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The effect of irradiation on the tensile properties of oil palm empty fruit bunch (OPEFB) fiber reinforced poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blend using HAAKE Rheomixer at 150 °C. The composites were then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 100 kGy in air and room temperature. The tensile strength, Young’s modulus, elongation at break and gel fraction of the composites were measured. Comparative studies were also made by using poly(methyl acrylate) grafted OPEFB fiber in the similar blend system. An increase in tensile strength, Young’s modulus and gel fraction, with a concurrent reduction in the elongation at break (Eb) of the PVC/ENR/OPEFB composites were observed upon electron beam irradiation. Studies revealed that grafting of the OPEFB fiber with methyl acrylate did not cause appreciable effect to the tensile properties and gel fraction of the composites upon irradiation. The morphology of fractured surfaces of the composites, examined by a scanning electron microscope showed an improvement in the adhesion between the fiber and the matrix was achieved upon grafting of the fiber with methyl acrylate.

Polyurethane/clay nanocomposites have been synthesised from renewable sources. A polyether polyol was obtained by a method involving the synthesis of palm oil-based oleic acid from glycerol. This was then used in the production of a polyurethane by reaction with an isocyanate. Dodecylbenzene sulfonic acid (DBSA) was used as catalyst and emulsifier. The unmodified clay (kunipia-F) was treated with cetyltrimethyl ammonium bromide (to form “CTAB-mont”) and octadodecylamine (to form “ODA-mont”). The d-spacing in CTAB-mont and ODA-mont were 1.571 nm and 1.798 nm respectively, i.e. larger than that of the original “pure-mont” (1.142 nm). The organoclay was intercalated in the polyurethane, as confirmed by a wide angle x-ray diffraction (WAXD) pattern. The mechanical properties (including the dynamic mechanical properties) of pure polyurethane (PU) and PU/clay nanocomposites were measured. The results indicate that 1–5 wt.% of organoclay gave the most significant improvements in tensile properties and in glass transition temperature.

Effect of electron beam irradiation on the thermal and mechanical properties of poly(ethylene-co-vinyl acetate) (EVA)/clay nanocomposites prepared by melt blending method has been investigated. The hot set test results show that elongation at high temperature under static load decreased with the increase of irradiation dose. The tensile modulus increased continuously with increasing dose. While the tensile strength increased up to 100 kGy, it decreased with further increase in dose. The elongation at break decreased continuously with increasing dose. Thermogravimetric analysis showed that thermal stability of the EVA/clay nanocomposites improved with increasing dose. The improvement in the mechanical and thermal properties is attributed to the formation of radiation-induced crosslinking as evidenced by the gel content results.

Graft copolymerization of methyl acrylate (MA) onto OPEFB fiber has been successfully carried out using hydrogen peroxide and ferrous ammonium sulfate as initiators in an aqueous medium. The effects of reaction temperature, reaction period, and amount of monomer and initiators on the percentage of grafting were investigated. The results show that the percentage of grafting depends on reaction period and temperature as well as concentration of monomers and initiators. With 33.36 mmol of MA, the optimum percentage of grafting was obtained when the reaction was carried out using 6.00 mmol of H2O2 and 0.191 mmol of Fe2+ for 210 min at 75°C. The presence of the functional group in the grafted polymers was characterized by FTIR spectroscopy. Scanning electron microscopy was used to study the surface morphology. Thermogravimetric analysis indicated that the grafted OPEFB is thermally stable than the OPEFB

Fatty hydroxamic acid (FHA) immobilized in polyvinyl chloride (PVC) has been studied as a sensor element of an optical fibre chemical sensor for V(V). By using this instrument, V(V) in solution has been determined in the log concentration range of 0-2.5 (i.e. 1.0-300 mg/L). The detection limit was 1.0 mg/L. The relative standard deviation (R.S.D.) of the method for the reproducibility study at V(V) concentration of 200 mg/L and 300 mg/L were calculated to be 2.9% and 2.0%, respectively. Interference from foreign ions was also studied at 1:1 mole ratio of V(V):foreign ions. It was found that, Fe(III) ion interfered most in the determination of vanadium(V). Excellent agreement with ICP-AES method was achieved when the proposed method was applied towards determination of V(V).

Sorption conditions of arsenate ions onto Sn-loaded poly (hydroxamic acid) chelating resin (Sn-PHA) have been studied. Sorption isotherms data correlated well to the Langmuir model with maximum capacity of 38.46 mg g-1 at pH 2. Sorption process follows pseudo-second order kinetics. Intraparticle diffusion was found to take part in sorption processes. The free energy (E) was 11.18 kJ mol-1 which shows the sorption is an ion-exchange process. Thermodynamic parameters, ΔH°, ΔS° and ΔG° were also calculated from the experimental data. Standard heat of sorption was found to be endothermic and entropy change value was calculated to be positive. Negative ΔG° value indicates that the sorption process for the arsenic anions onto Sn-PHA is spontaneous.

