Study On Relationship Between The Tensile Properties Of Jute/Polypropylene And Nonwoven Reinforcement Structure

Natural fiber reinforced composite has become more and more widely used because of its low price,strong mechanical properties and environmental friendliness.Jute fiber reinforced composites are more common than other natural fiber.Jute nonwoven fabric is a kind of common reinforcement with the advantages of short process,high production efficiency,can be applied to a wide range of fiber.Because of the difficulty of the structure characterization of nonwovens,the theoretical research of the composite material reinforcement is very little,which affects the development and application of nonwovens.This paper tested fineness,moisture regain and tensile properties of the jute fiber,Preparation of needle punched materials and jute spunlace materials with different areal density.Then,test the surface density,thickness,tensile strength and bending rigidity.Test the tensile properties of the composites and study the effect of the reinforcement method and the areal density on the tensile properties of the composites.In addition,the paper also makes use of image processing technology to characterize the fiber distribution uniformity and orientation distribution of nonwoven materials,and analyzes the influence of the reinforcement structure on the mechanical properties of the composites.After image preprocessing,the image is binarized using the Otsu threshold and the CV value obtained by the weighing method is used to obtain the image data.The optimal threshold and the Otsu threshold were fitted by straight line to determine the calibration threshold,and the characterization of the enhancement uniformity was completed.On the basis of preprocessing images,the Canny operator is used to detect the edge of the image,and the orientation distribution of the whole block is obtained by calculating the secant angle.The results of analysis on tensile properties of composites shows that the tensile properties of spunlace composites was significantly higher than that of needle punched material.The areal density of the reinforcement is linearly dependent on the tensile properties of the composites.By comparing the mechanical tensile uniformity and the fiber distribution of the reinforcement in the 10 specimens of each plate.In the same composite,the tensile property of each position is consistent with that of the fiber covering rate of the area.Compared with the tensile test results of each plate in 1 directions and 2 directions,the fiber orientation distribution of the reinforcement is consistent with the mechanical orientation distribution of the composite.Thus,the difference between tensile properties of the composites in different positions and directions can be predicted by the characterization of the fiber distribution uniformity and orientation distribution.