Analysis of Selected Properties of Polymer Mixtures Derived from Virgin and Re-Granulated PP with Glass Fibers

Tomasz Stachowiak; Dariusz Kwiatkowski; Marcin Chmielarz; Dominik Grzesiczak

doi:10.3390/ma17061433

Analysis of Selected Properties of Polymer Mixtures Derived from Virgin and Re-Granulated PP with Glass Fibers

Materials (Basel). 2024 Mar 21;17(6):1433. doi: 10.3390/ma17061433.

Authors

Tomasz Stachowiak¹, Dariusz Kwiatkowski¹, Marcin Chmielarz², Dominik Grzesiczak²

Affiliations

¹ Department of Technology and Automation, Faculty of Mechanical Engineering and Computer Science, Częstochowa University of Technology, Armii Krajowej 21 St., 42-201 Częstochowa, Poland.
² Granulat-Bis Company, Hallera 8A St., 42-202 Częstochowa, Poland.

Abstract

The problem of the growing amount of waste polymer materials currently affects virtually every area of the global economy. New actions taken by the E.U. and member states could lead to a reduction in the burden on the natural environment, as well as the reuse of thermoplastic waste. The aim of this study was to analyze the possibility of reusing post-industrial waste (recycled polypropylene-rPP) in order to produce mixtures with original polypropylene (PP) and glass fibers. The research undertaken is characterized by a high level of innovation and was carried out on an industrial scale from industrial waste. The primary goal of the analyses was to determine changes in the properties of the polymer mixtures depending on the amount of recycled polymers. For this purpose, four types of mixtures were prepared, characterized by different degrees of filling with recycled material obtained from big-bag packaging (the filling levels were 0 wt.%, 20 wt.%, 30 wt.%, and 70 wt.%). A detailed analysis of the physical properties of the obtained mixtures was carried out to determine changes in the densities depending on the amount of rPP material. In addition, changes in the MFIs (melt flow indexes), characterizing viscosity changes, were analyzed depending on the amount of secondary raw material used. An analysis of the mechanical properties was also carried out based on static tensile testing, the impact strength (the Charpy method), and the Rockwell hardness test (the M method). The analysis of the thermal changes was performed using the DSC method. The results showed that the composites made of virgin polypropylene (PP GF30) and those made from re-granulates and glass fibers (rPP GF30) are characterized by similar mechanical properties and significantly different processing properties, determined by MFI. This means that the addition of re-granulates significantly affects the processability of the obtained materials, while the addition of glass fibers maintains the basic mechanical properties.

Keywords: polymer composites; polymer materials; polymer reprocessing; recycling.

Grants and funding

This publication was created in cooperation with Granulat-BIS with the involvement of the company’s owner, Marcin Chmielarz, and the laboratory manager, Dominik Grzesiczak.