Agus Arsad

A comparative study of various oil extraction techniques from plants

Abstract Researchers have shown that techniques such as microwave-assisted extraction, ultrasound-assisted extraction, pressurized liquid extraction, and supercritical fluid extraction developed for extraction of valuable components from plants and seed materials have been successfully used to effectively reduce the major shortcomings of the traditional method such as Soxhlet extraction. These include shorter extraction time, increase in yield of extracted components, decrease in solvent consumption, and improvement of the quality of extracts. This review presents a detailed description of the principles and mechanisms of the various extraction techniques for better understanding and summarizes the potential of these techniques in the extraction of oil from plants and seed materials. Discussions on some of the parameters affecting the extraction efficiency are also highlighted, with special emphasis on supercritical fluid extraction. A comparison of the performance of traditional Soxhlet extraction with that of other extraction techniques is also presented.

Green composites based on recycled polyamide-6/recycled polypropylene kenaf composites: mechanical, thermal and morphological properties

Abstract The objective of this work was to investigate the effect of kenaf contents on mechanical, thermal and morphological properties of recycled polyamide-6 (rPA-6)/recycled polypropylene (rPP) blends. Kenaf was used to enhance the properties of composites. Alkali treating of kenaf by sodium hydroxide (NaOH) and combination with propylene grafted maleic anhydride (PPgMA) as a compatibilizer produced good adhesion both between rPP and rPA-6, and rPA-6/rPP and kenaf. Tensile, flexural and Izod impact tests were evaluated to study the mechanical properties. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were carried out to investigate thermal properties. Scanning electron microscopy (SEM) was performed for morphological analysis. Generally, the mechanical properties were successfully enhanced, especially Young’s modulus, flexural modulus, flexural strength and elongation at break, while there were some problems which caused the tensile strength and impact strength to be inferior. Thermal analysis showed that the crystallization of composites decreased as kenaf contents were increased. SEM showed a problem with kenaf and rPP/rPA-6 compatibility, which led to insufficient matrix at some places and agglomeration of kenaf at other places. Morphologically, there was unidirectional presence of kenaf in rPP main composites and random orientation in rPA-6 main composites.

Mechanical and Rheological Properties of PA6/ABS Blends With and Without Short Glass Fiber

Polyamide-6 (PA6), acrylonitrile-butadiene-styrene (ABS), and their blends are an important class of engineering thermoplastics that are widely used for electronic and automotive industries. Many efforts have been made to improve the properties of both pure components and the blends. It was for this reason that the mechanical and rheological properties of PA6/ABS blend systems compatibilized by acrylonitrile-butadiene-styrene-maleic anhydride was studied. Short glass fiber was also used to enhance the compatibilized blends. The systems were prepared using a twin screw extruder. The specimens for mechanical test were molded using injection molding. The compatibilized blends showed higher mechanical properties compared to uncompatibilized blend. However, the impact strength reduced with the introduction of short glass fiber in the blends. The processing properties of the materials have been investigated using dynamic rheometer. The rheological measurements confirmed the increased in interaction between the blend components with the incorporation of compatibilizer. The incorporation of short glass fiber (SGF) into the compatibilized blends increased the storage and loss modulus as well as the viscosity of the blends.

Mechanical properties of poly(lactic acid)/multiwalled carbon nanotubes nanocomposites

Abstract In this study, the mechanical properties of polylactic acid reinforced with carboxylic functionalized multiwalled carbon nanotubes were investigated. The polylactic acid/multiwalled carbon nanotubes nanocomposites were prepared using direct melt-blending method in a counter-rotating twin screw extruder with various loadings of nanotube. The extruded nanocomposites were then pelletized and injection moulded into test specimens for mechanical testing. The effects of the increased content of nanotube on the mechanical properties of polylactic acid nanocomposites were investigated through tensile, flexural and impact tests. The analysis showed that the tensile strength and modulus increase with increasing amount of multiwalled carbon nanotubes, indicating the ability of multiwalled carbon nanotubes to improve the stiffness of polylactic acid. The optimum loading of 5 phr gave the best tensile and flexural strength of 40·949 and 54·132 Mpa, respectively. However, both flexural and the tensile strength experienced rapid decrease after the optimum loading owing to agglomeration of nanotubes. The highest modulus was observed at 7 phr with 3·483 GPa, while the highest flexural modulus was observed at 7 phr with 4·244 GPa. On the other hand, the impact strength decreases with increasing amount of multiwalled carbon nanotubes.

