Conversion of palm oil to new sulfur-based polymer by inverse vulcanization

Abstract

The conversion of palm oil into a sulfur-based polymer by copolymerization with sulfur powder at its molten state is herein reported. The obtained sulfur-containing polymer was characterized using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to demonstrate the successful conversion. The disappearance of the peaks related to vinylic groups of oil together with the appearance of a peak representing C-H rocking vibrations in the vicinity of C-S bonds confirmed the copolymerization of sulfur with oil. TGA revealed that the polymers have thermal stability up to 230°C under nitrogen and the polymers leave 10% sulfur-rich ash. DSC proved that a small amount of elemental sulfur remained unreacted in the polymer, which showed amorphous and heavily crosslinked structure resembling thermosets. These copolymers are an environmental-friendly polymeric material promoting the utilization of the abundant sulfur while also adding value to palm oil.

Copolymerization of palm oil with sulfur using inverse vulcanization to boost the palm oil industry

“…It was previously shown by the TGA thermograms that the degradation onset temperatures of the copolymers with 70 and 80 wt% sulfur take place sooner at around 200°C, whereas copolymers with 50 and 60 wt% initial sulfur contents show higher onset temperatures (about 230°C) compared with elemental sulfur. 41 Poly (S-Palm oil) with all feed ratios showed a different weight-loss trend in DTG curves compared with elemental sulfur which itself confirms the formation of a polymeric structure. 41 This trend for poly (S-Palm oil), regardless of its feed ratio, consisted of a rapid first degradation step (sulfur content of the polymer) accompanied by a slight second step and finally a gradual reduction in the weight percentage.…”

“…11 In our recent reported paper proceeding, we briefly presented the preliminary copolymerization of sulfur with palm oil with a limited study of different feed ratios and also a narrow investigation of the product properties. 41 Herein, a full report including the copolymerization of sulfur with palm oil using different feed ratios and a detailed investigation of their properties together with a full comparison between sulfur-palm oil and the other reported sulfur-oil polymers is presented that not only proposes a new application for palm oil and as a consequence helps the domestic palm oil industry but also suggests an innovative use of the stockpile of sulfur to reduce the environmental concern of its pollution in soil. The effect of different feed ratios on the properties of the obtained polymer is discussed.…”

A Degradable Inverse Vulcanized Copolymer as a Coating Material for Urea Produced under Optimized Conditions

“…A 25-mL glass vial was filled with the designed weight of the elemental sulfur and placed in a thermoset oil bath preheated to a required reaction temperature under vigorous stirring to initiate the formation of the thiyl radicals. First, the elemental sulfur upon heating starts to melt, after which when the temperature reaches >159 • C, octet structure of the sulfur starts to open to form the thiyl radicals, which is accompanied by the color change from yellow color to orange color liquid; at this point, the designed amount of the jatropha oil is added in a dropwise manner to avoid a sudden decrease in temperature [30][31][32]. After adding jatropha oil to the glass vial, a plaque mixture was formed, which was allowed to react under vigorous stirring for the designed time.…”

“…Vegetable oils consist of an unsaturated portion and a saturated portion, of which the unsaturated portion can act as a comonomer to produce sulfur-based polymers; nevertheless, the complex structure of vegetable oils and also their impurity (saturated portion) make it more difficult to produce controlled sulfur-based polymers using vegetable oils as monomers [21,23,24]. Oils of different vegetables including canola [25][26][27][28], castor [29], rubber seed [30,31], palm [32], linseed [33], corn [34], olive [33], sunflower [33], rice bran [29], soybean [35], and cottonseed [36] have been employed as monomers in the production of sulfur-enriched polymers. Due to the presence of the unsaturated section of vegetable oils, their copolymerization with sulfur results in composite structures because of the presence of the unreacted sulfur.…”

“…Due to the presence of the unsaturated section of vegetable oils, their copolymerization with sulfur results in composite structures because of the presence of the unreacted sulfur. The morphological properties of these composites are highly dependent on the composition of the utilized vegetable oil [32,34]. These polymers have been investigated in several applications, such as Li-S battery cathodes, mercury removal, hydrocarbon removal, and fertilizers [21].…”