Molecular structure

Multi-detector GPC for characterizing the structure of polymers and bio-molecules

The physical and even the chemical properties of a polymer in a final manufactured product can be closely related to the polymer structure.

Types of polymer structure:

  • Linear
  • Random branched
  • Comb structure
  • Starburst polymers or dendrimers
  • Copolymers
  • Cross-linked

Determining molecular structure

Multi-detector SEC can be used to determine a number of the factors that determine structure:

  • Branching ratio
  • Branching frequency
  • Molecular density / Intrinsic Viscosity
  • Copolymer composition
  • Backbone modification

Structure is determined using a combination of an intrinsic viscosity detector that is sensitive to density, and a light scattering detector that provides molecular weight. These parameters are used to construct a Mark–Houwink plot from which a range of structural information can be deduced.

Application example

Acrylonitrile-butadiene copolymers, commonly called nitrile rubbers (NBR), are used widely for adhesive compounding, and gloves used for examination and cleaning.

The composition of the copolymers, the polymer cross-linking and branching as well as the molecular weight of NBR affect the macroscopic properties of NBR such as flexibility and puncture resistance.

Zetasizer Advance Range

Zetasizer Advance Range

Light Scattering for every application

Empyrean Nano Edition

Empyrean Nano Edition

Versatile X-ray scattering platform

Measurement type
Molecular structure
Molecular size
Molecular weight
Technology
Gel Permeation Chromatography
Size Exclusion Chromatography (SEC)
Dynamic Light Scattering
X-ray Diffraction (XRD)