Reduction of enthalpy relaxation in gelatine films by addition of polyols

Paulo Díaz Calderón, Bill MacNaughtan, Sandra Hill, John Mitchell, Javier Enrione

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The aim of this study was to evaluate the effect of plasticisers with different molecular weights (glycerol and sorbitol) on the structural relaxation kinetics of bovine gelatine films stored under the glass transition temperature (Tg). Plasticisers were tested at weight fractions of 0.0, 0.06 and 0.10. Films conditioned in environments under ∼44% relative humidity gave moisture contents (w/w) in the range 0.14–0.18. The enthalpy relaxation (ΔH) was determined using differential scanning calorimetry (DSC). Samples used had Tg values in the range 24–49 °C. After removing the thermal history (30 °C above Tg, 15 min), samples were isothermally stored at 10 °C below Tg for between 2 and 80 h. The addition of plasticisers induced a significant reduction in the rate of structural relaxation. The linearisation of ΔH by plotting against the logarithm of ageing time showed a reduction in the slope of samples plasticised with both polyols. The reduction in relaxation kinetics may be related to the ability of polyols to act as enhancers of molecular packing, as recently reported using positron spectroscopy (PALS). However, a direct correlation between the relaxation kinetics and the plasticiser's molecular weight could not be established, suggesting that this phenomenon may be governed by complex molecular gelatin-plasticiser-water interactions.

Original languageEnglish
Pages (from-to)634-638
Number of pages5
JournalInternational Journal of Biological Macromolecules
Volume109
DOIs
StatePublished - 1 Apr 2018

Bibliographical note

Funding Information:
The authors are grateful to Professor Yrjo Ross for his valuable scientific discussions regarding this work . The authors also acknowledge the financial support from the grants FONDECYT N°1171553 and PAI N°79130039 .

Publisher Copyright:
© 2017 Elsevier B.V.

Keywords

  • Gelatin
  • enthalpy relaxation
  • plasticisers

Fingerprint Dive into the research topics of 'Reduction of enthalpy relaxation in gelatine films by addition of polyols'. Together they form a unique fingerprint.

Cite this