Meaning
Molecular knotting prevents the long-strand molecules of a resin from sliding past each other freely when the material is in a molten or solid state. This polymer chain entanglement is the primary reason why plastics have high viscosity and structural toughness. Without these knots, the material would behave more like a simple liquid than a structural solid.
Melt Viscosity
Resistance to flow increases as the number of molecular overlaps grows. A higher degree of polymer chain entanglement means that the machine must use more pressure to force the plastic through the mold. This property is directly related to the molecular weight of the resin.
Stretch Capability
Deformation during processes like blow molding or thermoforming is limited by the way these chains are knotted. If polymer chain entanglement is too high, the material will tear rather than stretch. If it is too low, the part will sag under its own weight during the heating phase.
Strength Contribution
Impact resistance is derived from the ability of these entanglements to distribute stress across the entire molecular network. A part with high polymer chain entanglement can absorb more energy before the chains actually break. This makes the final product more durable.
