H 2 O (Wako Chem. Co.) at 140°C under high vacuum. PMAO diluted with toluene kindly supplied from Tosoh-Fine Chem. Co. was used as received. Solvents and other reagents were used after purification by conventional methods. After the reaction of NiCl 2 with MAO at 25°C for 0.5 h, 5.0 Å pore filter (Milipore Co.) was used to separate them into the soluble and the insoluble fraction. Average particle size of 25 mm, 500 mm and 1 mm of NiCl 2 was used. Unless refer to the particle size 500 mm particle size was used. Polymerization of 1,3-Butadiene with NiCl 2 in Combination with MethylaluminoxaneKiyoshi ENDO* and Yoshihiro YAMANAKA Abstract The polymerization of 1,3-butadiene (Bd) with NiCl 2 /methylaluminoxane (MAO) catalyst was investigated. The reaction mixture of NiCl 2 and MAO was separated into soluble and insoluble part. Both parts initiated the polymerization of Bd to give a high cis-1, . The activity for the polymerization of the soluble part was higher than that of the insoluble part. The M w /M n of the polymer obtained with the soluble part was around 2.0, but that obtained with the insoluble part was 4.5. The polymerization of Bd with NiCl 2 in combination with MAO depended on a particle size, i.e., surface area of NiCl 2 , and the activity for the polymerization with a small particle size of NiCl 2 was higher than that with a large particle.