Enhanced dispersion of carbon nanotubes in high density polyethylene matrix using secondary nanofiller and compatibilizer

In this study, we have attempted to explain the influence of secondary filler on the dispersion of carbon nanotube (CNT) reinforced high density polyethylene (HDPE) nanocomposites (CNT/HDPE). In order to understand the mixed-fillers system, Montmorillonite (MMT) in addition with Maleic anhydride grafted high density polyethylene (PE-g-MA) was added to CNT/HDPE nanocomposites. It was followed by investigating their effect on the thermo-mechanical, rheological and morphological properties of the aforesaid nanocomposite. Incorporation of 3 wt% each of MMT and PE-g-MA into CNT/HDPE nanocomposites resulted to the increased values for the tensile and flexural strength (32 % increase in both), as compared to the pure HDPE matrix. The thermal analysis result showed improved thermal stability of the formulated nanocomposites. The initial decomposition temperature (Ti) for such nanocomposite with 9 wt% of MMT and 3 wt% of PE-g-MA reached to 296 °C from 265 °C (Ti for neat HDPE matrix). Addition of MMT to CNT/HDPE nanocomposites also increased the rheological properties indicating a dominating elastic response. A significant increase in loss, storage modulus and complex viscosity was observed upon addition of PE-g-MA, whereas Tan δ was found to be reduced. This might be due to better interfacial adhesion between MMT and HDPE phases that attributes to the elastic dominance. Improvement in dispersion of CNT upon addition of MMT and PE-g-MA was further supported by the morphological analysis. Transmission electron microscopy (TEM) images revealed that larger aggregates of CNTs were disappeared upon addition of these two components leading to the enhancement of thermo-mechanical properties for such composites.

The Effect of Natural Rubber Toughening on Mechanical Properties of Poly(lactic Acid)/Multiwalled Carbon Nanotube Nanocomposite

nvestigation was done on the use of natural rubber (NR) as impact modifier in polylactic acid (PLA) nanocomposite containing carboxylic functionalized multiwalled carbon nanotubes (MWCNT) as nanofillers. NR toughened PLA nancomposite consisting of 1 phr MWCNT and NR contents varies from 5 to 20 wt% were prepared by direct melt blending in a counter-rotating twin-screw extruder followed by injection moulding into test specimens for mechanical properties analysis. The tensile, flexural and impact test analysis were carried out to investigate the mechanical properties of PLA/NR/MWCNT nanocomposites at different loading of NR. As comparison, pure PLA, PLA/NR with 5 wt% NR and PLA/MWCNT with 1 phr nanotubes were also prepared with similar method. Results indicated that introduction of NR into PLA/MWCNT contributed to significant improvement in impact strength and ductility of the nanocomposite. Moreover, the deterioration effect of nancomposites stiffness, mechanical and flexural strength due to the introduction of NR was minimized with the presence of MWCNT in the nanocomposite system.

INFLUENCE OF COMPATIBILIZER ON MECHANICAL PROPERTIES OF POLYLACTIC ACID/NATURAL RUBBER BLENDS

Derived from renewable resources, Poly (lactic) acid (PLA) exhibits good mechanical properties comparable with conventional polyolefins. However, major obstacle in PLA which may limit its application is due to brittleness. Thus, PLA requires toughening to overcome the weakness. In this study, PLA was blended with different ratio of natural rubber (0 to 20 wt.%) through melt blending in a twin screw extruder. The results of tensile strength and Young’s modulus of PLA/NR blends were decreased. In order to enhance the blend performance, PLA grafted maleic anhydride (PLA-g-MA) was used as compatibilizer. The preparation of PLA-g-MA was carried out using internal mixer by free radical melt grafting reaction followed by Fourier Transform Infrared Spectroscopy (FTIR) analysis to confirm the grafting reaction. To investigate the compatibilization effect on the mechanical properties of PLA/NR blends, PLA-g-MA was added to the blends at various compositions (1 – 10 phr). Mechanical properties increased markedly compared to the virgin PLA/NR blends and FTIR result confirmed grafting reaction occurred between MA and PLA.

