Optimization and Kinetics of Solid Liquid Extraction of Malaysian Jatropha Curcas Seeds

The Jatropha is a plant which grows in most of tropical and subtropical regions of the world. The oil from the Jatropha seeds can be used as fuel alternative and for making biodiesel. This work aimed to determine the optimum parameters to achieve maximum oil yield in solid liquid extraction of Jatropha seeds under experimental conditions. The optimum condition was then applied in ultrasound assisted and microwave pretreatment extraction methods to determine the amount of yield. The kinetics of the extraction was also studied based on the assumption of a second order mechanism. The extraction was carried out using a soxhlet extractor equipped with condenser and hot plate. The effects of five main factors which are namely type of solvents, temperature, solvent to solid ratio, reaction time and size of the raw material were investigated experimentally on the solid liquid extraction of Jatropha seed to optimize the extraction process. The optimum condition was found at eight hours reaction time, temperature of around 68°C, coarse particle size (0.5-0.75 mm), solvent to solid ratio of 6:1 (v/w) and using hexane as the solvent. The maximum amount of yield at optimized condition was at 47.3 % by wt. The activation energy was found to be 7145.05 (J/mol) and the highest initial extraction rate was calculated to be and 4.21 (g/L min). The maximum amount of oil extracted by ultrasound assisted and microwave pretreatment methods were 51.4 and 49.4% respectively. The oil extracted by conventional, ultrasound assisted and microwave pretreatment extraction methods contained, respectively, 0.62, 0.67 and 0.63% free fatty acid and 98.3, 97 and 97.7% triglyceride

Solid liquid extraction of Jatropha seeds by microwave pretreatment and ultrasound assisted methods

Jatropha curcas has a variety of uses which are of great economic significance. Jatropha oil can be used as fuel alternative and for making biodiesel that is supposed to overcome the source limitation problem. In this study, conventional, ultrasound assisted and microwave pretreatment solid liquid extraction of Jatropha seed were studied in terms of amount and quality of the extracted oil. The free fatty acid content which is an important oil quality index was also investigated for the obtained oil. Both ultrasonication and microwave pretreatment of the seeds had a positive effect on amount of yield. However, by application of ultrasound, more oil could be extracted compared with that obtained by conventional and microwave pretreatment extraction methods. The maximum amount of oil which could be extracted by conventional, ultrasound assisted and microwave pretreatment methods were 47.33, 51.4 and 49.36%, respectively. Regarding the quality, oil extracted by conventional, ultrasound assisted and micmicrowave pretreatment extraction methods did not show any significant difference in terms of Free Fatty Acids (FFA) content

Optimisation of solid liquid extraction of jatropha oil using petroleum ether.

Jatropha curcas I. is an oil-bearing seed plant with a wide range of applications. The oil from the seeds of this plant has been used as an industrial raw material for many years. One of the important characteristics of jatropha oil is its potential for fuel and biodiesel production to meet the global energy demand. In this paper, solid–liquid extraction of jatropha oil from seeds using petroleum ether was optimised on the basis of the amount of the extracted oil. Four main factors, namely temperature, the solvent-to-solid ratio, the reaction time and the size of the raw material, were investigated to optimise extraction conditions for achieving the highest oil yield under experimental conditions. The kinetics of the extraction using petroleum ether as the solvent were also studied and fitted to a second-order model. The free fatty acid (FFA) content of the oil was used as an index of the oil quality. The optimum conditions were found to be 7 h of reaction time, a temperature of 68 °C, a coarse particle size of 0.5–0.75 mm and a solvent-to-solid ratio of 6 : 1. Storing the ground seeds for one week before extraction had a remarkably negative effect on the quality of the oil produced (FFA ≈ 6.99%), whereas the quality of the oil was satisfactory when extracted from the seeds immediately after grinding (FFA ≈ 0.62%). The experimental data fitted well to the second-order model with the saturation extraction capacity and the initial extraction rate increasing with increasing temperature

Extrusion printed graphene/polycaprolactone/ composites for tissue engineering

In this work fibres and complex three-dimensional scaffolds of a covalently linked graphene-polycaprolactone composite were successfully extruded and printed using a melt extrusion printing system. Fibres with varying diameters and morphologies, as well as complex scaffolds were fabricated using an additive fabrication approach and were characterized. It was found that the addition of graphene improves the mechanical properties of the fibres by over 50% and in vitro cytotoxicity tests showed good biocompatibility indicating a promising material for tissue engineering applications

