Recently, the China Chemical Fiber Industry Association released 8 standard group standards including “Determination of Oligomers in Polyethylene Terephthalate by High Performance Polymer Chromatography (APC)” (T/CCFA 00009-2021). It will be implemented in the industry from May 1, 2021.
“Determination of oligomers in polyethylene terephthalate by high performance polymer chromatography (APC)” (T/CCFA 00009-2021)
“Polyethylene terephthalate Determination of relative molecular mass and distribution of glycol esters High Performance Polymer Chromatography-Multi-angle Laser Light Scattering (APC-MALLS)》(T/CCFA 00010-2021)
《Polyethylene terephthalate Determination of oligomers in glycol esters by high performance polymer chromatography (APC)” (T/CCFA 00009-2021) standard released and implemented
1. Background of standard formulation
Poly pair Ethylene glycol phthalate (PET) has developed rapidly since its industrialization. Its products have developed from the initial fiber-grade PET to bottle-grade PET and film-grade PET. The size of its molecular weight directly affects its final use. fields and uses, and the oligomer content in PET will also affect its processing and molding technology and product quality. During the spinning process, oligomers tend to condense on the spinneret and become scorched after long-term high-temperature oxidation, thus contaminating the spinneret and affecting the service life of the spinning components. In addition, cyclic oligomers with high melting points are easy to deposit on the spinneret. The fiber surface will reduce the quality of the fiber and will also have a negative impact on subsequent weaving processes. Generally, industrially produced PET products contain 2% to 3% oligomers, usually mainly cyclic trimers.
Extraction and separation of oligomers from PET products is an important basis for studying the composition and content of oligomers. Although traditional chromatography can separate oligomers, the separation effect is not good. , and the efficiency and stability are not high. The high-efficiency polymer chromatography (APC) used in this standard is an emerging chromatographic instrument for characterizing relative molecular mass and distribution. Compared with traditional chromatographic instruments, the chromatographic column used in it will not be affected by solvents and will not swell, so it can enhance The stability of the system and the selection of appropriate chromatographic columns can effectively separate the oligomers extracted from polyester chips and fibers and measure the oligomer content.
II. Main contents of the standard
This standard specifies the method for determining the oligomer content in polyethylene terephthalate (PET) by high performance polymer chromatography (APC). method.
This standard applies to polyethylene terephthalate (PET) chips and fiber products.
3. The significance or expected benefits after the promulgation of the standard
The promulgation of this standard has developed an effective method for rapid determination of oligomer content in polyester, which is beneficial to the study of possible effects in PET The different oligomer components and contents of spinning processing properties provide technical support for optimizing polyester product preparation and spinning processing technology, and provide effective methods for enterprise production process control, product quality management and new product development.
“Determination of the relative molecular weight and distribution of polyethylene terephthalate by high-efficiency polymer chromatography-multi-angle laser light scattering (APC-MALLS)” (T/CCFA 00010-2021) Standard release and implementation
1. Background of standard formulation
The molecular weight of polyethylene terephthalate (PET) directly affects its final application fields and uses, and the molecular weight The distribution also has an important impact on its processing properties such as extrusion, injection, blow molding, spinning, etc. Therefore, accurately measuring the molecular weight and distribution of PET is of great significance for controlling the PET molding process and improving material performance and quality. At present, the Ubbelohde viscometer method is mainly used (GB/T 14190-2008, “Test method for fiber grade polyester chips (PET)”; GB/T 17931-2018, “Polyethylene terephthalate (PET) for bottles” ) Resin”; GB/T 17932-2013, Film Grade Polyester Chips (PET)) tests the intrinsic viscosity of polyester, but these test methods can only be used to compare polymers when the solvent, temperature and molecular shape are the same The size of the molecular mass cannot reflect the structure, morphology and degree of expansion of the polymer molecules in the solvent, nor can it obtain the molecular mass distribution that affects sample processing and application performance. Gel permeation chromatography (GPC) is used to test the relative molecular mass and distribution of PET, which has higher requirements on solvents and mobile phases. Although the relative molecular mass and distribution of polyester products can be obtained, narrow distribution standards are generally used. , there is a big difference in structure from polyester, so the test deviation usually exceeds 50%, and the repeatability is poor.
High performance polymer chromatography (APC) is an emerging chromatographic instrument for characterizing relative molecular mass and distribution. Compared with traditional chromatographic instruments, the chromatographic columns used in it will not be affected by solvents and will not swell. Enhances system stability and ensures flow rate accuracy at higher pressures. This standard proposes to use the APC-MALLS combination to test the molecular weight and distribution of PET samples, achieving a more stable, more accurate and faster determination of the molecular weight and distribution of PET samples.
II. Main contents of the standard
This standard specifies the determination of polyethylene terephthalate ( PET) relative molecular mass and its distribution.
This standard applies to polyethylene terephthalate (PET) chips and fiber products.
3. The significance or expected benefits after the introduction of the standard original dispersant imported from Germany
This standard breaks through the technical bottleneck of accurate and stable determination of polyester molecular weight and distribution, and provides High-performance, differentiated polyester and fibers in textile chemical fiber and material related fieldsWe provide effective evaluation standards and technical support for our R&D and production. Compared with the traditional GPC method and Ubbelohde viscometer method, the combined technology of this standard can quickly and accurately measure the molecular weight and distribution of polyester samples, which is helpful for monitoring product quality changes caused by process changes in actual production, and can Better understanding of the expected properties of polyester products, promoting the development of high-quality polyester, and having important application value in achieving product quality control and process optimization.
