Lignin is a natural organic compound widely present in plant cell walls, including wood, bamboo, cotton, etc. It is a polymer compound with multiple functions and application values. Lignin can be used as pigments, plasticizers, fungicides, protective agents, asphalt stabilizers, lubricants, etc., and can also be used to produce high-strength cellulose paper and biofuels.
Lignin is a natural organic polymer compound with various physical and chemical properties. The following are some properties and corresponding detection methods that may need to be tested for lignin, as shown in the table below:
| performance | Test items | Detection method |
|---|---|---|
| Appearance and form | appearance and form | visual inspection |
| color | color | photometry, colorimetry |
| Composition | chemical composition | Infrared spectroscopy, nuclear magnetic resonance, elemental analysis, mass spectrometry, etc. |
| granularity | Particle size distribution | Laser particle size analyzer, electron microscope |
| thermal properties | Thermogravimetry | Thermogravimetric Analyzer |
| Solubility | Solubility | Specific gravity method, ion chromatography, infrared spectroscopy, etc. |
| electrical properties | Conductivity | conductivity meter |
| optical properties | Transparency, Refractive Index, Scattering Rate | Photometry, Refractometer, Scatterometer |
| mechanical properties | Strength, hardness, modulus of elasticity, etc. | Tensile test, compression test, bending test, Vickers Hardness Tester, etc. |
Testing the properties of lignin requires the use of different methods and techniques, as follows:
Content detection: methods such as colorimetry, ultraviolet spectrophotometry, and effective liquid chromatography can be used to determine the content of lignin.
Structure detection: The structure of lignin can be analyzed by techniques such as Fourier transform infrared spectroscopy (FTIR) or nuclear magnetic resonance (NMR).
Thermal performance testing: Thermal stability and thermal degradation temperature of lignin can be tested by thermogravimetric analyzer (TGA).
Optical performance testing: UV-visible Spectrophotometer and fluorescence spectrometer are used to measure the absorption spectrum and fluorescence properties of lignin.
Solubility detection: Use infrared spectrometer and microscope to observe the dissolution and morphological changes of lignin in different solvents.
Antioxidant performance detection: Use free radical scavenging ability, metal ion chelating ability and other indicators to evaluate the antioxidant performance of lignin.
Biological activity detection: Use cytotoxicity test, antibacterial test and other methods to evaluate the biological activity of lignin.