The development of graphene/biocomposites for biomedical applications

The development of biomaterials with appropriate properties is a requirement in biomedical research, particularly in tissue engineering. The aim of this thesis was to develop biocompatible, processable biocomposites for biomedical applications using graphene and graphene oxide (GO) as filler. Graphene, a unique two-dimensional carbon structure with excellent electrical, thermal and mechanical properties has been shown to be an appropriate filler for the development of composites for biomedical applications. Chemically converted graphene (CCG) dispersions were synthesized through reduction of GO, also a suitable filler for developing biocomposites. Polycaprolactone (PCl), a synthetic biodegradable and biocompatible aliphatic polyester with high processability and low cost, was chosen for development of biocomposites in Chapter 3. Two synthetic approaches were taken to develop graphene/PCl composites, a mixing method where graphene is mixed with the polymer (mixPCl-CCG), and a covalent attachment method by which graphene nanosheets are linked to the polymer chains (cPCl-CCG). In both methods, the addition of graphene resulted in significant improvement in the conductivity and the mechanical properties of PCl. Covalent links between PCl and CCG resulted in a homogenous dispersion of CCG sheets in the polymer matrix and higher flexibility of the cPCl-CCG composites. The synthesis of graphene/PCl composites was also achieved by a microwaveassisted method in which GO was reduced to graphene during the polymerization process. Graphene/PCl samples were subjected to enzymatic degradation to study the effect of graphene addition on the degradation of PCl. The composites were successfully processed into fibres and 3D structures using an additive fabrication approach that demonstrates the excellent processability of the graphene/PCl composites. The biocompatibility of the composites was also confirmed through cell culture experiments. Chitosan, a natural polymer, was used for the development of graphene biocomposites in Chapter 4. .Lactic acid was utilised as a crosslinking agent to form the composites. Similar to PCl-CCG composites, graphene/chitosan composites were prepared through mixing and covalent attachment methods. Graphene/chitosan composites, prepared by the mixing approach, showed great improvement in their conductivity and mechanical properties. Furthermore, the swelling rate of the composites could be controlled on addition of CCG. The composites were also extruded into multilayer 3D scaffolds using an extrusion printing technique. The composites and printed scaffolds exhibited excellent biocompatibility with fibroblast cells. The covalent attachment of the chitosan polymer chains and graphene sheets did not considerably improve the properties of the polymer compared to noncovalent ones, leaving the process open for further optimization in the future. The development of a UV-crosslinkable biocomposite was undertaken in Chapter 5. UV-crosslinkable chitosan (ChiMA) was developed through methacrylation of the polymer backbone. ChiMA composites were fabricated using both GO and CCG aqueous dispersions. The addition of either GO or CCG resulted in improvement in the mechanical properties of the polymer. The incorporation of CCG into the ChiMA matrix also greatly improved the electrical conductivity of the composites. The composites showed good biocompatibility with L929 murine fibroblasts, highlighting their suitability for biomedical applications. The excellent processability of the ChiMA biocomposites was demonstrated by the fabrication of multilayer 3D scaffolds via extrusion printing

Effect of Graphene Addition on Polycaprolactone Scaffolds Fabricated Using Melt-Electrowriting

Melt-electrowriting (MEW) is an emerging method that combines electrospinning and extrusion printing, allowing the fabrication of micron-scale structures suitable for tissue engineering. Compared to other additive fabrication methods, melt-electro written structures can offer more appropriate substrates for cell culture due to filament size and mechanical characteristics of the fabricated scaffolds. In this study, polycaprolactone (PCL)/graphene composites were investigated for fabrication of micron-size scaffolds through MEW. It was demonstrated that the addition of graphene can considerably improve the processability of PCL to fabricate micron-scale scaffolds with enhanced resolution. The tensile strength of the scaffold prepared from PCL/graphene composite (with only 0.5 wt.% graphene) was proved significantly (by more than 270%), better than that of the pristine PCL scaffold. Furthermore, graphene was demonstrated to be a suitable material for tailoring the degradation process to avoid undesirable bulk degradation, rapid mass loss and damage to the internal matrix of the polymer. The findings of this study offer a promising route for the fabrication of high-resolution scaffolds with micron-scale resolution for tissue engineering

Fabrication of 3D structures from graphene-based biocomposites

With the advancement of new material technologies and the invention of new techniques such as 3D printing over recent decades, the fabrication of more complex and versatile structures from biocomposites can now be easily achieved. Graphenic fillers are being increasingly used to improve and tune the electrical conductivity and mechanical properties of biodegradable/biocompatible polymers thus opening the way for the fabrication of biocomposite structures critical for areas such as tissue engineering. This review provides an overview of recent work on the fabrication of structures using graphene-based biocomposites, which provide constructs with properties better tailored to a variety of biomedical applications

Materials Science, Slow Textiles, Ecological Futures

Genuine interdisciplinary collaboration between the arts and sciences can be complex. Andrew Barry, Georgina Born and Gisa Weszkalnys characterize the emergent field of art-science as an intersection where practice runs ahead of theory [1]. Harriet Hawkins urges researchers to build critical reflections across disciplines that not only spark deeper conversation but that also induce a desire for interdisciplinary rigor [2]. To advance art-science research, it is crucial that artists and scientists critically reflect on their collaborative process. This paper contributes to this dialogue by presenting the challenges encountered in the art-science research project Material Science, Slow Textiles & Ecological Futures (MSSTEF)