Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites

Abstract

The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A Statistical Design of Experiments was applied to study the influence of the addition of sisal (0 %wt-30 %wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermooxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied to simulate the potential of thermal recovery technologies, such as pyrolysis and controlled combustion, to use these biocomposites after the end of their service life. The mathematical descriptions of both thermo-chemical reactions were helpful in the evaluation of the eventual optimal operational conditions to carry out a suitable energetic valorisation. A minimum of 240 °C and 137 kJ/mol of activation energy in inert conditions and 236 °C and 118 kJ/mol in oxidative conditions ensured the feasibility of the reactions regardless the composition of the PHBV/sisal biocomposites, which may ease the operability of further energy valorisation with the aim to turn biowaste into new fuels.

Evaluation of the Mechanical and Thermal Properties Decay of PHBV/Sisal and PLA/Sisal Biocomposites at Different Recycle Steps

“…A previous thermogravimetric analysis [30,31] showed that the trigger of decomposition happened far above their melting point, which ensured a good performance of the composites at high processing temperatures. Figure 9 shows the calorimetric analysis of the samples submitted to recycling.…”

“…The study of the thermal decomposition of materials stands out as the main basis for the correct tuning of facilities for energy recovery purposes. In this sense, PLA/sisal and PHBV/sisal have proved their suitable behaviour for thermal recycling [30,31].…”

Reduction of Nitrates in Waste Water through the Valorization of Rice Straw: LIFE LIBERNITRATE Project

“…Thermogravimetric analysis (TGA) was applied to assess the thermal decomposition profiles as previously described for persimmon [31], apple tree residues [32] or biopolymers [33]. Experiments were carried out in a Mettler Toledo TGA/SDTA 851 (Columbus, OH, USA).…”

Production, Characterization, and Evaluation of Pellets from Rice Harvest Residues

“…Rice straw, for example, is usually eliminated by uncontrolled burning with harmful consequences related to air, flora, and fauna pollution in wetlands. As an alternative, rice waste is abandoned or sunk, being decomposed in fields, causing major die-off of fish and other aquatic fauna in deeper areas [2]. Currently, different European moratoria permitting uncontrolled burning are being applied, since no reliable solutions are being implemented.…”