ISSN:
1572-882X
Keywords:
bacterial cellulose
;
transmission electron microscopy
;
cellulose Iα
;
cellulose Iβ microfibrils
;
carboxymethyl cellulose
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Abstract Effects of polymer additives on the formation of microfibrils of bacterial cellulose have been examined by transmission electron microscopy. Among additives with different degrees of polymerization (DP) or substitution (DS), carboxymethyl cellulose sodium salt (CMC) with DP = 80 and DS = 0.57 is the most effective in producing separate, smaller-size microfibrils. By increasing the concentration of this CMC from 0.1 to 1.5%, the percentage of microfibrils measuring 3–7 nm wide is increased and levels off at around 1.0%. Other polymer additives such as xyloglucan are less effective than CMC in producing microfibrils with smaller sizes and the resulting microfibrils still tend to aggregate. The number of charged substituents and the molecular weight seem to be important factors in the production of highly separate smaller-size microfibrils. The reduction in average microfibril size is well correlated to the decrease in mass fraction of cellulose Iα in bacterial cellulose crystals. On the basis of these results, the mechanism of the crystallization of celluloses Iα and Iβ is discussed. The effect of colony types, smooth and rough, on the formation of microfibrils in the presence of CMC is also described.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009233323237
Permalink