Effects of modifying oil palm mesocarp fibers (OPMF) by methacrylate silane on polylactic acid (PLA)/ polycaprolactone (PCL)/clay/OPMF hybrid composites were investigated. The composites were prepared by a melt blending technique and characterized by dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The silane-treated OPMF hybrid composites showed better tensile strength, tensile modulus, and elongation at break than unmodified OPMF hybrid composites. DMA analysis showed an increase in storage modulus when silane-treated OPMF was added to a hybrid composite. The loss modulus curve showed that the incorporation of silane-treated OPMF into a hybrid composite shifted the two glass transition temperatures (Tg) of composites closer to each other. The low tan δ peak indicated good fiber/matrix adhesion for the silane-treated OPMF hybrid composites. SEM micrographs revealed that silane-treated OPMF hybrid composites showed better fiber/matrix adhesion than unmodified OPMF hybrid composites because of absence of gap between silane-treated OPMF and the matrix in the composite.

Layered double hydroxides (LDHs) has attracted much attention of many industrialists as well as academicians as these materials can be used as catalysts, adsorbents, anion exchangers, stabilizers and fillers for polymers. The materials which consist of divalent and trivalent cations, and anions are nontoxic and easy to prepare. In addition, the exchangeability of their anions makes them easy to be modified to increase their hydrophobicity property through anion exchange process using long chain surfactant anions. In this study, sodium lauryl ether sulphate (SLES) modified LDHs was prepared by co precipitation of LDHs and followed SLES ions modification via ion exchange process. Intercalations of the anions into the LDHs layers were confirmed by X-ray diffraction analysis. The presence of functional groups before and after modification was studied by FTIR spectrometry. Thermalgravitmeric analysis also was carried out to determine the amount of surfactant intercalated into LDHs.

This study investigates the adsorption of Reactive Blue 19 using dewatered alum sludge. The dewatered alum sludge was a sludge produced from drinking water treatment plant. Batch adsorption experiments were performed to investigate the mechanism of the dye adsorption. The adsorption was rapid at its initial stage but the rate decreased as it approached equilibrium. The adsorption data were evaluated by Langmuir and Freundlich isotherm models but was best described by the Langmuir isotherm model as it gave the highest correlation.

Agricultural wastes such as orange peels, tea leave waste, rice husk and corn cobs have been widely studied as sorbents for heavy metal ion removal from various wastewaters. In order to understand their sorption mechanism, the adsorption kinetics is studied. This report describes the kinetics study of a thermally treated rice husk to adsorb Zn (II) ion from an aqueous solution. The adsorbent was obtained by heating the rice husk in a furnace at 500°C for two hours. Increase the contact period improved percentage of the removal of Zn (II) ion until an equilibrium was reached. The data obtained showed that the adsorption of Zn (II) ion by thermally treated rice husk obeyed pseudo-second order kinetics model, which is in agreement with chemisorption as the rate limiting mechanism.

Polyurethanes (PUs) are very versatile polymeric materials with a wide range of physical and chemical properties. PUs also have desirable properties, such as high abrasion resistance, tear strength, shock absorption, flexibility, and elasticity. Although they have poor thermal stability, it can be improved by using treated clay. The objective of the present work is to study the thermal stability of polyurethane, polyurethane/montmorillonite (PU CTAB-mont 3% wt), and polyurethane/montmorillonite containing moca (PU Moca CTAB-mont 3% wt) nanocomposites based on palm oil polyol. The interest of investigating the synthesis of polyurethane/clay nanocomposites based on palm oil polyol is to explore the use of palm oil polyol to partially replace petrochemical-based polyol. Polyurethane/clay nanocomposites were prepared by a pre-polymer method and evaluated by Fourier Transform Infrared Spectra (FTIR) to determine micro-domain structures of segmented PU, PU CTAB-mont 3% wt, and PU Moca CTAB-mont 3% wt. The morph...

Natural rubber (NR)/poly(ethylene-co-vinyl acetate) (EVA) blend–clay nanocomposites were prepared and characterized. The blend nanocomposites were prepared through the melt mixing of NR/EVA in a ratio of 40/60 with various amounts of organoclay with an internal mixer followed by compression molding. X-ray diffraction patterns revealed that the nanocomposites formed were intercalated. The formation of the intercalated nanocomposites was also indicated by transmission electron microscopy. Scanning electron microscopy, used to study the fractured surface morphology, showed that the distribution of the organoclay in the polymer matrix was homogeneous. The tensile modulus of the nanocomposites increased with an increase in the organoclay content. However, an increase in the organoclay content up to 5 phr did not affect the tensile strength, but the organoclay reduced this property when it was increased further. This study also indicated that a low silicate content dispersed in the blend matrix was capable of increasing the storage modulus of the material. The addition of the organoclay also increased the decomposition temperature of the NR/EVA blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 353–362, 2006

A mixture of fatty hydroxamic acids (FHA), synthesized from a commercial palm olein, was evaluated as an extractant for extraction of copper ion from aqueous media. The content of hydroxamic acid groups in the FHA, analyzed by elemental analysis, was 3.52 mmol/g. Copper extraction from aqueous media was studied by solvent extraction technique using octanol as an organic phase. The extraction of copper ion was through the formation of 1∶2 (Cu(II)∶FHA) complex, pH dependent and not affected by the presence of a large amount of Co(II), Ni(II), Cd(II) and Zn(II) ions.

