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The development of polyurethane foams’ market, as well as ongoing trends associated with sustainable development cause increasingly growing interest in the utilization of materials from renewable resources. Great example of such phenomenon is the use of vegetable oils in manufacturing of foamed polyurethanes. These materials can be applied directly...
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... in order to be useful in production of polyurethane materials, vegetable oils need to be modified. An exception is castor oil, which could be directly applied, due to the very high content of ricinoleic acid, possessing in its structure both carboxyl and hydroxyl groups, as well as unsaturated bond (structure presented in the Figure 3) [25] . ...
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The world is striving for petrol and diesel. As we all know but don't care about the fact that the use of non renewable resources beyond limitation is creating a lot of issues. One such issue is Global Warming which is caused by increasing green house effect. The effect increase due to higher combustion of carbondioxide. The main reason of this is...
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... What sets castor oil apart from other vegetable oils is its unique hydroxyl (-OH) group structure. It is a triglyceride that consists solely of ricinoleic acid, an 18-carbon monounsaturated fatty acid with a hydroxyl group at the 12 th carbon [35]. Moreover, castor oil falls under the category of non-edible oils among vegetable oils. ...
Non-edible oils hold great potential as a viable feedstock for bio-lubricant production. Among these oils, castor oil stands out due to its unique hydroxyl group structure. Castor oil finds applications in various fields such as lubrication, dielectrics, and heat transfer. This study focused on investigating the dynamic viscosity and thermal conductivity of castor oil and graphene nanoplatelets/castor oil nanofluids. The nanofluids were synthesized through a two-step process involving the combination of graphene nanoplatelets crystal powder with pure castor oil. Morphological and crystallographic analyses revealed platelet-shaped graphene nanoplatelets with a prominent (002) reflection. Dynamic viscosity measurements were performed using a rheometer at temperatures ranging from 40 °C to 100 °C, and thermal conductivity assessments were conducted using the Modified Transient Plane Source technique from 30 °C to 70 °C. Investigation revealed that as temperature increased, the nanofluids exhibited a significant decrease in dynamic viscosity. Conversely, the dynamic viscosity increased moderately with higher concentrations of graphene nanoplatelets. Importantly, the addition of graphene nanoplatelets did not disrupt the Newtonian flow behavior of castor oil. Furthermore, the study demonstrated a remarkable enhancement in thermal conductivity with increasing concentrations of graphene nanoplatelets. This enhancement can be attributed to the high conductivity of graphene nanoplatelets. Overall, biodegradable graphene nanoplatelets/castor oil nanofluid present promising prospects as an advanced lubricating oil with superior heat transfer properties. This research contributes to the understanding and utilization of nanofluids for effective thermal management applications.
Palm olein-based polyol (PP) was used as a partial replacement for commercial sucrose/glycerine initiated polyether polyol (GP) for the production of low density rigid polyurethane foams (RPUFs). The hydroxyl value (OHV) of the GP was 380 mg KOH/g, whereas the OHV for PP was 360 mg KOH/g. The RPUFs were prepared by replacing the GP with PP up to 50 parts per hundred parts of polyols (pph). Characterisation of the RPUFs, including density, compressive strength and strain, cell morphology and thermal conductivity ( k-value), were conducted. The dimensional stability of the foams was also evaluated. The study showed improvement in the compressive strength and strain for palm-based RPUFs with the incorporation of up to 30 pph PP as compared to GP foams. The lowest k-value (0.0232 W/m.K) of RPUF with density below 30 kg/m ³ was obtained with the incorporation of 10 pph PP. This was due to the smallest and uniform pore size distribution observed using SEM images. The dimensional stability of the RPUF prepared from PP was within the acceptable range. Thus, the RPUFs made from PP are potential candidates to be used as insulation for refrigerators, freezers and piping.
