The factors responsible for the low solubility percentage of oil palm empty fruit bunch (OPEFB) cellulose pulp compared
to kenaf when dissolved in aqueous NaOH/urea solvent system was reported. Physical and chemical properties of both
cellulose pulp were studied and compared in terms of the lignin content, viscosity average molecular weight (Mη),
crystallinity index (CrI), cellulose pulp structure and their zero span tensile strength. The structure of both OPEFB and
kenaf cellulose pulp were characterized using high powered microscope and field emission scanning electron microscopy
(FESEM) assisted by ImageJ® software. The results show that the most significant factor that affected the OPEFB and
kenaf cellulose dissolution in NaOH/-urea solvent was the Mη with OPEFB having a higher Mη of 1.68×105 compared to
5.53 × 104 for kenaf. Overall, kenaf cellulose appeared to be produced in higher quantities presumably due to its lower
molecular weight with superior tensile strength and permeability in comparison to OPEFB.
Cellulose was extracted from kenaf core pulp (KCP) by a series of bleaching processes (D) and alkali treatment (E) in the sequence of (DEED) and pretreated with acid hydrolysis in room temperature for 6 hours. The pretreated and non-treated cellulose were dissolved in lithium hydroxide/urea (LiOH/urea) and subsequently used to produce cellulose membrane cross linked with various percentages of glyoxal from 2.5 to 20%. The effects of acid hydrolysis pretreatment on solubility, crystallinity and morphology were investigated. The acid hydrolysis pretreatment leads to higher solubility of the cellulose solution. The formation of cellulose II and crystallinity index of the cellulose membrane were examined by X-ray diffraction (XRD). Cellulose membrane without acid hydrolysis pretreatment cross linked with higher percentage of glyoxal has higher tensile strength compared with the treated cellulose.
In this study oil palm empty fruit bunches (EFB) fibres was used to synthesize biophenolic resin (BPR) at a different
formaldehyde/liquefied empty fruit bunches (F/LEFB) molar ratio which is 1.0, 1.5 and 2.0. The higher molar ratio of F/
LEFB used has resulted in an increased of viscosity and solid content of BPR resin. The first decomposition of BPR resin
occured around 86 to 130°C due to the evaporation of low molecular weight substance which were water, free phenol
and formaldehyde. Glass fibre reinforced biophenolic composite (BPC) and glass fibre reinforced biophenolic elastomer
composite (BPEC) was successfully fabricated using BPR resin. The impact strength and flexural strain of BPEC were
higher than that of BPC. The impact strength of BPEC 1.5 was the highest at 47.71 kJm-2. However, the flexural strength
of BPEC was lower compared with BPC, which the highest flexural strength was obtained by BPC 1.0 at 65.18 MPa. The
cross-sectional image from scanning electron microscope (SEM) of BPEC and BPC confirmed the presence of epoxidized
natural rubber (ENR) improved the compatibility between glass fibre and BPR resin.
In this study, magnetic cellulose membranes (MCM) have been prepared by using cotton linter as cellulose source and NaOH/urea as cellulose solvent at different magnetite content. Cellulose was dissolved in pre-cooled NaOH/urea solvent at -13°C to form cellulose solution. The cellulose solution then was mix with magnetite (Fe3O4) nanoparticles synthesized via co-precipitation method of Fe2+ and Fe3+ in the presence of sodium hydroxide (NaOH) to form MCM. The MCMs formed at different percentage of Fe3O4 i.e., 10, 20 and 30%. Analysis from vibrating sample magnetometer (VSM) shows that the saturation magnetization of the MCM increase as the percentages of Fe3O4 nanoparticles increased. However, the addition of Fe3O4 nanoparticles in the regenerated cellulose membrane has decreased the crystallinity index of MCM. The surface morphology of the MCM showed that the Fe3O4 nanoparticles were dispersed in the pore of the membrane. Tensile test showed decreasing in the tensile strength of the cellulose membrane with the addition of Fe3O4 nanoparticle.
Oil palm is the major crop grown and cultivated in various Asian countries such as Malaysia, Indonesia and Thailand.
