Study On The Compressibility Of Kapok Fibrous Assemblies

With the enhancing awareness of environmental protection and health, people pay more attention to the natural fiber and fabrics. As a kind of green ecological textile materials, kapok fiber is a light fiber with an extraordinary thin-walled lumen, the hollow rate can be more than 80%-90%, thus very excellent in warmth retention,oil absorption,natural antibacterial wet conduction,moisture absorption etc, kapok fiber has the extensive application prospect.and market potential for development.But kapok fiber was affected by different external environment factors in manufacturing and applications, such as tensile strength,compression strength,thermal and humid processing, it resulted in the deformation of originally huge lumen. Understanding of the dependency relation between the round-hollow structure of kapok fiber and external pressure has practical significance in fair using of kapok fiber and correct design of its processing technology.The main contents and results are as follows:(1) Analysised the compression performance of kapok fibrous assemblies under dry, wet and pressure combined treatments by KES (Kawabata Evaluation Systems) handy compression apparatus. The results showed that, the resilience rate of wet kapok fibrous assemblies were smaller than dry assemblies, it meant the compression elasticity of wet kapok fibrous assemblies was not very good, its bulkness would get worse under cyclic compression. The bulkiness and the pore of dry and wet kapok fibrous assemblies both reduced after 100kPa-press-treatment which continued 15s. However, the pore among wet kapok fibrous assemblies and their hollow structure were easier to decrease than dry assemblies when they were pressed. The effect of external pressure on the dry and wet kapok fiber was different, dry kapok fibrous assemblies was not easy to produce the plastic deformation under external pressure. So we should minimize the environmental humidity or fiber moisture regain in order to keep the huge hollow structure of kapok fiber in manufacturing and increase environmental humidity or fiber moisture regain when need to flatten or compress the kapok fibrous assemblies (such as packing).(2) Through simulation analysing the compressed thickness of the ideal state of kapok fibrous assemblies,which kapok fiber arranged tightly, comparing with the actual tested thickness of kapok fibrous assemblies under different humidity conditions and pressure treatment and combinating with its scanning electron micrographs, we can see that, wet kapok fibers partially collapsed after 100kPa-press-treatment which continued 15s. The external pressure significantly reduced the kapok fiber hollowness. According to former compressibility tested by KES, an indirect testing and evaluation method could be established for the hollowness of kapok fiber. Selected four indexes to indirect evaluate the hollowness of kapok fiber, including compression energy,bulkiness,compressible thickness and thickness in maximum test-pressure. The thickness in maximum test-pressure stands for the hollowness of kapok fiber; the compressible thickness stands for the voids between kapok fibers; the bulkness and compression energy stand for total pore in kapok fibrous assemblies, which included the hollow in fiber and the voids between fibers.(3) Collected comparable kapok blended fabrics and cotton fabric samples, tested its fabric compression performance,section SEM photos,hand property,permeability,anti-pilling properties and surface frictional properties. The result showed, the rib fabric made from kapok blended yarn was fluffy and soft, the hollow structure of kapok fiber in the blended fabric was not fully compressed in weaving process, its manufacturing technology can be better for preservation of hollow srtucture of kapok fiber; the handy properties of kapok blended fabrics were better than the cotton fabrics which had some specifications, and the handy properties of plain kapok blended fabrics were better than the twill fabrics; the porosity of kapok blended fabrics were higher than cotton fabrics but the porosity of the twill kapok blended fabrics were relatively lower. The finishing process contributed to the improvement of fluffy of kapok blended fabrics, but could cause the loss of fabric's quality, which adversed to the hollowness replied of kapok blended fabric; when the fabric warp tension was higher than 50%, the permeability of kapok blended fabric will go with the kapok content; the pilling resistance properties of plain kapok blended fabrics were superior to those of twill fabrics, and the pilling resistance properties of kapok blended fabrics were better than cotton fabrics which had some specifications; there was no difference in the surface friction coefficient between kapok blended fabrics and cotton fabrics.