Grafting of acrylamide (AAm) onto oil palm empty fruits bunch fiber using hydrogen peroxide as initiator and methyl acrylate as comonomer was investigated. The amount of comonomer needed to make grafting of acrylamide possible was determined. The percentage of poly(acrylamide) and the comonomer in the final graft copolymer was estimated by elemental analysis. Results obtained indicated that methyl acrylate facilitated the incorporation of acrylamide monomer onto OPEFB. The reactivity ratios for both monomers were determined by using Fineman–Ross plot. The effects of reaction temperature and period as well as amount of the initiator, solvent, monomer and comonomer on the percentage of grafting at fixed amount of comonomer (11 mmol) were studied. Maximum percentage of grafting was achieved when the amount of initiator and solvent 3.98×10−3 mol and 50 mL respectively. The optimum reaction temperature was 50 ○C and the reaction period was 90 min. Highest percentage of grafting was 232% when 25.6 mmol of acrylamide was used under these optimum conditions. The presence of functional group in the grafted polymer is characterized by infrared spectroscopy and the surface morphology is observed by scanning electron microscopy. Thermoanalytic investigation on OPEFB and OPEFB-g-PAAM were carried out to evaluate the thermal stability and respective activation energy of the materials.

Radiation crosslinking of natural rubber (NR)/clay nanocomposites was studied by using Standard Malaysian Rubber (SMRL) grade natural rubber and sodium montmorillonite (Na-MMT) clay that had been modified with cationic surfactants, dodecyl ammonium chloride (DDA) and octadecylamine ammonium chloride (ODA). The NR/clay nanocomposites were prepared by melt mixing to produce NR/Na-MMT, NR/DDA-MMT and NR/ODA-MMT composites. X-ray diffraction results indicated the intercalation of the NR into silicate nano-size inter-layers for NR/DDA-MMT and NR/ODA-MMT nanocomposites. An optimum electron beam dose of 250 kGy for crosslinking of NR, NR/DDA-MMT and NR/ODA-MMT was determined by gel content and tensile strength measurements. Upon electron beam irradiation, the tensile modulus of the nanocomposites keeps increasing with the increase of clay content up to 10 phr. However, the tensile strength and gel content of the nanocomposites show optimum values at a range of 3.0–5.0 phr clay content. From these results, NR/DDA-MMT shows higher tensile strength, whereas NR/ODA-MMT exhibits higher tensile modulus. The optimum tensile strengths of NR/DDA-MMT and NR/ODA-MMT are 12.1 and 9.5 MPa, respectively. TGA studies showed that NR/DDA-MMT and NR/ODA-MMT nanocomposites have higher decomposition temperatures in comparison with the NR/Na-MMT.

Fatty hydroxamic acids (FHA) have been successfully synthesized from palm oils by a one-step lipase catalyzed reaction. The use of immobilized lipase as the catalyst for the preparation reaction provides an easy isolation of the enzyme from the products and other components in the reaction mixture. In addition, it also allows the reaction to be carried out under mild conditions, which reduces the reaction’s side products. The percentages of conversion of commercial palm olein (CPOn), RBD (refined, bleached and deodorized) palm olein (POn), RBD palm oil (PO), RBD palm stearin (PS) and RBD palm kernel olein (PKOn) into their fatty hydroxamic acids are 89, 79, 77, 90 and 98, respectively.

Graft copolymerization of poly(methyl acrylate) (PMA) onto rubberwood fiber (RWF) was carried out by free radical initiation. Hydrogen peroxide and ferrous ions were used as an initiator system. Effects of various parameters (reaction temperature and reaction time, as well as hydrogen peroxide, ferrous ammonium sulfate and monomer concentrations) on the grafting percentage were investigated. A high percentage of grafting was achieved when optimum reaction conditions were used. The optimum temperature of the reaction was determined to be about 55 °C and the reaction time was 120 min. The optimum concentration of H2O2 was 0.03 M and the amounts of Fe2+ and MA were 0.4 mmol and 0.05 mol, respectively. The PMA homopolymer was removed from the graft copolymer by Soxhlet extraction using acetone. The presence of PMA on the fiber was confirmed by FT-IR spectroscopy and gravimetry. The surface morphology of the poly(methyl acrylate)-graft-(rubberwood fiber) was studied by means of scanning electron microscopy. Copyright © 2004 Society of Chemical Industry

