Civil Engineering Reference
In-Depth Information
h e characteristic tridimensional network of nano and microi brils of BC was clearly
visible on the surface and cross-section of the BC and grat ed BC-membranes. However,
at er grat ing an increment of the diameter of the cellulose i brils was observed which
was obviously associated with the chemical sleeving by the PMMA or PBA polymeric
chains. h is ef ect was more pronounced for the PMMA nanocomposites which were
in agreement with the higher weight-gains observed for this set. h is increase of diam-
eter of the cellulose i brils with weight gain was clearly evidenced by the SEM images of
BC-g- PMMA (I
1
M
0.5
) and BC-g-PMMA (I
1
M
1
), as well as BC-g- PBA (I
1
M
1
).
h ey proved the versatility of this procedure by using dif erent initiator/monomer
ratios of ering the possibility to tune the hydrophobicity of the ensuing nanocomposites
Br
O
OC
R
1
R
2
CH
2
Step 1
Step 2
Br
Br
O
O
O
O
OH
Br
O
O
OH
OH
OH
O
OH
Br
MMA or
n
-BA
(B/BBr)
DMAP,
DMF, 3 h, rt
CuBr / PMDETA
DMF / H
2
O
BC
BC-B/B
BC-
g
-PMMA or BC-
g
-PBA
or BC-
g
-PMMA-co-PBA
R
1
= -CH
3
or -(CH
2
)
3
-CH
3
R
2
= -CH
3
or - H
Figure 5.8
Bacterial cellulose functionalization with the ATRP initiator and ATRP grat ing of MMA
or BA from modii ed bacterial cellulose. Reproduced from [63] with permission of American Chemical
Society.
Membrane cross-section
BC-
g
-PMMA(I
1
M
1
)
BC
BC-
g
-PMMA(I
1
M
0.5
)
BC-
g
-PBA(I
1
M
1
)
Membrane surface
Figure 5.9
SEM images of the cross-sections and surfaces of BC and grat ed nanocomposites
Reproduced from [63] with permission of American Chemical Society.
