Comparative Investigation of the Viscoelastic Behavior of Virgin and Recycled PET by DMA: The Role of Rigid and Mobile Amorphous Fractions
Year: 2026
Type: conference-paper
Abstract: The present study investigates the effect of repeated mechanical recycling on the phase composition and viscoelastic behavior of injection-molded poly(ethylene terephthalate) (PET). Virgin PET and materials subjected to one, two, and three consecutive recycling cycles were characterized using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The crystalline fraction (CRF), mobile amorphous fraction (MAF), and rigid amorphous fraction (RAF) were determined using a three-phase model based on DSC measurements. Recycling modified both the crystalline and amorphous phase composition of PET, producing a moderate increase in mean crystallinity and non-monotonic changes in the amorphous fractions. DMA measurements showed an overall tendency toward higher mean storage modulus after repeated recycling, although specimen-to-specimen scatter was considerable, whereas the glass-transition temperatures changed only slightly. Normalized modulus-plane trajectories indicated differences in relaxation behavior but, because they were obtained from single-frequency temperature sweeps, were not interpreted as conventional frequency-domain Cole–Cole spectra. The combined DSC and DMA results reveal associations between phase composition and the viscoelastic response of mechanically recycled PET while also identifying important experimental limitations.
Authors: Pál Hansághy, Péter Gerse, Attila Bata
Institutions: Obuda University, John von Neumann University
Language: English
Subfield: Polymers and Plastics
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7225752828