The capillary flow properties of several commercial ionomers (sodium and zinc) were studied to assess their processability in terms of instabilities such as wall slip and melt fracture. Using capillary dies of various diameters and lengths to control capillary extrusion pressure, it was found that the viscosity of these polymers exhibits a relatively small dependence on pressure, more importantly at relatively smaller pressures. Using capillaries of various diameters at fixed length-to-diameter ratios, it was also found that the no-slip boundary condition is a valid assumption for these polymers due to the strong ionic associations and strong interactions with the capillary wall. All ionomers were found to exhibit gross melt fracture (no sharkskin), a phenomenon more dominantly observed at lower temperatures. The occurrence of gross melt fracture and the absence of surface (sharkskin) melt fracture is a characteristic of extensional strain-hardening polymers, noting that all ionomers examined exhibit this phenomenon. The critical shear stress for the onset of gross melt fracture was found to depend on the lifetime of associations, τS (τS∝ZE/ZS21/5, where ZE is the number of entanglements and ZS is the number of associations), independent of temperature, molecular weight, and type of ion (zinc or sodium).The capillary flow properties of several commercial ionomers (sodium and zinc) were studied to assess their processability in terms of instabilities such as wall slip and melt fracture. Using capillary dies of various diameters and lengths to control capillary extrusion pressure, it was found that the viscosity of these polymers exhibits a relatively small dependence on pressure, more importantly at relatively smaller pressures. Using capillaries of various diameters at fixed length-to-diameter ratios, it was also found that the no-slip boundary condition is a valid assumption for these polymers due to the strong ionic associations and strong interactions with the capillary wall. All ionomers were found to exhibit gross melt fracture (no sharkskin), a phenomenon more dominantly observed at lower temperatures. The occurrence of gross melt fracture and the absence of surface (sharkskin) melt fracture is a characteristic of extensional strain-hardening polymers, noting that all ionomers examined exhibit this...

中文翻译：

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钠离子和锌离子聚合物的毛细管流动

研究了几种商业离聚物（钠和锌）的毛细管流动特性，以评估它们在不稳定性方面的可加工性，例如壁滑移和熔体破裂。使用不同直径和长度的毛细管模头来控制毛细管挤出压力，发现这些聚合物的粘度对压力的依赖性相对较小，更重要的是在相对较小的压力下。以固定的长径比使用不同直径的毛细管，还发现由于强离子缔合和与毛细管壁的强相互作用，无滑移边界条件是这些聚合物的有效假设。发现所有离聚物都表现出严重的熔体破裂（无鲨鱼皮），这种现象在较低温度下更为明显。发生严重熔体破裂和没有表面（鲨鱼皮）熔体破裂是拉伸应变硬化聚合物的一个特征，注意到所有被检测的离聚物都表现出这种现象。发现熔体开始断裂的临界剪切应力取决于缔合的寿命 τS（τS∝ZE/ZS21/5，其中 ZE 是缠结数，ZS 是缔合数），与温度无关、分子量和离子类型（锌或钠）。研究了几种商业离聚物（钠和锌）的毛细流动特性，以评估它们在不稳定性方面的可加工性，例如壁滑移和熔体破裂。使用不同直径和长度的毛细管模头来控制毛细管挤出压力，发现这些聚合物的粘度对压力的依赖性相对较小，更重要的是在相对较小的压力下。以固定的长径比使用不同直径的毛细管，还发现由于强离子缔合和与毛细管壁的强相互作用，无滑移边界条件是这些聚合物的有效假设。发现所有离聚物都表现出严重的熔体破裂（无鲨鱼皮），这种现象在较低温度下更为明显。发生严重熔体破裂和不存在表面（鲨鱼皮）熔体破裂是拉伸应变硬化聚合物的一个特征，请注意所有被检查的离聚物都表现出这种... 以固定的长径比使用不同直径的毛细管，还发现由于强离子缔合和与毛细管壁的强相互作用，无滑移边界条件是这些聚合物的有效假设。发现所有离聚物都表现出严重的熔体破裂（无鲨鱼皮），这种现象在较低温度下更为明显。发生严重熔体破裂和不存在表面（鲨鱼皮）熔体破裂是拉伸应变硬化聚合物的一个特征，请注意所有被检查的离聚物都表现出这种... 以固定的长径比使用不同直径的毛细管，还发现由于强离子缔合和与毛细管壁的强相互作用，无滑移边界条件是这些聚合物的有效假设。发现所有离聚物都表现出严重的熔体破裂（无鲨鱼皮），这种现象在较低温度下更为明显。发生严重熔体破裂和不存在表面（鲨鱼皮）熔体破裂是拉伸应变硬化聚合物的一个特征，请注意所有被检查的离聚物都表现出这种... 发现所有离聚物都表现出严重的熔体破裂（无鲨鱼皮），这种现象在较低温度下更为明显。发生严重熔体破裂和不存在表面（鲨鱼皮）熔体破裂是拉伸应变硬化聚合物的一个特征，请注意所有被检查的离聚物都表现出这种... 发现所有离聚物都表现出严重的熔体破裂（无鲨鱼皮），这种现象在较低温度下更为明显。发生严重熔体破裂和不存在表面（鲨鱼皮）熔体破裂是拉伸应变硬化聚合物的一个特征，请注意所有被检查的离聚物都表现出这种...