Oil palm empty fruit
bunch (EFB) pulp with the highest cellulose
content of 83.42% was obtained from an optimized process of acid pretreatment
(0.5% v/v H
2
SO
4
), alkaline extraction (15% w/w
NaOH), and hydrogen peroxide bleaching (10% w/v H
2
O
2
), respectively. The EFB cellulose was carboxymethylated,
and the obtained carboxymethyl cellulose (CMC) was readily water-soluble
(81.32%). The EFB CMC was blended with glycerol and cast into a composite
film. Lignin that precipitated from the EFB black liquor was also
incorporated into the film at different concentrations, and its effect
on the UV-blocking properties of the film was determined. Interestingly,
the EFB CMC film without lignin addition completely blocked UV-B transmittance.
The incorporation of lignin at all concentrations significantly enhanced
the UV-A blocking and other physical properties of the film, including
the surface roughness, thickness, and thermal stability, although
the tensile strength and water vapor permeability were not significantly
affected. Complete UV-A and UV-B blocking were observed when lignin
was added at 0.2% (w/v), and the film also exhibited the highest antioxidant
activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals
with an half-maximal inhibitory concentration (IC
50
) value
of 3.87 mg mL
–1
.