Polymer solids and melts

Synthetic polymers are usually produced from hydrocarbon monomers through polymerization reactions, with the end product being a resin in powder, flakes or pellet form. A variety of additives are then added to the resin to modify or to obtain desirable properties. The compounded resin can then be processed - melted and shaped to a final product through molding, extrusion, or other conversion process.

In selecting a polymer for an end-product application, there is usually a balance between performance and its ability to be processed. To optimize the melt processing of polymers, a variety of chemical and engineering properties are usually determined, to ensure the processability criteria are met. The quality of a finished part is assessed based on its ability to perform end-use service functions, which could involve load-bearing, barrier properties, high temperature, or chemically aggressive environment.

It is therefore usually desirable for a polymer or compound to be characterized in a melt state, typically under conditions similar to when being processed– temperature, pressure, deformation rates, etc., and frequently in a solid state , in powder or pellet form, or as a representative sample from a solid processed part.

Material characterization tools from Malvern Instruments employ a range of technologies for meeting these analytical needs: Capillary and Rotational rheometers are used for melt rheological characterization and DMA testing of polymer in solid state. Dilute solution viscometers ( DSV) for solution viscosity , Laser Diffraction for particle size and distribution of resin powder, GPC for MW and MWD, and Imaging Systems for size and shape of resin powder or pellets.