How temperature-induced depolymerization and plasticization affect the process of structural relaxation

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F62690094%3A18470%2F24%3A50021142" target="_blank" >RIV/62690094:18470/24:50021142 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11150/24:10477725 RIV/00216275:25310/24:39922022

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0032386123008790?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0032386123008790?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.polymer.2023.126549" target="_blank" >10.1016/j.polymer.2023.126549</a>

Jazyk výsledku

angličtina

Název v původním jazyce

How temperature-induced depolymerization and plasticization affect the process of structural relaxation

Popis výsledku v původním jazyce

The self-plasticization, i.e., the increase in the polymer segmental mobility by the inclusion of its own monomer, has a major impact on the structural, thermal, and mechanical properties of the polymer. Differential scanning calorimetry (DSC) was used to investigate the influence of thermally induced self-plasticization on the structural relaxation of polydioxanone (PDX). Depolymerization (based dominantly on the end-chain scission mechanism) was found to be controlled by the depolymerization temperature Td as well as the actual number of re-melting cycles (while keeping the time spent at Td constant). PDX samples with the glass transition temperature (Tg) ranging from-52 (highly plasticized) to-13 degrees C (virgin) were prepared. The DSC data were described in terms of the Tool-Narayanaswamy model; a consistent structural relaxation behavior associating the degree of plastici-zation with Tg was identified. The activation energy first decreased with plasticization from 430 kJ mol-1 to 210 kJ mol-1 in the Tg range of-40 to-13C, which is consistent with the plasticization-caused spacing-apart of the polymer chains resulting in larger free volume and increased freedom for the relaxation movements. For the highly plasticized PDX samples, the activation energy increased from 210 kJ mol-1 to 310 kJ mol-1, which appears to be associated with the possible segregation of the portion of the plasticizer into a discrete phase. The width of the relaxation times distribution increased with plasticization as a consequence of the plasticizer loosening the polymeric chains and enabling a wider variety of the segmental movement. The plasticization also leads to a higher dependence of the segmental relaxation movements on their current physico-chemical and steric surrounding.

Název v anglickém jazyce

How temperature-induced depolymerization and plasticization affect the process of structural relaxation

Popis výsledku anglicky

The self-plasticization, i.e., the increase in the polymer segmental mobility by the inclusion of its own monomer, has a major impact on the structural, thermal, and mechanical properties of the polymer. Differential scanning calorimetry (DSC) was used to investigate the influence of thermally induced self-plasticization on the structural relaxation of polydioxanone (PDX). Depolymerization (based dominantly on the end-chain scission mechanism) was found to be controlled by the depolymerization temperature Td as well as the actual number of re-melting cycles (while keeping the time spent at Td constant). PDX samples with the glass transition temperature (Tg) ranging from-52 (highly plasticized) to-13 degrees C (virgin) were prepared. The DSC data were described in terms of the Tool-Narayanaswamy model; a consistent structural relaxation behavior associating the degree of plastici-zation with Tg was identified. The activation energy first decreased with plasticization from 430 kJ mol-1 to 210 kJ mol-1 in the Tg range of-40 to-13C, which is consistent with the plasticization-caused spacing-apart of the polymer chains resulting in larger free volume and increased freedom for the relaxation movements. For the highly plasticized PDX samples, the activation energy increased from 210 kJ mol-1 to 310 kJ mol-1, which appears to be associated with the possible segregation of the portion of the plasticizer into a discrete phase. The width of the relaxation times distribution increased with plasticization as a consequence of the plasticizer loosening the polymeric chains and enabling a wider variety of the segmental movement. The plasticization also leads to a higher dependence of the segmental relaxation movements on their current physico-chemical and steric surrounding.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10404 - Polymer science

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Polymer

ISSN

0032-3861

e-ISSN

1873-2291

Svazek periodika

290

Číslo periodika v rámci svazku

January

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

"Article Number: 126549"

Kód UT WoS článku

001131270100001

EID výsledku v databázi Scopus

2-s2.0-85178091542