This study was carried out to determine the suitability of sago starch as a paper additive. The basic properties (i.e., pH, viscosity, and solid content) of the 5% weight over volume basis of unmodified and modified sago starch (sago starch blended with acrylamide, sago starch grafted with acrylamide in an acidic and adjusted to alkaline conditions) were determined. The starches were then used to coat laboratory handsheets made from recycled pulp fibers. The incorporation of acrylamide into sago starch through grafting significantly reduced the viscosity of the solution. Generally, coating the handsheets with unmodified sago starch significantly improved some properties as compared to the uncoated handsheets. Among the three types of sago starch modification methods, blending gave superior performance when coated on the handsheets, except for smoothness and air permeance, due to insufficient curing shown by the micrographs. FTIR spectra showed that the interactions between the blended acrylamide–starch solutions and the pulp fiber were weak. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 154–158, 2004

Glycerol residue, a by-product of glycerol refining from a palm kernel oil methyl ester plant, was found to be a good source of glycerol and medium chain fatty acids. From analyses of twelve samples, it was found to contain, on average, 20.2 % glycerol and 6.6 % fatty acids. The fatty acids comprised mainly C8:0 (30.3 %), C10:0 (9.4 %) and C12:0 (40.8 %).

In this article, the graft copolymerization of methyl methacrylate (MMA) onto sago starch (AGU) was carried out in aqueous medium using potassium persulfate (PPS) under nitrogen gas atmosphere. The maximum percentage of grafting achieved was 90% under optimized conditions of reaction temperature, monomer, PPS, AGU, and reaction period corresponding to 50°C, 47 mmol, 1.82 mmol, 6.17 × 10−3 mol L−1, and 1.5 h, respectively. The grafting of MMA onto sago starch was confirmed by the differences in infrared spectroscopy. The viscosity measurement and the average molecular weight determination were estimated using Huggin's and Mark Houwink's equations, respectively. This material may have application as a biodegradable plastic. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1891–1897, 2004

Graft copolymerization of methyl methacrylate (MMA) onto oil palm empty fruit bunch fiber (OPEFB) was successfully carried out in aqueous medium using hydrogen peroxide as an initiator. Results from the investigation of the optimum conditions for grafting are presented. Maximum percentage of grafting was achieved when the amount of initiator, cocatalyst, and nitric acid were 5.877 × 10−3 mol, 2.63 × 10−4 mol, and 3.24 × 10−3 mol, respectively. The optimum reaction temperature was 50°C and the reaction period was 120 min. The highest percentage of grafting and grafting efficiency were 220 and 47%, respectively, under optimum conditions. The grafted copolymer was characterized by FTIR spectroscopy and scanning electron microscopy. The presence of a band at 1730 cm−1 provides strong evidence of grafting. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2233–2238, 2003

Methyl methacrylate (MMA) was successfully grafted onto rubber-wood fiber in a free-radical solution polymerization initiated by ferrous ion and hydrogen peroxide. The effects of the reaction parameters (reaction temperature, reaction period, influence of hydrogen peroxide, ferrous ammonium sulfate, and monomer concentrations) were investigated. The grafting percentage showed dependency on H2O2, Fe2+, and monomer concentrations, as well as reaction temperature and reaction period. The optimum reaction temperature was determined to be about 60°C and the reaction period was 60 min. The optimum concentration of H2O2 was 0.03M and optimum amounts of Fe2+ and MMA were 0.26 mmol and 2.36 × 10−2 mol, respectively. Poly(methyl methacrylate) (PMMA) homopolymer was removed from the graft copolymer by Soxhlet extractor using acetone. The presence of PMMA on the fiber was shown by FT-IR spectroscopy and gravimetric analysis. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2499–2503, 2003

The photobleaching of Methylene blue embedded in the solid matrix PMMA (poly(methylmethacrylate)), PVA (poly(vinyl alcohol)) and gelatin has been investigated using a photoacoustic technique. Photoacoustic signals were measured as a function of time, chopping frequency, and the beam power. Experimental results indicate that the photobleaching rate is proportional to the incident laser power (260–300 mW) and decreased with increasing the concentration of dopant molecules. Methylene blue embedded in PVA shows the highest photobleaching rate then followed by gelatin and PMMA. The increase of photobleaching rate in PVA is also noticed when the beam power is increased. The thermal diffusivity values obtained for bleached PMMA, PVA and gelatin are 1.46 × 10-3 cm2/s , 0.83 × 10-3, cm2/s and 1.10 × 10-3 cm2/s respectively. Spectrophotometer and Raman spectroscopy were used to confirm the photoacoustic results.

