Abstract:

A novel technology was presented to produce bimodal polyethylene with home-made metallocene catalyst APE-1G(Cp*₂ZrCl₂·2LiCl·THF) in single gas-phase reactor through oscillating operation of hydrogen periodically.The effects of hydrogen concentration, oscillating time distribution and oscillating operation period on molecular weight distributions were studied.The results showed that catalyst activity and molecular weight of the obtained polymers decreased due to the addition of hydrogen.Bimodal polyethylene obtained through oscillating hydrogen concentration periodically had a polydispersity index (PDI) range from 11.2 to 34.2.It was viable to control molecular weight distributions of bimodal polyethylene through hydrogen oscillating operation, especially through changing the oscillating operation period.

Key words:

双峰聚乙烯, 氢气, 茂金属催化剂, 振荡操作, 气相聚合

摘要：

在单一气相反应器中，采用国产APE-1G(Cp*₂ZrCl₂·2LiCl·THF)型茂金属催化剂，通过强制振荡反应器内的氢气浓度制备双峰聚乙烯。实验考察了氢气浓度、振荡时间分配和振荡周期对聚乙烯分子量分布的影响。实验结果表明，氢气的加入使得催化剂活性降低，产物分子量也减小。通过强制振荡氢气的浓度可以得到双峰分布的聚乙烯，M_w/M_n达到11.2～34.2。研究表明，通过调节氢气振荡操作的实验条件，尤其是调节振荡时间分配，可以很好地控制双峰聚乙烯的分子量分布。

关键词:

双峰聚乙烯, 氢气, 茂金属催化剂, 振荡操作, 气相聚合