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Title: Effect of reprocessing cycles on the degradation of polypropylene copolymer filled with talc or montmorillonite during injection molding process

Mechanical recycling of polymeric materials is a favorable technique resulting in economic and environmental benefits, especially in the case of polymers with a high production volume as the polypropylene copolymer (PP). However, recycling by reprocessing techniques can lead to thermal, mechanical or thermo-oxidative degradation that can affect the structure of the polymer and subsequently the material properties. PP filled with montmorillonite (MMT) or talc are widely produced and studied, however, its degradation reactions by reprocessing cycles are poorly studied so far. In this study, the effects of reprocessing cycles in the structure and in the properties of the PP/MMT and PP/Talc were evaluated. The samples were mixed with 5% talc or MMT Cloisite C15A in a twin-screw extrusion. After extrusion, this filled material was submitted to five reprocessing cycles through an injection molding process. In order to evaluate the changes induced by reprocessing techniques, the samples were characterized by DSC, FT-IR, Izod impact and tensile strength tests. The study showed that Young modulus, elongation at brake and Izod impact were not affected by reprocessing cycles, except when using talc. In this case, the elongation at brake reduced until the fourth cycle, showing rigidity increase. The DSC results showed that meltingmore » and crystallization temperature were not affected. A comparison of FT-IR spectra of the reprocessed indicated that in both samples, between the first and the fifth cycle, no noticeable change has occurred. Thus, there is no evidence of thermo oxidative degradation. In general, these results suggest that PP reprocessing cycles using MMT or talc does not change the material properties until the fifth cycle.« less
Authors:
;  [1] ; ; ; ;  [2]
  1. Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Gonçalves, 9500, Porto Alegre, 91501-970 (Brazil)
  2. Laboratory of Design LDSM, Federal University of Rio Grande do Sul, UFRGS (Brazil)
Publication Date:
OSTI Identifier:
22391873
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1664; Journal Issue: 1; Conference: PPS-30: 30. International Conference of the Polymer Processing Society, Cleveland, OH (United States), 6-12 Jun 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CALORIMETRY; COMPARATIVE EVALUATIONS; COPOLYMERS; CRYSTALLIZATION; ELONGATION; EXTRUSION; FOURIER TRANSFORMATION; INFRARED SPECTRA; MELTING; MOLDING; MONTMORILLONITE; OXIDATION; POLYPROPYLENE; RECYCLING; REPROCESSING; TALC; TENSILE PROPERTIES; YOUNG MODULUS