Analysis of the initial process in pyrolysis of poly(p-dioxanone)

Poly(p-dioxanone) (PPDO) is an excellent feedstock recyclable polymer. The initial process in PPDO pyrolysis was investigated to clarify the whole process of PPDO thermal degradation. The pyrolysis and analysis were carried out with pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and thermogravimetry (TG) measurements. The Py-GC/MS results showed some minor products, such as vinyl compounds and acid anhydride derivatives. The degradation kinetics was analyzed based on TG data using methods including a plot of log[-log{1-( 1-w)(1/2)}] against 1/T, where w is the fractional weight ratio. The analytical results indicated that minor reactions proceeded besides the main zero-order unzipping depolymerization. From simulation studies, it was estimated that random degradation reactions proceed competitively, especially in the initial stages. The random reactions are considered to influence the main depolymerization reaction. The new plot used in this study is an effective method for the analysis of the pyrolysis process. (C) 2002 Elsevier Science Ltd. All rights reserved.