以芴二醚为外给电子体制备高熔体流动速率的聚丙烯

摘要

High melt flow rate polypropylene (PP) was produced by adjustment of hydrogen concentration in bulk liquid phase propylene polymerization with Ziegler-Natta catalyst as main catalyst, triethyl aluminum as a cocatalyst and 9,9-bis(methoxylmethyl)fluorine (BMF) as a external electron donor. The results show that BMF has high hydrogen response, the melt flow rate of the PP rises from 11 g/10 min to 67 g/10 min when the molar ratio of hydrogen to propylene increases from 2.16×10-3 to 8.62×10-3. The PP obtained exhibits an obvious shear-thinning phenomenon. High melt flow rate PP possesses lower shear viscosity with identical shear rate. The melt temperature decreases from 165.7 ℃ to 162.7 ℃ and the crystallization temperature decreases from 115.3 ℃ to 109.3 ℃ with the increase in the melt flow rate of the PP. The change of the melt flow rate of the PP has only little impact on the mechanical properties of the PP.%丙烯液相本体聚合中，以Ziegler-Natta催化剂为主催化剂，三乙基铝为助催化剂，9,9-二(甲氧基甲基)芴(BMF)为外给电子体，利用氢调法制备了高熔体流动速率(MFR)的聚丙烯(PP)。结果表明：BMF具有很高的氢调敏感性，氢气与丙烯摩尔比从2.16×10-3增加到8.62×10-3时，PP的MFR从11g/10min增至67g/10min；PP熔体表现出明显的剪切变稀现象，在剪切速率相同的情况下，高MFR的PP具有更低的剪切黏度；随着PP的MFR升高，其熔融温度从165.7℃降至162.7℃，而结晶温度则从115.3℃降至109.3℃；PP的力学性能受MFR影响较小。