In this study, polypropylene (PP) binary blends with obviously different molecular weight were produced and melt spun using a capillary rheometer aided with an aspirator for aerodynamic stretching for the first time. A comprehensive processing map on the spinnability of all the seven PP blends regarding to three extrusion speeds and six take-up pressures was originally presented. According to a detailed investigation on the diameter information and tensile properties of all the PP fibers (modulus, tenacity, elongation at break), the optimum processing parameters of the advanced technology of aspirator for preparing PP fibers were revealed: processing temperature at 250 C, extrusion speed at 0.075 mm/s and take-up pressure at 1.5 bar. Most importantly, the reliability of a novel mathematic model was verified to predict PP fiber diameters in this study, which provides practical guidance for the research or mass production of PP blend fibers in the academia and industry.

The elongational viscosity of polymers can be determined by utilizing different devices such as extensional rheometer after Sentmanat (SER), oil bath rheometer after Meissner or tensile rheometer after Münstedt (MTR), with strain rates up to 10 s–1. Although these investigations are already complex, they do not depict real fiber spinning processes where higher elongation strain rates occur. Therefore, a novel method is developed to calculate the elongational viscosity of polymers during the fiber spinning process. To reduce the complexity of the system, two polymethylmethacrylates (PMMAs) with different molar masses are investigated using a capillary rheometer to exclude crystallization effects. The diameter of the polymeric strand is determined via a high‐speed camera from the die exit to the aspirator. In addition, simulations are carried out to describe the temperature profile of the polymeric strand along the spinline. It is possible to determine the elongational viscosity of the polymers in dependence of temperature and strain rates up to 100 s–1, by calibration of the force in an aerodynamic stretching device (aspirator).

Polymeric materials were evaluated with regard to their spinnability and respective fibre diameters. A modified single fibre spinning device was firstly used to derive a novel generalised model, utilising process parameters (die diameter, throughput, and stretching relevant take-up pressures) and material properties (zero shear viscosity) to predict the diameter of polymeric fibres on the basis of four different polymers. Further evaluation of the resulting power law dependence was conducted on filaments produced via conventional melt spinning and meltblown processes. Fibres produced on the pilot machines showed close agreement with the model equation with only the need to adjust an easily calculable device dependent factor. The outcome of the presented work is a user-friendly model of high practical relevance, which can be used to predict the diameter of amorphous and semicrystalline polymeric fibres, independent of material and machine used with sufficient accuracy for fast estimations.