Study of mechanical properties of short fiber glass reinforced PA 6.6 recycled repeatedly

Some of the parts manufactured with engineering polymers such as short fiberglass reinforced polyamide (PA) are rejected for failing quality controls or are removed due to their breakage in service. The recovery of this technical material would be a major economic and environmental savings. The aim of this work is to determine the degree of recycling or number of times that the material can be re-injected maintaining the mechanical properties suitable for the in-service conditions. Then a physic-mechanical characterization for ten successive recycles was performed. The results show that as the number of recycles increases the PA matrix reduces its viscosity. About the mechanical properties, in static conditions, the ductility, strength and toughness decreases linearly with the number of recycles. This data is repeated in dynamic conditions. Observations of the fracture surfaces by SEM show a great appearance of pores from recycling number 5.