Detail publikace

Chemical modification and characterization of hydrogels from natural polysaccharide Gum Karaya

POŠTULKOVÁ, H. VOJTOVÁ, L. JANČÁŘ, J. CHAMRADOVÁ, I.

Originální název

Chemical modification and characterization of hydrogels from natural polysaccharide Gum Karaya

Anglický název

Chemical modification and characterization of hydrogels from natural polysaccharide Gum Karaya

Jazyk

en

Originální abstrakt

Gum Karaya (GK) is a natural gum exudate of Sterculia urens tree. GK is a partially acetylated, insoluble and anionic polysaccharide. It is obtained as calcium and magnesium salt and contains of β-D-galactose, L-rhamnose, β-D-glucuronic acid and D-galacturonic acid. The swelling behaviour of GK is caused by the presence of the acetyl groups and multivalent ions in the GK structure. The present study deals with purification and chemical modification of GK to developed soluble material by alkali treatment for subsequent potential use in medicine (e.g. hydrogels for soft tissue regeneration of drug delivery systems). Conditions of modification reaction such as type of hydroxide, concentration of GK dispersion and time of reaction were optimized and mechanism of the reaction was proposed. Original GK and modified GK samples were studied by SEM, FTIR, TGA, DSC, ICP OES, GPC, NMR and rheological studies. The linear viscoelastic region was determined by rheological measurements. The effect of NaCl on viscosity of original GK was performed. Decreasing viscosity of GK solution with higher amount of NaCl was explained by exchange of multivalent ions by monovalent ions in the GK structure and release of the physically bonded structure resulting in higher solubility of original GK in water.

Anglický abstrakt

Gum Karaya (GK) is a natural gum exudate of Sterculia urens tree. GK is a partially acetylated, insoluble and anionic polysaccharide. It is obtained as calcium and magnesium salt and contains of β-D-galactose, L-rhamnose, β-D-glucuronic acid and D-galacturonic acid. The swelling behaviour of GK is caused by the presence of the acetyl groups and multivalent ions in the GK structure. The present study deals with purification and chemical modification of GK to developed soluble material by alkali treatment for subsequent potential use in medicine (e.g. hydrogels for soft tissue regeneration of drug delivery systems). Conditions of modification reaction such as type of hydroxide, concentration of GK dispersion and time of reaction were optimized and mechanism of the reaction was proposed. Original GK and modified GK samples were studied by SEM, FTIR, TGA, DSC, ICP OES, GPC, NMR and rheological studies. The linear viscoelastic region was determined by rheological measurements. The effect of NaCl on viscosity of original GK was performed. Decreasing viscosity of GK solution with higher amount of NaCl was explained by exchange of multivalent ions by monovalent ions in the GK structure and release of the physically bonded structure resulting in higher solubility of original GK in water.

Dokumenty

BibTex


@misc{BUT112206,
  author="Hana {Poštulková} and Ivana {Chamradová} and Lucy {Vojtová} and Josef {Jančář}",
  title="Chemical modification and characterization of hydrogels from natural polysaccharide Gum Karaya",
  annote="Gum Karaya (GK) is a natural gum exudate of Sterculia urens tree. GK is a partially acetylated, insoluble and anionic polysaccharide. It is obtained as calcium and magnesium salt and contains of β-D-galactose, L-rhamnose, β-D-glucuronic acid and D-galacturonic acid. The swelling behaviour of GK is caused by the presence of the acetyl groups and multivalent ions in the GK structure. The present study deals with purification and chemical modification of GK to developed soluble material by alkali treatment for subsequent potential use in medicine (e.g. hydrogels for soft tissue regeneration of drug delivery systems). Conditions of modification reaction such as type of hydroxide, concentration of GK dispersion and time of reaction were optimized and mechanism of the reaction was proposed. Original GK and modified GK samples were studied by SEM, FTIR, TGA, DSC, ICP OES, GPC, NMR and rheological studies. The linear viscoelastic region was determined by rheological measurements. The effect of NaCl on viscosity of original GK was performed. Decreasing viscosity of GK solution with higher amount of NaCl was explained by exchange of multivalent ions by monovalent ions in the GK structure and release of the physically bonded structure resulting in higher solubility of original GK in water.",
  address="Masaryk University",
  booktitle="Book of Abstracts CEITEC Annual Conference "Frontiers in Material and Life Sciences"",
  chapter="112206",
  howpublished="print",
  institution="Masaryk University",
  year="2014",
  month="october",
  pages="203--203",
  publisher="Masaryk University",
  type="abstract"
}