Utility of multiple-pulse NMR to determine the amorphous fraction of polyethylene

Multiple pulse NMR techniques are utilized to determine the amorphous fraction of polyethylene. The averaging condition of the multiple pulse experiment, tc∥?int∥≪1, where tc is the cycle time and ∥?int∥ the magnitude of the internal interaction averaged by the multiple pulse sequence in question, allows for unique separation of the response of the protons in the amorphous phase from the response of the total system by means of appropriate adjustment of tc.