Polyacrylamide (PAM) is a commonly used polymer compound widely used in many fields, such as water treatment, soil consolidation, pulp and paper industry, etc. Below are some information on storage methods and molecular weight determination of polyacrylamide.

1. Storage method:

    - Storage temperature: Polyacrylamide should be stored at room temperature, away from fire sources and high temperature environments, to prevent its decomposition or degradation.

    - Packaging: Polyacrylamide usually comes in solid or powder form and should be stored in well-sealed containers to avoid moisture ingress.

    - Avoid contact: Polyacrylamide should be kept away from strong oxidants and acids to avoid possible dangerous reactions. Maintain a clean working environment and avoid contact with organic solvents and other substances.

2. Determination of molecular weight of polyacrylamide:

    - Gel permeation chromatography (GPC): GPC is currently one of the most commonly used methods for determining the molecular weight of polymers. This method is based on the relationship between the diffusion properties of polymers in gels and their molecular weight. The molecular weight range of polyacrylamide can be determined by comparing it with reference materials of known molecular weight.

    - Dynamic Light Scattering (DLS): DLS is a method of measuring the size and molecular weight of particles or molecules in solution. For polyacrylamide solutions, DLS can provide information about the molecular aggregation state and average molecular weight.

    - Nuclear Magnetic Resonance (NMR): NMR technology can be used to determine the molecular weight and distribution of polyacrylamide. By measuring the NMR spectrum of the sample and comparing it with the standard material according to the integrated intensity of the peak, the molecular weight information of the polymer can be obtained.

These methods are often used in combination to obtain more accurate and comprehensive molecular weight data for polyacrylamide. The selection of the appropriate method should be determined based on actual needs and equipment availability. Due to different experimental conditions, laboratories may choose different methods when determining molecular weight.