Structure-Property Relations for Recycled HDPE at Large Deformations in the Liquid State and Effect on Crystallization
Author
Term
4. semester
Education
Publication year
2024
Submitted on
2024-05-31
Pages
42
Abstract
This thesis investigated the changes to the degree of crystallinity and structure of HDPE as a result of thermo-oxidative degradation. The aim of this investigation was to characterize the relationship between the internal structure of recycled HDPE and increased sensitivity seen in cyclic loading failure. The thermal, rheological and optical properties of virgin HDPE (vHDPE), degraded vHDPE (vHDPEdeg280) and post-consumer recycled HDPE (rHDPE) were investigated by TGA, DSC, OIT, rheology, solvent swelling, FTIR, optical microscopy and SEM. The results of thermal testing yielded a decrease in the degree of crystallinity for degraded samples, as well as an increase in the degradation temperature seen by TGA. Large amplitude oscillatory shear rheology (LAOS) was found to be an effective method of characterizing the changes in the behavior of the internal structure of the HDPE melt as a result of degradation. Optical microscopy and SEM highlighted the complex effects of degradation on the crystalline structure, showing greater inhomogeneity of the crystalline structure for degraded samples. The effects of degradation on HDPE were investigated through LAOS and crystallinity analysis, showing clear changes to the internalstructure as a result of complex degradation mechanisms.
Keywords
HDPE ; Degradation ; LAOS ; Recycling
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