Tube Longitudinal Rouse relaxation

Here, tr and K are the longitudinal Rouse relaxation time and the velocity gradient tensor, respectively, and X Y indicates a sum of components of tensors X and Y, namely, X Y=Y,a,p=x,y,z XafiYfia. On the other hand, if the interchain pressure effect due to confinement in the tube disturbs the stretch relaxation, the time evolution equation is modified as ... 

---