Study On Polypropylene Bionic Dendrites And Their Water Conductivity

With the requirements of the clothing comfort increase,the development of moisture transported and dry-fast fabric has been wildly interested by the researcher. Plants have extremely efficient water transport systems. Plant structure fabrics was designed with superb liquid water transport properties,which emulates the branching structure of the plants.In this fabric, the warp yarn system constructs many tree-shaped channel nets in the thickness direction of the fabric.Besides, tree-shaped channel nets create a continuous water transport from the bottom layer to the top layer.To discuss the principle of optimizing design of the plant structure fabrics, we designed 16 types of fabrics with some essential factors for fabric specifications such as covering factor,warp count,warp and weft twist combination.All fabrics were tested with Moisture Management Tester (MMT) for measuring the one-way transport properties.Results reflected that the plant structure fabrics have significant advantages in one way transport properties. The biomimic fabric exhibits a fractal hierarchic inner structure.The warp yarns move back and forth between the top layer and the bottom layer in the fabric providing a continuous path for moisture transportation,the new fabric made a positive effect on the moisture permeability of the biomimic fabric.In addition the fabric configuration also plays an important role in moisture transfer ability.However, covering factor had no significant influence on the one-way transport properties. When the striped short flats layer are selected as water inlet, moisture transfer ability of fabric which the fineness of yarn is 600D has a better liquid transport property.In conclusion,the fabric specifications made a positive effect on the moisture permeability of the biomimic fabric.Based on the actual structure of the fabric.the mathematical model is established. Numerical study of biomimic fabric not only reduce the complexity of the numerical simulation,but also has high accuracy.In this study, unit cell of the fabric is developed by Texgen software.Numerical simulation of the biomimic fabric are studied using FLUENT software to investigate the moisture management property. The present numerical simulation considers flow of water through biomimic woven fabric and along a single yarn.The flow model under various types of boundary conditions was established to get the corresponding velocity contour.The results show thatrthe fabrics emulating the branching structure of plants exhibited excellent the one way transport property.When the striped short flats layer are selected as water inlet, moisture transfer ability of fabric is better than plain weave layer as water inlet.These holes between yarns are conduits of liquid water transport from the bottom to the top.The step by step reduction of the whole size from the striped short flats layer to plain weave layer simulates the basipetal increase in conduit diameter, which creates a pull of capillary pressure towards the plain weave layer.Thus, liquid in the fabric flow into the plain fabric layer rapidly.As water is transported towards the top layer, water is spread into a larger number of smaller holes, before the fabric is fully saturated with water.the spreading of water in the top surface creates faster surface evaporation.Good agree-ment is obtained between the results of numerical simulation and experimental observations.Numerical simulation is provided some academic reference to study on liquid water transport properties of fabric with complex structure and development of comfort fabric.