When the acid concentration was increased, the presence of
macropores (560 A) ˚ was favored over small mesopores (39 A) ˚
(Fig. 9, top). Pores with diameter of 91 A ˚ were more frequent when
0.5 M acid was used but otherwise significant changes were not
observed between 139 and 290 A. ˚ Sum of the mesopore frequencies
indicates that they are more dominant when acid concentration is
low (0.5 M 0.669; 2 M 0.649 and 6 M 0.598). In this case, coagulation
was slower and cellulose had more time to arrange itself and form
smallercavities.Incontrast,whenacidconcentrationwasincreased
and coagulation was more rapid, more macropores were formed
(0.5 M 0.276, 2 M 0.289, and 6 M 0.348). Formation of mesopores
seemed to be inversely proportional to the formation of macropores (560 A). ˚ Higher amounts of small pores also explains the
higher specific surface area in case of beads coagulated from lower
acid concentrations.