Preparation of poly(butyl acrylate)-grafted oil palm empty fruit bunch fibre (OPEFB) has been successfully carried out using H2O2/Fe2+ as a redox initiator in aqueous solution. The effects of reaction temperature and period, as well as the amount of monomer, initiator and nitric acid, on the percentage of grafting were investigated. The percentage of grafting increases with amount of monomer and can be controlled by setting the appropriate reaction conditions. The maximum percentage of grafting (about 265%) was obtained when the reaction was carried out without acid under optimum conditions (reaction period: 2 h, reaction temperature: 55 °C, amount of H2O2: 5.88 mmol) with 42.2 mmol of monomer. Mechanisms of grafting of butyl acrylate onto OPEFB were proposed. Characterization of the grafted OPEFB was done by Fourier-transform infrared spectroscopy and scanning electron microscopy. The thermal properties were studied by thermogravimetric analysis. Copyright © 2003 Society of Chemical Industry

Polystyrene grafting onto sago starch was carried out by using ceric ammonium nitrate as a redox initiator. The grafted copolymers were characterized by FTIR, thermogravimetry (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). FTIR spectra analysis of the grafted chain and commercial polystyrene was identical, indicating that styrene was successfully grafted onto sago starch. TGA thermograms and analysis of DSC curves showed that the thermal stability of starch increases as a result of grafting. SEM micrographs showed the deformed prolate ellipsoidal shape of sago starch particles and this shape disappeared in polystyrene grafted sago starch being replaced with a spongy surface with pores. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2053–2058, 2003

Syntheses of novel liquid-crystalline polymers containing azobenzene moieties were performed by a convenient route with an acrylate backbone. The azobenzenes were key intermediates of the monomers, and side-chain liquid-crystalline polymers were prepared, that is, poly[α-{4-[(4-acetylphenyl)azo]phenoxy}alkyloxy]acrylates, for which the spacer length was 3 or 11 methylene units. In addition, poly[3-{4-[(3,5-dimethylphenyl)azo]phenoxy}propyloxy]acrylate was prepared with a spacer length of 3 methylene units. The structures of the precursors, monomers, and polymers were characterized with Fourier transform infrared, 1H-NMR, and 13C-NMR techniques. The polymers were obtained by conventional free-radical polymerization with 2,2′-azobisisobutyronitrile as an initiator. The phase-transition temperatures of the polymers were studied with differential scanning calorimetry, and the phase structures were evaluated with a polarizing optical microscopy technique. The results showed that two of the monomers and their corresponding polymers exhibited nematic liquid-crystalline behavior, and one of the monomers and its corresponding polymer showed smectic liquid-crystalline behavior. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2653–2661, 2002

Plasticized poly(lactic acid) (PLA)‐based nanocomposites filled with graphene nanoplatelets (xGnP) and containing poly(ethylene glycol) (PEG) and epoxidized palm oil (EPO) with ratio 2 : 1 (2P : 1E) as hybrid plasticizer were prepared by melt blending method. The key objective is to take advantage of plasticization to increase the material ductility while preserving valuable stiffness, strength, and toughness via addition of xGnP. The tensile modulus of PLA/2P : 1E/0.1 wt % xGnP was substantially improved (30%) with strength and elasticity maintained, as compared to plasticized PLA. TGA analysis revealed that the xGnP was capable of acting as barrier to reduce thermal diffusion across the plasticized PLA matrix, and thus enhanced thermal stability of the plasticized PLA. Incorporation of xGnP also enhanced antimicrobial activity of nanocomposites toward Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Listeria monocytogenes.

In this work, surface modifications of oil palm mesocarp fiber were carried out by using superheated steam, alkali, and consecutive superheated steam-alkali treatments, aiming at modification of fiber’s surface for biocomposite applications. The chemical compositions of fiber were modified after treatments as validated by chemical analysis and Fourier transform infrared spectroscopy. The treated fibers under microscopy observation showed relatively clean, rough, and textured surfaces due to the elimination of impurities and hemicellulose. The crystallinity index and thermal stability of treated fibers were relatively higher than that of untreated fiber as determined by X-ray diffraction and thermogravimetric analyses, respectively. A reduction in water absorption of fiber after treatments was also noted. These results indicated those treatments were effective in modifying the chemical compositions and microstructure of fiber. The treatments also increased the crystallinity and thermal stability, as well as reduced the hygroscopicity of fiber. Those treatments could increase the suitability of fiber to be used in the development of biocomposites.

The graft copolymerization of methyl methacrylate (MMA) onto sago starch was carried out in aqueous media by different initiators of ceric ammonium nitrate (CAN) and potassium persulfate (PPS) and under a nitrogen gas atmosphere. Using CAN as an initiator, the maximum percentage of grafting (%G) was ascertained to be 246% at the following optimum conditions: a 70°C reaction temperature, a 2-h reaction period, 2.0 mmol of CAN, 0.4 mmol of nitric acid, and 141 mmol of MMA. The maximum %G achieved with PPS as the initiator was 90%. The optimum conditions were a 50°C reaction temperature, a 1.5-h reaction period, 47 mmol of monomer, and 1.82 mmol of PPS. The grafting of MMA onto sago starch was confirmed by the IR spectra of pure sago starch, MMA, and MMA grafted sago starch. This material may have application as a biodegradable plastic. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1375–1381, 2001

