Characterization and Selection of Microcrystalline Cellulose from Oil Palm Empty Fruit Bunches for Strengthening Hydrogel Films

Microcrystalline cellulose (MCC) is one of the cellulose derivatives produced as a result of the depolymerization
of a part of cellulose to achieve high crystallinity. When implemented in other polymers, high crystallinity cor-
relates with greater strength and stiffnes, but it can reduce the water-holding capacity. The acid concentration and hydrolysis time will affect the acquisition of crystallinity and water absorption capacity, both of which have significance as properties of hydrogel filler. The study aimed to evaluate the properties and select the MCC generated
from varying the proportion of hydrochloric acid (HCl) and the appropriate hydrolysis time as a filler for film
hydrogel. MCC was produced by hydrolyzing cellulose of oil palm empty fruit bunches (OPEFB) with the HCl
solution at varied concentrations and periods. The results show that the longer hydrolysis times and higher HCl
concentrations increase crystallinity and density while lowering yield and water absorption. The extensive acid
hydrolysis reduces the amorphous area significantly, allowing the depolymerization to occur and extend the crys-
talline area. The morphological properties of the MCC, which are smaller but compact, indicate the presence of
disintegrating and diminishing structures. A 2.5 N HCl concentration and a 45-min hydrolysis time succeed in
sufficient crystallinity as well as maintaining good water absorption capacity. The treatment produced MCC with
absorption capacity of 4.03 ± 0.26 g/g, swelling capacity of 5.03 ± 0.26 g/g, loss on drying of 1.44% ± 0.36, bulk
and tapped density of 0.27 ± 0.031 g/cm 3 and 0.3 ± 0.006 g/cm 3
, respectively, with a crystallinity index of 88.89%
± 4.76 and a crystallite size of 4.23 ± 0.70 nm. The MCC generated could potentially be utilized as a hydrogel film
filler, since a given proportion will be able to maintain the strength of the hydrogel, not readily dissolve but absorb
water significantly.