Journal of Applied Polymer Science, Vol.86, No.10, 2472-2485, 2002
Closed-loop recycling of postused garden chairs based on PP using the restabilization technique. I. Evaluation of processing parameters
A remelting-restabilization technique was applied to evaluate the closed-loop recycling of postused, white pigmented, garden chairs made from CaCO3-filled polypropylene (PP). Analysis of the randomly collected postused chairs showed only an insufficient quantity of residual active stabilizers. Different stabilization systems in selected concentrations were employed to investigate the optimum restabilization recipe for eliminating degradation effects during reprocessing. For monitoring the processing stability of the restabilized and nonrestabilized material a multiple extrusion procedure at two different reprocessing temperatures was performed. Furthermore, a repigmentation step was applied to investigate the role of the additional pigment on the processing stability of the recycled product. Finally, mechanical tests were carried out, for studying further the effect of restabilization on the mechanical performance of the recycled material. The results lead to the conclusion that restabilization for quality improvement of postused filled PP chair material during reprocessing is permitting its reuse in the original application.