Truly, anything that’s not in a pure form can be considered a composite, which makes this area of analysis more difficult to contain in a single definition.
Essentially, a composite material is an integration of two or more other materials (like hybrids of polymers and ceramics) to create a new material that exceeds the performance of either one of the individual components.
Composite materials are often created using twin-screw extruders. To ensure scalability of newly developed processes, the different scale machines should be similar in geometry.
New, hyphenated techniques that combine rheometry with other non-mechanical analytical methods such as microscopy, FTIR and Raman spectroscopy or dielectric analysis (DEA) enable analysts to monitor not only changes in the viscoelastic behavior of a material, but also to understand what causes these changes on a microscopic or molecular level. The results allow for a better understanding of complex processes such as cross-linking and curing reactions in the development of new materials.
Polyvinyl chloride or PVC is a popular polymer produced in rigid form (e.g. pipes, framing, etc.) or made flexible with the addition of plasticizers (e.g. cord insulation, inflatables, etc.)
PVC blends are complex mixtures of PVC particles, fillers, lubricants, stabilizers and plasticizers. They’re designed to provide unique properties to a multitude of end products. But, because of technological advances, cost pressures, or regulatory requirements, manufacturers are often forced to modify the complex recipes for PVC blends.
About 100 different plasticizers are used to soften PVC. The type and amount of plasticizer added have a major influence on the melt and processing behavior of the resulting alternate blends. Such product development processes benefit from the use of torque rheometers to determine substitutions or enhancements to PVC blend ingredients.