Synthesis and Characterization of Vulcanized Vegetable Oil from Rubber Seed Oil

Vulcanized vegetable oil (VVO) is a product synthesized from unsaturated vegetable oil and a vulcanizing agent such as sulphur. It is used in rubber industry as processing aid and is imported into Nigeria whereas there are potential plant oils such as rubber seed oil (RSO) locally available in the country for its synthesis. Rubber seed oil is obtained from the seeds of the rubber tree (hevea brasiliensis) and are in abundance in Nigeria but unexploited. Its use in the synthesis of VVO was investigated by using sulphur as the vulcanizing agent. The effects of various doses of additives such as iodine, magnesium oxide, sodium carbonate, 2-mercaptobenzothioazole and zinc diethyldithiocarbonate on the vulcanization process were investigated. The vulcanized rubber seed oil (VRSO) obtained was characterized in terms of hardness, free sulphur, ash content and acetone extract. The type of vulcanized oil produced from rubber seed oil was found to depend on the level of sulphur and additive used. As the level of sulphur used in the synthesis without additives was increased from 15wt% to 30wt% of oil, the gel time was reduced from 35minutes to 14minutes and the physical properties of the VRSO improved. The use of some of the additives markedly affected the gel time particularly magnesium oxide which at 10wt% and 30wt% sulphur loading reduced gel time to 6minutes while some others seemed to have little effect on the gel time. The study shows that VVO can be produced from RSO when the right combination of additives is used instead of when sulphur is used separately

Deacidification of high acidic rubber seed oil by reesterification with glycerol

Some studies have shown that rubber seed oil (RSO) from the seed of rubber tree (hevea brasiliensis)has potential technical applications. However, the high free fatty acid (FFA) associated with the oil may be a limiting factor in its applications. In this study, crude rubber seed oil (RSO) containing 37.69% FFA was deacidified using 4.3-5.6% of glycerol. The reactions were carried out at a pressure of 20mmHg in the presence of zinc dust and zinc chloride catalysts added separately at high temperature (150 – 2500C). The progress of the reaction was monitored by determining the FFA at various time intervals.The FFA content in the RSO was reduced to 1.5% in six hours when 4.3% glycerol was used with zinc dust at a temperature of 2000C while the triglycerides content of the oil increased from 40.32% in the crude oil to 80.62% in the deacidified RSO. The study showed that this process is effective in the deacidification of RSO without loss of neutral glycerides as in alkali neutralization

Considerations of the extraction process and potential technical applications of Nigerian rubber seed oil

Rubber seeds from the rubber tree (hevea brasiliensis) are in abundance in Nigeria from which nonedible oil could be obtained. However, the seeds are wasted in the rubber plantations annually even though the extractable oil has potential technical applications. If the full potentials of the oil are to be realized, there is need to have a data base information on the oil extraction process and its properties. Rubber seeds were collected from different rubber clones and extracted first by n-hexane to determine the yield characteristics. Second, the seeds were extracted by a hydraulic press at varied operating conditions: pressure range (5-8MPa), temperatures, 40-90ºC; and moisture content, 7-16%. The effect of particle size and other operating variables on oil yield were studied. The physico-chemical properties of the extracted oil were evaluated. It was found that the percentage oil yield from the seeds of the rubber clone NIG800 at 45.03% was higher than the yield from other clones; GTI (40.21%) and RRIM 707 (38.42%) when the particle size of 1.16 mm was used. Oil yield increased with increase in temperature and pressure. Maximum oil yield was obtained during mechanical pressing at a moisture content of 10% (wt), temperature of 70ºC and pressure of 8MPa. The physicochemical characteristics of the oil showed high incidence of free fatty acid (FFA) of 37.96% (wt) and the high iodine value (IV) of 142.45 is indicative of the presence of high unsaturation. Rubber seed oil could therefore serve as semi-drying oil used in ingredients for surface coating and in the formulation of products where the presence of unsaturation is important

Optimising the Effect of Stimulants on Citric Acid Production from Cocoyam Starch Using Aspergillus Niger

