Study On Testing Methods Of Polyester Fibers

Fiber and human life are inextricably linked,according to statistics,fiber material evidence may be extracted from 60%of the cases on the scene.Such as the clothing fiber attached to the car bumper in traffic accidents,the residual fiber in the gloves left on the doors and windows by suspects in the burglary,the residue of textile burning left on the fire and explosion sites,and the scraps of the corpse packaging on the scene of the homicide case and so on.So fiber evidence is one of the most common and important evidence in the field forensic science.The timely and accurate examination and analysis of the fiber material evidence can provide clues,directions,and narrow investigation scope for case detection,and can provide important evidence for case trial and court proceedings.Through investigation,it has been found that most of the tests for fiber material certificates currently remain in the comparison and identification of species;at the same time,as a big country in the textile industry,many manufacturers or small workshops produce textiles with the same fiber composition and are affected by factors such as raw materials and production processes.Even the same kind of fiber can be different in some aspects.Consequently,if we only identify and distinguish the types of fiber,problems such as unreliable inspection results due to incomplete information on the evidence will be caused,and the orientation of fiber evidence in the case will be greatly limited.Therefore,it is very important to study the method of identifying the same kind of fiber.In this paper,160 samples of polyester fibers were tested by Raman spectroscopy,Differential scanning calorimetry and Cross-sectional method,then the following experimental results were obtained:1.In the experimental part of the Raman spectroscopy method used to test polyester fibers,the experimental conditions were optimized:laser:473nm;spectral range:200-2000cm^-1;grating:1200gr/mm;spectral resolution:1cm^-1;exposure time:10s;cumulative number:2.At the same time,ChemPattern?advanced chemometrics software was used to process and analyze the experimental data.It was verified that Raman spectroscopy combined with similarity and principal component analysis had a certain ability to discriminate polyester fibers of eight colors in the experimental samples.2.In the experimental part of the Differential scanning calorimetry method used to test polyester fibers,the T-test method was completed by MATLAB programming,which realized rapid batch processing of large amounts of data and verified the method to process data with the combination of thermodynamic parameters and MATLAB mathematics software have a certain ability to distinguish massive polyester fiber samples of the same color.3.Through a large number of experiments,the Cross-sectional inspection method has been further improved and good experimental results have been obtained.The effectiveness of quick-drying adhesive as an embedding agent and Cross-section method to distinguish polyester fibers was verified.In this paper,polyester fibers are used as the main research object and three methods are used to test the experimental samples,to process and analysis the experimental data from the three following aspects:polyester fiber color,thermodynamic parameters,and cross-section with the aim to testify the effectiveness of the test method used to further differentiate polyester fibers and to break through the current situation of distinguishing types of fiber physical evidence,providing more diverse and valuable information for the application of fiber evidence in actual cases.