Experimental study of particle migration in polymer processing
Experimental study of particle migration in polymer processing
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DOI：
10.1002/pc.25018
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发表时间：
2019-06-01
影响因子：
5.2
通讯作者：
Osswald, Tim
中科院分区：
文献类型：
--
作者：
Quintana, Jose Luis Colon;Heckner, Tobias;Osswald, Tim
填充聚合物的挤出和注塑成型工艺由于其高强度重量比以及其制造各种几何形状同时改善整体机械和热性能的能力而广泛用于工业中。然而，加工过程中填料迁移和填料-基质分离是尚未完全理解的现象。为了更好地理解这些现象，使用挤出、注塑和内部定制的无螺杆挤出机制造具有不同玻璃珠浓度的聚丙烯样品。对样品进行计算机断层扫描，观察材料凝固后颗粒的位置和分布。对于所有三种工艺，均观察到填料迁移和填料-基质分离。在挤出和无螺杆挤出过程中，颗粒向壁面迁移，这与当前的理论和观点相反。在注射成型过程中，填料-基体分离表现为中心区域的无珠区和螺旋模具的入口区域的螺旋模具的壁。这些无珠区随后在螺旋模具的远端填充，表明颗粒沿着流动迁移，在模具的末端几乎没有无珠区。在流动过程中，由于迁移和喷泉流效应，可能发生了颗粒向壁面和中心的重新分布。Polym.比较器：40：2165-2177，2019. (c)2018年塑料工程师协会
Extrusion and injection molding processes of filled polymers are widely used in industry due to their high strength-to-weight ratios and for their ability to manufacture a variety of geometries while improving the overall mechanical and thermal properties. However, filler migration and filler-matrix separation during processing are phenomena that are not fully understood. To gain an improved understanding of these phenomena, polypropylene samples with different glass bead concentrations were manufactured using extrusion, injection molding and a customized screwless extruder that was built in-house. Computed tomography was performed on the samples to observe particle position and distribution after material solidification. For all three processes, filler migration and filler-matrix separation was observed. In the extrusion and screwless extrusion processes, particles migrated towards the wall, contrary to current theories and believes. During the injection molding process, filler-matrix separation was manifested as bead-free zones in the center region and the walls of the spiral mold at the entrance region of the spiral mold. These bead-free zones were later filled at the far end of the spiral mold suggesting migration of particles along flow with almost no bead-free zones at the end of the mold. Particle redistribution towards the wall and the center during flow could possibly have happened due to migration and fountain flow effects. POLYM. COMPOS., 40:2165-2177, 2019. (c) 2018 Society of Plastics Engineers