Non Aqueous Potentiometric Acid Value Determination in Mixed Polyolefin Extrusion Compounds
Non-aqueous potentiometric titration isolates active maleic grafts from oxidative degradation acids in polyolefin blends using hot o-dichlorobenzene and KOH.
Tie Layer Adhesion
Meaning
Bond strength between a functionalized adhesive resin and dissimilar layers in a multi-layer film or part. Packaging applications utilize tie layer adhesion to join incompatible materials such as polyethylene and ethylene vinyl alcohol. The adhesive resin contains reactive groups that interpenetrate the adjacent surfaces.
Failure of this bond leads to delamination, which destroys the barrier properties and structural integrity of the container.
Interfacial Bonding
Interaction at the molecular level involves both physical entanglement and chemical grafting. Barrier properties are maintained by functional groups that promote tie layer adhesion in the laminate. Effective bonding prevents the ingress of oxygen or moisture through the edges of the laminate.
Processing Compatibility
Rheological properties of the adhesive must match the flow characteristics of the other layers in the co-extrusion die. Co-extrusion die performance depends on maintaining tie layer adhesion across the entire width of the film. If the viscosities are too divergent, the layers will not distribute evenly across the width of the film.
Peeling Resistance
Quantifiable force required to separate the layers serves as the primary metric for performance. Peel testing is the standard method for measuring tie layer adhesion in multi-layer structures. This value must remain stable even after the material has been subjected to sterilization or long-term storage.