Free radical grafting of glycidyl methacrylate onto polypropylene in a co‐rotating twin screw extruder
Free radical grafting of glycidyl methacrylate onto polypropylene in a co‐rotating twin screw extruder
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DOI：
10.1002/app.1995.070570903
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发表时间：
1995-08
影响因子：
3
通讯作者：
Yi-Jun Sun;G. Hu;M. Lambla
中科院分区：
文献类型：
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作者：
Yi-Jun Sun;G. Hu;M. Lambla
在同向旋转双螺杆挤出机中研究了甲基丙烯酸缩水甘油酯（GMA）自由基接枝到熔融聚丙烯（PP）上。在各种实验条件下沿螺杆长度获得的 GMA 接枝率可以很好地评估化学参数（苯乙烯的存在以及过氧化物和单体的浓度）和加工参数（进料速率、螺杆速度和比吞吐量）的影响。与间歇式混合器中获得的结果类似，1 在存在或不存在苯乙烯的情况下在挤出机中进行的 GMA 自由基接枝反应快速进行，因为它几乎在挤出机下游的中途完成。此外，苯乙烯作为第二单体的存在大大提高了 GMA 接枝产率，同时减少了 PP 链的降解。最终的GMA接枝产率随着过氧化物1,3-双(叔丁基过氧异丙基)苯浓度的增加而增加。间歇式混合机和挤出机之间的这种相似性与以下事实有关：在这两种情况下，过氧化物的浓度及其半衰期决定了接枝率和最终的接枝产率。另一方面，GMA接枝率随着螺杆转速或进料速度的增加而降低。对于特定的比吞吐量（吞吐量与螺杆速度的比率），吞吐量的增加以及螺杆速度的伴随增加导致GMA接枝产量的降低。结论是，GMA 接枝产率主要受自由基未耗尽区域中的停留时间的影响。螺杆速度、进料速率和比吞吐量的影响主要通过这种局部停留时间分布来体现。就 GMA 自由基漂流到 PP 而言，比能并不能很好地衡量挤出机的性能。 © 1995 约翰威利父子公司。
Free radical grafting of glycidyl methacrylate (GMA) onto molten polypropylene (PP) was studied in a co-rotating twin screw extruder. Grafting yields of GMA obtained under various experimental conditions along the screw length allowed for a good appreciation of the effects of chemical parameters (the presence of styrene and the concentrations of peroxide and monomers) and those of processing parameters (feed rate, screw speed, and specific throughput). Similar to the results obtained in a batch mixer,1 free radical grafting of GMA carried out in the extruder in the presence or absence of styrene proceeded rapidly, as it was virtually completed half-way down stream of the extruder. Additionally, the presence of styrene as a second monomer increased the GMA grafting yield reatly with reduced PP chain degradation. The ultimate GMA grafting yield increased with increasing concentration of peroxide, 1,3-bis(tert-butylperoxyisopropyl)benzene. This similarity between the batch mixer and the extruder is related to the fact that in both cases it is the concentration of the peroxide and its half lifetime that determine the grafting rate and the ultimate grafting yield. On the othe hand, the GMA grafting yield decreased with increasing screw speed or feed rate. For a particular specific throughput (the ratio of throughput to screw speed), an increase in throughput with a concomitant increase in screw speed brought about a decrease in GMA grafting yield. It was concluded that the GMA grafting yield is affected primarily by the residence time in the zone in which free radicals are not depleted. The effects of screw speed, feed rate, and specific throughput manifest mainly through this local residence time distribution. Specific energy is not a good measure of the performance of the extruder with respect to the free radical rafting of GMA onto PP. © 1995 John Wiley & Sons, Inc.