B. Morgenstern et T. Roder, Investigations on structures in the system cellulose/N-methylmorpholine-N-oxide monohydrate by means of light scattering measurements, PAPIER, 52(12), 1998, pp. 713-717
N-methylmorpholine-N-oxide monohydrate (NMMNO. MH) has became increasingly
more important as a solvent for the forming of cellulose. However; the stru
ctures which exist in the NMMNO MH solutions have not yet been sufficiently
investigated With respect to this, cellulose samples differed in their ini
tial structures, were investigated by light scattering measurements.
The results obtained from static light scattering show that even in dilute
solutions of cellulose in NMMNO . MH, clusters exist in which more than 100
0 cellulose molecules are aggregated The existence of quite extended struct
ures was confirmed by dynamic light scattering measurements. These cellulos
e particles are probably entanglements of residues of original structures.
Their geometric shape is between that of globular particles and that of an
homogeneous branched particle.
Activation of cellulose prior to dissolution led to more strongly swollen p
articles consisting of significantly less cellulose molecules than without
activation. Shape and size of the particles were not substantially changed.
As kinetic studies revealed cellulose degradation occurs in the solutions,
and different parts of the particles are destroyed with different rates.