Micro Knitting Yarn Structure And Its Permeability

Thermoplastic composites offer a number of important advantages over thermosetting plastics. Such as unlimited shelf-life, better toughness/damage tolerance, high recycle ability, chemical and environmental resistance. Since no chemical reaction occurs during the processing, the processing is rapid.But the molten viscosity of thermoplastic resin, particularly high performance thermoplastic resin is high, which creates difficulty in impregnation into fiber bundles. In the last decade, great efforts have been made to overcome the difficulty in impregnation. Hybrid yarn technique is proved to be a cost-effective method .By using this method, complicated structure can be manufactured easily. At present, hybrid yarn includes commingled yarn, core-spun yarn, and co-wrapped-yam. Many studies show that the distortion and damage of the reinforcing fiber in core-spun yarn made by micro-braiding technology is little, and because the yarn is wrapped tightly and uniformly, the reinforcing fiber can be protected effectively in the following process, and the yarn can get good impregnation.In this paper, the process technique and structure of the micro-braided yarn are investigated, in addition, the model of the micro-braided yam is made. The relationship among the parameters concerned is analysed and tested. The arrangement of reinforcing fiber after fabrication is investigated. Research shows that the fiber arrangement is at random. According to this, a model is established, and it matches with the result of the test. The model of the relation of impregnation depth and time has been proposed, but the technique used before was the so-called sudden stopping method, and the efficiency is low. We design a test to measure the change of impregnation depth at different temperature and pressure, and the relationship between impregnation depth and processing condition (temperature, pressure and time) was revealed.