Solution properties of chitin in alkali.
The solution properties of alpha-chitin dissolved in 2.77 M NaOH are discussed. Chitin samples in the weight-average molecular weight range 0.1 x 10(6) g/mol to 1.2 x 10(6) g/mol were prepared by heterogeneous acid hydrolysis of chitin. Dilute solution properties were measured by viscometry and light scattering. From dynamic light scattering data, relative similar size distributions of the chitin samples were obtained, except for the most degraded sample, which contained aggregates. Second virial coefficients in the range 1 to 2 x 10(-3) mL.mol.g(-2) indicated that 2.77 M NaOH is a good solvent to chitin. The Mark-Houwink-Sakurada equation and the relationship between the z-average radius of gyration (Rg) and the weight-average molecular weight (Mw) were determined to be [eta] = 0.10Mw0.68 (mL.g(-1)) and Rg = 0.17Mw0.46 (nm), respectively, suggesting a random-coil structure for the chitin molecules in alkali conditions. These random-coil structures have Kuhn lengths in the range 23-26 nm.
Einbu
Aslak
A
Department of Biotechnology, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim.
Naess
Stine Nalum
SN
Elgsaeter
Arnljot
A
Vårum
Kjell M
KM
D000468:Alkalies / Q000032:analysis* / Q000737:chemistry*; D000818:Animals; D002686:Chitin / Q000032:analysis* / Q000737:chemistry*; D003445:Crustacea; D019999:Pharmaceutical Solutions / Q000032:analysis / Q000737:chemistry
D000468:Alkalies; D019999:Pharmaceutical Solutions; D002686:Chitin