The viscoelasticity of a series of monodisperse molten polystyrenes was investigated over a wide molecular weight range (9200 to 756 300). The plateau modulus was determined as the value of G' at the minimum of tan 6 in the rubbery zone, because this point defines a gel-like viscoelastic behaviour. A possible dependence of the entanglement density on chain length was explored, as a recent model predicts such an effect. The experimental indication is that the onset of the entanglement network occurs rather abruptly around M e and that the entanglement density is constant for M > M e.
Посилання на статтю:
Effect of chain length on the network modulus and entanglement / Paolo Lomellini // Polymer. – 1992. – Vol 33. – P. 1255-1260.