The core of oil palm trunk (COPT) consists of high sugar content, hence suitable for synthesis of fine chemicals and
biofuels. Increase of sugar content was reported previously during prolonged COPT storage. However, until now, there
has been no report on protein profiles during storage. Therefore, in this study, protein expression of the COPT during the
storage period of one to six weeks was investigated using sodium dodecyl sulphate polyacrylamide gel electrophoresis
(SDS-PAGE) coupled with optical density quantification and multivariate analyses for measuring differentially expressed
proteins. Accordingly, protein bands were subjected to tryptic digestion followed by tandem mass spectrometry (nanoLCMS/MS)
protein identification. The results from SDS-PAGE showed consistent protein bands appearing across the biological
replicates ranging from 10.455 to 202.92 kDa molecular weight (MW) regions. The findings from the principal component
analysis (PCA) plot illustrated the separation pattern of the proteins at weeks 4 and 5 of storage, which was influenced
mainly by the molecular weights of 14.283, 25.543, 29.757, 30.549, 31.511, 34.585 and 84.395 kDa, respectively. The
majority of these proteins are identified as those involved in stress- and defense-related, disease resistance, as well
as gene/protein expression processes. Indeed, these proteins were mostly upregulated during the later storage period
suggesting that long-term storage may influence the molecular regulation of COPT sap.
In this study, graphene oxide (GO), produced using the simple Hummer’s method, was used as adsorbent to remove methylene blue (MB) from aqueous solution. Characterizations using transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy were carried out on the GO before the MB adsorption experiments. The adsorption kinetics and isotherm studies were conducted under different conditions (pH = 3-7 and MB concentration = 100-400 mg/L) to examine the adsorption efficiency of the GO towards MB in aqueous solution. The adsorption kinetics data were analyzed using different kinetic models to investigate the adsorption behavior of MB on GO. The obtained results showed that the maximum adsorption capacity of the GO towards MB can achieve up to ~700 mg/g for the adsorption at 300 mg/L MB. The adsorption kinetic data were found to fit pseudo-second order model as compared with pseudo-first-order model. The intraparticle diffusion model suggested that the adsorption process of GO towards MB was dominated by the external mass transfer of MB molecules to the surface of GO.
Oil palm empty fruit bunch (EFB) fibers were subjected to solvolytic liquefaction to convert into liquid products using ethylene glycol (EG) as a supporting agent. The process was carried out at 250˚C for 60 min. The water-insoluble product fraction was exhaustively extracted with acetone (ASL fraction) to separate all less polar. FTIR and comparative analytical pyrolysis GC/MS of the parent EFB fiber and the ASL fraction confirmed the formation of larger amounts of long-chain lipophilic compounds under liquefaction conditions. Furthermore, a considerable amount of less polar thermal lignin degradation products were obtained comprising all of the three main lignin building blocks, i.e. 4-hydroxyphenyl- (P units), 4-hydroxy-3-methoxyphenyl- (G units) and 3,5-dimethoxy-4-hydroxyphenyl (S units) substituted compounds. 4-Prop-2-en-1-yl substituted phenolic compounds contributed mostly to the cumulated peak area of all lignin derived pyrolysis products obtained by analytical Curie point pyrolysis GC/MS at 600°C. The results of both instrumental-analytical methods confirm the formation of phenol and its derivatives, furan derivatives, organic acids, hydrocarbon, ester, benzene groups and alcohols.
Recent developments have found the viability of chitosan as a new alternative additive in the pulp and paper technology.
This study was carried out to investigate the effect of chitosan as a paper coating which were prepared by dissolution in
acetic acid solution. The mechanical properties of coated paper were improved significantly compared with non-coated
paper. The FT-IR spectra showed peak evolution at 1558 cm-1 for coated paper due to the existence of amine group. Since
FT-IR spectra for the coated paper was almost identical to the chitosan spectrum, it is assumed that there is an obvious
physical interaction rather than the chemical interaction. The SEM micrographs showed that some of the chitosan has
occupied the pores and some of them adhered only on the surface. This may be due to the chemical similarities between
cellulose and chitosan which enhanced the strength of fiber matrixes via hydrogen bonding. The antibacterial property
of coated paper showed that chitosan in dried form has no significant effect but effective when applied as wet solution.