Additives such as low molecular weight alcohols, trace metals, phytate, lipids etc have been reported to stimulate citric acid production. Hence the objective of this study was to investigate the effect of stimulating the metabolic activity of Aspergillus niger for the purpose of improved citric acid production from cocoyam starch. A  three-variable,  three-level  Box-Behnken  design  (BBD)  was  used  to develop  a  statistical  model  to study the effects of Zinc (II) ion, Iron (III) ion and methanol on the production of citric acid. Response surface methodology (RSM) was used to optimise the effects of these stimulants. The results of analysis of variance (ANOVA) carried out on the model showed that the model was statistically significant (p< 0.0001) and did not show lack of fit (R2=0.997). The results also showed that citric acid production increased when the levels of zinc and methanol were increased. Intermediate levels of iron were required to produce citric acid at optimum levels. Results obtained from RSM showed that the optimum levels of zinc, iron and methanol were 4.5 g/L, 6.87 g/L and 3.0 %v/v respectively. Under these conditions, the maximum citric acid concentration was obtained as 108 g/L. Validation of the model indicated no significant difference between predicted and experimental values.http://dx.doi.org/10.4314/njt.v34i4.

Optimisation of Solid State Fermentation of Banana Peels for Citric Acid Production

In this study, design of experiment (DOE) for response surface methodology (RSM) was used to analyse and optimise the simultaneous effect of solid substrate loading, initial pH and inoculum density on citric acid production from banana peels via solid state fermentation using Aspergillus niger. A three-variable, three-level Box-Behnken design was used to develop a statistical model to describe the relationship between citric acid concentration and the chosen independent variables and to optimise the production of citric acid using RSM. The model was statistically significant (p<0.0001) with a low standard deviation (0.43) and did not show lack of fit (R2=0.999). Citric acid production was significant at high levels of solid loading, low levels of pH and intermediate levels of inoculum density. Solid loading positively influenced citric acid production while the reverse was the case for initial pH. The optimum values of solid loading, pH and inoculum density were 20 g/L, 8 and 4.97×106 spores/mL respectively. Under these conditions, the citric acid concentration was obtained as 49.9 g/L. Validation of the statistical model showed an insignificant difference between experimental and model predicted results.http://dx.doi.org/10.4314/njt.v34i4.

Tapered Double Cantilever Beam Fracture Tests of Phenolic-Wood Adhesive Joints: Part II. Effects of Surface Roughness, the Nature of Surface Roughness, and Surface Aging on Joint Fracture Energy

Tapered double cantilever beam specimens were used to test the effect of surface roughness, the nature of surface roughness, and surface aging on the fracture energy of phenolic-wood adhesive joints. The fracture energy and the failure characteristics of the joints were found to depend not only on the surface roughness but also on the method of surface preparation. The fracture energy increased monotonically with surface roughness for specimens derived from hand-sanded surfaces but exhibited a minimum for specimens obtained from machine-sanded surfaces. Generally, joints from hand-sanded surfaces had higher fracture energies than those derived from the machine-sanded surfaces. Within the joints derived from the machine-sanded surfaces, those sanded perpendicular to the direction of crack growth had higher fracture energies than those sanded parallel to the direction of crack growth. Aging surfaces prior to bonding significantly decreased adhesive joint strength.Notwithstanding the differences in roughness, microscopic examination revealed little difference in the appearance of the sanded surfaces. Adhesive did not penetrate hand-sanded surfaces to any appreciable extent, but did deeply penetrate both the vessel and fiber lumens on the machine-sanded surfaces. Microscopic examination of the fractured surfaces did reveal significant differences that related to the fracture toughness of the bond

Statistical Analysis as a Tool in the Assessment of Detergents Produced from Seed Oils

Detergents are materials whose solutions aid in the removal of dirt or other foreign matter from contaminated surfaces. Until the 1940s, soap was the only important detergents. Today, soap is but one of a great many detergent products. The primary ingredient used in detergent manufacture is often called surface active agent or surfactant because it acts upon a surface. Detergents were produced from neat, benzene-modified and esterified seed oils; their properties were compared with those of OMO using statistical analysis (ANOVA). The analyses showed that: rubber seed oil is better than cherry seed oil in the production of detergent, esterification of the oil improved the detergent action and unmodified rubber and cherry seed oils produced soap and not detergent. Keywords: Detergents, soap, statistical analysis, ANOVA, seed oil, and esterificatio

Polymer Science And technology

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