Macromolecules, Vol.37, No.3, 813-825, 2004
Observation of chain branching in polyethylene in the solid state and melt via C-13 NMR spectroscopy and melt NMR relaxation time measurements
Branch contents in sparsely short-chain branched polyethylenes ( 100 000 g/mol was shown to be feasible in both solid-state and melt measurements in less than a one-day measurement, obtained on a 500 MHz spectrometer and 4 mm rotor. Using this enhanced signal intensity, NMR relaxation times were investigated in the melt with respect to their inherent sensitivity to the branching architecture. These measurements included T-1rho, T-1, and T-1(NOE). It was found that T-1(NOE) seems to have the best sensitivity to determine the approximate length of the side chain branches for n > 6.