Magnetite (Fe3O4) nanoparticles have been synthesized using the chemical coprecipitation method. The Fe3O4 nanoparticles were likely formed via dissolution-recrystallization process. During the precipitation process, ferrihydrite and Fe(OH)2 particles formed aggregates and followed by the formation of spherical Fe3O4 particles. The synthesized Fe3O4 nanoparticles exhibited superparamagnetic behavior and in single crystal form. The synthesis temperature and the degree of agitation during the precipitation were found to be decisive in controlling the crystallite and particle size of the produced Fe3O4 nanoparticles. Lower temperature and higher degree of agitation were the favorable conditions for producing smaller particle. The magnetic properties (saturation magnetization and coercivity) of the Fe3O4 nanoparticles increased with the particle size.
Membran selulosa terjana semula (MS) daripada pulpa teras kenaf telah berjaya dihasilkan menggunakan kaedah pra penyejukan dan digumpal menggunakan larutan asid sulfurik. MS disediakan daripada pelarutan selulosa kenaf dalam larutan akues NaOH/urea dan larutan selulosa seterusnya digumpal dengan H2SO4 pada kepekatan 5-12 peratus berat (% bt.) selama 1-10 min. Pengaruh kepekatan penggumpal H2SO4 dan masa penggumpalan ke atas struktur, saiz liang, sifat mekanik dan ketelusan cahaya MS telah dikaji menggunakan pembelauan sinar-X (XRD), imbasan mikroskop elektron tekanan boleh ubah (VPSEM), penguji regangan dan spektrofotometer ultra-violet sinar tampak (UV-vis). Keputusan VPSEM menunjukkan perubahan saiz liang membran bergantung kepada kepekatan larutan penggumpal H2SO4, manakala masa penggumpalan tidak mempengaruhi saiz liang membran. Membran yang direndam dengan larutan penggumpal pada kepekatan 10 % bt. dan masa pembekuan yang sederhana iaitu 5 min menunjukkan sifat mekanik yang lebih baik dengan nilai kekuatan regangan masing-masing 41.9 dan 43.5 MPa. Oleh itu, kajian ini dapat memberikan maklumat mengenai penyediaan MS dengan pelbagai saiz liang dan sifat mekanik dengan pengubahsuaian kepekatan dan masa penggumpalan.
Bio-novolac fibre made from phenol-formaldehyde derived oil palm empty fruit bunch (EFB) was produced using electrospinning method. The bio-novolac phenol-formaldehyde was prepared via liquefaction and resinification at two different molar ratios of formaldehyde to liquefied EFB (LEFB) (F:LEFB = 0.5:1 and 0.8:1). Electrospinning was applied to the bio-novolac phenol-formaldehyde (BPF) in order to form smooth and thin as-spun fibre. The BPF was electrospun at 15 kV and 15 cm distance between needle and collector at a flow rate of 0.5 mL/h. At lower molecular weight of BPF resin, beads formation was observed. The addition of poly(vinyl) butyral (Mw = 175,000 - 250,000) has improved the fibre formation with lesser beads hence produced more fibre. Polymer solution with higher molecular weight produced better quality fibre.
Chemical and thermal properties of pure lignin are depending on the plant origin, extraction method and type of
lignocellulosic. In this study, lignin from oil palm empty fruit bunch (EFB) and kenaf core were recovered from soda black
liquor by two steps of acid precipitation with hydrochloric acid and followed by soxhlet with n-hexane. The XRD analysis
of purified EFB lignin (EAL) and purified kenaf core lignin (KAL) exhibited amorphous properties, similar to the standard
alkali lignin (SAL). The FTIR and Raman spectra showed that all samples consist of HGS unit. In FTIR, the syringyl unit is
assigned at (1125 cm-1), (1327 and 1121 cm-1) and (1326and 1117 cm-1) meanwhile the guaicyl unit is assigned at (1263,
1212 and 1028 cm-1), (1271, 1217 and 1028 cm-1) and (1270, 1211 and 1030 cm-1) for SAL, EAL and KAL, respectively.