Poly(methyl acrylate) (PMA) grafted sago starch was prepared from the reaction between methyl acrylate and sago starch by free radical initiating process in which ceric ammonium nitrate (CAN) was used as an initiator. The common procedure was used to prepare a new polymer containing hydroxamic acid functional group from PMA grafted sago starch and hydroxylamine under alkaline solution. The PMA grafted sago starch and poly(hydroxamic acid) was characterized by FT-IR spectroscopy. The water absorbency or swelling of the poly (hydroxamic acid) absorbent was measured as a function of different sago starch concentration in absorbent. It was observed that the swelling in distilled water and various salt solutions increases with decreasing sago starch concentration. The maximum absorbency in water was 192 g water g−1 at 31% sago starch content in absorbent. The absorbency in the various salt solutions decreases with the increasing salt concentration in solution. At the same salt concentration in solution, the swelling has the following tendency: Na+>Ca2+>Fe3+.

The graft copolymerization was carried out by methyl acrylate with sago starch in which ceric ammonium nitrate was used as an initiator. It has been found that the rates of graft polymerization and grafting efficiency were dependent upon the concentration of ceric ammonium nitrate (CAN), methyl acrylate (MA), sago starch (AGU, anhydro glucose unit), mineral acid (H2SO4), and as well as reaction temperature and period. A rate equation of polymerization was established from the proposed reaction mechanism, and the rate of polymerization (Rp) was the first-order dependence of the MA monomer concentration and square root of the CAN concentration. A new kinetic model of the grafting reaction has been proposed, and a normal kinetics of methyl acrylate polymerization was observed. An equation of a predicted model relating the graft fraction of poly(methyl acrylate) with the sago starch has been derived, and validity of the predicted model was verified by the experimental results. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 784–791, 2000

A grafted material based on chitosan and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) has been successfully prepared in homogenous solution using potassium persulfate as a redox initiator. The grafted copolymer was precipitated during the reaction polymerization. The effects of the reaction temperature and chitosan–potassium persulfate contact time as well as concentrations of AMPS, potassium persulfate, and acetic acid on grafting yield were investigated. The percentage of grafting is gradually increased with the increasing of the AMPS concentration. The extent of grafting can be controlled by setting the appropriate reaction conditions. The maximum percentage of grafting was about 180% under the optimum conditions (1% v/v acetic acid, 50°C reaction temperature, 10 min chitosan–potassium persulfate mixing period, 0.37 mmol of potassium persulfate, and 28.96 mmol AMPS). The grafted chitosan was insoluble in the acid of the grafting. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2314–2318, 2000

A new chelating ion-exchange resin containing the hydroxamic acid functional group was synthesized from poly(methyl acrylate) (PMA)-grafted sago starch. The PMA grafted copolymer was obtained by a free-radical initiating process in which ceric ammonium nitrate was used as an initiator. Conversion of the ester groups of the PMA-grafted copolymer into hydroxamic acid was carried out by treatment of an ester with hydroxylamine in an alkaline solution. The characterization of the poly(hydroxamic acid) chelating resin was performed by FTIR spectroscopy, TG, and DSC analyses. The hydroxamic acid functional group was identified by infrared spectroscopy. The chelating behavior of the prepared resin toward some metal ions was investigated using a batch technique. The binding capacities of copper, iron, chromium, and nickel were excellent and the copper capacity was maximum (3.46 mmol g−1) at pH 6. The rate of exchange of the copper ion was very fast that is, t1/2 Fe3+ > Cr3+ > Ni2+ > Co2+ > Zn2+ > Cd2+ > As3+ > Pb2+. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1256–1264, 2001

Iron(III)-poly(hydroxamic acid) resin complex has been studied for its sorption abilities with respect to arsenate and arsenite anions from an aqueous solution. The complex was found effective in removing the arsenate anion in the pH range of 2.0 to 5.5. The maximum sorption capacity was found to be 1.15 mmol/g. The sorption selectivity showed that arsenate sorption was not affected by chloride, nitrate and sulphate. The resin was tested and found effective for removal of arsenic ions from industrial wastewater samples.

Lipase from Candida rugosa was chemically modified by reductive alkylation with aldehydes of various chain lengths. The derivatised lipases showed a higher esterification activity compared to native enzyme. The degree of activity enhancement depended on the type and molecular weight of the modifiers used and the degree of modification of the enzyme. They exhibited higher activities in non-polar than in polar solvents. The optimum esterification temperature and preference of fatty acids as acyl donors of the derivatised lipases were very similar to those of native enzyme. Lipase derivatised with dodecyldehyde was more thermostable than those modified with acetaldehyde. Alkylated lipases are relatively more stable in organic solvents than the native enzyme.

