Mechanical recycling of polypropylene garden chairs via restabilization

The remelting-restabilization technique was applied to evaluate the closed loop recycling of post-used, white garden chairs made from filled polypropylene (PP). Different commercial stabilization systems in selected concentrations were employed to investigate the optimum restabilization recipe for eliminating degradation effects during reprocessing and successive service life. For monitoring the processing stability of the restabilized and non-restabilized material, a multiple extrusion procedure at two different reprocessing temperatures was performed. In addition, mechanical tests were carried out, for further studying the effect of restabilization on the performance of the recycled material. The long-term thermal stability of the recycled material was studied by mechanical tests and by determining the time to embrittlement in accelerated heat ageing experiments. The results lead to conclusions about the success of restabilization for quality improvement of post-used filled PP chair material during recycling, permitting its re-use in the original application.