The peak around 1160 cm-1 represents C-O stretching of conjugated ester group present in HGS lignin. As for Raman, the
HGS unit exists in the range of 1100-1400 cm-1. Among the purified samples, the TGA result showed that KAL has a better
thermal stability with the residue of 36.49% and higher Tg value which is 152.69°C.
The physico-mechanical and chemical properties of enzyme retting kenaf and shredded empty fruit bunch of oil palm
fibres (EFB) were analyzed by chemical extraction, microscopic, spectroscopic, thermal and X-ray diffraction method.
Polypropylene (PP), a petroleum based fibre, was also included to compare the properties of synthetic fibre with natural
fibres. Chemical extraction analysis showed that cellulose was the major component in both kenaf and EFB fibres which
are 54% and 41.34%, respectively. Silica content of EFB was 5.29% higher than kenaf that was 2.21%. The result of
thermogravimetric analysis showed that kenaf has higher thermal decomposition rate compared to EFB fibre. However,
the residue for EFB fibre was higher than kenaf due to higher content in inorganic materials. The residual content of PP
fibre was only 1.13% which was lower than the natural fibre. The diameter of EFB fibre bundle was 341.7 µm that was
three times higher than kenaf. Microscopy study demonstrated that EFB surface was rough, porous and embedded with
silica while kenaf showed smooth surface with small pith. Higher porosity in EFB was due to the lower fibre density that
was 1.5 kg/cm3 compared to kenaf that was 1.62 kg/cm3. Kenaf has illustrated significant higher tensile strength (426.4
MPa) than EFB (150 MPa) and this result is in parallel to the pattern of the crystalline value for both fibres, 65% and
50.58%, respectively.
Absorption is one of the effective, simple and economical methods to remove oil from oily wastewater. The most widely
used approach is to utilize lignocellulosic biomass as oil absorbent. However, the hygroscopic of cellulose have limited
the oil-water separation capability of lignocellulosic fibers. In this study, the surface functionality of oil palm empty
fruit bunch (EFB) fibers was slightly altered by grafting reduced graphene oxide (rGO). The modified EFB fibers show
a distinct morphological and chemical characteristics changes as the surface of fibers has been coated with rGO. This
was supported by FTIR analysis with the diminishing peak of hydroxyl group region of EFB fibers. While the surface
modification on EFB fibers shows a diminution of a hydrophilic characteristic of 131.6% water absorption in comparison
with 268.9% of untreated EFB fibers. Moreover, modified fibers demonstrated an oil-water separation increment as well,
as it shows 89% of oil uptake and improved ~17 times of oil selectivity in oil-water emulsion than untreated EFB fibers.
Natural rubber (NR) latex gloves are widely used as a very important barrier for healthcare workers. However, they
can still be perforated easily by sharp devices and instruments. The aim of this study was to investigate the effect of the
addition of graphene oxide (GO) to low-ammonia NR latex on its puncture resistance, mechanical properties and thermal
stability. GO was synthesized using modified Hummers’ reaction. The produced GO was mixed into the NR latex solution at
various doses (0.01-1.0 wt. %), followed by a coagulant dipping process using ceramic plates to produce film samples.
Puncture resistance was enhanced by 12% with 1.0 wt. % GO/NR. Also, the incorporation of GO improved the stress at
300% and 500%, the modulus at 300% and 500% and the tear strength of low-ammonia NR latex films.
A simple and green method was presented to embed TiO2 on regenerated cellulose membranes via cellulose dissolution-regeneration process. The physical, chemical and mechanical properties of the composite membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier- Transform Infrared (FTIR), ultraviolet (UV) - visible spectroscopy and tensile test. The results indicated that cotton linter has been converted from cellulose I to cellulose II after the regeneration process, while the TiO2 nanoparticles embedded inside the membrane maintaining its original crystal structures. The TiO2 composite membranes possessed high ability of water absorption with total pore volume ranged from 0.45±0.01 to 0.53±0.02 cm3/g. The elongation at break of the prepared membranes increased 29% averagely from dry state to wet state. The tensile strength of the membranes remained at a minimum value of 0.50±0.03 MPa in wet state thus enabled the films to withstand in wet for long period of time under weak UV irradiation. The regenerated cellulose membranes with TiO2 performed well in photocatalytic activity while exhibiting distinct absorption abilities. This study provides a potential application in energy-saving decomposition system in which the dye compound can be easily removed via two simultaneous pathways: Absorption and photocatalytic decomposition.