A mycelial lipase from Rhizopus rhizopodiformis was prepared in fragment form. The lipase was examined to catalyze the alcoholysis of palm oil mid-fraction (PMF) in organic solvents. High percentage conversions of PMF to alkyl esters were achieved when methanol or propanol was used as acyl acceptor. Of the two most prevalent fatty acids in PMF, palmitic acid seemed to be preferred over oleic acid in the formation of methyl and propyl esters. The optimal ratio of oil to methanol in the alcoholysis reaction is 1 to 2 moles. The lipase exhibited high alcoholysis activities in nonpolar solvents (log P>2), such as hexane, benzene, toluene, and heptane. The enzyme showed exceptionally high thermostability.

Preparation and characterization of novel polysulfone/zinc oxide (PSf/ZnO) mixed matrix membranes (MMMs) with different ZnO loadings for high selective CO2/CH4 separation were aimed in this study. Scanning electron microscopy photographs demonstrated that spongy and small tear like pores in plain PSf membrane (0 wt % of ZnO) replaced with large tear like pores close to surface layer by increasing ZnO content up to 0.1 and 1 wt %. In contrast, a dense and less free volume structure was obtained in membranes having 3 and 5 wt % of ZnO. Membrane porosity increased from 28.68 to 50.51% with increasing ZnO content from 0 to 1 wt %. Then, a reduction in porosity was observed for membranes containing 3 and 5 wt % of ZnO. Atomic force microscopy images presented variation in membrane surface roughness. Surface roughness decreased from 67.64 nm for plain PSf to 47.86 nm for membrane containing 1 wt % of ZnO. While, surface roughness increased and reached to 115.5 and 122.4 nm for MMMs having 3 and 5 wt % of ZnO. Gas separation properties of PSf/ZnO MMMs were examined and CO2/CH4 selectivity of MMMs containing 3 and 5 wt % of ZnO were 22.29 and 54.29, respectively, in 1 bar feed pressure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39745.

Polyhydroxybutyrate (PHB)/polycaprolactone (PCL)/stearate Mg-Al layered double hydroxide (LDH) nanocomposites were prepared via solution casting intercalation method. Coprecipitation method was used to prepare the anionic clay Mg-Al LDH from nitrate salt solution. Modification of nitrate anions by stearate anions between the LDH layers via ion exchange reaction. FTIR spectra showed the presence of carboxylic acid (COOH) group which indicates that stearate anions were successfully intercalated into the Mg-Al LDH. The formation of nanocomposites only involves physical interaction as there are no new functional groups or new bonding formed. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the mixtures of nanocomposites are intercalated and exfoliated types. XRD results showed increasing of basal spacing from 8.66 to 32.97 Å in modified stearate Mg-Al LDH, and TEM results revealed that the stearate Mg-Al LDH layers are homogeneously distributed in the PHB/PCL polymer blends matrix. Enhancement in 300% elongation at break and 66% tensile strength in the presence of 1.0 wt % of the stearate Mg-Al LDH as compare with PHB/PCL blends. Scanning electron microscopy (SEM) proved that clay improves compatibility between polymer matrix and the best ratio 80PHB/20PCL/1stearate Mg-Al LDH surface is well dispersed and stretched before it breaks.

Oil palm mesocarp fibers (OPMFs) are left as a waste material after oil extraction. A new application of OPMF is needed to economically utilize these fibers; thus OPMFs need to be modified to render them hydrophobic. Hydrogen peroxide was used to initiate the graft copolymerization of butyl acrylate onto OPMF in aqueous solution. The duration of reaction, temperature, and amounts of butyl acrylate and initiator were optimized using response surface methodology (RSM) coupled with a four-factor central composite design (CCD). The response variable was percentage grafting (%G). A quadratic model was obtained and developed to correlate the independent variables to %G. The optimum conditions predicted through RSM were 110 min duration of reaction, 50 °C temperature, 28 mmol of monomer, and 5.99 mmol of initiator, with a %G of 116.2%. Synthesized graft copolymers were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis. The thermal stability of OPMF improved significantly after grafting. The FTIR and SEM results showed that graft copolymerization successfully occurred onto the OPMF backbone. The tensile test results support the utilization of grafted OPMF as a potential compatibilizer.

Poly(lactic acid) PLA was plasticized with low molecular weight poly(ethylene glycol) PEG-200 to improve the ductility of PLA, while maintaining the plasticizer content at maximum 10 wt%. Low molecular weight of PEG enables increased miscibility with PLA and more efficient reduction of glass transition temperature (Tg). This effect is enhanced not only by the low molecular weight but also by its higher content. The tensile properties demonstrated that the addition of PEG-200 to PLA led to an increase of elongation at break (>7000%), but a decrease of both tensile strength and tensile modulus. The plasticization of the PLA with PEG-200 effectively lowers Tg as well as cold-crystallization temperature, increasing with plasticizer content. SEM micrographs reveal plastic deformation and few long threads of a deformed material are discernible on the fracture surface. The use of low molecular weight PEG-200 reduces the intermolecular force and increases the mobility of the polymeric chains, thereby improving the flexibility and plastic deformation of PLA.

