Comparisons Of Morphologies And Tensile Behaviors Between Indonesia And Hainan Island Kapok Fibers

Kapok fibers,with the special structure and some excellent properties,have being focused in the past few years.But as for kapok fibers,there were relatively large differences in length,fineness and mechanical property with different variety,planting conditions and growth site in kapok fruit.The existing research data was not comprehensive and lack of systematic,what's more,the testing methods for kapok morphological characteristics were not perfect yet.In order to provide a reliable basis for the cultivation,processing,and products development of kapok,it was necessary to explore related testing methods that fitting in kapok fiber's structure and to find out the performance differences between kapok varieties.This paper aimed to make clearly the characteristics such as the morphology,fineness,tensile property of kapok fibers from Indonesia and Hainan Island,and investigate the relationship between the characteristics and their planting places,growth sites in fruits,and also to explore a testing method for kapok diameter.The research would enlighten the planting,processing and product development of kapok fibers.The main methods and conclusions were as follows:(1)The morphology and structure of kapokThe kapok fruit was shuttle-shaped and the fibers inside the fruit could be divided into fiber bundles and short fibers.Observed by SEM JSM-5600LV,the single kapok fiber was smooth with no convolution,and like a tube with large hollow before rupturing,but it became a belt after rupturing.The wall thickness of Indonesia kapok fibers were tested by Fiber Automatic Image Acquisition and Recognition System.The result showed that the mean wall thickness is 1.21?m,and the distribution range was 0.78 to 1.83?m.(2)The diameter of kapok fiberAn indirect method was designed to measure the diameter of kapok fiber based on the perimeter constant principle.In this method the long axis of the completely squashed kapok fibers were tested by F6 Fiber Fineness Equipment.Then,the measured values were converted into diameters of kapok fibers according to a mathematical relationship.The diameters of Indonesia and Hainan Island kapok fibers were tested by this method.The result indicated that the mean diameters of Indonesia and Hainan Island kapok fibers were 14.89?m and 18.06?m,the distribution range of them were 9.82-22.50?m and 10.89-28.28?m respectively.The diameter-frequency histograms implied that the diameter distribution of kapok fibers followed normal distribution.We could conclude that planting places had a relatively great impact on kapok fiber diameter,and growth sites in the fruits had no obvious relationship with the diameter of kapok fiber.(3)The linear density of kapok fiberThe linear density of Indonesia and Hainan Island kapok fibers were tested by middle-cut weighing method.It was found that the linear density of Indonesia and Hainan Island kapok fibers were 0.67dtex and 0.95dtex.The result showed a consistency to that of kapok fiber diameter.As the diameter,planting places also had a relatively great impact on kapok fiber linear density,and growth sites in the fruits also had no obvious relationship with linear density of kapok fiber.(4)The tensile property of kapok fiberAfter the 'U-shaped'paperclip sample preparation,the tensile property of Indonesia and Hainan Island kapok fibers were tested by XQ-2 Tensile Tester.The result showed that tensile curve of kapok fiber was similar to that of cotton.The breaking strength and elongation of Indonesia and Hainan Island kapok fibers were 1.53cN,3.04%and 1.85cN,3.02%respectively.Moreover,the research indicated that planting places had a relatively great influence on kapok fibers' breaking strength,but had little impact on the breaking elongation.Also,breaking strength and elongation of kapok fibers had no clear relationship with growth sites.