The role of microstructure in the pyrolysis of polypropylene. A preliminary study on the syndiotactic stereoisomer

The pyrolysis of two syndiotactic polypropylene samples with different molar mass and microstructure has been studied by means of TGA. The volatiles evolved have been analysed as a whole by mass spectrometry. The relative content of the different low mass alkenes, alkanes and dienes provides a fingerprint which has been used to asses the similarity of the mechanism. The changes in the apparent E-a with conversion have been shown by means of the Friedman's method. The results show that, even though the chemical pattern is identical in both samples, important differences in the E-a trends are found. Such disparity in the energy requirements for the pyrolysis to take place can be reasonably attributed to the different microstructure of the samples. (C) 2011 Elsevier Ltd. All rights reserved.