The effects of hydrophilic nanoclay, Nanomer PGV, on mechanical properties of Polylactic Acid (PLA)/Polycaprolactone (PCL) blends were investigated and compared with hydrophobic clay, Montmorillonite K10. The PLA/PCL/clay composites were prepared by melt intercalation technique and the composites were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). FTIR spectra indicated that formation of hydrogen bond between hydrophilic clay with the matrix. XRD results show that shifting of basal spacing when clay incorporated into polymer matrix. TEM micrographs reveal the formation of agglomerate in the composites. Based on mechanical properties results, addition of clay Nanomer PGV significantly enhances the flexibility of PLA/PCL blends about 136.26%. TGA showed that the presence of clay improve thermal stability of blends. DMA show the addition of clay increase storage modulus and the presence of clay Nanomer PGV slightly shift two Tg of blends become closer suggest that the presence of clay slightly compatibilizer the PLA/PCL blends. SEM micrographs revealed that presence of Nanomer PGV in blends influence the miscibility of the blends. The PLA/PCL blends become more homogeneous and consist of single phase morphology.

Lipase from Candida rugosa was immobilized on three different supports, i.e. Amberlite XAD7, poly(methylmethacrylate) (PMMA) and celite. With the conditions tested, maximum adsorption can be achieved after 30 min. The activities of the immobilized lipases were determined by the esterification reaction of oleic acid and butanol. The immobilized lipases were found to be very effective in the esterification reaction. The immobilized activities generally were high in apolar organic solvents with log P values from 2·0 to 4·0. The preference for fatty acids as acyl donors differed in all cases of immobilized lipases. Lipase immobilized on XAD7 and PMMA exhibited high preference of acyl donors (fatty acids) with chain lengths 12–18 and 8–18, respectively. Lipase immobilized on celite, however, showed high activity in all cases of fatty acids. The nucleophile (alcohol) selectivity studies showed that lipase immobilized on XAD7 and celite was more accessible to alcohols of chain lengths 3–12. However, lipase immobilized on PMMA showed a significant preference towards alcohols of chain lengths from 3 to 10.

Monomethoxypolyethylene glycols (PEG) of molecular masses 1900 and 5000 were activated using p-nitrophenyl chloroformate to form PEG–nitrophenyl carbonates (activated PEG) with high yield (96–98%). The activated PEG was covalently attached to Candida rugosa lipase. Increasing the molar ratio of activated PEG to the enzyme increased the degree of lipase modification. These modified lipases exhibited specific ester synthesis activities on organic solvents compared with native lipase. The degree of activity enhancement depended on the size of activated PEG used and the degree of modification of the enzyme. Maximal activity was attained after exhaustive of modification. The effects of different solvents, reaction temperature, and fatty acids on the esterification activity and the stability of the modified enzyme were investigated. The optimum esterification temperature (40° C) and preference of fatty acids as acyl donors of the modified lipase were very similar to those of the native enzyme. The modified lipase exhibited higher activity non-polar solvents than in polar solvents, and showed higher temperature, solvent and storage stability then the native lipase.

Yttrium‐loaded poly(hydroxamic acid) ion‐exchange resin (YPHA) has been studied to sorb fluoride ion from aqueous solutions. The resin was effective in decreasing the fluoride concentration from 5 mM down to 0.002 mM in the pH range of 2.8 to 4.2. The rate constant for the sorption was found to be 5.6 x 10‐2 min‐1. The sorption of the fluoride was the Langmuir type and its capacity was 0.68 mmol‐F/g resin. The sorption selectivity shows that the fluoride removal may be interfered by the presence of phosphate and sulphate but was not affected by chloride, bromide, iodide and nitrate ions. The removal of fluoride from actual industrial wastewaters was more than 96%. A column test shows that fluoride ion was retained on the column until the breakthrough point. The fluoride ion sorbed can be eluted from the resin with 100 mM sodium hydroxide, and the column can be reused after being conditioned with 1 mM hydrochloric acid.

Lipase fromCandida rugosa was modified with several hydrophobic modifiers before being adsorbed onto organic polymer beads. The effects of different enzyme modifiers, supports, solvents, reaction temperatures, fatty acids, and alcohols on the activity of the immobilized enzyme were investigated. The immobilized lipases were good biocatalysts for esterification reactions in organic solvents. They exhibited high activities in all solvents tested, including polar solvents. The activity seemed to depend on the type of support rather than on the modifier of the enzyme. The medium polar support, XAD7, appeared to be the best for the modified lipases. The immobilized lipase favored the medium-chain fatty acids rather than the long-chain fatty acids as acyl donors. The alcohol selectivity of the enzyme was unchanged upon immobilization. The native and immobilized lipases favored the short-chain and terpene alcohols as nucleophiles.