Magnetic paper were prepared via the in situ synthesis method with ferrites in the presence of polyethylenimine (PEI). In this work, the thermomechanical pulp (TMP) fibers were used due to low percentage of collapse lumen and the large lumen size for optimum loading degree. Four cycles of the reaction were performed on the TMP fibers with pH values of 4-10. It was found that variation of pH value played an important role in the loading degree of pulp during synthesis process. The magnetic, morphological and structural properties of the magnetic paper obtained were reported. At the
optimum pH of 6.0, saturation magnetization was found to be 3.08 emu/g, remainance magnetization was 0.11 emu/g and coercive force was 12.64 Oe. The optimum loading degree was found to be 23.25%.
Precipitated calcium carbonate fillers were loaded into the lumen of bleached mixed tropical hardwood pulp using polyethylenimine (PEI) and alum. Our results indicated that the addition of (PEI) increased the degree of loading of precipitated calcium carbonate (PCC) into the lumen of fibers. The degree of loading also increased with the addition of alum together with PEI. The mechanical strengths of the produced lumen loaded paper increased with the addition of PEI and alum. Meanwhile the mechanical strength without alum had slightly increased the mechanical strengths of the paper. Electron micrographs revealed that the PCC fillers were successfully loaded into the lumen of the fibers.
Liquefactions of kenaf core wood were carried out at different phenol-kenaf (P/k) ratios. Characterizations of kenaf core wood liquefied residue were carried out to measure the degree of liquefaction. This provides a new approach to understand some fundamental aspects of the liquefaction reaction. Functional groups on the raw kenaf core wood and liquefied residue were examined using Fourier transform infrared spectroscopy (FTIR). The crystallinity index of the kenaf wood liquefied residue, which represents crystallinity changes of the cellulose component after the liquefaction process, was studied using X-ray diffraction (XRD). The surface morphology of the wood residue was observed using scanning electron microscopy (SEM). The thermal behavior of the residues was analyzed using thermogravimetric analysis (TGA). Abroad peak around 3450-3400 cm-1 representing OH stretching in lignin start to disappear as P/K ratio increases. The results showed that the higher the P/K ratio the greater the liquefaction of the lignin component in the kenaf core wood. The crystallinity index (CrI) on the kenaf liquefied residues increased with the increase in P/K ratio. SEM images showed that the small fragments attached on the liquefied kenaf residue surface were gradually removed as the P/K ratio was increased from 1.5/1.0 to 2.5/1.0, which is mainly attributed to the greater chemical penetration toward reactive site of the kenaf fibres. Residue content decreased as the P/K ratio increased from 1.5/1.0 to 2.5/1.0. TGA results showed the increase of heat resistance in the residue as the P/K ratio was increased.
Hydrogels were produced from cellulose derived from kenaf core powder with weight average molecular weight of cellulose was 1.68 x 105 and was dissolved in NaOHlurea solvent at -13°C. To obtain the optimal dissolving parameters, different percentage of NaOH, urea and kenaf core cellulose was used to study the degree of dissolution and formation of hydrogel. From the results obtained, it was found that the ratio of 6% NaOHI4% urea and 2% cellulose produced a good hydrogel. uv-Vis spectroscopy and xRD analysis were performed to analyze the transparency and crystallinity index of the cellulose solution and hydrogel, respectively. It showed that the hydrogel with the highest degree of solubility gave highest transparency due to the reduction of cellulose crystallinity as a result of the dissolution process. XRD analysis results showed the crystallinity of cellulose from kenaf core decreased by 70% after dissolution and hydrogel formation. Samples with 4% urea possess highest water content of 73% and decreased with increasing urea content.