A rheometer measures the rubbery plateau modulus of a polymer melt to be at

PHYSICS · Subjective · Fermi University Physics · Condensed Matter, Materials & Soft Matter · Soft condensed matter · Soft condensed matter

Soft Matter at the Thermal Scale, Ch Polymer dynamics and viscoelasticity

Problem

A rheometer measures the rubbery plateau modulus of a polymer melt to be GN0=4.0×105 PaG_N^0 = 4.0\times10^5\,\mathrm{Pa} at T=450 KT = 450\,\mathrm{K}, where the melt density is ρ=900 kg m−3\rho = 900\,\mathrm{kg\,m^{-3}}. Using the entanglement plateau relation GN0≈45ρRT/MeG_N^0 \approx \tfrac45\rho RT/M_e, where R=8.314 J mol−1 K−1R = 8.314\,\mathrm{J\,mol^{-1}\,K^{-1}} is the gas constant, find the entanglement molar mass MeM_e in g mol−1\mathrm{g\,mol^{-1}}.

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