Development of thermoplastic composites based on recycled polypropylene and waste printed circuit boards.

In the last several years, the electronic waste, especially printed circuit boards have significantly increased over the world, generating one of the highest rates of solid waste. The recycling process of the printed circuit boards implies mainly the recovery of metals and glass fibers, while the reuse of the polymeric support has remained largely in the phase of research. In this paper, the non-metallic part of printed circuit boards was used as filler (up to 30%), but also to improve the fire resistance of thermoplastic composites based on recycled polypropylene and diene block-copolymers. The synergy between the elastic effect of elastomers and the reinforcing effect of the waste powder into the thermoplastic matrix was studied by mechanical and dynamo-mechanical analysis, X-ray diffraction, optical microscopy, micro-calorimetry and thermo-gravimetrical analysis. Improved mechanical properties, especially impact strength was observed. The compatibization of components considering the interactions between the ethylene-butylene blocks from the hydrogenated and maleinized styrene-butadiene block-copolymer and recycled polypropylene, respectively between the MA groups and the functionalities of the waste powder, evidenced by FTIR, was highlighted by changes in the X-ray pattern and an increased fire resistance and thermal stability.

Effect of Styrene-Diene Block Copolymers and Glass Bubbles on the Post-Consumer Recycled Polypropylene Properties.

The recycled polypropylene (rPP) materials that meet technical requirements such as reducing the dimensions and improving the tensile, elongation, impact strength, thermal stability, as well as melt processing, are required for the manufacturing industry. In this paper, we studied the mechanical and thermal properties of post-consumer rPP by adding both synthesized thermoplastic elastomers, and glass bubbles (GB) by a melt allowing process. Styrene-butadiene (SBS) and styrene-isoprene (SIS) block-copolymers that had a styrene content of 30 wt% were synthesized by anionic sequential polymerization. The obtained post-consumer rPP composites were characterized by optical microscopy, scanning electron microscopy (SEM), mechanical analyses (tensile, density, hardness, VICAT softening temperature (VST), heat deflection temperature (HDT), dynamic mechanical analysis (DMA), IZOD strength) and thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). Weight reduction and improvement of the tensile, elongation, impact strength, thermal stability, as well as melt processing of post-consumer recycled polypropylene (rPP) properties compounded with thermoplastic elastomers and glass bubbles, sustain the use of these formulations for engineering applications.