THE RECYCLING OF THERMOPLASTICS - PREDICTION OF THE PROPERTIES OF MIXTURES OF VIRGIN AND REPROCESSED POLYOLEFINS

A theoretical basis for the prediction of the properties of mixtures o f virgin and reprocessed polymers is presented. The concept is develop ed using equations that describe the loss of polymer properties as a f unction of processing cycles. These equations correspond to properties that are important in characterization and quality control, such as m elt flow index and tensile and impact strengths. Experimental data wer e determined and used to test the models derived. For glass-fiber-rein forced thermoplastics, the data on the degradation of fiber lengths an d mechanical properties can help to understand the effect of reprocess ing on the fiber-matrix interaction.