Secondary Amide Additives in Polyolefin Thermal Sealing Operations
Secondary amides eliminate seal jaw smoking and hot tack decay in polyolefin film sealing by maintaining low volatility at elevated operating temperatures.
FTIR-ATR
Meaning
Analytical spectroscopy techniques identify chemical structures on the surface of solid materials without requiring destructive sample preparation. Specifically, ftir-atr measures the absorption of infrared light by a sample in contact with a high-refractive-index crystal, providing data on additive bloom or surface contamination. The infrared beam undergoes total internal reflection within the crystal, creating an evanescent wave that penetrates a few micrometers into the polymer.
This allows for the detection of slip agents, antioxidants and other surface-concentrated species. It is a standard tool for troubleshooting adhesion and sealing failures in the plastics industry.
Chemical Fingerprint
Absorbance patterns reveal the presence of specific functional groups such as amides, esters or hydroxyls. Each chemical species has a unique spectrum that serves as an identification mark. By comparing the sample spectrum to a library of known polymers and additives, a technician can determine the composition of a surface bloom.
This is useful for identifying if the wrong slip agent was used or if a tie-layer has migrated.
Depth Penetration
Sampling depth is limited to the top one or two micrometers of the material surface. This surface-sensitive nature makes the technique ideal for studying thin films and coatings. It captures the chemistry at the exact interface where bonding or friction occurs.
Because the beam does not travel through the entire thickness of the part, the bulk properties do not obscure the surface data.
Troubleshooting Utility
Failure analysis often relies on this method to explain why a part cannot be painted or glued. If a moulder sees a high concentration of stearamide on a surface intended for bonding, the spectroscopic data provides the proof needed to adjust the resin formulation. It also detects oxidized species that indicate the polymer was degraded during processing.
The rapid nature of the test allows for quick decisions in a production environment.
Fatty Acid Amide Transport Kinetics in Flexible Polyolefin Packaging
Polyolefin slip kinetics depend on additive supersaturation, where migrating fatty acid amides form nanometer-scale boundary layers to balance friction and seal integrity.