Theory 05/Polymer Physics
The Plateau Is a Packing Length
The claim
The entanglement plateau modulus of a polymer melt is set by the packing length rather than by molecular weight, so two polymers of very different molecular weight can have the same modulus.
01The mechanism
Entanglement spacing is set by how tightly chains pack, not by how long they are; the packing length captures the local stiffness and volume.
02Predictions
- P1Modulus should collapse onto packing length across polymers.
- P2Molecular weight should shift the plateau width, not its height.
03Refutation
Modulus tracking molecular weight would remove the packing control.