Effect of moisture in κ-carrageenan films on their tensile and relaxation behavior studied by correlation between stress and birefringence

• Published in: Rheologica acta Vol. 59; no. 11; pp. 765 - 770
• Main Authors: Horinaka, Jun-ichi, Ishibashi, Yurina, Takigawa, Toshikazu
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2020; Springer Nature B.V
• Subjects: Birefringence; Carrageenan; Characterization and Evaluation of Materials; Chemistry and Materials Science; Complex Fluids and Microfluidics; Deformation; Food Science; Hydrogels; Materials Science; Mechanical Engineering; Moisture effects; Original Contribution; Polymer melts; Polymer Sciences; Soft and Granular Matter; Stress-strain curves; Structural models; Viscoelasticity; Stress-optical coefficient; Gel film; Birefringence; carrageenan; Moisture
• ISSN: 0035-4511; 1435-1528
• DOI: 10.1007/s00397-020-01242-4

A picture on the molecular level describing the deformation and the following relaxation of κ -carrageenan chains has been proposed based on the three-domain structural model for κ -carrageenan films and on the idea of the modified stress-optical rule. The uniaxial tensile and the relaxation behavior for dry and moist κ -carrageenan films has been examined by using a homemade apparatus available for the simultaneous mechanical and birefringence measurements. It has been suggested that the continuous amorphous phase of κ -carrageenan in the dry film is deformed together with the local glass component, and only the glass component relaxes in the following process. On the other hand, concerning the moist film, the crosslinks of κ -carrageenan aggregates in addition to the continuous phase are movable with deformation, while the following relaxation is attributed only to the unbridged κ -carrageenan chains in the continuous phase.