to 10%) of citrus peel biomass can successfully replace conventional
pulp.
Fig. 2 shows the effect of organic materials on bursting
strength. All materials (except for orange peels at a proportion
of 2.5%) give statistically significant higher values for
bursting strength compared to those of conventional pulp.
Algal biomass gave the highest values followed by combined
materials and citrus peel addition. Increased bursting
strength after the addition of citrus peels may also be
attributed to small particles being embedded among paper
fibers; the embedded particles make the fiber matrix more
resistant to the stresses exerted by the Mullen tester, especially
close to the rupture area, where pressure is higher.
Tearing resistance data is presented in Fig. 3. Added
algal biomass increased tearing resistance significantly,
whereas the addition of citrus peels seems to have had
the opposite effect. It is evident that the mixing of citrus
peels resulted in lower mechanical strength compared to
that of algal biomass for all the paper strength properties
examined. As far as tearing resistance is concerned, this
may happen due to the occasional presence of citrus peel