Natural fibre is known useful in many applications however, the existing fibre treatment method able to reduce its overall properties. In this study, a new, simple and cost-effective fibre coating treatment method was developed which was able to improve the physical and morphological properties that open a new path for natural based materials to be used in a more robust application. The physical and morphological properties of various coated kenaf fibres were analysed to comprehend the cutting behaviour of coated fibres after subjected to the pulverisation process. The kenaf fibres were individually immersed in 1:4, 1:5 and 1:6 epoxy to acetone coating solutions prior cured, and pulverised consecutively using 5 mm, 1 mm, 0.5 mm and 0.25 mm mesh sizes aperture. The morphological characteristic was analysed using polarised optical and scanning electron microscope. The result showed that 1:6 coating ratio solution able to effectively coat the fibres’ aspect ratio that forming individual coated fibre which in long length pulverised fibres. Moreover, the low viscous 1:6 solution able to penetrate inside fibre structure that supported by density and fibre crosssection analysis compare to the other solutions. In future, this analysis is crucial to give insight on the coated fibres behaviour after subjected to the mechanical means of cutting process that later relates to the reinforcing mechanism in the composite samples.
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.
Proses pencecairan lignin soda telah dilakukan dengan menggunakan fenol dengan nisbah 1:3. Proses dilakukan selama 90 minit pada suhu 130oC dalam keadaan refluk. Hasil pencecairan iaitu pemfenolan lignin (PL) telah dianalisis dengan Spektrometer Inframerah Transformasi Fourier (FTIR), reometer dan analisis termogravimetri (TGA). Sampel yang disintesis dengan menggunakan asid hidroklorik sebagai mangkin memberikan keputusan yang terbaik. Analisis FTIR menunjukkan kehadiran kumpulan berfungsi yang signifikan seperti gelang aromatik, alkohol dan karbonil. Kesemua sampel PL mematuhi persamaan Arhenius dan bersifat pseudo-plastik. Peratus kehilangan berat sampel dan kadar penguraian sampel PL dipengaruhi oleh jenis mangkin yang digunakan. Sampel PL yang disintesis dikelaskan sebagai biopolimer resin fenolik.
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.
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.
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.
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.
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.
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.
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.
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.
Solvolysis liquefaction of soda lignin in the presence of various transition metal sulfide catalysts was studied to investigate the catalyst effects on the oil and gas yields, conversion rate and higher heating value (HHV) of oil. Nanosized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesized via a simple hydrothermal method under reaction temperature 200°C for 90 min. The addition of transition metal sulfide based catalysts (CuS, MoS2 and FeS2) enhanced both production of the oils and gas and the higher heating value (HHV) of oil products. A high oil and gas yields of 82.1% and 2890 cm3 was obtained with MoS2 at 250°C for 60 min. Elemental analyses for the oils revealed that the liquid products have much higher heating values than the crude soda lignin powder.
The liquefaction of oil palm empty fruit bunch (EFB) in phenol was carried out in the presence of sulfuric acid as a catalyst in the reflux condenser system. The effect of initial phenol input and EFB on liquefaction reaction was investigated by measuring the reaction yield, EFB residue and combined phenol. The initial ratio of phenol to EFB has the greatest influence on the residue and reaction yield. The liquefaction products consist of some liquid by products with high amount of OH groups. The amount of this byproduct is 0.5 time of the solid product (phenolic resin).
The functionalization of surface charges on oil palm empty fruit bunch (EFB) fibers was modified by grafted carboxylic
acid and polymer amine groups. Single and binary adsorption of Cu(II), Ni(II), Mo(VI) and As(V) were investigated
by competitiveness in the adsorbents. The mechanism of each metal ion was deliberately studied on kinetics-diffusion
(intraparticle diffusion) and isotherm adsorption models (Langmuir and Freundlich). Competitiveness of metal ions was
found in the selectivity of Cu(II) > Ni(II) and Mo(VI) > As(V) in the binary solution. The regeneration of adsorbents
was performed up to five cycles of an adsorption/desorption process and the reduction of adsorption performance was
less than 14.5%. Therefore, this promises low-cost adsorbents for metal ion uptake, showing potential for removal and
recovery in industrial wastewater treatment.
Nano sized copper sulfide, iron sulfide and molybdenum sulfide were successfully synthesised via a simple hydrothermal method. Sodium thiosulfate pentahydrate (Na2S2O3×5H2O) and hydroxylamine sulfate ((H3NO)2×H2SO4) were used as the starting materials and reacted with the transition metal source at 200oC for 90 min. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and Fourier transform infrared spectroscopy (FTIR). Spherical shape CuS and FeS2 nanoparticles with high crystallinity were successfully produced. The transmission electron micrographs revealed the well-dispersibility of the produced nanoparticles. Scanning electron micrograph showed the MoS2 nanoparticles possessed a spherical shape with sheet-like structure covering on the outer surface of the particles.
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.
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.
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.
This paper reports on the preparation of magnetic lumen loaded handsheets from bleached and unbleached mixed tropical hardwood kraft pulps. The lumen coating technique is a physical approach whereby fillers were deposited inside the fibre lumen. In order to produce magnetically responsive fibres, magnetic fillers were loaded into the fibre lumen. The magnetic filler chosen was magnetite which is usually used to make mylar as found in a diskette. Low and high molecular weights of polyacrylamide (PAM) were used as retention aids. The effect of different molecular weight of PAM on filler content in the bleached and unbleached handsheets were studied. The results showed that the amount of fillers deposited in the pulp fibres increased with increasing molecular weight of PAM using both pulps. However the bleached pulps gave better lumen loading than the unbleached when using high molecular weight of PAM.
The mechanical strength of magnetic lumen loaded handsheets was reported to be lower than the unloaded handsheets. This effect is due to the deposition of filler inside the fiber lumen and some on the fibre surface which interfere with the fibre to fibre bonding. Hence, in order to improve the handsheets strength, cationic starch is used as a dry strength additive. In this study, mixed tropical hardwood pulps were used throughout the experiment. The magnetite particles were deposited in the fibre lumen via the lumen loading technique. The addition of cationic starch was found to increase the handsheet strength. However, it disturbed and influenced the location and distribution of the magnetic fillers. Some of the magnetite particles were observed to be displaced from the fiber lumen and pit apertures. The charges of the filler particles and cationic starch played an important role in producing charge repulsion and pulling effect which lead to filler dislocation.