Performance of kapok fiber reinforced polyvinyl alcohol bicomposite by alkali treated

Raw Kapok (Ceiba pentandra) fibre was initially washed and dried before undergoes chemical treatment. Upon dried, the kapok fibre was bleached and delignified at room temperature, in an acidic solution containing 6% of sulphuric acid and 4% hydrogen peroxide to remove hemicellulose and wax. The treated kapok was filtered and washed thoroughly with distilled water and vacuum dried at 60 oC for 10 hours. Finally, the treated kapok was converted to alpha-cellulose (α-cellulose) by alkali treatment. In this step, treated kapok was immersed in 17.5% of sodium hydroxide solution for 30 minutes at a temperature of 50 oC to remove alkali-soluble components. The obtained α-cellulose, termed as alkali treated kapok fiber (AKTF) was filtered, washed thoroughly with distilled water until pH is neutral and vacuum dried at 60 oC for 10 hours. In this stage, a certain weight of ATKF (0%, 10%, 20%, 30%, and 40%) were mixed with a hot solution of PVA and dried at room temperature. In the mechanical test, ATKF – PVA biocomposite shows an increase in tensile strength and elastic modulus up to 30% content of kapok fibre but drop at 40% kapok loading. The result shows that both ATKF – PVA biocomposite film (30%) were having the highest mechanical properties among the others and was chosen for next characterizations. It is evidence in FTIR spectra that the composites indicate the formation of new hydrogen interaction between kapok fibre and PVA which might help to improve the mechanical properties. As for XRD analysis, the ATKF – PVA biocomposite film (30%) blend was found to be a heterogeneous as the peaks of diffractogram were overlap each other. This is supported by SEM micrograph in which ATKF – PVA biocomposite (30%) show a heterogeneous phase. Additionally, in the TGA data, ATKF – PVA biocomposite (30%) was founded less thermally stable than raw kapok and pure PVA is the least thermally stable among other samples

Optimization studies of microwave-induced co-pyrolysis of empty fruit bunches/waste truck tire using response surface methodology

The central composite design of RSM was utilised for the optimization of experimental conditions of microwave-assisted co-pyrolysis of empty fruit bunch (EFB) and waste truck-tire (TT) to maximise the co-pyrolysis oil and energy yield. The predicted maximum co-pyrolysis oil of 40.0 wt% and energy yield of 59.0% were obtained at the optimum conditions of 505 °C pyrolysis temperature, 65.0% of EFB ratio and 60.0 g of activated carbon loading. The reaction temperature and TT ratio in EFB feedstock were identified as the most significant variables that affect the oil and energy yield. A design of experiment was performed to determine the quality of liquid oil. The result indicates the co-pyrolysis oil (PO65) properties were significantly improved after adding TT to EFB biomass. Olefin-rich pyrolytic oil (39.0%) with high selectivity of D-limonene was produced (28.6%). While, the oxygenates and polyaromatics hydrocarbon were reduced to 9.9% and 7.4%, respectively. The energy recovery analysis shows that the optimised co-pyrolysis oil (PO65) was 20.0% higher as compared to the TT alone. In view of the improved yield and quality of co-pyrolysis oil (PO65), this work shows that co-pyrolysis of EFB/TT presents a viable method to produce diesel-like fuel using the microwave-assisted heating method

Acidity, Solubility and Chemical Utilization of Local Leucaena Leucocephala Stem Bark

Acidity, solubility and chemical properties of eleven years old of Leucaena leucocephala stem bark were investigated. The bark was peeled from the stem of tree and gentle washed in tap water to remove dirt before air-dried in the laboratory at room temperature (24 + 3°C) for 2-3 weeks. The bark was minced into coarse powder and grind to pass BS 250µm mesh sieve. After air-dried for several days, the samples were conducted to chemical analyses (ash content and pH value; solubility in 1%NaOH, hot and cold water solubility; extractive, cellulose and lignin content) based on ASTM standard methods. The results show that L. leucocephala stem bark considered as least acidic (pH value 6.04) and high ash content (15.76%). The solubility of bark components was higher in 1% NaOH (41.36%) compared to hot water (14.45%) and cold water (11.06%). Holocellulose and hemicellulose was 132.85% and 103.66%, respectively. Lignin was the major composition in L. leucocephala stem bark (38.4%) followed by cellulose (29.19%) and extractive (8.39%). This study indicated that the bark of L. leucocephala had less acidity. The high solubility of the bark potential as a carbohydrate resource, while the chemical component of the bark might influence rapid combustion during pyrolysis

Chemical functional groups of extractives, cellulose and lignin extracted from native Leucaena leucocephala bark

Bark from trees is considered a worthless raw material. However, this resource could be economically benefcial if utilized efciently due to its rich chemical compounds. In this study, an ethanol toluene-soluble extractive, alpha-cellulose and lignin obtained from Leucaena leucocephala bark were characterized to determine their chemical functional groups. Based on FTIR spectral analysis, the results indicated that the bands of the functional groups of the extractive from the original bark remain unchanged; however, the absorbance intensity was found to be weaker in the group frequency and fngerprint regions. Removal of extractive, pectin, hemicellulose and lignin from the bark indirectly increased the strong absorbance intensity of cellulose. Broad peaks of OH stretching found in all spectra were assigned to the presence of phenolic OH and aliphatic structures for extractive and aromatic structures of lignin. It was revealed that aromatic functional groups were mainly found in the extractive, while water, carbonyl and ether were the dominant groups in cellulose, and methyl, methylene, carbonyl and carboxyl groups were enriched in lignin

