On the use of fracture mechanics techniques to assess the performance of recycled polymer blends

C. ROSALES; A. COSTANTINO; T. ECHEVERRÍA; C. BERNAL; V. PETTARÍN

Merseburg

Conferencia; PolymerTec 2021; 2021

Selbstverlag der Hochschule Merseburg

Plastic waste accumulation is one of the main environmental problems of the XXI century.Plastics could be seriously harmful for environment due to their slow and complexdegradation process. Some plastics are difficult or expensive to separate in individualmaterials, and then an effort is done in order to recycle them as blends. The difficult task ofdealing with blends is to obtain a material with good mechanical properties, since thepresence of a polymer dispersed in a second one may strongly change these properties andlimit their use in conventional applications. It is then evident that one of the big engineeringchallenges in recycling thermoplastic blends is to manufacture competitive products in termsof mechanical properties such as toughness or strength, i.e. to upcycling, understandingupcycling as a process by which recycled waste is transformed into materials with improvedperformance, adding value and widening their application field. Nowadays, most works whichdeal with recycled blends evaluate mechanical performance by means of conventionalmechanical tests such as tensile, flexural or non instrumented impact tests which in manycases are not representative of actual loading situations [1]. In a desire to characterizetoughness of ductile polymers, we have turned to fracture mechanics, believing that fracturetests, that imply a more severe loading condition, i.e., load triaxiality, are more adequate toevaluate mechanical integrity of final pieces [2]. Through this work, a complete morphologicaland mechanical evaluation of different recycled thermoplastic blends is presented.Microstructure and morphology of blends were analyzed by XRD, DSC and SEM. Tensile andfracture tests were carried out on mode I double edge-notched tensile specimens (DDENT) atquasi-static loading conditions. Fracture surfaces were studied by SEM. Results arisen fromfracture tests, both qualitative and quantitative, were proven to be a very efficient tool toevaluate the performance of this type of blends.