5 - Molecular weight of polymers used in biomedical applications

Abstract

There is a close connection between molecular weight of polymers and their physical and chemical properties, reason why their processing requires good control of it. Therefore for a particular application of a specific polymer, a certain molecular weight range is required; this range refers to the connection between optimal properties and ease of processing. For example, as the molecular weight of polymer increases, so does its viscosity in solution; but the higher the viscosity, the more difficult the polymer processing will be. When it comes to polymers, we actually refer to molecular weight averages: number average molecular weight, weight average molecular weight, average molecular weight, higher average molecular weight. Over time, the structure determination techniques have evolved from traditional ones (IR spectroscopy, NMR spectroscopy, RAMAN, UV-vis, viscosimetry) to specific techniques used to investigate molecular weight values and molecular weight distribution such as gel permeation chromatography/size exclusion chromatography or matrix-assisted laser desorption/ionization mass spectrometry.