Abstract

CARDENAS-GIRALDO, Juan; ROJAS-GONZALEZ, Andrés  and  GALVIZ-GARCIA, Beatriz. Changes in the Chemical Structure of High-Density Polyethylene when Undergoing Multiple Reprocessing. Rev. ing. univ. Medellín [online]. 2019, vol.18, n.35, pp.111-124. ISSN 1692-3324.  https://doi.org/10.22395/rium.v18n35a7.

In this paper, which presents the original results of a research funded by Colciencias and Facultad de Ingeniería y Arquitectura from the Universidad Nacional de Colombia, headquarters Manizales, publishes the changes of high-density polyethylene extrusion and injection grade identified after being subjected to five reprocessing processes in extrusion, injection and extrusion/ injection. The identification of the changes is made through the comparison of the FTIR spectrum with those reported in different bibliographical references. The spectra were obtained by means of a Platinum ATR spectrometer. The thermal degradation was greater in the extrusion/injection process, followed by injection, extrusion at 80 rpm and extrusion at 20 rpm. It is concluded that there is a low degradation of high-density polyethylene after being reprocessed in five cycles, evidencing the appearance of the carbonyl group, vinyl groups and COC group.

Keywords : thermal degradation; FTIR; injection reprocessing; extrusion reprocessing; high-density polyethylene.

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