Cassava starch (CS) and chitosan (CH) are biopolymers used alone or blended (CS/CH) to produce films, thanks to their excellent film-forming properties. Their main physical properties have been characterized, but their physical and water state have not yet been studied. The objective of this research was to study the water and macromolecular physical state of CS, CH and CS/CH films by DSC and dielectric properties, after sorption isotherms determinations. Biopolymers and obtained films were also analyzed by SEM, FTIR, X-ray diffraction and gas permeability. Dielectric properties of active films containing pitanga leaves hydroethanolic extract were also analyzed. All films presented type II sorption isotherms. Glass transition temperature of films decreased with the increase of moisture content (Xw) following the Gordon and Taylor model. The dielectric constant behaves depending of the monolayer moisture content (Xm): increased linearly as a function of Xw when Xw > Xm. For Xw ≤ Xm, the dielectric constant remained constant. An exponential relationship between α-relaxation and Tg was calculated.

Studying physical state of films based on casava starch and/or chitosan by dielectric and thermal properties and effects of pitanga leaf hydroethanolic extract

Iaccheri E.;Siracusa V.;Ragni L.;De Aguiar Saldanha Pinheiro A. C.;Romani S.;Rocculi P.;Dalla Rosa M.;
2022

Abstract

Cassava starch (CS) and chitosan (CH) are biopolymers used alone or blended (CS/CH) to produce films, thanks to their excellent film-forming properties. Their main physical properties have been characterized, but their physical and water state have not yet been studied. The objective of this research was to study the water and macromolecular physical state of CS, CH and CS/CH films by DSC and dielectric properties, after sorption isotherms determinations. Biopolymers and obtained films were also analyzed by SEM, FTIR, X-ray diffraction and gas permeability. Dielectric properties of active films containing pitanga leaves hydroethanolic extract were also analyzed. All films presented type II sorption isotherms. Glass transition temperature of films decreased with the increase of moisture content (Xw) following the Gordon and Taylor model. The dielectric constant behaves depending of the monolayer moisture content (Xm): increased linearly as a function of Xw when Xw > Xm. For Xw ≤ Xm, the dielectric constant remained constant. An exponential relationship between α-relaxation and Tg was calculated.
Iaccheri E.; Siracusa V.; Ragni L.; De Aguiar Saldanha Pinheiro A.C.; Romani S.; Rocculi P.; Dalla Rosa M.; Sobral P.J.D.A.
File in questo prodotto:
File Dimensione Formato  
pagination_JFOE_111280.pdf

embargo fino al 11/09/2023

Tipo: Postprint
Licenza: Licenza per Accesso Aperto. Creative Commons Attribuzione - Non commerciale - Non opere derivate (CCBYNCND)
Dimensione 1.31 MB
Formato Adobe PDF
1.31 MB Adobe PDF   Visualizza/Apri   Contatta l'autore

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/894818
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 0
  • ???jsp.display-item.citation.isi??? ND
social impact