[Chemical Knowledge]：Detection Method and Analysis Technology of LDPE

Low density polyethylene (LDPE) as an important plastic material, has a wide range of applications in packaging, construction, medical and other fields. In order to ensure the quality and performance of LDPE products, many aspects of testing and analysis are needed. This article will detail the common detection methods and analysis techniques of LDPE to help readers better understand and apply these methods.

Physical Performance Testing

The physical property test of LDPE is an important means to evaluate its basic mechanical properties and processability. Common physical performance tests include:

Tensile property testing: The tensile properties of LDPE directly affect its strength and ductility in engineering applications. Tensile testing evaluates the mechanical properties of a material by measuring its tensile stress and strain under different loads. The main test parameters include tensile strength, yield strength, elongation at break, etc.

Hardness test: Hardness test is an important means to evaluate the compression resistance of LDPE materials. Commonly used hardness test methods are Rockwell hardness test and Barcol hardness test. The hardness value is calculated according to the depth of the indentation by applying pressure to the surface of the material through different hardness testers.

Impact performance test: The impact performance test is used to evaluate the impact resistance of LDPE when subjected to impact or extrusion. Commonly used impact tests include simply supported beam impact test and notch impact test. The impact resistance of the sample is evaluated by different impact loads.

Thermal performance test: Thermal performance test is an important means to evaluate the thermal stability and heat distortion temperature of LDPE at different temperatures. Commonly used thermal performance tests include thermal gravimetric analysis and thermal distortion temperature tests to evaluate thermal performance by heating a specimen and monitoring its mass change or shape change.

chemical analysis

Chemical analysis of LDPE is mainly to evaluate its composition, additive content and molecular structure and other key information, common chemical analysis methods include:

Infrared spectroscopy (FTIR) analysis: FTIR analysis is a commonly used chemical analysis technique to analyze the molecular structure and composition of a material by detecting its absorption peaks in the infrared spectral region. For LDPE,FTIR can be used to detect the structural features of its main component, polyethylene, and possible additives.

Thermogravimetric analysis (TGA):TGA analysis is to analyze the thermal decomposition and thermal stability of materials by heating the sample and measuring its mass change. In the analysis of LDPE, TGA can be used to evaluate the thermal decomposition temperature, thermal weight loss characteristics and the content of additives.

Nuclear magnetic resonance (NMR) analysis: NMR analysis is a high-resolution analysis technique, mainly used for the accurate analysis of molecular structure, chain segment length and branch structure in LDPE materials. NMR can provide detailed information about the molecular chain of LDPE to help analyze the performance and processing characteristics of the material.

Solvent extraction analysis: Solvent extraction analysis is used to extract additives and impurities in LDPE, and to evaluate the purity and composition distribution of LDPE samples by analyzing the components in the solvent.

The above physical performance testing and chemical analysis methods provide basic data support for the quality control and research of LDPE materials, but with the development of instrument technology, modern LDPE analysis technology is constantly updated and improved.

Advanced Instrumental Analysis Techniques

With the progress of science and technology, the instrument analysis technology of LDPE is also developing, which provides more accurate and detailed data support for the research and quality control of LDPE materials.

Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS):SEM-EDS hyphenated technology can be used to observe the surface morphology and microstructure of LDPE with high resolution and chemical composition analysis, which can help to analyze the surface characteristics and morphological changes of materials.

X-ray diffraction analysis (XRD):XRD analysis can be used to analyze the crystal structure and crystal morphology of LDPE, determine the crystallinity and crystallization behavior of LDPE by analyzing the X-ray diffraction pattern, and evaluate the heat treatment effect and processing characteristics of the material.

Laser Raman spectroscopy (Raman): Raman spectroscopy can provide molecular vibration information and structural characteristics of LDPE, help analyze the molecular chain structure, orientation and phase changes of materials, and have an important impact on the processability and thermal stability of LDPE.

Gas chromatography-mass spectrometry (GC-MS):GC-MS technology can be used to analyze additives, residues and degradation products in LDPE, and to evaluate the composition and possible contaminants of LDPE materials by analyzing gas chromatography and mass spectrometry data.

The detection methods and analysis techniques of LDPE include physical performance testing, chemical analysis and advanced instrumental analysis techniques. These methods and techniques can not only be used for quality control and research of LDPE materials, but also provide important support for their performance and stability in different application fields. With the continuous progress of instrument technology and the innovation of application methods, LDPE material analysis technology is also developing, which provides a broader development space for its application and research.

It is hoped that this paper can help readers understand the detection and analysis technology of LDPE more deeply, and provide useful reference and guidance for the research and development of LDPE materials.