Determination of Molecular Weight Distribution of Polymers

Polymers, unlike low molecular weight compounds, do not have a fixed molecular weight, but rather a mixture of homologues of different molecular weights. The molecular weight distribution is closely related to the physical and mechanical properties of polymers and processing processes such as molding, film forming and spinning. So, the study of molecular weight distribution is an important factor to control and improve product quality.

Alfa Chemistry's services

Alfa Chemistry provides professional polymer molecular weight distribution detection services, our services include but are not limited to:

• Molecular weight distribution of adsorbent resin materials
• Molecular weight distribution of photosensitive polymer materials
• Molecular weight distribution of conductive polymer materials
• Molecular weight distribution of polyethylene, polyethylene glycol and other plastics
• Molecular weight distribution of medical intermediates such as medical polymer materials

Common detection technology

Gel permeation chromatography

Gel permeation chromatography (GPC) is a method to characterize molecular weight and molecular weight distribution of polymers.In recent years, the application of GPC has been expanding due to the continuous improvement of instruments, including the use of high-efficiency fillers, the combination of various detectors and computers, and the automation of instrument operation and data processing. When using highly sensitive instruments and detectors, GPC can not only measure the average molecular weight and distribution of linear polymers, but also provide a variety of information, such as polymer branching, molecular weight and chemical composition of copolymers.

Light scattering method

When the incident optical electromagnetic wave passes through the medium, the electrons in the polymer produce forced vibration, resulting in a secondary wave source that emits scattered light waves in all directions with the same frequency as the oscillating electric field (the incident optical electromagnetic wave). The strength of this scattered wave is related to the number of dipoles in the polymer, that is, to the mass or molar mass of the polymer. According to the above principle, the scattering light intensity of incident light at a small Angle (2℃-7℃) was measured by laser scatterometer, and the absolute weight average molecular weight (MW) value of polymer in dilute solution was calculated.

Alfa Chemistry's test standards

• ASTM D4001-2013 Standard Test Method for Molecular weight and Average Molecular Weight determination of Polymers by Low Diffusion Method
• ASTM D4001-1993(1999) Standard Test Method for Determination of Weight Average Molecular Weight of Polymers by Photothermal Method
• ASTM D4001-1993(2006) Standard Test Method for Molecular weight and Average Molecular weight determination of Polymers by Low Diffusion Method

Alfa Chemistry provides customers with molecular weight distribution determination of polymers with different molecular weight range based on gel permeation chromatography, viscosity and other classical methods. If you have need, please contact us.