A STUDY THE FINE STRUCTURE OF VALONIA MACROPHYSA BT ALKALI TREATMENT

Abstract

The fine structure of the microfibril of Valonia macrophysa was examined using X-ray diffraction and by determination of changes that take place in the capacity for moisture regain of Valonia on treatment with various concentrations of NaOH at 20°C, leveling off the _??_ and weight loss of alkali-treated samples hydrolyzed with 4N HCl aquous solution at the boiling point.
1) Measurements of the alkali-treated or hydrolyzed samples by X-ray diffraction and leveling off the _??_ and weight loss indicate that the structure of the microfibril changes at a NaOH concentration in the range of 17.5-18.0% to 24-26%, but the capacity for moisture regain changes at a 3-4% lower concentration than that used in other methods.
2) It is suggested that the NaOH penetrates the lamellaes or microfibrils at a concentration in the range of 13% to 17.5% and the crystalline region at a concentration in the range of 17.5% to 24%.
3) The average length of a crystalline region calculated from the leveling off of the _??_ of Valonia treated with a NaOH solution at a concentration from 0% to 17.2% is about 1μ. Furthermore, calculating from the leveling off of the _??_ of a sample treated with a NaOH solution of 18.4%, and in which X-ray measurements indicate the presence of cellulose I and II lattices, the length of an extended molecular chain was determined to be about 5600 Å. On the basis of these determinations, the Valonia microfibril fits the model composed of an extended chain rather than the model (folding period 40 Å-700 Å) containing a folded conformation.
4) It is believed that the microfibril of the Valonia macrophysa defect consisting of chain-end dislocations does not exist at random throughout the microfibril, but rather, generally at intervals of about 1μ (average value).