Molecular structure of citric acid cross-linked starch films
Författare
Summary, in English
The effect of citric acid (CA) on starch films has been examined. A new method to detect cross-linking of starch by CA in solution-cast films by molecular weight measurements is described. Furthermore, we managed to distinguished between free, mono- and di-esterified CA and quantify di-ester content within starch films by using a modification in the method of complexometric titration with copper(II)-sulfate. Cross-linking of starch by CA occurred at low temperature, 70C, which we assumed is so far the lowest temperature reported where cross-linking reaction occurred. This is essential for starch coating applications within paper industry since no high temperatures for curing will be required. However, curing at 150C and high CA concentrations, 30 pph, increased cross-linking reaction. Furthermore, the physical properties like water solubility, gel content and glass transition temperature, were highly reflected by changes in the molecular structure i.e. cross-linking and hydrolysis, as well as CA content and curing temperature.
Avdelning/ar
Publiceringsår
2013
Språk
Engelska
Sidor
270-276
Publikation/Tidskrift/Serie
Carbohydrate Polymers
Volym
96
Issue
1
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Physical Sciences
- Natural Sciences
Nyckelord
- Starch-base films
- citric acid
- cross-linking
- molecular weight
- hydrolysis
- amorphous starch
- plasticization
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0144-8617