Molecular characterization of commercial polypropylene with narrow and broad distribution of molar mass

The molar mass and the molar mass distribution of two commercial grades of isotactic polypropylene, Moplen S30S of Himont S, r. l. and Daplen PT55 of PCD Polymere GmbH., were investigated by 16 laboratories. For Moplen S30S M-w = 467 kg/mole +/- 6.0 % (relative standard deviation), M-n = 83.7 kg/mole +/- 9.8 % and M-w/M-n = 5.70 +/- 10.1 % were determined by size exclusion chromatography (31 SEC runs). for Daplen PT55 M-w = 206 kg/mole +/- 13.6 %, M-n = 61.4 kg/mole +/- 13.4 % and M-w/M-n = 3.42 +/- 17.3 % were found (38 SEC runs). Light scattering measurements gave M-w = 445 kg/mole +/- 4.1 % for Moplen S30S (4 labs) and M-w = 212 kg/mole +/- 10 % for Daplen PT55 (3 labs). The intrinsic viscosity in 1,2,4-trichlorobenzene at 140 degrees C of Moplen S30S [eta] = 1.87 dl/g +/- 5.4 % and of Daplen PT55 [eta] = 1.12 dl/g +/- 6.7 % was measured (9 independent measurements). Samples of the respective lots are available from the authors, Moplen S30S from IM, Daplen PT55 from KL.