title: Kinetics and mechanism of thermal degradation of pentose- and hexose-based carbohydrate polymers.
abstract: This work aims at study of thermal degradation kinetics and mechanism of pentose- and hexose-based carbohydrate polymers isolated from Plantago ovata (PO), Salvia aegyptiaca (SA) and Ocimum basilicum (OB). The analysis was performed by isoconversional method. The materials exhibited mainly two-stage degradation. The weight loss at ambient-115°C characterized by low activation energy corresponds to loss of moisture. The kinetic triplets consisting of E, A and g(α) model of the materials were determined. The major degradation stage represents a loss of high boiling volatile components. This stage is exothermic in nature. Above 340°C complete degradation takes place leaving a residue of 10-15%. The master plots of g(α) function clearly differentiated the degradation mechanism of hexose-based OB and SA polymers and pentose-based PO polymer. The pentose-based carbohydrate polymer showed D(4) type and the hexose-based polymers showed A(4) type degradation mechanism.
authors.affiliation: Department of Chemistry, University of Sargodha, Sargodha 40100, Pakistan.
authors.forename: Jamshed
authors.initials: J
authors.lastname: Akbar
authors.forename: Mohammad S
authors.initials: MS
authors.lastname: Iqbal
authors.forename: Shazma
authors.initials: S
authors.lastname: Massey
authors.forename: Rashid
authors.initials: R
authors.lastname: Masih
mesh_terms: D006601:Hexoses / Q000737:chemistry*; D006358:Hot Temperature; D007700:Kinetics; D008956:Models, Chemical; D018649:Ocimum basilicum / Q000737:chemistry*; D010429:Pentoses / Q000737:chemistry*; D010943:Plantago / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*; D027544:Salvia / Q000737:chemistry*
chemical_list: D006601:Hexoses; D010429:Pentoses; D011134:Polysaccharides