Effect of inter-needle distance on jet roping and laydown structure in solution blowing

Abstract

Here, a model lab-scale solution blowing setup was developed. Experiments were carried out in a model situation of two needles at several inter-needle distances and air velocities to investigate jet roping. Polymer jets issued from two needles were employed at the inter-needle distances of L = 4.5, 4, 3.5, 3, and 2.5 mm. Polymer jet intersections and merging near the needle tip and at a distance of ∼150 mm from the needle tip and near the collector were recorded employing a high-speed camera. The laydown images captured for each inter-needle distance were analyzed using scanning electron microscopy to link the laydown morphology to roping, which stems from the polymer jet–jet intersection in flight.

Probability of jet roping in solution blowing of multiple jets

“…Figures S1–S5). The morphologies associated with jet roping are similar to those observed with the two‐jet apparatus in our previous work 33 …”

“…Figure 10 compares the probability of roping in the present case of four jets with that for two jets measured in our previous work 33 . The insets in Figure 10 illustrate the corresponding laydowns.…”

“…At L = 3.5 mm the trend reverses, that is, similar to the case of P = 137.89 kPa (Figure 8), at P = 172.37 kPa and L ≤ 3.5 mm the probability of roping is lower for four polymer jets than for two polymer jets. At L = 2.5 mm in the case of two polymer jets, the probability of roping appears to be quite low, albeit a detailed investigation of the laydown structure in our previous work reveals a highly roped laydown 33 …”

“…Laydown structure corresponding to four and two 33 polymer jets. The operating pressure P = 137.89 kPa and the inter‐needle distance L = 3 mm.…”

“…The operating pressure P = 137.89 kPa and the inter‐needle distance L = 3 mm. Panel: (a) four polymer jets, and (b) two polymer jets 33 . [Color figure can be viewed at wileyonlinelibrary.com]…”