TG/FT–IR/MS study on thermal decomposition of polypropylene/biomass composites

Abstract

Thermogravimetry/Fourier Transform Infrared Spectroscopy/Mass Spectrometry (TG/FT–IR/MS) coupled methods were used to determine the mass loss and the main decomposition compounds produced under dynamic conditions of polypropylene/biomass composites heating. The PP/Eucalyptus globulus, PP/Norway spruce, PP/energy grass, PP/Brassica rapa, PP/pine cones and PP/grape seeds biocomposites were studied. PP decomposition takes place in a single step, while polypropylene biocomposites decomposition occurs in two steps. The first process is assigned to the decomposition of biomass components, while the second (the main one), and was assigned to PP decomposition. Under the influence of lignocellulosic materials on the initiation of PP degradation, the main decomposition step is shifted to higher temperatures. The main gaseous products obtained from the thermal degradation of polypropylene/biomass composites were H2O, CO2, CO, formaldehyde, methanol, acetic acid, formic acid, and methane. The thermal behaviour of the biocomposites depended on biomass type and its composition in main constituents: hemicelluloses, cellulose, lignin and ash, the variation recorded in the following order: by-products (pine cones and grape seeds) < annual plant (energy grass and B. rapa) < woody biomass (Norway spruce and E. globulus).