W.D. Wan Rosli

UV radiation curing of epoxidized palm oil–cycloaliphatic diepoxide system induced by cationic photoinitiators for surface coatings

Epoxidized palm oil (EPO) can be cured with ultraviolet (UV) radiation using either radical, cationic or hybrid initiation. Cationic curing system has been chosen in this study due to the fact that epoxy groups present in EPO can be utilized directly to form cross links. Curing was carried out in a 20 cm wide UV IST machine. Triaryl sulphonium salts and ferrocenium salt were used as cationic photo initiators. Formulations were developed based on selected grades of EPO. Other materials employed included different types and concentrations of photo initiators, monomers and photosensitizer. The effect of post-cure conditions was also studied. The properties of the cured film, namely, pendulum hardness, percentage of gel content and tensile strength were determined. It was found that triarylsulphonium hexafluorophosphate exhibited low solubility in EPO. Addition of a vinyl ether monomer to the formulation did not enhance pendulum hardness and gel content of the cured films. Post-cure temperature had no significant effect on the properties of the cured film. The FTIR studies showed evidence of the ring opening of the epoxide groups present in the formulation.

Optimisation of soda pulping variables for preparation of dissolving pulps from oil palm fibre.

Summary A water prehydrolysis-soda pulping sequence for the preparation of dissolving pulps from oil palm fibre (empty fruit bunches) was investigated using a response surface methodology (RSM) statistical experiment design. Five response variables of screened yield, Kappa number, α-cellulose, viscosity and ash content were statistically analyzed with respect to the three input variables of pulping temperature (T), time-at-temperature (t) and alkali level (A), while keeping the prehydrolysis conditions constant. Optimum conditions were: T = 161°C, t = 100 min and A= 26.1%. Values predicted by RSM for screened yield, Kappa number, α-cellulose, viscosity and ash content at the optimum are 31.2%, 6.0, 96.9%, 16.1 cps and 0.15%, respectively. These values were experimentally verified and very close agreement between experimental and predicted values was obtained.

Carboxymethyl Cellulose (CMC) from Oil Palm Empty Fruit Bunch (OPEFB) in the new solvent Dimethyl Sulfoxide (DMSO)/Tetrabutylammonium Fluoride (TBAF)

The surplus of Oil Palm is the most galore wastes in Malaysia because it produced about half of the world palm oil production, which contributes a major disposal problem Synthesis from an empty fruit bunch produced products such as Carboxymethyl Cellulose (CMC), could apply in diverse application such as for paper coating, food packaging and most recently, the potential as biomaterials has been revealed. In this study, CMC was prepared by firstly dissolved the bleached pulp from OPEFB in mixture solution of dimethyl sulfoxide(DMSO)/tetrabutylammonium fluoride (TBAF) without any prior chemical modification. It took only 30 minutes to fully dissolve at temperature 60°C before sodium hydroxide (NaOH) were added for activation and monochloroacetateas terrifying agent. The final product is appeared in white powder, which is then will be analyzedby FTIR analysis. FTIR results show peaks appeared at wavenumber between 1609 cm-1 to 1614 cm-1 proved the existence of carboxymethyl groups which substitute OH groups at anhydroglucose(AGU) unit. As a conclusion, mixture solution of DMSO/TBAF is the suitable solvent used for dissolved cellulose before modifying it into CMC with higher Degree of Substitution (DS). Furthermore, the dissolution of the OPEFB bleached pulp was easy, simple and at a faster rate without prior chemical modification at temperature as low as 60°C.

Alkaline Peroxide in Synergy with Mechanical Refining as Factor in the Development of EFB Paper Properties

Pulp from the oil palm empty fruit bunches (EFB) was extracted via Alkaline Peroxide Pulping (APP). The pulping process was conducted through three main steps; dewaxing of EFB, impregnation of alkaline peroxide (AP) into EFB and refining of biomass to finally produce the pulp. The varying peroxide levels and number of impregnation stages were found to affect the refining energy consumption and the properties of the resultant pulp and paper. Diagnosis by electron microscopic imaging revealed a strong correlation between paper properties development and paper surface morphologies. By multiplying the stages of the low alkaline peroxide level (2:2.5% AP) impregnation, refining energy could be reduced by 30% while improving brightness and paper mechanical properties. Higher alkaline peroxide level (4:5% AP) could reduce the refining energy by 50% while still improving brightness. Beyond these AP levels (8:10% AP), refining energy could be reduced by 67% by increasing the number of impregnation stages, with positive effects on brightness and paper mechanical properties. The findings suggest that increasing the AP impregnation stages had exposed more active sites to react with AP. The enhanced AP accessibility to EFB structures facilitated mechanical fibrillation of EFB vascular bundles through the refining process. The proper synergy between AP and the adopted mechanical refining was the factor that triggered the liberation of nanocells from EFB biomass and this had ultimately improved paper properties.