Bio-based thermoset nanocomposite derived from vegetable oil: A short review

Abstract This review presents recent research advances in defining the curing and thermal characteristics, mechanical properties and appropriate processing techniques of thermoset resin derived from vegetable oils. Vegetable oil is the latest alternative found to replace the dependence on petroleum-based synthetic resin. Petroleum based resin reinforced with synthetic fiber composite is unbiodegradable, cannot be reused and recycled. Thus, it is very valuable to replace the dependance petroleum based resin to renewable source which contributes to green environment. However, biocomposites synthesized from vegetable oil-based resin matrix, reinforced with natural fiber, have some limitations. The properties are differentiated based on the type of vegetable oil. Modifying the fatty acid chain and applying nanoclay in composites as filler, helps to improve some properties due to the addition of vegetable oil in the resin system. Within this contribution, special emphasis was placed on a broad-brush approach over the potential opportunities concerning the use of renewable feedstock, such as modification of soybean oil, linseed oil, and nahar oil in thermoset resin. This review is focusing on investigating the approaches that have been proposed to produce bioresin and bio-based nanocomposites.

Influence of MMT as reinforcement on rheological behavior, mechanical and morphological properties of recycled PET/ABS thermoplastic nanocomposites

Abstract The objective of this research was to investigate the effect of incorporating nanofiller, montmorillonite (MMT) on mechanical, morphological and rheological properties of acrylonitrile-butadiene-styrene (ABS) and recycled poly(ethylene terephthalate) (rPET) nanocomposites. The MMT contents in 70:30 ABS/rPET and 30:70 ABS/rPET ranged from 1 to 5 wt%. The ABS/rPET nanocomposites were extruded and injection-molded into tensile, flexural and impact test samples. Samples underwent rheological testing by using melt flow index (MFI) and capillary rheometer and the morphology of the nanocomposites was investigated by using field emission scanning electron microscopy (FESEM). The maximum tensile strength and flexural strength were at 1 wt.% of MMT for both blends. However, tensile modulus and flexural modulus reached maximum point at 3 wt.% and started to decrease beyond 3 wt.%% of MMT. Impact strength for both blending decreased significantly with the incorporation of MMT. MFI values decreased with the increment of MMT for 30:70 ABS/rPET, but increased for 70:30 ABS/rPET. The incorporation of MMT increased the melt strength of 30:70 ABS/rPET nanocomposites. Shear viscosity showed increment with the increasing MMT concentration for 30:70 ABS/rPET nanocomposites. However, shear viscosity decreased with the increment of MMT for 70:30 ABS/rPET. FESEM micrographs show good distribution and dispersion of MMT in 30:70 ABS/rPET, but poor dispersion and agglomeration of MMT in 70:30 ABS/rPET.

Effects of Compatibilizer on Thermal and Mechanical Properties of PLA/NR Blends

The aim of the research is to study the effects of compatibilizer on thermal and mechanical properties ofbiopolymer poly (lactic acid) (PLA) and natural rubber (NR) blends. PLA was blended with NR in the composition of 95/5 weight percentage with present of compatibilizer. The compatibilizers, PLA grafted maleic anhydride (MA) (PLA-g-MA) and NR grafted MA (NR-g-MA) were synthesized in a composition of 9 phr of MA by using internal mixer in presence of benzoyl peroxide (BPO). The formulations of PLA/NR blended with the compatibilizer were in the range of 1, 3, 5 and 10 wt.% of PLA-g-MA and NR-g-MA, respectively. Blending process was conducted using twin screw extruder then were pelletized and hot pressed before characterized. The mechanical (tensile, flexural, impact) and thermal properties of the blends was investigated and from the results, the addition of PLA-g-MA in PLA/NR blendimproved the impact strength and elongation at break of the blends as compared with neat PLA and PLA/NR blend without compatibilizer and for thermal stability, it only had a slight influence on the blends. Addition of NR-g-MA on contrary did not give improvement on mechanical properties but increasing in thermal stability.