Material consistency analysis
Project introduction
The consistency of materials in different batches of the same product determines the final quality of the product. The consistency comparison test can identify whether the materials used in different batches of products meet the standards to ensure the consistency of raw materials in different batches. At the same time, it can check whether the quality of raw materials purchased from suppliers meets the product requirements, thereby preventing suppliers from using excessive recycled materials or scraps.

For polymer materials, there are many types (including plastics, rubber, fiber, adhesives, coatings, etc.), and their excellent properties have been deeply applied to all aspects of our lives. Since the performance requirements of products with different needs are different, improper material selection, replacement of raw materials, and unreasonable recycling will affect the performance and quality of the product. Therefore, it is very important to strengthen the monitoring of product quality.

Material consistency analysis

Detection range
Plastics, fibers
Experimental principle
1. Different polymer materials have different infrared fingerprint spectra and molecular fragmentation thermal cracking spectra;
2. The molecular weight of the recycled polymer material will decrease, resulting in changes in the material's glass transition temperature, crystallinity, melting temperature and decomposition temperature;
3. Changes in pigment-to-base ratio and pigment-filler ratio will be reflected in the thermogravimetric changes of the polymer material and in the final residual ash;
4. Changes in polymer materials generally lead to changes in specific gravity (or density).
Using the above-mentioned spectrum characteristics, the specified rapid detection and evaluation method is the consistency analysis technology.
Reference standards
Infrared spectrum: refer to ASTM E1252-98(2013)ε1/ GB/T 6040-2019
Differential scanning calorimetry (DSC) curve: refer to GB/T 19466.2-2004/ GB/T 19466.3-2004/ISO 11357-2:2013/ISO 11357-3:2018
Thermogravimetric analysis (TGA) curve: refer to ISO 11358-1:2014
Analysis case
The laboratory received two bottles of a certain type of glue from a customer, and it was necessary to determine whether the glue was the same through material consistency comparison.
Testing environment: ambient temperature 23.7℃; humidity 50%R.H
Testing standards:
GB/T 6040-2002 General principles for infrared spectroscopy analysis methods
GB/T 19466.1 Plastics Differential scanning calorimetry (DSC) Part 1: General principles ISO 11358-1-2014 Plastics. Thermogravimetric analysis (TG) of polymers: General principles Testing process:
(1) FTIR test spectra of the two samples were obtained.