Blending quality of co-air-textured yarn: Optimization parameters of Kevlar/polypropylene applicable for thermoplastic composites

Nowadays, hybrid yarns, which consist of at least one-component thermoplastic fibers, are used in thermoplastic textile composites. The uniformity of the fibers in hybrid yarns is a key factor that directly influences the composite properties. Accordingly, one of the main aims of the present research was to optimize the air texturing parameters to achieve the uniform blending of Kevlar/polypropylene fibers. To evaluate the blending uniformity of yarns, the radial, lateral and angular distribution of fibers, based on the position of the pixels of the constituent fibers, was evaluated using the image processing data of yarn cross sections. According to this method, the production parameters, namely, blend ratio, delivery speed, feed rate and air pressure, were optimized simultaneously via the response surface method to obtain the blending uniformity of the fibers. The uniform blending distribution could be achieved by a higher blend ratio of Kevlar/PP (1:6), a lower production speed (300 m/min), a higher feed rate (500 m/min), and a higher air pressure (10 bar). Eventually, it was confirmed that there was a good correlation between the blending quality of the real samples and the predicted quality of the response surface method model.