Nonlinear time-dependent behavior of rheodictic polymers : a theoretical and experimental investigation

Oseli, Alen (avtor), Mihelčič, Mohor (avtor), Šobak, Matic (avtor), Slemenik Perše, Lidija (avtor)

The present study examined the nonlinear time-dependent behavior of rheodictic polymers, a class of noncrosslinked materials that exhibit flow. Such behavior was addressed with extended Schapery’s nonlinear viscoelastic model by introducing new physical quantities, i.e., the flow term Φ$_{flow}$ and corresponding nonlinear shift parameter g$_{2,flow}$. While Φ$_{flow}$ portrays irrecoverable deformation, g$_{2,flow}$ depicts a nonlinear contribution to flow acceleration. This theory was accompanied by analytical and experimental methodologies for identifying all the parameters in the linear and nonlinear viscoelastic domains. Predictions of long-term time-dependent behavior (in shear) at various stress states show excellent agreement with the experimental data, i.e., within 5% error, obtained for polycarbonate at 130 °C. Surprisingly, the newly introduced g$_{2,flow}$ indicates that flow retardation occurs with increasing stress, implying that a highly deformed entangled system hinders molecular reptation/disentanglement. Nevertheless, the proposed extension of Schapery’s nonlinear viscoelastic model not only allows accurate predictions of the nonlinear time-dependent behavior of rheodictic polymers but also enables a detailed outlook on the underlying molecular mechanisms under severe environmental and loading conditions.

• Jezik: Angleški jezik
• Ključne besede: rheodictic polymers, nonlinear behavior, time-dependent mechanical properties, creep process, Schapery’s nonlinear model
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FS - Fakulteta za strojništvo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2024
• Št. strani: 11 str.
• Številčenje: Vol. 137, art. 108535
• PID: 20.500.12556/RUL-159934
• UDK: 620.17:678.7
• ISSN pri članku: 1873-2348
• DOI: 10.1016/j.polymertesting.2024.108535
• COBISS.SI-ID: 203185923
• Datum objave v RUL: 31.07.2024

Gradivo je del revije

• Naslov: Polymer testing
• Založnik: Elsevier
• ISSN: 1873-2348
• COBISS.SI-ID: 23025669

Licence

• Licenca: CC BY-NC 4.0, Creative Commons Priznanje avtorstva-Nekomercialno 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc/4.0/deed.sl
• Opis: Licenca Creative Commons, ki prepoveduje komercialno uporabo, vendar uporabniki ne rabijo upravljati materialnih avtorskih pravic na izpeljanih delih z enako licenco.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: reodiktični polimeri, nelinearno vedenje, časovno odvisne mehanske lastnosti, proces lezenja, Schaperijev nelinearni model