Polymer characterization :


Polymer has a specific parameter which should be specified. This is because a polymer actually contains of a statistical distribution of chains of varying lengths, and each chain consists of monomer residues which affect its properties.

A lot of laboratory methods are used to control the properties of polymers. Techniques such as wide angle X-ray scattering, small angle X-ray scattering, and small angle neutron scattering are used to determine the crystalline structure of polymers. Gel permeation chromatography is used to determine the number average molecular weight, weight average molecular weight, and polydispersity. FTIR, Raman and NMR can be used to determine composition. Thermal properties same as the glass transition temperature and melting point could determine by differential scanning calorimetry and dynamic mechanical analysis. Pyrolysis followed by analysis of the fragments is one more method for determining the possible structure of the polymer. Thermogravimetry is a useful method to evaluate the thermal stability of the polymer. Detailed analysis of TG curves also let us to recognize a bit of the phase segregation in polymers. Rheological properties are also usually used to help determine molecular architecture (molecular weight, molecular weight distribution and branching) as well as to comprehend how the polymer will process, by the measurements of the polymer in the melt point. Another polymer characterization technique is Automatic Continuous Online Monitoring of Polymerization Reactions (ACOMP) that can affords real-time characterization of polymerization reactions. It can be used as an analytical method in R&D, as a device for reaction optimization at the bench and pilot plant level, finally, for feedback control of full-scale reactors. ACOMP measures in a model-independent fashion the evolution of average molar mass and intrinsic viscosity, monomer conversion kinetics and, in the case of copolymers, also the average composition drift and distribution. It is applicable in the areas of free radical and controlled radical homo- and copolymerization, polyelectrolyte synthesis, heterogeneous phase reactions, including emulsion polymerization, adaptation to batch and continuous reactors, and alterations of polymers.