Original scientific paper

Influence of recycling on thermal properties and kinetics of thermal degradation of polypropylene

Matko ERCEG orcid.org/0000-0002-8626-1193 ; University of Split, Faculty of chemistry and Technology, Split
Lucija KURTE ; University of Split, Faculty of chemistry and Technology, Split
Marija KURSAN ; University of Split, Faculty of chemistry and Technology, Split

Abstract

The influence of repeated extrusions of polypropylene (PP) on its thermal properties is investigated by differential scanning calorimetry and non-isothermal thermogravimetric analysis. PP is extruded six times on a laboratory extruder at a temperature of 190 °C and screw speed of 120 min-1. Extruded samples show a slight reduction of the melting point and the crystallization degree compared to the original PP. The non-isothermal degradation of all samples occurs through one degradation step and the extruded samples show a slightly lower thermal stability compared to the original PP. Kinetics analysis of the non-isothermal degradation of all samples was performed by isoconversional Flynn-Wall-Ozawa method. All extruded samples show higher values of activation energy compared to the original PP. Activation energy is constant in a wide range of conversion for all samples what also indicates that the non-isothermal degradation of PP occurs through one degradation step, without change of the reaction mechanism due to extrusion. Therefore, repeated extrusions under these conditions slightly worsen the thermal properties of PP and can be used for recycling its waste.

Keywords

kinetic analysis; mechanical recycling; polypropylene (PP); thermal properties

Hrčak ID:

75723

URI

https://hrcak.srce.hr/75723

Publication date:

30.12.2011.

Article data in other languages: croatian

Visits: 1.812 *