Search

This study propounds a sustainable alternative to petroleum-based polyurethane (PU) foams, aiming to curtail this nonrenewable resource's continued and uncontrolled use. Coconut fatty acid distillate (CFAD) and crude glycerol (CG), both wastes generated from vegetable oil processes, were utilized for bio-based polyol production for rigid PU foam application. The raw materials were subjected to catalyzed glycerolysis with alkaline-alcohol neutralization and bleaching. The resulting polyol possessed properties suitable for rigid foam application, with an average OH number of 215 mg KOH/g, an acid number of 7.2983 mg KOH/g, and a Gardner color value of 18. The polyol was used to prepare rigid PU foam, and its properties were determined using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/derivative thermogravimetric (TGA/DTA), and universal testing machine (UTM). Additionally, the cell foam morphology was investigated by scanning electron microscope (SEM), in which most of its structure revealed an open-celled network and quantified at 92.71% open-cell content using pycnometric testing. The PU foam thermal and mechanical analyses results showed an average compressive strength of 210.43 kPa, a thermal conductivity of 32.10 mW·m−1K−1, and a density of 44.65 kg·m−3. These properties showed its applicability as a type I structural sandwich panel core material, thus demonstrating the potential use of CFAD and CG in commercial polyol and PU foam production. [ABSTRACT FROM AUTHOR]

Cellulosic substrates, including wood and thatch, have become icons for sustainable architecture and construction, however, they suffer from high flammability because of their inherent cellulosic composition. Current control measures for such hazards include applying intumescent fire-retardant (IFR) coatings that swell and form a char layer upon ignition, protecting the underlying substrate from burning. Typically, conventional IFR coatings are opaque and are made of halogenated compounds that release toxic fumes when ignited, compromising the roofing's aesthetic value and sustainability. In this work, phytic acid, a naturally occurring phosphorus source extracted from rice bran, was used to synthesize phytic acid-based fire-retardants (PFR) via esterification under reflux, along with powdered chicken eggshells (CES) as calcium carbonate (CaCO 3) bio-filler. These components were incorporated into melamine formaldehyde resin to produce the transparent IFR coating. It was revealed that the developed IFR coatings achieved the highest fire protection rating based on UL94 flammability standards compared to the control. The coatings also yielded increased LOI values, indicative of self-extinguishing properties. A 17 °C elevation of the IFR coating's melting temperature and a significant ∼172% increase in enthalpy change from the control were observed, indicating enhanced fire-retardancy. The thermal stability of the coatings was improved, denoted by reduced mass losses, and increased residual masses after thermal degradation. As validated by microscopy and spectroscopy, the abundance of phosphorus and carbon groups in the coatings' condensed phase after combustion indicates enhanced char formation. In the gas phase, TG-FTIR showed the evolution of non-flammable CO 2 , and fire-retardant PO and P– O –C. Mechanical property testing confirmed no reduction in the adhesion strength of the IFR coating. With these results, the developed IFR coating exhibited enhanced fire-retardancy whilst remaining optically transparent, suggestive of a dual-phase IFR protective mechanism involving the release of gaseous combustion diluents and the formation of a thermally insulating char layer. [Display omitted] • A bio-based transparent intumescent fire-retardant (IFR) coating was developed for cellulosic substrates. • The IFR coating achieved the highest fire-retardancy rating (5VA) based on UL94 standards. • The IFR coating exhibited improved thermal stability and enhanced thermal behavior. • A carbon-rich char layer with high intensities of phosphorus was developed. • A dual-phase fire-retardant mechanism is proposed. [ABSTRACT FROM AUTHOR]

Abstract: The study involved the extraction of oil from Moringa oleifera (MO) kernels using supercritical fluid extraction (SFE) technique. The arrays of operating parameters are extraction condition, loading configuration, and SC-CO2 with ethanol addition for substrate pretreatment. It identifies a combination of operating parameters that provide a higher yield. The experiments were conducted in the pressure range of 15–30MPa, 35–60°C temperature interval, average particle size of 0.16–1.12mm and CO2 flow rate of 0.5m3/h. Adding 10% EtOH for substrate pretreatment, increased 10% in the yield. No significant difference in yield and fatty acid content between the oil from SC-CO2-EtOH and Soxhlet extraction with n-hexane was detected. Loading the seeds in multiple-staged trays increased to as much as 26.89% in the yield against randomly packed configuration. Response surface methodology, predicted an optimal oil yield of 37.84% at a pressure of 28.97MPa, 44.30°C temperature, and particle size of 0.54mm. A crossover pressure point of Ben oil was found within the range 22.5–30MPa. [Copyright &y& Elsevier]