Method for quick lossless distinguishing of polyamide product

Abstract

The invention relates to a method for the quick lossless distinguishing of a polyamide product. The method comprises the following steps: determining an analysis part of the product through a scanningelectron microscope; carrying out the element analysis through an EDS (Energy Disperse Spectroscopy), and calculating the atomic percent of carbon elements in the product; determining whether the measured polyamide product is a polyamide product of a first type or a polyamide product of a second type according to the size of the content of the carbon elements. The polyamide product of the first type is a product which is formed by the polymerization of amide monomers, wherein the number of carbon elements in the biggest monomer of the product is greater than ten. The polyamide product of thesecond type is a product which is formed by the polymerization of amide monomers, wherein the number of carbon elements in the biggest monomer of the product is less than seven. The method cannot cause the loss of a sample when the method is used for the analysis of the polyamide product, and enables the sample to be maintained. The method can quickly discriminate the polyamide products, and is simple in operation. The method also enables the fiber discriminating methods to be abundant, and provides a new thinking for the fiber discrimination.

Description

technical field [0001] The invention relates to a method for identifying physical evidence such as fibers, in particular to a method for quickly and non-destructively distinguishing polyamide products. Background technique [0002] Polyamide is also called nylon (Nylon), nylon, English name Polyamide, referred to as PA, which is the general term for polymers containing amide groups in the repeating unit of the macromolecular main chain. Polyamides can be prepared by ring-opening polymerization of lactams, or by polycondensation of diamines and dibasic acids. PA has good comprehensive properties, including mechanical properties, heat resistance, wear resistance, chemical resistance and self-lubricating properties, low friction coefficient, certain flame retardancy, easy processing, suitable for glass fiber and Other fillers are filled and modified to improve performance and expand application range. There are many varieties of PA, including PA6, PA66, PA11, PA12, PA46, PA61...

AI Technical Summary

Problems solved by technology

Among the above-mentioned standard methods, the combustion method, dissolution method, melting point method, color reaction method, etc. cannot meet the demand; using spectral means such as infrared spectroscopy can only determine the sample composition through several typical absorption bands of polyamide, but it is difficult to significantly The distinguishing components are also polyamide products, so the sample is usually characterized as polyamide by infrared spectroscopy, and then other methods are used to confirm its type

[0005] Some non-standard methods also face the same problem. The differential calorimetry scanning method can accurately distinguish polyamide products by using the difference in melting point and melting heat, etc.; the thermal cracking gas chromatography-mass spectrometry can be determined according to the difference in mass spectrum fragment ions after pyrolysis. Different cracking products can be distinguished, which can significantly distinguish the types of polyamides, but all samples must be lost; Raman spectroscopy can use the subtle differences in the spectra to distinguish samples, but because of the small peak strength, overlap, and poor repetition of the fingerprint spectra, it is difficult to determine It is difficult to distinguish significantly due to various reasons such as attribution; the use of x-ray diffraction analysis often results in poor response because the crystallinity of daily polyamide products is not high enough

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