The effect of crystallization time and temperature on Hydrothermal Synthesis of Zeolite Nax from Bongawan Kaolin

Hydrothermally synthesised zeolite NaX was produced by using kaolin procured from Kg. Gading, Bongawan. The kaolin was treated using sodium hexametaphosphate and calcined at 800oC to form metakaolin. Treated kaolin and prepared metakaolin were characterized using X-ray Fluorescence (XRF) and X-ray Diffraction (XRD). Reaction mixture was obtained by mixing metakaolin, sodium hydroxide and sodium silicate. The reaction mixture underwent aging for 15 hours before they were crystallized at various crystallization times (0 - 48 hours) and temperatures (80 – 130oC). The effect of crystallization time and temperature was studied using SEM and XRD. Optimum time and temperature for the synthesis was found to be 8 hours at 100 oC, respectively

Mercerized natural Cellulose based-solid Polymer Electrolyte

Cellulosic materials derived from three different types of local wood samples (sawmill woods sawdust, Acacia mangium and belian (Euxideroxilon zwagery) were extracted at atmospheric pressure using organosolv method. In an initial stage, the wood samples were delignified using peroxyacetic acid pulping to remove lignin. Then the pulp was bleached in 0.01 M solution of sodium hydroxide (NaOH) with addition of 4% hydrogen peroxide of absolute dry pulp (ODP). Conversion to alpha-cellulose or mercerized cellulose was achieved by soaking bleached cellulosic materials in 17.5% solution of NaOH for 15 minutes at 25oC. The mercerized cellulose was thoroughly washed with large amount of distilled water until pH of the filtrate reached to natural, then vacuum dried at 60oC. From Scanning electron microscope (SEM) all mercerized woods cellulose were differ in microfibril size with high irregularity observed in sawmill sawdust. Formation of cellulose II was confirmed with X-Ray Diffraction (XRD) and Fourier transform infrared spectroscopy (Ft-IR) analysis. Preparation of solid polymer electrolyte (SPE) membrane was obtained by dissolving dry mercerized cellulose in molten 1 butyl-3-methylimidazolium chloride ([bmim]Cl) in the presence of lithium perchlorate (LiClO4) to produce a transparent solid gel film. All SPE membranes exhibit conductivity in the range of 3.6 x 10-6 to 5.7 x 10-5 Scm-1 at room temperature. It was also observed that the conductivity of the SPE is affected by the size of cellulose microfibril and type of extraction. It was then further characterized with SEM, XRD, FTIR and TGA

Chemical composition and potential uses of Leucaena leucocephala stem bark

Leucaena leucocephala stem bark that was eleven years old was studied for its chemical composition and usage. The samples were subjected to chemical analyses based on ASTM standard procedures after being air-dried for several days. The results found that the bark of L. leucocephala has a pH value of 6.04 and that the solubility of the bark in 1% NaOH alkali is the highest compared to the solubility in hot water (14.45%) and cold water (14.36%), while the chemical composition of the bark of L. leucocephala was ash (15.76%); extractives (8.39%); holocellulose (132.85%); hemicellulose (103.66%); cellulose (29.19%) and lignin (38.24%). Based on the findings, L. leucocephala bark was less acidic. When used as a source of carbohydrates, bark has a high solubility, and its chemical composition may have an impact on how quickly it burns when it is pyrolysed

Synthesis and mesomorphic properties of non-symmetric liquid crystalline dimers containing azobenzene groups

Four novel nonsymmetric dimers containing azobenzene mesogenic groups were synthesized. The nonsymmetric dimers compounds namely, ethyl 4-[(4-{4-(4-((4-nitrophenyl)diazenyl)phenoxy)alkyloxy}phenyl)diazenyl]benzoate were obtained from the alkylation of ethyl 4-[(4-(4-bromoalkyloxy)phenyl)diazenyl]benzoate with 4-[(4-nitrophenyl)diazenyl]phenol. The mesomorphic properties of the compounds were determined by DSC and polarizing optical microscopy. The first member of the series was nonliquid crystalline while all other homologues display nematic and smectic A phases. The trans-azobenzene groups of the dimers display a high-intensity –* transition at about 365nm and a low-intensity n–* transition at around 465 nm, therefore, photochromism can be achieved by the introduction of the azo linkage to the dimeric liquid crystalline molecules

Chemical surface modification of CNTs via three oxidative acid treatments

Carbon nanotubes are commonly used to create polymer-nanotube composite for various applications. To suffice the needs of the emerging interest in utilizing nanotube, a great concern in creating a stable dispersion of the nanotube in solvent emerged. There is a paramount need to enhance the adhesion between the polymer and carbon nanotube to give a homogenous and stable dispersion throughout the polymer matrix. Thus, oxidative acid treatments are often chosen to chemically functionalize carbon nanotube in order to give such dispersing ability to the nanomaterials. In this study, purified multi-walled carbon nanotubes (MWCNTs) is oxidized under the influence of three types of oxidants i) hydrogen peroxide, ii) citric acid monohydrate and iii) mixture of 3:1 sulphuric and nitric acid. All the MWCNTs suspensions ultrasonicated for 8 hours to create opening defects on the MWCNTs to allow the surface modification to occur. In this comparative study of chemically surface modification using oxidative acid treatments, FTIR was used to examine the formation of -OH, -COOH and -C=O groups on the surface of the MWCNTs, TGA and XRD used to determine the thermal behaviour and the crystal structure studies of the modified MWCNTs respectively