Density-Adjustable Bio-Based Polysulfide Composite Prepared by Inverse Vulcanization and Bio-Based Fillers

Abstract

Excess sulfur has become a global problem in petrochemical industry. Inexpensive and easily available cottonseed oil (CSO) is still underutilized. To resolve these issues, bio-based polysulfide composites were prepared via inverse vulcanization of sulfur and CSO. The density of polysulfide composites was adjusted by fillers. The results showed that Elm and cattail as the fillers had no effects on the thermal properties and chemical structures of polysulfide composites. However, the morphologies of polysulfide composites were significantly influenced by the fillers. Different types and amounts of fillers produced significantly different holes and folds in the composites. The fillers were embedded in polysulfide composites by physical filling. This study provides an alternative and promising approach for preparing affordable density-adjustable bio-based polysulfide composite.

Synthesis and Characterization of Disiloxane Cross-Linked Polysulfides

“…In previous studies, excess unreacted sulfur causes holes to form in the surface and inside the material due to the uneven distribution of sulfur. 41 The other explanation involves the difference in the lengths of the vinyl and allyl groups in both cross-linkers. In the case of the longer chains (allyl groups), the polysulfide is more flexible and can more readily undergo intramolecular folding.…”

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

“…33,34,39 The first weight loss onsets at around 200-230°C for all the reported polymers. Just like poly (S-Corn oil), 32 poly (S-Soybean oil), 36 poly (S-Sunflower oil), 39 poly (S-Linseed oil), 39 poly (S-Olive oil), 39 and poly (S-Cottonseed oil), 38 no T g was detected in the case of poly (S-Palm oil) in the experimental temperature range; nevertheless, poly (S-rubber seed oil), 33,34 poly (S-canola oil), 37 poly (S-algae oil), 40 poly (S-Rice bran oil), 37 and poly (S-Castor oil) 37 (all with 50 wt% initial sulfur content) exhibited glass transition temperatures at À6.41, À17, 32, À13, and À24°C, respectively. Regardless of the feed ratio, vegetable oils, in general, are not capable to stabilize all the initial sulfur content against depolymerization over time, and thus, melting peaks resembling the phase transition of different crystalline structures of elemental sulfur can be detected in the DSC thermograms of their resultant sulfur-based polymers.…”

“…27 TGA thermograms of poly (S-Palm oil) with different percent compositions showed a two-step degradation pattern similar to most of the reported polymers. 32,37,38,40,41 However, polymers made by using rubber seed, sunflower, olive, and linseed oils showed a three-step weight loss pattern. 33,34,39 The first weight loss onsets at around 200-230°C for all the reported polymers.…”

“…However, some bio-based monomers such as farnesene, 19 myrcene, 19 squalene, 29 limonene, 30 and diallyl disulfide 31 were also reported. Oil of some vegetables including corn, 32 rubber seed, 33,34 canola, 35 soybean, 36 rice bran, 37 castor, 37 cottonseed, 38 sunflower, 39 linseed, 39 olive, 39 and algae 40 were also studied in the production of sulfur-based polymers. Nevertheless, the complex chemical structure of vegetable oils together with their unknown mechanism of reaction makes it practically very difficult to control the properties of the products.…”

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

“…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.…”