The Use of Oil Palm Empty Fruit Bunches (OPEFB) Fibers as Partial Replacement for Imported Recycled Fibers

Papermaking in Malaysia is basically based on recycled (secondary) fibers which are sourced from various parts of the world with prices depending on the quality of the fibers procured. The costs of paper production could possibly be reduced by using local fibers as partial replacement provided that the strength requirements are not compromised; and one such type is the oil palm fibers which are obtained as the by-product of the palm oil industry. This paper reports the use of the oil palm empty fruit bunch (OPEFB) fiber as a partial substitute in the production of corrugating medium. Both unbleached and totally chlorine free (TCF) bleached OPEFB pulps were mixed in different ratios with high quality recycled pulps which had been mechanically and chemically treated. Burst strength results indicate as high as 70% recycled pulp can be replaced by OPEFB pulps yet still having strength properties that are comparable with the industrial produced corrugating medium. Although the effect of bleached pulp is significant at high addition levels of more than 70%, the cost-energy balance will not be effective to use these bleached fibers, and furthermore the utilization of unbleached pulps also gave the same desired results. The use of the underutilized OPEFB fibers for replacement of imported recycled fibers without compromising the paper strength qualities could help the Malaysian paper industry in their quest for finding fiber alternatives.

Effects of Drying Techniques on the Crystallinity and Thermal Properties of Empty Fruit Bunch Nanocrystalline Cellulose

The effect of drying techniques on the crystallinity and thermal stability nanocrystalline cellulose (NCC) prepared from oil palm empty fruit bunch (OPEFB) via the TEMPO-oxidation process was investigated. NCC was subjected to three separate drying techniques viz. oven drying (OD), freeze drying (FD) and solvent exchange (SE). The crystallinity and thermal properties were investigated for all samples using DSC and X-ray diffraction (XRD). There is no significant difference in the degree of crystallinity for both OD-NCC and FD-NCC as compared to the starting material of unbleached pulp (UP) (72% vs 76%), however SE-NCC showed a tremendous reduction with the crystallinity of only 40%. Both OD-NCC and FD-NCC have almost similar thermal behavior but the SE-NCC showed a significant difference. For the application of NCC in non-polar bionanocomposites, both OD-NCC and FD-NCC is recommended due to its relatively superior thermal stability and a higher crystallinity index.

Augmentation of EFB Fiber Web by Nano-Scale Fibrous Elements

Treatment of the abundant oil palm empty fruit bunches with alkaline peroxide chemicals and subsequent fibrillation at varying mechanical energies resulted in favourable morphological changes of the generated fibers. The produced fibrous mass composed of intensely fibrillated elements ranging from micro to nanodiameter fibrils. nanofibrils and webs of nanofibrils were factors contributing to the functionality of the fibrous mass as fibre web augmentation elements. Profound improvement in fiber network is particularly attributable to the ability of the collected elements to fill up inter-fiber gaps and this was attributable to the micro elements in the form of micro fines, segmented micro-fibrils and webs of nanofibrils. The uniquely generated thin layers of nanofibril webs (TN-webs), were found to increase fiber web density by gluing multiple layers of fibers, together. Having landed on the surface of micro-fiber web, these TN-webs were identified as responsible for the masking effects of the underlying micro-fibres. Under such condition, fibers were observed to coalesce, suggesting also an augmented fiber network as evident from the 130% increase in tensile index and a 450% enhancement in burst index of the resultant fiber web relative to those formed with the basic alkaline peroxide chemical-mechanical refining (CMR) synergy. This reveals a great promise to EFB for application as super-strong fibre-web materials such as packaging and specialty paper-based products.

Nanofibre Network Rooted from the Alkaline Peroxide Treatment of Oil Palm Empty Fruit Bunches

The increasing popularity of the oil palm empty fruit bunches (EFB) as a source of non-wood fibre has prompted a variety of research on processing and utilisation of the material. In an attempt to define the characters, reusability and end-of-life, oil palm EFB was processed by the alkaline peroxide variable treatment (APVT) systems. Low synergy between alkaline peroxide (AP) chemical and mechanical fibrillation through fibrillation (CMR synergy) revealed the yield of segments of EFB vascular bundles while heightening the mechanical forces further, generated more uniform but a mixture of fiber and segments of fibre bundles. An intermediate CMR synergy generated fibres forming a more well-defined but a rough resultant fibre network due to partial fibrillation of the vascular bundle. Applying maximal CMR synergy was found to generate higher yield of network strengthening fibrous cells. These were later identified as nanoscale fiber network or nanoscan, consisting of 10-80 nm diameter fibers arranging themselves in a systematic network. Analysis of the polarity of fibers harvested from the APVT systems manifests the systematic construction of nanofibrils winding in helical manner to form arrays of nanofibres that glue themselves together as micro-fibrils. Interconnections between fibers and other gluing elements led to the vascular bundle known as the EFB biomass that was once dross and that can now be marvelled as an alternative source of nanofibers for the nanoindustry sector.