Infrared and Thermal Fingerprinting Protocols for Polyolefin Blends
Infrared and thermal fingerprinting verifies polyolefin blend composition, oxidation levels, and phase contamination to enforce supplier compliance and landed part cost.
Carbon Black Loading
Meaning
Additive quantities of carbonaceous pigments incorporated into a polymer matrix determine both the aesthetic and functional performance of the resulting compound. In the compounding of industrial thermoplastics, carbon black loading dictates the resistance to ultraviolet degradation and the electrical conductivity of the finished part. This concentration is measured as a weight percentage of the total formulation, typically ranging from one to forty percent depending on the target performance.
The additive must be uniformly dispersed to prevent localized concentration gradients that would compromise the mechanical integrity of the polymer.
Concentration Effect
Weathering resistance requires a concentration of two to three percent of finely dispersed particles. At this level, the pigment absorbs harmful solar radiation before it can initiate polymer chain scission. Higher levels are needed when the compound must conduct electricity to prevent electrostatic discharge.
Molding Behavior
Viscosity of the melt increases as the concentration of the particulate filler rises. Injection molders must adjust injection pressures and melt temperatures to compensate for this reduced flowability. Tool wear can also increase during high-volume runs due to the abrasive nature of the pigment particles.
Property Measurement
Thermogravimetric analysis provides the standard method to verify the loading level in finished parts. This is done by heating the sample under nitrogen to pyrolyze the polymer, followed by a switch to air to burn off the carbon black.